Summary of public comments received on the draft  assessment for the commercial naphthenic acids group

Comments on the draft assessment for the Commercial Naphthenic Acids Group, assessed under the Chemicals Management Plan (CMP), were submitted by the Canadian Fuels Association, Ecojustice, and the Canadian Network for Human Health and the Environment.

Summarized public comments and responses are provided below, organized by topic.

Methodology

Comment Summary: The Government has not provided a rationale for limiting the draft assessment to only the naphthenic acids deliberately manufactured for commercial sale or use, and excluding a larger portion of naphthenic acids, including those found in oil sands process-affected water (OSPW).

It is requested that the Government reconsider its draft assessment of CAS RN 1338-24-5 and conduct a new assessment which:

1. Includes all components and sources of naphthenic acids, as listed on the Domestic Substances List (DSL) as “Naphthenic acids”, including those present in oil sands process-affected water (OSPW);
2. Considers the cumulative effects of naphthenic acids together with the other substances which constitute OSPW;
3. Arrives at the conclusion that naphthenic acids are toxic and that the Government is required to take further action; and
4. Arrives at a determination of whether OSPW is also toxic and requires further action.

Response: One of the primary objectives of the Chemical Management Plan (CMP) has been to address the approximately 4300 existing substances that have been identified as priorities for assessment through the Government of Canada’s categorization of the substances on the Domestic Substances List (DSL). The naphthenic acid substances on the DSL are refined or commercial naphthenic acids and their salts that are recovered from the extraction of petroleum distillates such as jet fuel, kerosene, and diesel during oil processing. The oil sands process-affected water (OSPW) naphthenic acids, which are generated from oil sands mining, extraction and processing of bitumen, are not on the DSL and were subsequently not subject to categorization under the Canadian Environmental Protection Act, 1999 (CEPA).

Environment and Climate Change Canada (ECCC) scientists have conducted extensive investigations of the chemical composition and toxicity of CAS RN 1338-24-5 (addressed in the assessment) and have directly compared those to naphthenic acids found in OSPW from four different OSPW sources. The results of this work (Marentette et al. 2015; Bartlett et al. 2017) indicate that the composition of CAS RN 1338-24-5 are distinct from OSPW naphthenic acids.

Commercial naphthenic acids are generally much simpler in composition than OSPW naphthenic acids. In addition, the substances bearing CAS RN 1338-24-5 were found to be significantly more hazardous to all tested species than any of the OSPW-extracted naphthenic acid mixtures.

The two commercial naphthenic acids addressed in the assessment were deemed to have low potential to be causing ecological risk based on their low ecological exposure. The approach used to determine this is risk-based and considered multiple metrics for both hazard and exposure, with weighted consideration of multiple lines of evidence for determining risk classification.

While OSPW naphthenic acids are not a part of the current assessment, activities to better understand them have been initiated under the Oil Sands Monitoring Program, and are being pursued further by ECCC (see Addendum for more information on these research activities). Additionally, naphthenic acid fraction compounds from OSPW and its salts have been added to the National Pollutant Release Inventory (NPRI) and there are plans to develop federal environmental quality guidelines (FEQGs) for water. ECCC is also exploring options for managing oil sands mine water to reduce the growth of tailings ponds and accelerate the future reclamation of mining sites.

New information generated with respect to the OSPW naphthenic acids will be considered as part of the identification of risk assessment priorities (IRAP) under CEPA.

Information and Data

Comment Summary: The draft assessment relies on older studies, as well as datasheets from the producers, which are often incomplete and inaccurate.

It is recommended that an additional literature search be conducted. Some relevant references have been cited or attached. That information raises enough concerns to change the assessment of these chemicals because of their human health and ecological hazards. The human health hazards are occupational as well as other public health concerns.

Response: Additional information submitted was considered and the final assessment was revised, where appropriate.

Assessments conducted under CEPA currently focus on risks of exposure to the general population. Hazards related to chemicals used in the workplace are defined within the Workplace Hazardous Materials Information System (WHMIS). The Government of Canada is currently working with the provinces and territories to explore ways to enhance the protection of workers from exposure to chemicals by integrating and leveraging the information, tools, and/or technical expertise of the Chemicals Management Plan and Health Canada’s Workplace Hazardous Products Program.

