The purpose of effluent characterization and water quality monitoring is to answer the following question: “What is the estimated mine-related change in contaminant concentrations in the exposed area?” Data generated from effluent characterization and water quality monitoring are used to:

monitor changes in the quality of the effluent and environmental conditions in the receiving environment;
provide an indication of variability in effluent quality and temporal or seasonal trends; and
provide supporting environmental variables to help interpret results from the biological monitoring (fish and benthic invertebrate community survey) and the sublethal toxicity testing.

Effluent characterization is conducted by analyzing a sample of effluent to provide information on the concentrations of potential contaminants in the mine effluent.

Water quality monitoring is conducted by collecting and analyzing samples of water from the exposure area surrounding the point of entry of effluent into water from each final discharge point and from the related reference areas. In addition, samples of water are collected and analyzed from sampling areas in receiving environments where biological monitoring is completed (Metal Mining Effluent Regulations [MMER], Schedule 5, section [s.] 7).

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5.2 Sampling Frequency

Effluent characterization and water quality monitoring shall be conducted 4 times per calendar year and not less than 1 month apart on the samples of effluent and water collected, while the mine is depositing effluent (MMER, Schedule 5, s. 7). It is recommended that, where possible, samples for effluent characterization and water quality monitoring be collected once in each calendar quarter. It is also recommended that samples for effluent and water be collected on the same day.

The following factors should be taken into consideration to decide when the aliquots of effluent samples are collected for effluent characterization:

seasonal variability of effluent, based on composition and flow;
the time of year when previous effluent samples have been collected;
the time of year when sampling for water quality monitoring is being conducted; and
the time of year when concentrations of the contaminants are expected to be highest in the exposure area.

For water quality monitoring, the following factors should be taken into consideration to decide when water samples are collected in the receiving environment:

seasonal variability in water quality and flow in the exposure area;
the time of year when concentrations in the exposure area of contaminants are expected to be highest;
the time of year when previous water quality monitoring samples have been collected;
the time of year when samples for effluent characterization are collected; and
the time of year when the biological monitoring is conducted.

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5.3 Variables Measured

Effluent characterization and water quality monitoring are conducted for the parameters listed in Table 5-1. If a mine does not use cyanide as a process reagent within the operations area, cyanide does not need to be recorded (MMER, Schedule 5, paragraph [p.] 7(1)(d). Also, if the concentration of total mercury is less than 0.10 mg/L in 12 consecutive samples, the recording of the concentration of total mercury may be discontinued (MMER, Schedule 5, subsection [ss.] 4(3)). It is recommended that a letter be sent to the appropriate authority in Environment Canada advising that the mine has fulfilled the above requirement. Table 5-1 also includes optional parameters recommended on a site-specific basis that the owner or operator of a mine may record as additional supporting information in order to conduct a more complete chemical characterization. In addition to the required parameters listed in Table 5-1, the measurement of some effluent parameters such as conductivity, sulphate or chloride concentrations may be useful as tracers to determine the extent of effluent mixing in the exposure area. In addition, the concentrations of calcium, magnesium, chloride, potassium, sodium, sulphate and dissolved organic carbon can be used to estimate the potential toxicity of some metals using the biotic ligand model approach (e.g., US EPA 2007; Reiley 2007). Appendix 5-1 includes the justification for the parameters for effluent characterization and water quality monitoring.

**Table 5-1**: Analytical parameters measured for effluent characterization and water quality monitoring (text description)
Effluent Quality Variables¹ (MMER, Schedule 5, s. 4)	Water Quality Variables¹ (MMER, Schedule 5, s. 7)	Site-specific Variables³ (not a regulatory requirement)
Aluminium	Aluminium	Fluoride
Cadmium	Cadmium	Manganese
Iron	Iron	Uranium
Mercury⁴	Mercury⁴	Total phosphorus
Molybdenum	Molybdenum	Calcium
Ammonia	Ammonia	Chloride
Nitrate	Nitrate	Magnesium
Hardness	Hardness^6,7	Potassium
Alkalinity	Alkalinity^6,7	Sodium
Selenium	Arsenic	Sulphate
Electrical conductivity^2,10	Copper	Thallium
Temperature²	Lead	Total thiosalts
	Nickel	Water depth²
	Zinc	Optical depth or transparency²
	Radium 226⁹	Dissolved organic carbon
	Cyanide⁵	Total organic carbon
	Total suspended solids	Water flow
	Dissolved oxygen concentration²
	Temperature²
	pH^2,6,7
	Salinity^2,7,8
	Selenium
	Electrical conductivity¹⁰

¹ All concentrations are total values; dissolved concentrations may also be reported; effluent loading (MMER, s. 20) will also be calculated and reported.
² In situ measured parameters.
³ These other parameters are potential contaminants or supporting parameters; analysis is optional and may be added based on site-specific historical monitoring data or geochemistry data.
⁴ The recording of the concentration of total mercury in effluent may be discontinued if that concentration is less than 0.10 µg/L in 12 consecutive samples (MMER, Schedule 5, ss. 4(3).
⁵ Cyanide does not need to be recorded if that substance is not used as a process reagent within the operations area (MMER, Schedule 5, s. 7(d)).
⁶ In the case of effluent that is deposited into freshwater, record the pH, hardness and alkalinity of the water samples.
⁷ In the case of effluent that is deposited into estuarine waters, record the pH, hardness, alkalinity and salinity of the water samples.
⁸ In the case of effluent that is deposited into marine waters, record the salinity of the water samples.
⁹ Radium 226 does not need to be recorded if the conditions of ss. 13(2) of the MMER are met.
¹⁰ Please refer to Environment Canada document: Guidance Document for the Sampling and Analysis of Metal Mining Effluent (EPS 2/MM/5) for methods. Temperature calibration, and compensation when measuring conductivity, should be done according to the manufacturer’s specifications.

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5.3.1 Calculation of Loadings

The MMER requires mines to record the monthly mass loadings of the MMER-prescribed deleterious substances (MMER, s. 20). As part of effluent characterization for environmental effects monitoring (EEM), it is also recommended that mines calculate effluent loadings of the other parameters monitored. Loading can be calculated by multiplying the mean effluent concentration of the parameter by the total volume of effluent discharge over the time period of interest (typically 1 year for effluent characterization).

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5.4 Sampling Locations

Samples for effluent characterization shall be collected from each final discharge point, identified by the owner or operator of the mine and in accordance with the MMER (Schedule 5, ss. 4(2)).

Guidance for determining the sampling location(s) for effluent characterization is provided in the Guidance Document for the Sampling and Analysis of Metal Mining Effluents: Final Report (Fowlie et al. 2001). This document focuses primarily on methods for collection of effluent samples from point sources (end of the pipe). If samples are to be collected from nonpoint sources, proposed sample collection locations and methods should be discussed with the Authorization Officer.

Water quality monitoring is conducted by collecting samples of water from the exposure area surrounding the point of entry of effluent into water from each final discharge point and from the related reference areas (MMER, Schedule 5, ss. 7(1)). These sampling stations will not likely be the same sampling stations used for biological monitoring. In selecting sampling stations for the exposure area, the owner or operator of a mine should take into consideration the location where effluent concentrations are the highest.

In addition to the above, the owner or operator of a mine shall collect samples of water from the sampling areas selected for the fish population and fish tissue studies and the benthic invertebrate community studies. Therefore, water quality monitoring is conducted at the same time as the biological monitoring studies, should the mine be required to conduct these studies (MMER, Schedule 5, p. 7(1)a(ii)). The water samples are analyzed for the water quality monitoring variables outlined in Table 5.1.

It is recommended that at least 3 water samples be collected at each sampling station to provide an estimation of the variability and determine if concentrations of the contaminants are homogeneous within the sampling station. However, this may not be sufficiently robust to assess data statistically. More sampling stations within each area may help to better understand contaminant concentrations in the exposure area. At the minimum, a composite sample, consisting of few sub-samples spaced within the station, should be collected.

It is strongly recommended, where the benthic and/or fish sampling areas are not in close proximity to the sampling stations for water quality monitoring, that samples be collected concurrently at the sampling stations for the routine water quality monitoring. This will help to interpret the results of analyses of water samples collected in the benthic and/or fish sampling areas in comparison with the results of water samples collected under water quality monitoring.

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5.5 Reporting

The results of effluent characterization and water quality monitoring shall be submitted to the Authorization Officer as part of an effluent and water quality monitoring report (MMER, Schedule 5, s. 8). As per Schedule 5, s. 8 of the MMER, a report on the effluent and water quality monitoring studies conducted during a calendar year shall be submitted to the Authorization Officer not later than March 31 of the following year. See Chapter 10 for information on electronic reporting of effluent and water quality monitoring data. The annual effluent and water quality monitoring report should include the following information.

(Note that in the list below, the regulatory requirements (as per the MMER, Schedule 5, s. 8) are written in italics; these requirements are followed by further recommendations and descriptions.

a) The dates on which each sample was collected for effluent characterization, sublethal toxicity testing and water quality monitoring:

four dates for effluent characterization (4 times per calendar year and not less than 1 month apart (MMER, Schedule 5, ss. 7(2)), while the mine is depositing effluent;
four dates for water quality monitoring (4 times per calendar year and not less than 1 month apart (MMER, Schedule 5, ss. 7(2)), while the mine is depositing effluent;
dates for sublethal toxicity testing (2 times each calendar year for 3 years and once each year after the third year, with the first testing to occur on an effluent sample collected not later than 6 months after the mine becomes subject to section 7 of these regulations (MMER, Schedule 5, s. 6)). The sublethal toxicity testing date(s) should match the date(s) for effluent characterization, as the sublethal toxicity sample must be an aliquot of the effluent characterization sample; and
if the required number of tests were not conducted, indicate the reason why (i.e., the number of days that the effluent was being discharged or the habitat conditions that prevented the collection of effluent characterization and/or water quality monitoring samples).

b) The locations of the final discharge points from which samples were collected for effluent characterization, noting that effluent characterization is conducted at ALL identified final discharge points (FDPs).

c) The location of the final discharge point from which samples were collected for sublethal toxicity testing and the data on which the selection of the final discharge point was based, in compliance with the MMER, ss. 5(2):

Indicate from which FDP the effluent was collected for the sublethal toxicity testing.
Indicate why that FDP was chosen, if there is more than one FDP at the mine site (e.g., effluent that discharges into a sensitive receiving environment, has the greatest mass loading).

d) The latitude and longitude of sampling areas for water quality monitoring, in degrees, minutes and seconds, and a description that is sufficient to identify the location of the sampling areas:

If units other than latitude and longitude were taken (e.g., UTMs) at the sampling station, there are Web-based tools provided by Natural Resources Canada that can be used to convert them.
Provide a written description (possibly supplemented with maps) of the sampling station that is sufficient to identify the location within the sampling areas. For example, “water collected under first bridge.” This description should allow for ease of re-sampling at the same stations.

e) The results of effluent characterization, sublethal toxicity testing and water quality monitoring:

Include the results from all analyses completed on effluent (chemical and physical parameters), sublethal toxicity testing and water quality monitoring.
Include results from all required parameters, as well as any optional site-specific parameters that were measured (see Table 5.1).
For sublethal toxicity testing, the laboratory reports should be included as an appendix in the annual report.

f) The methodologies used to conduct effluent characterization and water quality monitoring, and the related method detection limits:

Some sampling methods are outlined in the Guidance Document for the Sampling and Analysis of Metal Mining Effluent: Final Report (Fowlie et al. 2001); available at http://dsp-psd.pwgsc.gc.ca/Collection/En49-24-1-39E.pdf.
Indicate the methodology used (e.g., inductively coupled plasma combined with mass spectrometry [ICP-MS], graphite furnace atomic absorption spectrometry [GFAAS]) for effluent characterization and water quality monitoring.
Indicate the method detection limits for the methodology used--for MMER deleterious substances, the method detection limits identified in Schedule 3 of the MMER should be met. See section 5.6.2 of these guidelines for the method detection limit for mercury. Note that the Canadian Council of Ministers of the Environment’s Canadian Environmental Quality Guidelines (CCME 1999) (Chapter 4: Canadian Water Quality Guidelines for the Protection of Aquatic Life) or additional provincial water quality guidelines should also be considered.
Indicate whether the Canadian Water Quality Guidelines for the Protection of Aquatic Life (CCME 1999 - Chapter 4) or additional provincial water quality guidelines are met.

g) A description of quality assurance and quality control measures that were implemented and the data related to the implementation of those measures:

Provide a brief description of the quality assurance / quality control (QA/QC) measures that were taken and the results of such measures with respect to collection of the effluent and water sampling, shipping and storage.
See sections 7.3–7.5 of Fowlie et al. (2001) and section 5.8 below for further information.

Since effluent samples for effluent characterization are aliquots of samples collected for effluent compliance monitoring, the measurements of pH and the concentrations of the deleterious substances (arsenic, copper, total cyanide, lead, nickel, zinc, radium 226 and total suspended solids) should be available as part of the effluent characterization and water quality monitoring reports from each mine.

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5.6 Effluent Characterization

5.6.1 Sampling Methods and Laboratory Analysis

Since effluent samples for effluent characterization arealiquots of samples collected for effluent compliance monitoring as part of the MMER, the sampling and chemical analysis considerations and recommended procedures provided in the Guidance Document for the Sampling and Analysis of Metal Mining Effluent: Final Report (Fowlie et al. 2001) apply also to effluent characterization conducted as part of the EEM program. The volume of sample taken should be sufficient to allow for all required analyses and tests plus associated quality control samples (e.g., field duplicates, laboratory replicates and spiked sample).

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5.6.2 Method Detection Limit Change for Mercury

The method detection limit for mercury in effluent has been changed to 0.01 µg/L (0.00001 mg/L) so that the concentration of 0.1 µg/L specified in Schedule 5, s. 9(c) of the MMER can be detected with confidence. Analytical methodologies suitable to achieve this level of detection include cold vapour atomic absorption spectrometry (CVAAS), cold vapour atomic fluorescence spectrometry (CVAFS) and inductively coupled plasma mass spectrometry (ICP-MS).

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5.6.3 Methods for Determination of Thiosalts

Total thiosalts is an optional site-specific parameter that may be measured in mine effluent; however, information on sampling or analysis is not available in Fowlie et al. (2001). Thiosalts are soluble sulphur/oxygen ions that form as a result of the incomplete oxidation of sulphide minerals. They have the potential to be generated whenever sulphide minerals are in contact with oxygen, but in practice they tend to be formed during the processing of ores bearing sulphide minerals. If thiosalts occur in effluent, once the effluent is discharged the oxidation of the thiosalts is completed; this results in the generation of sulphuric acid and the lowering of pH in the exposure area. Such pH alterations in receiving waters could also be related to low levels of thiosalts and to thiosalt speciation, which cannot be addressed entirely with commonly used analytical techniques (Vigneault et al. 2002). At a concentration of 10 ppm, thiosalt degradation can still potentially drop the pH to 3.7 in unbuffered receiving water (Vigneault et al. 2002). Information related to thiosalt speciation may be required to predict pH depression, since individual thiosalt species can produce different amounts of acidity and are stable in markedly different conditions.

Despite the ability of thiosalts to alter pH in receiving water bodies, toxicity due to thiosalts in mine effluent has been limited to a few sites. This may be due to the low toxicity of thiosalts to animals. Thiosalts are not expected to be acutely lethal in mine effluents, with lethal concentrations for Rainbow Trout higher than 800 mg/L (Schwartz et al. 2006). Sublethal toxicity testing suggests further that the sensitivity of aquatic species to thiosalts and the toxicity of the different anions composing thiosalts vary by an order of magnitude. Schwartz et al. (2006) reported that Ceriodaphnia dubia was the most sensitive EEM test species, with a 25% inhibition concentration (IC₂₅) of 60 mg/L for thiosulphate. They further noted that tetrathionate was much less toxic than thiosulphate. Few mine sites in Canada have known thiosalt problems, but the potential for thiosalt generation may exist at many mine sites. As such, total thiosalt determination is optional for effluent characterization and water quality monitoring in the EEM program.

The total concentration of thiosalts is most commonly determined with a titration method having a detection limit around 10 ppm (expressed as thiosulphate) (Makhija and Hitchen 1979). Thiosulphate is stable at neutral pH and unstable at low pH, while the opposite is true for polythionates. Ion chromatography can be used to determine the concentration of different thiosalt species in synthetic solutions in the ppb range, but it is difficult to apply to field samples because of the instability of thiosalt. In order to better predict the environmental impacts of thiosalts and thiosalt degradation, more information regarding in situ speciation and measurement methods with lower detection limits are required.

The main concern with this method is that the samples should be analyzed within 24 hours. Given that every available preservation method has limitations, there is in fact no substitute for immediate analysis (O’Reillyet al. 2001). As a result, total thiosalts analyses should ideally be done on-site. These analytical capabilities are likely restricted to sites with known thiosalt problems. Alternatively, samples may be frozen immediately after collection and be analyzed within 7 days. Longer storage time of frozen samples may affect thiosalt stability. Alternatively, an anion exchange resin can also be used to preconcentrate and preserve thiosalts (Drushel et al. 2003; Vigneault et al. 2002).

5.7 Water Quality Monitoring

5.7.1 Preparation for the Field

The reagents for cleaning, operating or calibrating equipment and collecting, preserving and/or processing samples should be handled by appropriately qualified personnel, and the appropriate data for health and safety (e.g., Material Safety Data Sheets) should be available.

Written protocols and standard operating procedures (including QA/QC requirements) should be readily accessible at all times, to ensure proper and safe operation of equipment. Data forms and logbooks should be prepared in advance so that field notes and data can be quickly and efficiently recorded. Extra forms should be available in the event of a mishap or loss. These forms and books should be waterproof and tear resistant. Under certain circumstances, audio or audio/video recordings may prove valuable.

All equipment used to collect and handle samples should be cleaned and all parts examined to ensure proper functioning (e.g., on-site assembly or operation) prior to going into the field. A repair kit should accompany each major piece of equipment in case of equipment failure or loss of removable parts. Backup equipment, batteries and sampling gear should be available. Sampling equipment used for field measurements of water quality parameters should be properly calibrated or standardized according to the manufacturer’s recommendations.

All sample containers and required preservatives should be provided by the laboratory hired to conduct the analyses of the samples. Bottles should preferably be unused and purchased as certified clean. If bottles are reused, they should be cleaned by a documented cleaning procedure with a bottle lot number-control system, and cleanliness should be demonstrated by the use of blanks (Fowlie et al. 2001).

Storage, transportand sample containers, including extra containers in the event of loss or breakage, should be pre-cleaned and labelled appropriately (i.e., with a waterproof adhesive label to which the appropriate data can be added with an indelible ink pen capable of writing on wet surfaces). The containers should have lids that are fastened securely and the appropriate container lids and lid liners should be used to prevent contamination (e.g., lid liners should be lined with an inert material like Teflon^®, not paper or cardboard). A sample-inventory log and a sample-tracking log should be prepared in advance of sampling. The responsibility for these logs should be assigned to one individual who will be required to monitor the samples from the time they are collected until they are analyzed and disposed of or archived.

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5.7.2 Field Measurement of Water Quality Parameters

Standard in situ water quality parameters are dissolved oxygen, pH, conductivity, water temperature and salinity (marine and estuarine environments). Total water depth at the sampling area and water depth from where the water sample was collected should be recorded. Optical depth or transparency should also be measured in the field. Current flow should also be measured in riverine environments. Measurements of standard water quality parameters can be taken in the water directly, from a sample container in the boat or on shore immediately after collection of the sample, as long as the water is collected at the appropriate depth. If dissolved oxygen measurements are conducted on the shore, special care should be taken to ensure that air is not introduced into the sample.

In shallow water bodies ≤ 2 m deep, standard water quality parameters need only be measured at mid-depth. If the depth ranges from 2 to 4 m, standard water quality measurements should be taken at 2 depth intervals: approximately 25 cm above the bottom and 25 cm below the surface. In deeper bodies of water, measurement of standard water quality parameters should be taken throughout the water column. Information on bottom depth and water column profiles of conductivity, pH, hardness, alkalinity, salinity, temperature and dissolved oxygen should be obtained along intervals of 1 to 5 m (depending on total depth). For example, at a depth of 5 m, measurements should be taken every metre. At a depth of 25 m, measurements should be recorded at 5-m intervals.

For deep samples, a peristaltic sampler, with appropriate lengths of Teflon^® tubing, should be used in preference to other types of pumps. If other types are used, they should be Teflon^®-coated and non-metallic. Sampling should proceed from the least-contaminated to the most-contaminated station, with a weak nitric acid and distilled water rinse between stations. The solvent rinsate should be collected and returned to the laboratory for proper disposal. Laboratory blanks of the samplers should be run before and after use to demonstrate that no contamination is imparted to samples (Fowlie et al. 2001).

Profiles can be facilitated through the use of a data logger (or equivalent) equipped with a dissolved oxygen probe and associated stirrer, as well as pH, conductivity, depth and temperature probes, which evaluate water column quality simultaneously. Such a unit is particularly useful for deeper evaluations (> 50 m). During profiling, the operator is able to visually review incoming data, noting particular areas of interest during descent and ascent of the unit (e.g., conductivity spikes, thermocline, unusual data records). This information is recorded either manually or directly stored in the data logger. To supplement computer records, parameter readings should be recorded manually onto field data sheets (every 2 or 5 m) depending on total depth profiled.

