Biological test method for determining acute lethality of sediment to amphipods: appendices

Appendices

1. Members of the Inter-Governmental Aquatic Toxicity Group (as of October, 1998)
2. Environment Canada, Environmental Protection Service, Regional and Headquarters Offices
3. Members of the Scientific Advisory Group
4. Rhepoxynius abronius - Known Tolerance and Application Limits
5. Eohaustorius washingtonianus - Known Tolerance and Application Limits
6. Eohaustorius estuarius - Known Tolerance and Application Limits
7. Amphiporeia virginiana - Known Tolerance and Application Limits

Appendix A: Members of the Inter-Governmental Aquatic Toxicity Group (as of October, 1998)

Federal, Environment Canada

C. Blaise
Centre St. Laurent
Montreal, Quebec

S. Blenkinsopp
Environmental Technology Advancement Directorate
Edmonton, Alberta

C. Boutin
National Wildlife Research Centre
Hull, Quebec

C. Buday
Pacific Environmental Science Centre
North Vancouver, British Columbia

A. Chevrier
Marine Environment Division
Hull, Quebec

K. Day
National Water Research Institute
Burlington, Ontario

K. Doe
Environmental Conservation Branch
Moncton, New Brunswick

G. Elliott
Ecotoxicology Laboratory
Edmonton, Alberta

M. Fennell
Pacific Environmental Science Centre
North Vancouver, British Columbia

M. Harwood
Centre St. Laurent, Quebec

P. Jackman
Environmental Conservation Branch
Moncton, New Brunswick

R. Kent
Evaluation and Interpretation Branch
Hull, Quebec

N. Kruper
Ecotoxicology Laboratory
Edmonton, Alberta

D. MacGregor
Environmental Technology Centre
Gloucester, Ontario

D. Moul
Pacific Environmental Science Centre
North Vancouver, British Columbia

W.R. Parker
Atlantic Region
Dartmouth, Nova Scotia

L. Porebski
Marine Environment Division
Hull, Quebec

D. Rodrigue
Environmental Technology Centre
Gloucester, Ontario

R. Scroggins
Environmental Technology Centre
Gloucester, Ontario

A. Steenkamer
Environmental Technology Centre
Gloucester, Ontario

D. St.-Laurent
Quebec Region
Montreal, Quebec

G. van Aggelen
Pacific Environmental Science Centre
North Vancouver, British Columbia

R. Watts
Pacific Environmental Science Centre
North Vancouver, British Columbia

P. Wells
Atlantic Region
Dartmouth, Nova Scotia

W. Windle
Commercial Chemicals and Evaluation Branch
Hull, Quebec

S. Yee
Pacific Environmental Science Centre
North Vancouver, British Columbia

Federal, Atomic Energy Control Board

P. Thompson
Radiation and Protection Division
Fed. Natural Resources
Ottawa, Ontario

Provincial

S. Abernethy
Ministry of Environment and Energy
Etobicoke, Ontario

C. Bastien
Ministre de l'environnement et de la faune
Ste-Foy, Quebec

D. Bedard
Ministry of Environment and Energy
Etobicoke, Ontario

M. Mueller
Ministry of Environment and Energy
Etobicoke, Ontario

C. Neville
Ministry of Environment and Energy
Etobicoke, Ontario

D. Poirier
Ministry of Environment and Energy
Etobicoke, Ontario

G. Westlake
Ministry of Environment and Energy
Etobicoke, Ontario

Appendix B: Environment Canada, Environmental Protection Service, Regional and Headquarters Offices

Headquarters
351 St. Joseph Boulevard
Place Vincent Massey
Hull, Quebec
K1A 0H3

Atlantic Region
15th Floor, Queen Square
45 Alderney Drive
Dartmouth, Nova Scotia
B2Y 2N6