Conclusion

Comment Summary: We support the draft assessment and find it to be balanced and representative of relevant public hazard and exposure pathway information.

Response: Noted.

Comment Summary: It is unreasonable for the draft assessment to propose that CAS RN 1338-24-5 does not meet any of the criteria under section 64 of the Canadian Environmental Protection Act, 1999 (CEPA), given that the Government has already recognized naphthenic acids as being inherently toxic to aquatic species.

Response: Through categorization of substances on the Domestic Substances List, the Government identified CAS RN 1338-24-5 as being inherently toxic to aquatic organisms.

The term “inherently toxic” is different from the meaning of “toxic” under section 64 of CEPA. Meeting categorization criteria for “inherently toxic” does not, on its own, mean that criteria for “toxic” as defined under section 64 are met.

Under CEPA, the risk posed by a substance is determined by considering both its hazardous properties (its potential to cause adverse human health or ecological effects) and the amount of exposure to the general population or the environment. While CAS RN 1338-24-5 was identified as having a moderate ecological hazard potential based on information considered under the Ecological Risk Classification of Organic Substances approach, the risk to human health or to the environment was found to be low due to low potential exposure to the general population and the environment.

Following assessment, the Government proposed to conclude that CAS RN 1338-24-5 and calcium naphthenates are not harmful to human health at current levels of exposure, and that the substances are not entering the environment at levels that are harmful to the environment.

References

Bartlett AJ, Frank RA, Gillis PL, Parrott J., Marentette J, Headley JV, Peru K, Hewitt LM. 2017. Toxicity of naphthenic acids to invertebrates: Extracts from oil sands process-affected water versus commercial mixtures. Environ Poll. 227:271-279.

Marentette JR, Frank RA, Bartlett A, Gillis P, Hewitt LM, Peru K, Headley J, Brunswick P, Shang D, Parrott J. 2015. Toxicity of naphthenic acid fraction components extracted from fresh and aged oil sands process-affected waters, and commercial naphthenic acid mixtures, to fathead minnow (Pimephales promelas) embryos. Aquat Toxicol. 164:108-117.

Addendum to the summary of public comments received on the draft assessment for the commercial naphthenic acids group

Prepared by: Dr. Richard Frank & Dr. Mark Hewitt, ECCC Research Scientists

The following summary provides an overview of research conducted by Environment and Climate Change Canada (ECCC) scientists investigating the complex organic mixtures, which include naphthenic acids, found within bitumen-influenced waters in Canada’s oil sands region. This summary is not intended to be an overview of all related research, including what has been conducted under the Oil Sands Monitoring Program.

Research on naphthenic acids within the totality of water-soluble bitumen-derived organics has been under investigation by ECCC since 2009 under three primary research streams: 1) the development of analytical methodology to detect potential seepage of oil sands process-affected water (OSPW) chemicals from tailings containments; 2) effects-directed analysis of bitumen organics (including naphthenic acids) to isolate and identify the substances having effects on aquatic biota; and 3) research on the development of certified reference materials and a naphthenic acid standard.

Methodology to detect seepage of OSPW chemicals

The objective of this line of research has been to develop analytical methods that can identify OSPW-derived chemicals that may have migrated beyond tailings containments and then to discriminate any such mixtures from the natural bitumen background within the McMurray Formation located in Alberta (Frank et al. 2014, Hewitt et al. 2020, Milestone 2021). Such methodology is required to identify relevant chemical compound classes (to track potential seepage of OSPW) and to enforce the no discharge policy of Alberta mining lease conditions and the federal Fisheries Act. Since 2009, work has focussed on groundwater as the immediate recipient of any such seepage. There have also been significant challenges with analytical method development due to the complex mixtures involved, as well as difficulty distinguishing OSPW seepage from chemicals present due to the erosion and decomposition of naturally present bitumen. Progress made in this work has facilitated the other related research streams described below.