At shallow depths, hand-held meters are often the most convenient way to measure in situ water quality parameters. They are light, and several models are now available that can measure standard water quality parameters. The probes and the cables connecting them to the hand-held unit can range from 2 to 5 m, limiting the use of such a unit. These meters tend to require more regular maintenance and calibration, meaning extra care should be taken to make sure that the meters are in proper functioning order. Calibration and maintenance logs should be kept on file.

Water depth can be measured indirectly using a sonar-based fish finder, or directly using a calibrated tape, sounding cable or rod. Recommended accuracy is as follows:

Water depth less than 2 m: recommended accuracy of ± 25 cm
Water depth of 2-10 m: recommended accuracy of ± 50 cm
Water depth greater than 10 m: recommended accuracy of ± 1 m

Optical depth is a measure of the transparency of water, and can be measured with a turbidity meter in the field or in the laboratory. Optical depth can also be measured using a Secchi disk. The disk is 20 cm in diameter, and is painted white in two opposite quarters and black in the other two. The disk is attached to a calibrated tape. To measure optical depth, the disk is lowered into the water in the shade until it has disappeared. It is then raised slowly, and the water depth at which it reappears is recorded. At least two measurements should be made at each station, and optical depth should be estimated based on the median value of the measurements. Measurements should be made at midday, and sunglasses should not be worn while measurements are made (Nielsen and Johnson 1983).

Water quality data should be screened on-site during sample collection to prevent the measurement and recording of false readings, as doing so will permit the use of alternative instrumentation or instrument checks in the event of equipment or sampling error. All sampling and monitoring equipment should be checked and calibrated daily, if necessary, to ensure good working condition.

It is recommended that additional field measurements and observations be recorded:

sample number, replicate number, site identification (e.g., name);
time and date of the collection of the sample;
ambient weather conditions, including wind speed and direction, wave action, current, tide, vessel traffic, temperature of both the air and water, thickness of ice if present;
sampling area location (e.g., positioning information) and location of any replicate samples;
type of platform/vessel used for sampling (e.g., size, power, type of engine);
name of personnel collecting the samples;
details pertaining to unusual events that might have occurred during the operation of the sampler (e.g., possible sample contamination, equipment failure, unusual appearance, control of vertical descent of the sampler); and
deviations from standard operating procedures.

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5.7.3 Collection of Water Samples for Laboratory Analyses

Water samples collected in the field and sent to a laboratory for analysis make up the bulk of the water quality monitoring program and involve the analysis of metals, nutrients, major anions and cations, and several other general water quality variables.

Total metals analysis (total values) is required (MMER, Schedule 5, s. 4) during water quality monitoring, as studies often found no difference between measuring “total” and “dissolved” metals (ESG 1999). However, significant differences between total and dissolved metals can be found in some cases, and analyzing for metals in both the dissolved and total fractions could be relevant on a site-specific basis especially in the context of investigation of causes.

In general, samples should be collected at 2 depth intervals: the subsurface (epilimnion) and near bottom (hypolimnion) in order to obtain samples from both areas of the water column (above and below the thermocline). If the water depth is ≤ 2 m, it is sufficient to collect water samples only at mid-depth or at least 15 cm below the surface. Samples collected below the surface of the water can be collected by hand directly into the sample bottle.

Water collections at discrete depths should be facilitated through the use of appropriate samplers (e.g., Niskin sampler, non-metallic 2-16–L Van Dorn or 0.5-8–L Kemmerer samplers). For streams, depth-integrated samplers that are representative of the suspended sediment and related substances can be used. These samplers can be used from a boat, bridge or ice surface, and usually require two persons for safe operation. For very deep samples, a peristaltic sampler is preferred to other types. If other samplers are used, they should be Teflon^®-coated.

The water sampler should be triple-rinsed with the water from the sampling station between each sample. In addition, it is recommended that sampling in the reference area be completed first to avoid any potential contamination of the sampler with water from the exposure area. The sampler should be double-rinsed with reagent-grade weak nitric acid between sampling areas, particularly if it is not possible to complete sampling in the reference area first. The solvent residues should be collected and returned to the laboratory for proper disposal. Laboratory blanks of the samplers should be run before and after use to demonstrate that no contamination is imparted to the samples.

When collecting water samples, it is important to use as many of the following ultra-trace techniques and proper water sampling protocols as possible:

Sampling should proceed from the least-contaminated to the most-contaminated station.
Sample bottles and caps should be rinsed 3 times prior to water collection.
No preservatives should be placed into the sampling bottles prior to sample collection.
Samples should be collected with the bottle mouth facing up-current and away from the sample collector’s hand.
At no time should the inside of the sample container, the bottle mouth, or the inside of the container lid be touched by sample collectors, even while wearing disposable gloves.
Sample collectors should wear unlined, powder-free latex or nitryl gloves to avoid contamination of the sample.
Label all samples immediately and clearly, and follow proper preservation techniques. Record all sampling data in the field notebook immediately.
Caps of water containers should be held lid-down during sample collection.
The sampling-point locations should be recorded.

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5.7.4 Sample Handling, Storage and Analysis for Water Quality Monitoring

5.7.4.1 Sample Handling and Preservation

The Guidance Document for the Sampling and Analysis of Metal Mining Effluents: Final Report (Fowlie et al. 2001) contains information on sample handling recommendations regarding containers, preservatives and holding times for specific parameters. Where appropriate, preservatives should be added to the sample bottle immediately upon completion of the collection. The actual sample volumes required may vary depending on the needs of the laboratory.

Note that to reduce the number of samples collected, several analytes may be analyzed from one sample bottle. Prior to sample collection, the list of variables should be discussed with the laboratory to determine the number and type of sample bottles required.

When collecting samples, it is useful to have a checklist that lists the collection bottles, corresponding analytes, and whether or not a preservative is required. As a sample is collected it should be checked off the list. In certain situations, a maximum holding time of 7–10 days (major cations and anions, nitrate/nitrite, dissolved organic carbon) may be problematic. If the shipping of a mine’s water samples has been unavoidably delayed but the integrity of samples was retained, the Authorization Officer should be notified without delay.

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5.7.4.2 Sample Shipping and Storage

It is recommended that samples be cooled to 4°C during collection and stored at the same temperature for shipping, to minimize degradation. Samples should also be refrigerated, and shipping coolers should be equipped with ice packs or bagged ice to ensure that samples are kept cold.

Samples should be transported to a laboratory as soon as possible after collection (within 24-48 hours maximum). Analyses should be completed within the accepted storage times, which will vary depending on the variable. Storage time is defined as the time interval between the end of the sample collection period and the initiation of analyses. All samples should be stored for as short a time interval as possible and under conditions that minimize sample degradation. Samples should be maintained at temperatures above their freezing point and under 10°C, with minimal exposure to light. Samples digested for metals analysis may be maintained in a sealed container and analyzed within 30 days. For additional information refer to Fowlie et al. (2001).

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5.7.4.3 Laboratory Analyses of Samples

Laboratory analyses should be carried out in a qualified laboratory by trained personnel operating under quality-controlled conditions and using documented standard operating procedures. Laboratories contracted by the mining industryshould be accredited under the International Organization for Standardization standard ISO/IEC 17025:2005 entitled “General requirements for the competence of testing and calibration laboratories,” as amended from time to time. The analytical methods selected should be generally accepted and in common use in laboratories in Canada. The overall method principle should be peer-reviewed and published in a widely available publication so that it can be located easily for details.

The analytical methods selected should meet the criteria in this document plus any other objectives identified by the mine (or those acting on the mine’s behalf) or Environment Canada. The project manager and the laboratory need to confirm what parameters of interest will be measured and that holding times can be met. The laboratory and analysis methods should be selected and discussed before the sample is collected, to ensure that the laboratory sample requirements are met.

The methods chosen should reliably measure the detection limits indicated for the deleterious substances identified in Schedule 3 of the MMER (i.e., any concentration above about one-tenth of the maximum authorized sample concentration (Fowlie et al. 2001). Normally accepted methods, method detection limits, and precision and accuracy objectives for metal mining effluent analysis are discussed in Fowlie et al. (2001). For the other required or site-specific recommended water quality parameters, for which detection limits are not specified, if there is a CCME Canadian environmental quality guideline (CCME 1999) for the variable measured, the chosen method’s detection limits should be sufficiently low to determine if the parameters measured exceed these guidelines. CCME guidelines can be found at http://ceqg-rcqe.ccme.ca. Several provinces have also developed water quality guidelines, and in cases where both CCME and provincial water quality guidelines exist for a particular parameter, the provincial guidelines take precedence, although both should be reported.

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5.7.5 Comparison of Water Quality Data in Exposure and Reference Areas

It is recommended that the Biological Interpretative Report include a comparison of water quality data in the exposure and reference areas. This comparison would examine all parameters included as part of water quality monitoring. In particular, this comparison should identify any parameters for which there are differences in measurements taken in the exposure and reference areas of more than a factor of 2. This comparison is intended to help with the interpretation of biological data in the interpretative report.

The factor of 2 for exceedance of concentrations from the reference area is intended to ensure that differences between exposed and reference area concentrations are real differences, and not just differences that may be attributed to such factors as low concentrations of target contaminants, analytical variability, small minimal sample size (n = 4) and seasonable variability. At sites where the reference area is on a different water body or watershed than the exposed area, the factor of 2 difference may not be applicable.

Determination of whether or not concentrations are different between the exposure and reference areas should be based on the median value of a minimum of 4 samples collected over a 12-month period from the same exposure and reference area locations. The median in a set of n measurements y₁, y₂, y₃, … y_n is defined to be the value of y that falls in the middle when the measurements are arranged in order of magnitude. If there is an even number of measurements, then the median is the value of y halfway between the two middle measurements. If larger data sets (n >> 4) are available, determination of whether concentrations are elevated in the exposure area could be based on a statistical test such as mean or median greater than the 95% confidence interval or greater than 2 standard deviations. If there are adequate pre-mining water quality data in the exposure area, then pre-mining data may be used as a basis for comparison.

In cases where there are differences of more than a factor of 2, it is recommended that the mine estimate and report the geographical extent for which this condition exists, based on expanded water quality monitoring or modelling. However, before completing such an estimate, there are a number of factors that should be considered:

Site-specific water quality objectives: If there is a site-specific water quality objective for a particular parameter, and that objective is exceeded in the exposure area, the extent of this exceedence should be determined, regardless of the concentration in the reference area.
Water quality guidelines: If there are water quality guidelines for a particular parameter (e.g., federal or provincial), and the concentrations of that parameter in the exposure area are greater than concentrations in the reference area by more than a factor of 2, and are greater than the water quality guideline, then the extent of this exceedence should be determined.