Quebec Region
14^th Floor
105 McGill Street
Montreal, Quebec
H2Y 2E7

Ontario Region
4905 Dufferin St., 2nd Floor
Downsview, Ontario
M3H 5T4

Western and Northern Region
Room 210, Twin Atria No. 2
4999 - 98th Avenue
Edmonton, Alberta
T6B 2X3

Pacific and Yukon Region
224 Esplanade Street
North Vancouver, British Columbia
V7M 3H7

Appendix C: Members of the Scientific Advisory Group

SAG Members

Dr. Peter Chapman
EVS Environment Consultants
195 Pemberton Avenue
North Vancouver, British Columbia  V7P 2R4
Phone: (604) 986-4331
Fax: (604) 662-8548

Ms. Chantal Côté
Beak Consultants Ltée.
Carré Dorval
455 Boul. Fénélon, Suite 104
Dorval, Quebec  H9S 5T8
Phone: (514) 631-5544
Fax: (514) 631-5588

Mr. Ken Doe
Environment Canada
Toxicology Laboratory
Environmental Quality Section, ECB
Environmental Science Centre
P.O. Box 23005
Moncton, New Brunswick  E1A 6S8
Phone: (506) 851-3486
Fax: (506) 851-6608

Ms. Michelle Fennell
Environment Canada
Pacific Environmental Science Centre
2645 Dollarton Highway
North Vancouver, British Columbia  V7H 1V2
Phone: (604) 924-2516
Fax: (604) 924-2554

Ms. Carol Harris
Harris Industrial Testing Services Ltd.
P.O. Box 92, Milford Station
Hants County, Nova Scotia  BON 1YO
Phone: (902) 758-2638
Fax: (902) 758-3064

Ms. Emilia Jonczyk
Beak Consultants Limited
Toxicology Section
14 Abacus Road
Brampton, Ontario  L6T 5B7
Phone: (905) 794-2325
Fax: (905) 794-2338

Ms. Deanna Lee
B.C. Ministry of Environment, Lands & Parks
Lower Mainland Region
10470 -152nd Street
Surrey, British Columbia  V3R 0R3
Phone: (604) 582-5266
Fax: (604) 582-5335

Ms. Cathy McPherson
EVS Environment Consultants
195 Pemberton Avenue
North Vancouver, British Columbia  V7P 2R4
Phone: (604) 986-4331
Fax: (604) 662-8548

Ms. Mary Murdoch
Jacques Whitford Environment Ltd.
607 Torbay Road
St. John’s, Newfoundland and Labrador  A1A 4Y6
Phone: (709) 576-1458
Fax: (709) 576-2126

Ms. Linda Porebski
Environment Canada
Marine Environment Division
12th Floor
Place Vincent Massey
351 St. Joseph Boulevard
Hull, Quebec  K1A 0H3
Phone: (819) 953-4341
Fax: (819) 953-0913

Mr. Phil Riebel
P. Riebel and Associates
30 Birch Hill Street
Baie d’Urfe, Quebec  H9X 3H7
Phone: (514) 457-9452
Fax: (514) 457-3302

Ms. Jennifer Stewart
EVS Environment Consultants
195 Pemberton Avenue
North Vancouver, British Columbia  V7P 2R4
Phone: (604) 986-4331
Fax: (604) 662-8548

Ms. Dixie Sullivan
Environment Canada
Pacific and Yukon Region, EPS
224 West Esplanade Street
North Vancouver, British Columbia  V7M 3H7
Phone: (604) 666-2730
Fax: (604) 666-7294

Dr. Kok-Leng Tay
Environment Canada
Marine Disposal Division, EPS
5th Floor, Queen Square
45 Alderney Drive
Dartmouth, Nova Scotia  B2Y 2N6
Phone: (902) 426-8304
Fax: (902) 426-3897

Mr. Graham van Aggelen
Environment Canada
Pacific Environmental Science Centre
2645 Dollarton Highway
North Vancouver, British Columbia  V7H 1V2
Phone: (604) 924-2513
Fax: (604) 924-2554