Effects-directed analysis of bitumen organics

The recognition that soluble organic compounds, other than naphthenic acids alone, within bitumen-influenced waters could be impacting overall toxicity led to the development of a new comprehensive isolation protocol by ECCC scientists that recovers all bitumen organics (Bauer et al. 2019a). This new methodology separates the bitumen-derived organic mixtures into 3 distinct chemical fractions using differences in polarity and pH. This methodology was applied to an aged OSPW source (Bauer et al. 2019a) as well as 3 groundwater sources (Frank et al. 2021) that had been previously determined to have significant bitumen influence. Toxicological characterization was conducted using the marine bacterium Vibrio fischeri (Microtox® assay), two vertebrate species (Pimephales promelas [fathead minnow] and Oryzias latipes [Japanese medaka]), and five invertebrate species (Hyalella azteca [amphipod crustacean], Hexagenia spp. [mayfly], Ceriodaphnia dubia [water flea], Daphnia magna [water flea], and Lampsilis cardium [freshwater mussel]) using the generated fractions from the different water sources (Bauer et al. 2019b, 2022). Toxicity was observed in all samples that had a bitumen influence, regardless of whether this originated from natural or industrial OSPW sources. H. azteca and P. promelas were the organisms observed to be most sensitive to bitumen-derived organic mixtures, and L. cardium and D. magna were the organisms observed to be most sensitive to bitumen-associated inorganic mixtures.

This line of research has led to the discovery that naphthenic acid composition varies within and between sources (Marentette et al. 2015; Frank et al. 2016) and therefore expressing toxicity against total naphthenic acid concentration may not be accurate. Recent work has identified the toxicity of bitumen-influenced ground waters to be driven by the least and most polar fractions, the former of which contains the greatest relative abundance of oxygen containing compounds (which includes naphthenic acids).

Furthermore, acid extractable organics (AEOs) (organic chemicals, including naphthenic acids, that can be extracted from OSPW under acidic conditions) have long been attributed as the primary driver of toxicity in OSPW (Mackinnon and Boerger 1986); however, it was unknown if all naphthenic acids were of similar toxic potential. To address this, ECCC scientists led a study in which OSPW was obtained from 3 different sources, with one of those sources being sampled in consecutive years (Marentette et al. 2015; Bartlett et al. 2017). The AEOs (including naphthenic acids) were isolated from these 4 OSPW samples and their toxicity was evaluated along with 3 samples of CAS RN 1338-24-5 (extracted from petroleum distillates).  All of the samples of CAS RN 1338-24-5 were significantly more hazardous than any of the 4 AEOs (extracted from OSPW) to all of the tested species (P. promelas, H. azteca, V. fischeri, and L. cardium) (Marentette et al. 2015; Bartlett et al. 2017). However, other research conducted has also indicated that other compounds in OSPW need to be considered when assessing the toxicity of OSPW and other bitumen-influenced waters, because the inorganic mixtures within bitumen-influenced groundwaters were found to be of greater hazard or potency than any of the organic components to L. cardium and D. magna.

Development of certified reference materials and naphthenic acid standards

The objective of this research stream is to provide materials and data for the development of methods to accurately differentiate and quantify chemicals originating from anthropogenic (that is, OSPW) and natural bitumen sources. ECCC scientists developed a method to recover water-soluble bitumen organics, including naphthenic acids/AEOs, from natural and industrial sources on a preparative scale, described in Bauer et al. (2019a). This method is currently being used for the preparation of a bitumen-derived reference material from one of the three sources relevant to the oil sands: OSPW. To prepare this reference material, ten OSPW containment ponds were sampled from different locations and occasionally at different times (totalling 31 separate samples collected), itself representing an unprecedented sampling for the oil sands sector. The reference material generated from this work will be important for the accurate chemical and toxicological assessment of organic mixtures (that is, naphthenic acids) within water and biotic samples.

ECCC scientists have also undertaken custom synthesis of authentic standards of naturally occurring mono-aromatic naphthenic acid compounds proposed as OSPW seepage tracer compounds. While the structures of these tracer compounds have yet to be resolved, the synthetic work has resulted in a unique naphthenic acid standard that will assist with general analytical method development for naphthenic acids, as no such standards currently exist. It may be possible to offer these synthetic compounds as Certified Reference Materials, provided that a sufficient supply exists and that the purity of the standard could be assessed by the National Research Council. In complementary work, ECCC is working towards the development of analytical methodologies to use to quantify total naphthenic acids (Brunswick et al. 2015, 2016, 2017) and potentially track surface water plumes in the event of a tailings containment failure (Brunswick et al. 2020).