The CCME Canadian Environmental Quality Guidelines (CCME 1999 - Chapter 4: Canadian Water Quality Guidelines for the Protection of Aquatic Life) for water quality monitoring parameters are available at http://ceqg-rcqe.ccme.ca/. Several provinces have also developed water quality guidelines, and in cases where both CCME and provincial water quality guidelines exist for a particular parameter, the provincial guidelines take precedence, although both should be reported.
Detection limits: In cases where the generic water quality guideline for a parameter is close to the analytical method detection limit, and concentrations of the parameter in the study area are close to the guideline, a factor of 2 difference may not be meaningful (as a result of analytical uncertainty close to the detection limit). In such cases the Authorization Officer should be consulted. McQuaker (1999) provides a comparison of achievable detection limits with generic water quality guidelines and, for most parameters, method detection limits (MDL) significantly less than the water quality guideline (WQG) (at least a ratio of 1:10 MDL:WQG) are available. However, McQuaker concluded that there are some parameters (arsenic, cadmium, mercury, selenium, silver and cyanide) for which an MDL at least 10 times lower than the WQG is not currently achievable. As the MDL:WQG ratio decreases, the measurement uncertainty increases; beyond a ratio of 1:2, the results are not considered to be statistically significant.
pH: For pH, a difference of a factor of 2 may be particularly important, since the pH scale is logarithmic. If there is a site-specific objective for pH, and if the pH in the exposure area is outside the range specified in the site-specific objective, the geographical extent of pH values outside the range of the site-specific objective should be determined. If there is no site-specific objective for pH, and if the pH in the exposure area is more than 0.5 pH units different than the pH in the reference area and is also outside Canadian environmental guidelines (e.g., CCME 6.5 to 9.0), the geographical extent of the exposure area within which pH is more than 0.5 pH units different from the reference area should be determined. According to the Canadian Environmental Quality Guidelines (CCME 1999), human activity should not alter the pH by more than 0.2 pH units in marine or estuarine environments.
Location of the reference area: At sites where the reference area is on a different water body or watershed than the exposure area, a difference of a factor of 2 may not be applicable. If it is felt that this is the case, the Authorization Officer should be consulted.

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5.7.6 Estimation of Extent of Elevated Concentrations

Two methods may be used to estimate the extent of elevated concentrations:

direct measurement
modelling

1) Direct Measurement

Direct measurement requires an increase in the number of sampling stations within the exposure area to determine where within the exposure area concentrations of contaminant(s) of concern are no longer elevated. The number of additional stations needed would be determined on a site-specific basis, but generally, a minimum of 3 stations would be needed:

the exposure area station used for water quality monitoring, and
two or more further stations that bracket the location within the exposure area where the concentrations of parameters of concern are no longer expected to be elevated.

2) Modelling

If the seasonal variations of concentrations of the key parameter of concern in effluent and the exposure area are well understood, and if seasonal variations in effluent and receiving environment flow are well understood, it may be possible to predict the location within the exposure area where the concentrations of the parameter(s) of concern are no longer expected to be elevated.

5.8 Quality Assurance and Quality Control for Water Quality Monitoring

General aspects of quality assurance and quality control are discussed in Chapter 2.

5.8.1 General Aspects of Quality Control in the Field

General QC aspects of a field sampling program are as follows:

All personnel involved in field procedures should have appropriate education and training.
Sampling methods should be consistently applied among sites throughout the study.
Samples should be collected according to standard operating procedures that should be available to personnel at all times during the field study.
Sampling equipment should be appropriate for the habitat being studied, properly cleaned, and accompanied by the appropriate documentation (i.e., manual, calibration and maintenance schedule).
All samples should be properly labelled with date, location, type, number and collector’s name.
Samples should be in the proper container with the appropriate preservative or fixative if necessary.
Field technicians should maintain detailed field notes using indelible ink and waterproof notebooks.
Personnel should use chain-of-custody / sample submission forms and custody seals for contaminant samples.
Personnel should follow appropriate shipping and storage methods.
Standardized field collection forms should be used during the field program.

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5.8.2 Field Aspects of Quality Assurance

Field QA for water quality monitoring should be achieved through several methodologies, including duplicate readings, comparison of readings with known standards, collection of profile samples for analytical evaluation, and parameter evaluation using alternate equipment (e.g., Hanna CTD meter, thermometer).

Some of the most common quality problems are the result of mislabelling or switching bottles, failure to add proper preservatives, improper storage conditions, sample contamination from sampling equipment, and exceeding the holding time. Each sample should be clearly labelled in a manner that identifies the sample and distinguishes it from all other samples. Labels should be filled out in indelible ink and fixed to the sample container such that they will not fall off when wet or during transport.

The field logbook is an integral part of the sampling program and forms the basis of the sampling report. Items documented in the logbook are often highly relevant to the interpretation of the laboratory data. Any deviations from the sampling plan or any other observation about the sample or the sampling locations should also be noted in the logbook. Some common deficiencies in field logbooks include the failure to make planning notes, make notes at the time events occur, sign and date entries, and write legibly.

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5.8.3 Quality Assurance during Sample Handling, Shipping and Storage

The Canadian Association for Environmental Analytical Laboratories (CAEAL) (currently the Canadian Association for Laboratory Accreditation [CALA 1991]) recommends the following with respect to QA during sample handling, shipping and storage:

Chain of Custody: Chain-of-custody forms should be used in the transportation of samples, especially in cases where several contracted parties are involved in the sampling, shipping and analysis of the samples.
Sample Inspection: The condition of each sample should be noted upon receipt. Discrepancies between required sample conditions and the observed conditions should be recorded in a logbook or on a computer file. It is preferable to preserve samples in the field immediately. However, the samples should be preserved immediately if submitted unpreserved, and a record made of the preservation methodology.
Sample Tracking: Samples should be assigned a unique number or code to identify the sample in a tracking system. The sample tracking system should identify the sample, the source, the date of receipt, analyses, due date, and any other pertinent information. A computerized laboratory information management system (LIMS) is recommended for tracking samples in laboratories processing large numbers of samples for a variety of clients.
Sample Storage: Samples should be stored in an assigned location in a refrigerator or sample storage area accessible only to authorized personnel. Samples should be refrigerated at 4°C, where applicable, and removed only for inspection, logging and analysis. The temperature of the refrigerator should be measured and recorded daily.

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5.8.4 Use of Blanks and Duplicate Samples

The use of blanks and duplicate samples in the field and laboratory is an important component in a QC program.

Field blanks and field duplicates are essential throughout the execution of a field program involving the collection of water. Field QC samples are used to establish whether any errors are being introduced during the sampling process so that corrective action can be taken if necessary. Field QC samples are distinct from laboratory QC samples in that they measure sampling effects rather than laboratory effects.

Field blanks are used to check contamination from all potential sources of contamination of the sample. These include possible contamination of sample bottles, caps, preservatives, equipment, filter paper (if samples are to be filtered), atmospheric contamination, sampling techniques, and analysis. Field blanks are collected by obtaining blank water (i.e., deionized water) from the laboratory conducting the analyses, transporting the water to the field, and taking it through all sample collection, handling and processing steps that the test samples undergo (e.g., transfer to a sample container, preservation, and exposure to the environment). Field blanks are transported, stored and analyzed in the same manner as test samples (McQuaker 1999).

Duplicate samples should be taken to verify analytical results and equipment reliance. Field duplicates are used to evaluate homogeneity of the sample site and the ability of the sampling system to take the sample the same way every time. A field duplicate is a completely separate sample, not a split of a single sample into two bottles. Duplicate samples should be treated as blind samples, and are not identified to the laboratory.

The last type of QC sample is the trip blank, also referred to as travel or transport blanks. Trip blanks are used to check contamination from sample bottles, caps and preservatives during transport, storage and analysis. A sample bottle is filled in the laboratory with blank water (i.e., deionized water) and preserved in the same manner as the test samples (Fowlie et al. 2001). Trip blanks are transported to the field with regular sample bottles and submitted to the laboratory unopened, together with the test samples. They are opened at the time of analysis, and analyzed in the same manner as the samples (McQuaker 1999).

Field and trip blanks as well as duplicate field samples should be collected at a frequency of 5-10% of the total number of samples. Therefore, if a total of 10 water quality areas were being sampled, only one of each of the QC samples would be needed from each station. This proportion can be increased if necessary, to monitor errors due to sampling and matrix homogeneity. If field and trip QC samples are not used, any inaccuracy introduced due to sampling will go undetected or be inappropriately attributed to the analytical laboratory. The use of blanks and duplicate samples in the laboratory is further discussed in section 5.8.5. Table 5-2 summarizes recommended use of blanks and duplicate samples in the field and the laboratory, for larger sampling programs. For routine sampling, with one station from the exposure area and one from the reference area, it is recommended that a single field blank be submitted together with the test samples. In such cases, these samples will be analyzed by the laboratory as a batch, together with samples from other clients. The laboratory will achieve necessary internal QC using the complete batch.

**Table 5-2**: Summary of recommended use of blank and duplicate samples in the field and laboratory. Numbers are based on a batch of 20 samples or less (text description)
Parameter	Number of Samples	Internal or Field QC	Control Limits	Description
Field blank	1	Field		Checks contamination as a result of sample handling. One per day per matrix.
Trip blank	1	Field		Tests validity of sample preservation and storage conditions. One per day per matrix.
Field duplicate	1	Field		Used to evaluate homogeneity of the sample site and the ability of the sampling system to take the sample the same way every time.
Method blank	1	Internal	< detection limit (D.L.) or < 0.1 of sample concentration	Checks contamination from reagents and proceduresPPPPPa
Laboratory duplicate sample	1	Internal		Checks precision of sampling process. One per day per matrix type.^a
Glassware proof	1	Internal	< D.L. or < 0.1 of sample concentration	Checks contamination of lab glassware used during processing^a
Standard reference material (SRM)	1	Internal		Checks accuracy of method^a
Matrix spike	1	Internal	75-125%	Used interchangeably with SRM^b
Calibration control:
Within-run (blank and mid-range standard	1	Internal	10% drift max.	Statistical control over calibration can be confirmed between runs by means of two control standards, A and B, and within-run by means of blanks and mid-range standards (King 1976).
Between runs (20% and 80% of full scale)	2 per run	Internal	± 5% of target value

^a Intrinsic to every batch of 20 samples
^b Used interchangeably with SRM if SRM is not available

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5.8.5 Quality Control in the Laboratory

The following are general QC aspects of laboratory analyses performed:

Data should be verified and validated through transcription checks; chemical data will be verified by reference to the analytical laboratory QA reports accompanying the data.
Data analyses will be repeatable and robust and will be cross-checked with data quality objectives.
Data analyses will be rigorous and defensible and should include the rationale for all statistical analyses and data transformations.

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5.8.5.1 Details on Quality Control Aspects of Laboratory Analyses

Analytical QC procedures are designed to demonstrate statistical control over calibration, precision, accuracy/bias, and recovery (CALA 1991).

Statistical control over these parameters can be demonstrated by running specific QC samples during each analytical run. The results of these QC samples are compared statistically with confidence intervals calculated from historical data. These confidence intervals or control limits are normally calculated at 3 standard deviations (SDs) of the mean of the controlled variable. Warning limits are frequently set at 2 SDs. Indicators of a run considered out of control include the following:

two successive results for method blanks, laboratory duplicates, standard reference materials, spiked blanks, calibration control samples, or organic surrogate recoveries;
one of these results outside of the control limits.

QC data can be plotted on appropriate control charts. Control charts are graphic presentations of the QC data as a function of time or consecutive run number. Control charts demonstrate trends in time and provide graphic evidence of long-term statistical control of the analysis. Control limits and control charts are described in detail in ASTM (1986).

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5.8.5.2 Good Laboratory Practices

Well-established good laboratory practices (GLPs) should be followed. The following is a brief listing of recommended laboratory practices (a description of GLPs can be found in greater detail in ELAP 1988):

Records on reagent preparation should be maintained in a logbook. Prepared reagent containers should be labelled with the reagent, its date of preparation, the expiry date, and the person responsible.
Instruments should be maintained or serviced on a regular basis. Maintenance records should be kept in a logbook.
Written instructions should be available for all instruments.
Standard procedures for cleaning glassware and containers should be followed.
Routine checks of the purity of the distilled water should be conducted and documented. Distilled/deionized water should be checked on a conductivity meter at least daily.
Chemical reagents should meet the purity requirements of each analytical method.
Reagents and solvents should be stored according to the manufacturer’s directions.
Working standards and stock solutions should be checked to determine changes in concentration.
Reagents should be prepared and standardized against primary reference standards.
The temperatures of all refrigerators and incubators should be checked daily and temperature excursions should be recorded.
Each oven should have a dedicated thermometer and the temperature should be checked prior to and following each use.
Proper volumetric glassware should be used.
Glassware should be cleaned according to specifications of the method.
Gas cylinders should be replaced at 700–1400 kilopascals (kPa).
Laboratory personnel should have appropriate training in analytical laboratory procedures, and in the particular analysis for which they are responsible.

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5.8.5.3 Calibration Control

Statistical control over calibration can be confirmed between runs by means of two control standards, A and B, and within-run by means of blanks and mid-range standards.

Between-run Calibration Control: Two control standards, A and B, can be used to analyze and control between-run changes in calibration, once at the beginning of each analytical run. These standards are made up and maintained independently of the calibration standards and are normally chosen to be about 80% and 20% of full scale, respectively. Results are accumulated over many runs and the sums (A + B) and differences (A - B) are plotted on control charts. During a specific run, a significant change in the sum (A + B) from the historical mean implies that a significant change in intercept has occurred, other factors remaining constant. A significant change in the difference (A - B) implies a significant change of slope, other factors remaining constant. Control and warning limits for A - B are calculated for the mean and the SD of the population of differences:
- Upper and lower warning limits (UWL, LWL) = X_A-B ± 2 SD_A-B
- Upper and lower control limits (UCL, LCL) = X_A-B ± 3 SD_A-B
Control and warning limits for A + B are similarly calculated using the same SD:
- UWL / LWL = X_A+B ± 2 SD_A-B
- UCL / LCL = X_A+B ± 3 SD_A-B
The run should not proceed until it is shown that A + B and A - B are within control limits. Control limits should not exceed ± 5% of the average value for A + B and A - B.
Within-run Calibration Control (Inorganic Analyses): Within-run changes in calibration attributable to slope and baseline drift should be checked at regular intervals. This can be accomplished by use of a mid-range standard and reagent blank run after every 20 samples. Control limits should be established by each laboratory for each procedure. The drift should not exceed 10%. If a greater drift is detected, the analysis should be stopped, the instrument recalibrated, and samples run after the last acceptable check sample and blank are reanalyzed.
Within-run Calibration Control (Organic Analyses): In organic analyses by gas chromatography (GC), within-run changes in calibration should be checked by injection of a mid-level check standard at a frequency of 5% or every 12 hours. This injection is compared to the initial calibration by calculating the percent deviation in the response factor of each analyte in the check standard to the average response factor determined during the initial calibration. If the relative percent difference is greater than 25%, the calibration check should be repeated. If the repeated check standard still has a relative percent deviation greater than 25%, corrective action is recommended.

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5.8.5.4 Precision

Precision is the degree of variation among individual measurements of the same variable using a specific analytical method, and is usually expressed as the SD of replicates (US EPA 1990). Statistical control of analytical precision is maintained by analyzing within-run duplicates at a frequency of at least 10%. Laboratory duplicates are separate aliquots split in the laboratory from a single sample.

The absolute difference between within-run duplicates is compared to a control limit determined from historical data. To obtain these control limits, the results of duplicate analyses are accumulated over many runs and sorted according to concentration ranges.

Convenient concentration ranges are 0-20%, 20-50%, and 50-100% of full scale (King 1976). Within each concentration range, control limits for the absolute difference between within-run duplicates is determined from the formula:

UCL = D₄ x R

where D₄ (3.267) is a statistical factor and R is the mean difference between duplicates (ASTM 1986; Taylor 1987).

If the difference between laboratory duplicate analyses exceeds the upper control limit, the situation should be evaluated to determine the most appropriate corrective action.

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5.8.5.5 Accuracy and Bias

Accuracy is the degree of agreement between an observed value and the true value as determined by analysis of an accepted reference material (US EPA 1990). The converse of accuracy is the degree of systematic error in the analysis, i.e., the bias. Accuracy is controlled by means of method blanks and certified reference materials. Information on recommended quality control for inorganic analyses can be found in CALA (1991).

Method Blanks: A method blank is an aliquot of reagent water equivalent in volume to the samples being processed and run in exactly the same manner as the samples. The method blank quantifies the level of contamination introduced to the samples during sample processing and analysis. Method blanks should be analyzed at a frequency of 10% or 1/run, charted, and controlled at ± 2 SD (warning limits) and ± 3 SD (control limits). If a method blank is judged out of control and contaminated, those samples processed with the blanks and greater than the detection limit should be repeated for the variable(s) affected. In general, a method blank is considered free of contamination if the analysis yields results less than the detection limit or less than 0.1 times the level found in all associated samples (CALA 1991).
Standard Reference Materials: SRMs are samples available in different matrices that have been extensively analyzed by several laboratories and have concentrations certified by standard-setting organizations such as the National Institute of Science and Technology, the U.S. EPA, the National Water Research Institute of Environment Canada and the National Research Council. When available, an SRM should be analyzed at a frequency of 5% or 1/run (CALA 1991; King 1976). The matrix and concentration of the SRM should be as close as possible to the samples being analyzed. The results of SRMs should be accumulated, and control and warning limits determined as ± 3 SD and ± 2 SD, respectively.

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5.8.5.6 Recovery

Recovery of the analyte over the entire analytical process is determined from matrix spikes, spiked blanks, and surrogate spikes.

Matrix Spike: A matrix spike is a separate aliquot of a randomly chosen sample to which is added all the analytes of interest before processing of the sample. Analysis of a matrix spike gives an indication of the recovery efficiency obtained for the matrix particular to that sample. The sample should be spiked with all the analytes of interest at a concentration as close as possible to that concentration, giving a response equal to the mid-level calibration standard. The spiking solution should be prepared from a stock source separate from that used for calibration. The recommended distribution of matrix spikes is 10% or 1/run. One method to calculate recovery is:

The results of matrix spikes should be plotted on separate control charts for each matrix. In-house limits should be set on the basis of ± 3 SD on a minimum of 10 data points. In multi-parameter analyses, at least 90% of the analytes should have recoveries within the specified limits. Recoveries for inorganic analytes should fall within 75-125%. Recoveries for organic variables should fall within the limits specified in Table 4 of CALA (1991). If a matrix spike does not meet these criteria, the spike should be repeated. If the recoveries do not meet the criteria in the repeat analysis and there are no indications of other problems with the analysis, a matrix effect should be noted and reported.
Spiked Method Blank: The spiked method blank is a separate aliquot of the same reagent water used for the method blank that is spiked with the compound of interest at a concentration as close as possible to the concentration of the mid-level calibration standard. The spiked method blank gives an indication of the reliability of a method without the matrix effects of real samples. The spiked method blank should be processed with and in the same manner as the samples. As with the matrix spike, the spiking solution should be prepared from stocks separate from those used for calibration.

In-house recovery limits should be calculated for the spiked method blank based on ± 3 SD and a minimum of 10 data points. Recoveries for inorganic analyses should fall within 75-125%. Recoveries for organic variables should fall within 70-120%. If a spiked blank recovery does not meet the criteria established, the spike should be repeated. If the spike still does not recover, the samples related to the spike should be repeated. If insufficient sample remains for a repeat analysis, the results should be reported and flagged as suspect with an explanation.
Internal Standards (Organic Analyses): All analyses using GC should be performed using internal standards, or properly validated methods using external standards. An internal standard is a compound that behaves similarly in an analytical system as the compound of interest, but is unlikely to be found in the sample. Internal standards are added at the same level to all samples, standards, and control samples prior to measurement but after sample preparation. All analyte responses should be normalized for the internal standard response to correct for instrument variability in response to such factors as varying injection volumes, temperature fluctuations, and final extract volume. The response of the internal standard in the sample measurement should be within 20% of the internal response of a calibration standard analyzed within the same 12-hour period. If this criterion is not met, the sample should be repeated. If upon reanalysis the criterion is still not met, the sample results should not be corrected for internal standard response and should be flagged with an explanation.
Surrogate Spikes (Organic Analyses): A surrogate standard is a compound not expected to be found in the sample that behaves similarly to the analytes of interest during sample preparation and analysis. Where applicable, surrogates should be added to all samples (including QC samples) before sample preparation to indicate method performance and sample matrix effects. Analyses run by gas chromatography / mass spectometry (GC/MS) should have at least two surrogates, while those run by GC should have at least one surrogate. The amount of surrogate added to all samples should be the same as that added to the calibration solutions. In-house control limits for surrogate recoveries are based on ±3 SD on a minimum of 10 data points. In-house control limits for surrogate recoveries should be within 60-120%. If any surrogate is outside the expected recovery range, the sample should be reanalyzed. If, upon reanalysis, the surrogate recovery is still outside the permissible range, the results should be reported with a flag and an explanation.