References

Barrow MP, Peru KM, Fahlman B, Hewitt LM, Frank RA, Headley JV. 2015. Beyond naphthenic acids: Environmental screening of water from natural sources and the Athabasca oil sands industry using atmospheric pressure photoionization Fourier Transform Ion Cyclotron Resonance mass spectrometry. J Am Soc Mass Spec. 26:1508-1521.

Bartlett AJ, Frank RA, Gillis PL, Parrott J., Marentette J, Headley JV, Peru K, Hewitt LM. 2017. Toxicity of naphthenic acids to invertebrates: Extracts from oil sands process-affected water versus commercial mixtures. Environ Poll. 227: 271-279.

Bauer AE, Frank RA, Headley JV, Milestone CB, Batchelor S, Peru KM, Rudy MD, Barrett SE, Vanderveen R, Dixon DG, et al. 2019a. A preparative method for the isolation and fractionation of dissolved organics from bitumen-influenced waters. Sci Total Environ. 671:587-597.

Bauer AE, Hewitt LM, Parrott JL, Bartlett AE, Gillis PL, Rudy MD, Vanderveen R, Barrett SE, Campbell SD, Brown L, et al. 2019b. The toxicity of organic fractions from aged oil sands process-affected water to aquatic species. Sci Total Environ. 669: 702-710.

Bauer AE, Hewitt LM, Roy JW, Parrott JL, Bartlett AJ, Gillis PL, Norwood WP, Rudy MD, Campbell SD, Rodrigues MR, et al. 2022. The acute toxicity of bitumen-influenced groundwaters from the oil sands region to aquatic organisms. Sci Total Environ. 848: 157676.

Brunswick P, Shang D, van Aggelen G, Hindle R, Hewitt LM, Frank RA, Haberl M, Kim M. 2015. Trace analysis of total naphthenic acids in aqueous environmental matrices by liquid chromatography/mass spectrometry-quadrupole time of flight mass spectrometry direct injection. J Chrom A. 1405:49-71.

Brunswick P, Hewitt LM, Frank RA, van Aggelen G, Kim M and Shang D. 2016. Specificity of high resolution analysis of naphthenic acids in aqueous environmental matrices. Anal Methods. 8:6764-6773.

Brunswick P, Hewitt LM, Frank RA, van Aggelen G, Kim M, Shang D. 2017. A traceable reference for direct comparative assessment of total naphthenic acids concentrations in commercial and acid extractable organic mixtures derived from oil sands process water. Environ Sci Health A. 52:274-280.

Brunswick P, Shang D, Frank RA, van Aggelen G, Kim M, Hewitt LM. 2020. Diagnostic naphthenic acid ratio analysis: A concept for the tracking of oil sands process-affected water in surface waters. Environ Sci Technol. 54:2228-2243.

Frank RA, Bickerton G, Roy JW, Rowland SJ, Headley JV, Scarlett AG, West CE, Peru KM, Conly M, Hewitt LM. 2014. Profiling oil sands mixtures from industrial developments and natural groundwaters for source identification. Environ Sci Technol. 48(5):2660-2670.

Frank RA, Milestone C, Kavanagh RJ, Headley JV, Rowland SJ, Scarlett AG, West CE, Peru KM, Hewitt LM. 2016. Assessing variability of acid extractable organics within two containments of oil sands process-affected water. Chemosphere. 160:303-313.

Frank RA, Bauer AE, Rudy MD, Vanderveen R, Batchelor S, Barrett SE, Milestone CB, Roy JW, Bickerton G, Peru KM, et al. 2021. Preparative isolation and fractionation of dissolved organics from natural and industrially derived bitumen-influenced groundwaters within the Athabasca River watershed. Sci Total Environ. 777:146022.

Headley JV, Barrow MP, Peru KM, Fahlman B, Frank RA, Bickerton G, McMaster M, Parrott J, Hewitt LM. 2011. Preliminary fingerprinting of Athabasca oil sands acids in environmental samples using Fourier transform ion cyclotron resonance mass spectrometry electrospray ionization. Rapid Commun Mass Spectrom. 25(13):1899-1909.