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5.8.5.7 Detection Limits

Detection limits should be reported as the method detection limit (MDL) as described by the U.S. EPA (1984). The MDL is defined as the minimum quantity of an analyte that should be observed to justify the claim to have detected the analyte with a specified risk (normally 5% or 1%) of making a false detection.

One method to calculate the MDL is from the SD of the analysis at the lowest concentration range:

MDL = t_{0.05 n-1} x S

where: t_{0.05, n-1} is the one tailed value of Student’s t for a 5% risk of false detection, n-1 degrees of freedom, and S is the SD.

Ideally the SD is calculated from low-level replicate analysis on real samples having the same or similar sample matrix as the samples under consideration. This SD can be calculated from a minimum of seven replicates in the same run using the standard statistical formula (US EPA 1984). However, it is preferable to calculate S from between-within-run replicate pairs accumulated over many runs.

The SD of low-level replicate pairs accumulated over a large number of analytical runs is:

Equation showing the SD of low-level replicate pairs accumulated over a large number of analytical runs

where D is the individual replicate difference and n is the number of replicate pairs. A minimum of 40 replicate pairs is recommended (OMOE 1988). The value of either SD is then entered in the equation to calculate the MDL.

Values below the detection limit should be reported as < MDL, with the applicable MDL for that sample (Fowlie et al. 2001). There are three common approaches to deal with values that are < MDL when analyzing data: set the value at the MDL, half the MDL, or 0. For the purposes of the EEM program, half the MDL is currently used for all data analysis and interpretation. For additional information on how to interpret non-detectable data, refer to Helsel (2005a, 2005b) and Shumway et al. (2002).

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5.8.5.8 Data Reporting Conventions

Established protocols for rounding off analytical results should be followed. If too many figures are rounded off before reporting, information is lost and real differences in the concentrations of samples from different locations or occasions may be concealed. QC may be on a coarser basis than is desirable, or necessary, with the result that values of the mean, SD or other statistics of a set of results may be biased. Conversely, when too many significant figures are reported, relatively small, statistically insignificant differences may appear falsely large (Hunt and Wilson 1986).

The SD of the analysis is the preferred criterion for deciding the number of significant figures (King 1989). The process of rounding off should ensure retention of the digit that is in the same decimal position as the most significant digit in the calculated SD. For example, if the analysis provides a value such as 12.345 and the calculated SD based on within-run replicate analysis at this concentration level is 0.32, the result should be truncated to 12.3.

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5.8.5.9 Analytical Precision and Accuracy

Precision is the degree of agreement among replicate analysis of a sample, usually expressed as the SD. Reproducibility is the closeness of agreement between the results of measurement of the same parameter carried out under changed conditions of measurement. Reproducibility is the SD obtained measuring the same sample in different analytical runs and is called between-run precision. Between-run precision includes variability due to calibration on different days, instrument drift and many other factors.

Precision is affected by random errors and is a measurable and controllable parameter. Precision should be estimated for all analyses by processing separate sample aliquots through the entire analytical method. A laboratory should monitor their precision and be able to report precision using several days of data. For most parameters, the precision should be within 10%. For total suspended solids, the precision should be within 15% at concentrations greater than 10 times the MDL. For pH, precision should be within ± 0.1 pH unit (MMER, Schedule 3).

Accuracy is the combination of bias and precision of an analytical method, which reflects the closeness of a measured value to the true value of a sample. Bias is a systematic error caused by something in the measuring system resulting in the data being high or low. Bias can be caused by a number of factors including contamination, mechanical losses, blanks, spectral interference, calibration errors or the influence of different operators. Accuracy is measured as percent recovery of known concentrations such as certified reference materials, spiked samples or reference samples prepared by the laboratory and analyzed as samples.

Whether data are considered accurate or inaccurate is relative to the final use of the data. A laboratory should monitor their accuracy and be able to report this using several days of data. For metals and most other parameters, accuracy should be within 10%. For total suspended solids, accuracy should be within 15% at concentrations greater than 10 times the MDL. For pH, accuracy should be within ± 0.1 pH unit (MMER, Schedule 3).

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5.8.6 Quality Assurance in the Laboratory

QA encompasses a wide range of internal and external management and technical practices designed to ensure that data of known quality are commensurate with the intended use of the data.

External QA activities include participation in relevant inter-laboratory comparisons and audits by outside agencies. Outside audits may be based on performance in analysis of standard reference materials, or on general review of practices as indicated by documentation of sampling, analytical and QA/QC procedures, test results, and supporting data.

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5.8.7 Recording and Reporting of QA/QC Information

5.8.7.1 Documentation

Documentation of all aspects of the analysis is recommended to confirm the quality and reliability of the analytical results. The owner or operator of a mine shall keep all records, books of account or other documents required by the Metal Mining Effluent Regulations at the mine’s location for a period of no less than five years (MMER, s. 27). For each sample or batch of samples, information on the following is recommended:

Method Detection Limits: If MDLs are different from the laboratory-determined MDLs (due to interference, dilutions, etc.), this should be recorded.
Sample Storage Times: Records should be kept on the sampling date, date of receipt, date of sample preparation, and date of analysis. This information is normally handled as part of the sample-tracking process.
Instrument Performance and Maintenance: A log should be kept of instrument performance, including records of tuning and instrument response. Maintenance or service records should be kept for each instrument.
Quality Control Samples: Records of duplicate analyses, blanks, spiked blank recoveries, surrogate recoveries, matrix spike recoveries and results from certified reference materials, and records of calibration and calibration checks should be maintained.
Sample Reception, Preparation and Analysis: All anomalies in delivery, storage, condition, preparation and analysis of samples should be recorded. These include any deviations from standard operating procedures.

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5.8.7.2 Reporting of QA/QC Information

Analytical results are reported as a test or analysis report and should include all relevant data needed to assess the validity of the data, including QA/QC components. The report should be accurate, clear, unambiguous and objective. Items that should appear in the report include:

a title (Test Report, Report of Analysis, Quality Report);
name, address and location of laboratory, and location where tested;
unique identification of the report so it can be traced easily (serial number, group number);
name and address of client;
identification or description of the sample tested;
condition of the test item (unpreserved, leaking bottle--where relevant);
date of sample receipt, date of report;
identification of the analysis method and description of any non-standard tests;
reference to sample date and sampling method (grab sample, time-proportioned composite sample, etc.);
deviations from the usual test method (filtering, pH, adjustment, standard addition, etc.);
the analytical results with units clearly identified;
statement indicating whether the results were corrected for blanks;
QC data;
identify if result is qualified (did not pass QC tests, sample size too small, etc.);
signature of accountable person and date authorization;
name of technician who completed the test;
subcontractors clearly identified;
updates or corrections to reports clearly identified; and
the laboratory should notify clients if new information invalidates reports already issued.

Data below the analytical detection limit should be clearly reported as such along with the applicable MDL for that sample.

5.9 References

AQUAMIN. 1996. Assessment of the Aquatic Effects of Mining in Canada: Final report. Prepared by AQUAMIN Working Groups 7 and 8 for the AQUAMIN Steering Group.

[ASTM] American Society for Testing and Materials. 1986. Manual on presentation of data and control chart analysis. Committee E-11 on Statistical Methods. ASTM Special Technical Publication 15D. Philadelphia (PA): American Society for Testing and Materials.

[CALA] Canadian Association of Laboratory Accreditation. 1991. Code of practice and QA manual for laboratory analysis of sewage treatment effluent in support of the MISA program. Draft report prepared for CAEAL and the Ontario Ministry of the Environment by Zenon Environmental Laboratories.

[CCME] Canadian Council of Ministers of the Environment. 1999. Canadian environmental quality guidelines. Chapter 4: Canadian water quality guidelines for the protection of aquatic life. Hull (QC): Canadian Council of Ministers of the Environment. Available from: http://ceqg-rcqe.ccme.ca/

Druschel GK, Schoonen MAA, Nordstorm DK, Ball JW, Xu Y, Cohn CA. 2003. Sulfur geochemistry of hydrothermal waters in Yellowstone National Park, Wyoming, USA. III. An anion-exchange resin technique for sampling and preservation of sulfoxyanions in natural waters. Geochem Trans4:12-19.

[ELAP] Environmental Laboratory Approval Program. 1988. Environmental Laboratory Approval Program certification manual. New York State Department of Health.

[ESG] Ecological Services Group. 1999. AETE synthesis report of selected technologies for cost-effective environmental monitoring of mine effluent impacts in Canada (AETE Project No. 4.1.4). Report for AETE program. Ottawa (ON): CANMET, Natural Resources Canada.

Fowlie P, Hart DR, Turle R. 2001. Guidance Document for the Sampling and Analysis of Mine Effluents: Final Report. Ottawa (ON): Environment Canada, Environmental Protection Service, Minerals and Metals Division. Report EPS2/MM/5. Available from: http://dsp-psd.pwgsc.gc.ca/Collection/En49-24-1-39E.pdf

Helsel DR. 2005a. Nondetects and data analysis: statistics for censored environmental data. Hoboken (NJ): Wiley-Interscience. 250 p.

Helsel DR. 2005b. More than obvious: better methods for interpreting nondetect data. Environ Sci Technol 39(20):419A-423A.

Hunt DTE, Wilson AL. 1986. The chemical analysis of water; general principles and techniques. 2nd edition. London (UK): The Royal Society of Chemistry.

[ISO/IEC] International Organization for Standardization. 2005. ISO/IEC 17025: 2005. General requirements for the competence of testing and calibration laboratories. Geneva (CH): ISO/IEC.

King DE. 1976. Quality control and data evaluation procedures. Section I. Analytical responsibility. Special report to Laboratory Services Branch, Ontario Ministry of the Environment.

King DE. 1989. Code of practice for environmental laboratories. Special report to the Ontario Ministry of the Environment. ISBN 0-7729-5874-2.

Makhija R, Hitchen A. 1979. The titrimetric determination of sulphate, thiosulphate and polythionates in mining effluents. Anal Chim Acta 105(1):375-382.

McQuaker NR. 1999. Technical evaluation on water quality design and analysis (AETE Project No. 3.1.1). Draft report for AETE program. Ottawa (ON): CANMET, Natural Resources Canada.

Nielson LA, Johnson DL. 1983. Fisheries techniques. Bethesda (MD): American Fisheries Society. 468 p.

[OMOE] Ontario Ministry of the Environment. 1988. Estimation of analytical detection limits (MDL). Report by the Ontario Ministry of the Environment. ISBN-0-7729-4117-3.

Ontario Ministry of the Environment and Energy. 1993. MISA draft development document for the Effluent Limits Regulation for the Metal Mining Sector. Toronto (ON): Queen’s Printer for Ontario.

O’Reilly JW, Dicinoski GW, Shaw MJ, Haddad PR. 2001. Chromatographic and electrophoretic separation of inorganic sulfur and sulfur–oxygen species. Anal Chim Acta 432(2):165-192.

Reiley M. 2007. Science, policy, and trends of metals risk assessment at EPA: How understanding metals bioavailability has changed metals risk assessment at US EPA. Aquat Toxicol 84(2):292-298.

Schwartz M, Vigneault B, McGeer J. 2006. Assessing the potential toxicity of thiosalts in the context of the Metal Mining Effluent Regulation. Presentation made at the 33rd Aquatic Toxicity Workshop, Jasper, AB.

Shumway RH, Azari RS, Kayhanian M. 2002. Statistical approaches to estimating mean water quality concentrations with detection limits. Environ Sci Technol 36(15):3345-3353.

Taylor JK. 1987. Quality assurance of chemical measurements. Chelsea (MI): Lewis Publishers Inc.

[US EPA] United States Environmental Protection Agency. 1984. Definition and procedure for the determination of the method detection limit – Revision 1.11. Appendix B to Part 136. Federal Register. Vol. 49, no. 209. Oct. 26, 1984, Part VI, 40 CFR Part 136.

[US EPA] United States Environmental Protection Agency. 1990. Proposed glossary of quality assurance related terms. QAMS RD-680. Draft report.

[US EPA] United States Environmental Protection Agency. 2007. Aquatic life ambient freshwater quality criteria--Copper 2007 revision. EPA-822-F-07-001.

Vigneault B, Holdner J, Bélanger J. 2002. Validation of an anion exchange method for the preservation and analysis of thiosalt speciation in mining waste waters. Ottawa (ON): CANMET Mining and Mineral Science Laboratories. Division Report MMSL 03-002(TR).

Appendix 5-1: Justifications for Parameters for Effluent Characterization and Water Quality Monitoring

(text description)

Deleterious Substances and pH as per Schedule 3 of the MMER

Arsenic

AQUAMIN Working Groups 7 and 8 (1996) recommended that arsenic be measured in effluent characterization.
Arsenic can occur in effluent from a wide range of mine types, including gold, base metal and uranium, and can be expected to occur across Canada.
The MISA draft development document¹ (Ontario Ministry of the Environment and Energy 1993) stated that arsenic was found in 26% of the metal mine effluents sampled, with an average concentration of 0.036 mg/L.
Arsenic can bioaccumulate in fish and is known to be toxic to aquatic organisms.
The Canadian environmental quality guideline (CEQG)² for arsenic for the protection of freshwater aquatic life is 0.005 mg/L (0.0125 mg/L for marine environments).

Copper

AQUAMIN Working Groups 7 and 8 (1996) recommended that copper be measured in effluent characterization.
Copper can occur in effluent from a wide range of mine types, particularly gold and base metal, and can be expected to occur across Canada.
The MISA draft development document (Ontario Ministry of the Environment and Energy 1993) reported that for 39 Ontario effluent streams sampled for 12 months, the average copper concentration was 0.07 mg/L.
Copper is known to be toxic to aquatic organisms.
The CEQG for copper for the protection of freshwater aquatic life ranges from 0.002 to 0.004 mg/L, depending on the water hardness.

Lead

AQUAMIN Working Groups 7 and 8 (1996) recommended that lead be measured in effluent characterization.
Lead can occur in effluent from a wide range of mine types, particularly base metal mines, and can be expected to occur across Canada.
The MISA draft development document (Ontario Ministry of the Environment and Energy 1993) stated that lead was found in 20% of the metal mining effluents sampled. The average lead concentration in the sampled effluent was 0.02 mg/L.
Lead is known to be toxic to aquatic organisms.
The CEQG for lead for the protection of freshwater aquatic life ranges from 0.001 to 0.007 mg/L, depending on the water hardness.

Nickel

AQUAMIN Working Groups 7 and 8 (1996) recommended that nickel be measured in effluent characterization.
Nickel can occur in effluent from a wide range of mine types, particularly base metal and uranium mines, and can be expected to occur across Canada.
The MISA draft development document (Ontario Ministry of the Environment and Energy 1993) stated that nickel was found in 68% of the metal mine effluents sampled, with an average concentration of 0.14 mg/L.
Nickel is known to be toxic to aquatic organisms.
The CEQG for nickel for the protection of freshwater aquatic life ranges from 0.025 to 0.150 mg/L, depending on the water hardness.

AQUAMIN Working Groups 7 and 8 (1996) recommended that pH be measured in effluent characterization.
pH extremes can occur in effluent from a wide range of mine types and can be expected to occur across Canada.
pH often determines the solubility of metal species and, therefore, is linked to the toxicity of the effluent.
Extremes of pH are known to be toxic to aquatic organisms.
The CEQG for pH for the protection of freshwater aquatic life is 6.5 to 9.0 (7.0 to 8.7 for marine and estuarine environments).

Radium 226

AQUAMIN Working Groups 7 and 8 (1996) recommended that radium 226 be measured in effluent characterization.
Radium 226 occurs primarily in effluent from uranium mines. However, it does not occur across Canada.
There is no CEQG for radium 226.

Total cyanide

Cyanide is used as a process reagent at most gold mines and some base metal mines.
AQUAMIN Working Groups 7 and 8 (1996) recommended that cyanide be measured in effluent characterization, for mines that use cyanide as a process reagent.
The MISA draft development document (Ontario Ministry of the Environment and Energy 1993) stated that cyanide was found in 54% of the metal mine effluents sampled, with an average concentration of 0.084 mg/L in gold mining effluent and 0.006 mg/L in base metal mining effluent.
Cyanide is known to be toxic to aquatic organisms.
The CEQG for free cyanide for the protection of freshwater aquatic life is 0.005 mg/L.

Total suspended solids

AQUAMIN Working Groups 7 and 8 (1996) recommended that total suspended solids be measured in effluent characterization.
Suspended solids can occur in effluents from all mine types, and occur across Canada.
The MISA draft development document (Ontario Ministry of the Environment and Energy 1993) stated that suspended matter was found in 80% of the metal mine effluents sampled, with an average concentration of 7 mg/L.
Suspended solids can kill fish by clogging their gills, and can affect fish habitat by smothering fish habitat, contaminating sediments, or reducing light penetration in receiving waters.

Zinc

AQUAMIN Working Groups 7 and 8 (1996) recommended that zinc be measured in effluent characterization.
Zinc can occur in effluent from a wide range of mine types, particularly base metal mines, and can be expected to occur across Canada.
The MISA draft development document (Ontario Ministry of the Environment and Energy 1993) stated that zinc was found in 76% of the metal mine effluents sampled, with an average concentration of 0.07 mg/L.
Zinc is known to be toxic to aquatic organisms.
The CEQG for zinc for the protection of freshwater aquatic life is 0.030 mg/L.

Parameters Required in Schedule 5 of the MMER for Effluent Characterization and Water Quality Monitoring

Alkalinity

Alkalinity is a measure of the buffering capacity of water, and gives an indication of how sensitive water is to changes in pH.
Alkalinity is a factor affecting the fate and bioavailability of metals.

Aluminium

AQUAMIN Working Groups 7 and 8 (1996) recommended that aluminium be measured in effluent characterization.
Aluminium occurs in a number of important rock-forming minerals, and tailings pond effluents from a range of mine types may contain dissolved aluminium ions as well as chemically bound aluminium in the form of clays and other alumino-silicate mineral particles.
The MISA draft development document (Ontario Ministry of the Environment and Energy 1993) stated that aluminium was present in 70% of the Ontario metal mining effluents sampled, with an average concentration of 0.20 mg/L.
The draft development document also stated that dissolved aluminium is not a significant component of most metal mining effluents.
The CEQG for aluminium for the protection of freshwater aquatic life ranges from 0.005 to 0.100 mg/L, depending on the water hardness.
Aluminium is toxic to aquatic organisms and its toxicity varies with pH.
Aluminium data may assist in the interpretation of the potential impacts of metals and other parameters.

Cadmium

AQUAMIN Working Groups 7 and 8 (1996) recommended that cadmium be measured in effluent characterization.
Cadmium occurs in a relatively small range of ore types, but can be expected to occur at mines across Canada.
The MISA draft development document (Ontario Ministry of the Environment and Energy 1993) states that cadmium was found in 12% of the metal mine effluents sampled, with an average concentration of 0.003 mg/L.
Cadmium is known to be toxic to aquatic organisms and is bioaccumulative.
The CEQG for cadmium for the protection of freshwater aquatic life is 0.000017 mg/L. Note that a formula adjusting the guideline value based on hardness is given, i.e., cadmium guideline = 10^{{0.86[log(hardness)]-3.2}} (0.12 µg/L for marine environments).

Iron

AQUAMIN Working Groups 7 and 8 (1996) recommended that iron be measured in effluent characterization.
Iron occurs in virtually all ore types, and occurs in mines across Canada.
The MISA draft development document (Ontario Ministry of the Environment and Energy 1993) stated that iron was found in 100% of the metal mine effluents sampled, with an average concentration of 0.45 mg/L.
Iron is toxic to aquatic organisms, and iron hydroxide precipitates can affect fish habitat.
The CEQG for iron for the protection of freshwater aquatic life is 0.30 mg/L.
Iron can also have an important influence on the fate of other contaminants.
Iron data may assist in the interpretation of the potential impacts of metals and other parameters.

Nitrogen compounds (ammonia and nitrate)

AQUAMIN Working Groups 7 and 8 (1996) recommended that total ammonia be measured in effluent characterization.
Nitrogen compounds are used in explosives in most mines, and residue from these explosives can result in nitrogen compounds occurring in effluent. Nitrogen compounds can also occur in effluent as a result of the breakdown of cyanide.
During MISA development in Ontario, ammonia plus ammonium, total Kjeldahl nitrogen, and nitrate plus nitrite were measured in effluents.
“Ammonia plus ammonium” was found in all 50 (100%) of the metal mining effluents sampled. The average concentration of “ammonia plus ammonium” measured in the metal mining sector was 1.4 mg/L in base metal mining effluents and 6.3 mg/L in gold mining effluents.
“Total Kjeldahl nitrogen” was found in 96% of the metal mining effluents sampled. The average concentration of “total Kjeldahl nitrogen” measured in the metal mining sector was 8 mg/L.
Nitrate plus nitrite” was found in 90% of the metal mining effluents sampled. The average concentration of “nitrate plus nitrite” measured in the metal mining sector was 8.8 mg/L;
Nitrogen compounds can be toxic to aquatic organisms. In addition, nitrogen compounds are nutrients, and can lead to excessive plant growth. Excessive plant growth can lead to oxygen depletion, resulting in fish kills.
The CEQG for total ammonia for the protection of freshwater aquatic life ranges from 1.370 to 2.200 mg/L, depending in temperature and pH.
The proposed interim CEQG for nitrate is 13 mg/L in freshwater (16 mg/L for marine environments).
The CEQG for nitrite for the protection of freshwater aquatic life is 0.060 mg/L.