Headley JV, Peru KM, Frank RA, Martin JW, Hazewinkle RRO, Humphries D, Gurprasad NP, Hewitt LM, Muir DCG, Lindeman D, et al. 2013. Chemical fingerprinting of naphthenic acids and oil sands process waters – A review of analytical methods for environmental samples. J Environ Sci Health A. 48:1145-1163.

Hewitt LM, Roy JW, Rowland S, Bickerton G, DeSilva A, Headley JV, Milestone CB, Scarlett A, West C, Peru K, et al. 2020. Advances in distinguishing groundwater influenced by Oil Sands Process-affected Water (OSPW) from natural bitumen-influenced groundwaters. Environ Sci Technol. 54(3):1522-1532.

Lengger SK, Scarlett AG, West CE, Frank RA, Hewitt LM, Milestone CB, Rowland SJ. 2015. Use of the distributions of adamantane acids to profile short-term temporal and pond-scale spatial variations in the composition of OSPW. Environ Sci: Processes Impacts. 17:1415-1423.

MacKinnon MD, Boerger H. 1986. Description of two treatment methods for detoxifying oil sands tailings pond water. Water Pollution Research Journal of Canada. 21(4):496-512.

Marentette JR, Frank RA, Bartlett A, Gillis P, Hewitt LM, Peru K, Headley J, Brunswick P, Shang D, Parrott J. 2015. Toxicity of naphthenic acid fraction components extracted from fresh and aged oil sands process-affected waters, and commercial naphthenic acid mixtures, to fathead minnow (Pimephales promelas) embryos. Aquat Toxicol. 164:108-117.

Milestone CB, Sun C, Martin J, Bickerton G, Roy J, Frank RA, Hewitt LM. 2020.  Nontarget profiling of bitumen influenced waters for the identification of tracers unique to oil sands processed-affected water (OSPW) in the Athabasca watershed of Alberta, Canada. Rapid Commun Mass Spectrom. 35(3):e8984. 

Reinardy H, Scarlett AG, Henry TB, West CE, Hewitt LM, Frank RA, Rowland SJ. 2013. Aromatic naphthenic acids in oil sands process-affected water, resolved by GC×GC-MS, only weakly induce the gene for vitellogenin production in zebrafish (Danio rerio) larvae. Environ Sci Technol. 47: 6614-6620.

Rowland SJ, Pereira AS, Martin JW, Scarlett AG, West CE, Lengger S, Wilde M, Pureveen, J, Tegelaar E, Frank RA, et al. 2014. Mass spectral characterisation of a polar, esterified fraction of an organic extract of an oil sands process water. Rapid Commun Mass Spectrom. 28:2352-2362.

Rowland SJ, West CE, Jones D, Scarlett AG, Frank RA, Hewitt LM. 2011. Steroidal aromatic naphthenic acids in oil sands process-affected water: Structural comparisons with environmental estrogens. Environ Sci Technol. 45(22):9806-9815.

Roy JW, Bickerton G, Frank RA, Grapentine L, Hewitt LM. 2016. Assessing risks associated with constituents detected in shallow riparian groundwater near a tailings pond in the Athabasca oil sands region of northern Alberta, Canada. Groundwater. 51(4):545-558.

Scarlett AG, Reinardy HC, Henry TB, West CE, Frank RA, L.M. Hewitt, Rowland SJ. 2013. Acute toxicity of aromatic and non-aromatic fractions of naphthenic acids extracted from oil sands process-affected water to larval zebrafish. Chemosphere. 93: 415-420.

Wang Z, Yang C, Parrott J, Frank RA, Yang Z, Brown CE, Hollebone B, Landriault M, Fieldhouse B, Liu Y, et al. 2014. Forensic source differentiation of petrogenic, pyrogenic, and biogenic hydrocarbons in Canadian oil sands environmental samples. J Haz Mat. 271:166-177.

Wilde MJ, West CE, Scarlett AG, Lewis CA, Jones D, Frank RA, Hewitt LM, Rowland SJ. 2015. Bicyclic naphthenic acids in oil sands process water: Identification by comprehensive multidimensional gas chromatography-mass spectrometry. J Chrom A. 1378:74-87.

Workshop Report. A workshop to assess the current state-of-the-science and identify paths forward regarding analytical methods for monitoring ambient waters potentially influenced by bitumen in the Athabasca region. March 14, 2016, Edmonton, Alberta. 128p.