Mercury

AQUAMIN Working Groups 7 and 8 (1996) recommended that mercury be measured in effluent characterization.
Mercury occurs in a range of rock types. It can occur at gold and silver mines, and less commonly at base metal mines, and is expected to occur across Canada.
Mercury can come from a range of sources, including airborne transport, natural sources and mine effluent. As a result, AQUAMIN Working Groups concluded that it is often difficult to determine the source of mercury contamination within an aquatic environment. This was the basis for recommending that mercury be included in effluent characterization.
The MISA draft development document (Ontario Ministry of the Environment and Energy 1993) stated that mercury was found in 14% of the metal mine effluents sampled, with an average concentration of 0.0002 mg/L.
Mercury is toxic to aquatic organisms and is biomagnified within food chains.
The CEQG for mercury for the protection of freshwater aquatic life is as follows: inorganic mercury = 0.026 µg/L; methylmercury = 0.004 µg/L; inorganic mercury for marine environments = 0.016 µg/L.

Molybdenum

AQUAMIN Working Groups 7 and 8 (1996) recommended that molybdenum be measured in effluent characterization.
Molybdenum occurs primarily in uranium ores, but may also occur in base metal ores and a small number of gold ores, and is not expected to occur across Canada.
Molybdenum can be toxic to aquatic organisms, but its toxicity is not well understood.
Molybdenum can also affect drinking water quality and cause molybdenosis in cattle.
The CEQG for molybdenum for the protection of freshwater aquatic life is 0.073 mg/L.

Hardness

Water hardness is a measure of cations, predominantly divalent cations, dissolved in water.
Calcium and magnesium are the major contributors to hardness, and hardness can be calculated based on concentrations of these ions.
Hardness is an important factor affecting the fate, bioavailability and toxicity of metals.

Selenium

AQUAMIN Working Groups 7 and 8 (1996) did not consider selenium for inclusion in effluent characterization.
The MISA draft development document (Ontario Ministry of the Environment and Energy 1993) stated that selenium was found in 10% of the metal mine effluents sampled, with an average concentration of 0.007 mg/L.
Selenium occurs most commonly in association with sulphur, and is not common in mine effluents.
Selenium is toxic to aquatic organisms.
The CEQG for selenium for the protection of freshwater aquatic life is 0.001 mg/L.

Electrical conductivity

Conductivity is a measure of water’s ability to conduct an electrical current.
Conductivity can be measured in the field or in the lab.
Conductivity gives an approximate measure of total dissolved solids, and can be used to identify the location of an effluent plume in freshwater environments.

Required Parameters for Water Quality Monitoring Only

Dissolved oxygen

Dissolved oxygen can be measured in the field or in the lab.
Dissolved oxygen is a factor affecting the fate and bioavailability of metals.

Temperature

Temperature changes can affect limnological properties of lakes, and can also affect aquatic organisms.
The CEQG for temperature for the protection of freshwater aquatic life states that thermal additions should not alter thermal stratification or turnover dates, exceed maximum weekly temperature averages, or exceed maximum short-term temperatures.

Additional Site-specific Recommended Parameters for Effluent Characterization and Water Quality Monitoring

Calcium

AQUAMIN Working Groups 7 and 8 (1996) recommended that calcium be measured in effluent characterization.
Calcium is an important cation in aquatic ecosystems, and may also occur in mine effluent as a result of acid neutralization using lime.
Calcium discharges from mines may have effects on fish habitat.
Calcium concentrations are essential to calculating hardness.
Calcium is known to affect the toxicity of metals and/or other mine effluent parameters;.
Calcium data may assist in the interpretation of the potential impacts of metals and other parameters.

Chloride

The MISA draft development document (Ontario Ministry of the Environment and Energy 1993) stated that chloride was found in 80% of the metal mine effluents sampled, with an average concentration of 83 mg/L.
Chloride can affect the toxicity of metals and/or other mine effluent parameters.
Chloride data may assist in the interpretation of the potential impacts of metals and other parameters.

Fluoride

AQUAMIN Working Groups 7 and 8 (1996) recommended that fluoride be measured in effluent characterization for operations where it is likely to be present.
Fluoride occurs in a limited number of ore types, and is not expected to occur across Canada.
Fluoride has been shown to bioaccumulate in fish bones, but its effects on aquatic organisms are not well understood.
Fluoride is lethal to fish at concentrations ranging from 10 to 200 mg/L.
Fluoride was rated “toxic” following Priority Substance List 1 assessment for “having an immediate or long-term harmful effect on the environment.”

Magnesium

Magnesium is an important cation in aquatic ecosystems, and magnesium concentrations are essential to calculating hardness.
Magnesium is known to affect the toxicity of metals and/or other mine effluent parameters.
Magnesium data may assist in the interpretation of the potential impacts of metals and other parameters.

Manganese

AQUAMIN Working Groups 7 and 8 (1996) did not consider manganese for inclusion in effluent characterization.
Manganese occurs in many ore types, and is expected to occur at mines across Canada. Manganese makes up 0.1% of the Earth’s crust.
There is no CEQG for manganese for the protection of freshwater aquatic life.
Manganese can have an important influence on the fate of other contaminants, specifically on the availability of other metals.
Manganese is toxic to aquatic life but the factors that affect its toxicity are not well understood.

Potassium

Potassium is known to affect the toxicity of metals and/or other mine effluent parameters.
Potassium data may assist in the interpretation of the potential impacts of metals and other parameters.

Sodium

Sodium is known to affect the toxicity of metals and/or other mine effluent parameters.
Sodium data may assist in the interpretation of the potential impacts of metals and other parameters.

Sulphate

Sulphate is an important anion in water.
Mine effluents from mines with sulphide-bearing ore can be important sources of sulphate.
Sulphate data may assist in the interpretation of the potential impacts of metals and other parameters.
The MISA draft development document stated that sulphate was found in 86% of the metal mine effluents sampled, with an average concentration of 644 mg/L.

Total phosphorus

AQUAMIN Working Groups 7 and 8 (1996) did not consider total phosphorus for inclusion in effluent characterization.
The MISA draft development document (Ontario Ministry of the Environment and Energy 1993) stated that total phosphorus was found in 24% of the metal mine effluents sampled, with an average concentration of 0.1 mg/L.
Total phosphorus may occur in mine effluent in particulate or dissolved form.
Total phosphorus is a nutrient, and may lead to excessive plant growth.

Uranium

AQUAMIN Working Groups 7 and 8 (1996) did not consider uranium for inclusion in effluent characterization.
Small amounts of uranium occur in many rock types in Canada, but uranium is expected to occur primarily in effluents from uranium mines.
The MISA draft development document (Ontario Ministry of the Environment and Energy 1993) stated that uranium was found in 22% of the metal mine effluents sampled, with an average concentration of 0.06 mg/L.
Uranium has been shown to bioaccumulate in fish.

Parameters Recommended for Effluent Characterization Only

Total thiosalts

AQUAMIN Working Groups 7 and 8 (1996) recommended that thiosalts be measured in effluent characterization (listed in Table 4.1 of the AQUAMIN report, but not explicit in text) and also recommended that thiosalt impacts be monitored as part of EEM.
Thiosalts are a group of metastable oxysulphur anions formed by partial oxidation of sulphide minerals during processing.
Thiosalts have relatively low toxicity, but in the aquatic environment the oxidation of thiosalts can lead to significant reductions in pH.
Reductions in fish and benthic communities have been associated with thiosalts.
Thiosalts have the potential to occur at any mine that uses flotation to separate sulphide minerals, but only a few mines in Canada have known problems associated with thiosalts.

Site-specific Parameters Recommended for Water Quality Monitoring Only

Dissolved and total organic carbon

Dissolved and total organic carbon are important factors affecting the fate and bioavailability of metals.

Salinity

Salinity is an important parameter in marine environments, and may be a contaminant at some uranium mines.

Optical depth or Transparency

Optical depth is a field measurement of transmission of light through water as affected by water colour (dissolved constituents) and turbidity (particulate constituents).
Optical depth is measured in the field using a Secchi disk or a turbidimeter.
A low level of light transmission can reduce primary productivity in water and reduce the ability of predators to find prey.

Water depth

Water depth can affect temperature, dissolved oxygen, and the degree of effluent dilution, all of which are modifying factors in effluent toxicity.

Thallium

Metal mining can be a source of thallium to aquatic environments.
The CEQG for the protection of aquatic life is 0.0008 mg/L.

Footnotes

Footnote 1

Note: the MISA draft development document is referred to throughout this document. The MISA document summarizes data from one year of comprehensive effluent characterization at mines across Ontario in the early 1990s. These data are not representative of the current state of effluent quality from mines across Canada. Reference: Ontario Ministry of the Environment and Energy. 1993. MISA Draft Development Document for the Effluent Limits Regulation for the Metal Mining Sector. Queen’s Printer for Ontario, Toronto, Canada.

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Footnote 2

Note: throughout this document, the Canadian Environmental Quality Guidelines (CEQG) are referred to in order to provide a preliminary assessment of concentrations in the effluent for their ecological significance and their potential effects on the receiving environment. Reference: Canadian Council of Ministers of the Environment. 1999. Updated 2001. Canadian Water Quality Guidelines for the Protection of Aquatic Life, available from: http://ceqg-rcqe.ccme.ca/.

Return to footnote 2 referrer

Tables

Table 5-1 outlines the analytical parameters measured for effluent characterization and water quality monitoring. Effluent quality variables are aligned with water quality variables and site-specific variables.

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Table 5-2 provides a summary of the recommended use of blanks and duplicate samples in the field and laboratory. Each parameter is aligned with the number of samples, internal or field quality control, control limits, and a description is provided.

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Appendix Table 5-1 outlines the justifications for parameters for effluent characterization and water quality monitoring. Topics include deleterious substances and pH as per Schedule 3 of the MMER; parameters required in Schedule 5 of the MMER for effluent characterization and water quality monitoring; required parameters for water quality monitoring only; additional site-specific recommended parameters for effluent characterization and water quality monitoring; parameters recommended for effluent characterization only; and site-specific parameters recommended for water quality monitoring only.

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Date modified:: 2022-07-31