Scientific Authorities

Mr. Rick Scroggins
Environment Canada
Method Development and Application Section
Environmental Technology Centre
3439 River Road South
Gloucester, Ontario  K1A 0H3
Phone: (613) 990-8569
Fax: (613) 990-0173

Mr. Jim Osborne
Environment Canada
Marine Environment Division
12th Floor
Place Vincent Massey
351 St. Joseph Boulevard
Hull, Quebec  K1A 0H3
Phone: (819) 953-2265
Fax: (819) 953-0913

Consultant

Dr. Don McLeay
McLeay Environmental Ltd.
2999 Spring Bay Road
Victoria, British Columbia  V8N 5S4
Phone: (250) 472-2608
Fax: (250) 472-2609

Appendix D: Rhepoxynius abronius - Known Tolerance and Application Limits

Tolerance Limits for Reference Toxicant

Since 1988, Environment Canada’s Atlantic and Pacific regional laboratories have been undertaking “water-only” 96-h LC50 reference toxicity tests with each group of field-collected  Rhepoxynius abronius used in 10-day sediment toxicity tests. Results for these tests (n = 15), performed according to Environment Canada (1992) and Section 5 herein, have been plotted and summarized as warning limits (geometric mean ± 2 SD; Doe, 1997; Fennell, 1997). These summary values (Table D.1), should help guide inexperienced laboratories in selecting an appropriate range of test concentrations for undertaking reference toxicity tests with this species; and are useful for comparative purposes. Similar tolerances of R. abronius to cadmium, in 96-h “water-only” LC50s, have been reported elsewhere (e.g., DeWitt et al., 1989).

Tolerance and Application Limits for Salinity

R. abronius is very intolerant of low salinity. Swartz et al. (1985) reported that the 10-day survival of this species was reduced significantly when porewater salinity was 18.8‰ , and that no amphipods survived at salinities of 9.9‰ and 12.3‰. In a separate series of studies, Swartz et al. (1985) determined that the mean survival of R. abronius at interstitial salinity of 15‰ was significantly less than at 25‰. Based on their studies of salinity tolerance, these authors concluded “Conservatively, interstitial salinity of test sediment should be at least 25‰ before salinity effects on survival can be discounted”. They also concluded (Swartz et al., 1985) “The sensitivity of R. abronius to salinity effectively limits the application of this test procedure to field sediment samples collected from the coastal zone and higher salinity portions of estuaries. Attempts to raise interstitial salinity by adding or sieving into higher salinity water are likely to change the toxicological properties of the sample.”

Lee and Fennell (1995) re-examined the salinity tolerance of R. abronius. Ten-day survival tests were performed using Target^TM “superfine” (≤0.5 mm) sand and seawater with overlying salinity adjusted to values of 15‰, 20‰, 25‰, 30‰, 35‰, 40‰, and 45‰. Mean survival was 70 to 83% at salinities ranging from 25 to 35‰; these values did not differ significantly. Survival at 15‰ was 0%, and at 20‰ was only 31%. Mean survival rates at 40‰ and 45‰ were 32% and 39%, respectively.

USEPA (1994a) states that a “salinity tolerance range” of 25 to 32‰ is indicated for this species. For 10-day tests, USEPA (1994a) has specified an “application limit” of >25‰ for the overlying water.

Based on the findings of Swartz et al. (1985) and Lee and Fennell (1995), it is evident that R. abronius is tolerant of salinities ranging within 25‰ to 35‰. An R. abronius application limit of 25‰ to 35‰ is specified here for porewater salinity (see Table D.1 and Section 2.6). Test material with porewater salinity less than 25‰ must not be used for a 10-day sediment toxicity test with this species. Rather, such material should be evaluated for toxicity using another suitable species which is tolerant of low-salinity water (e.g., Eohaustorius estuarius; see Appendix F).

Tolerance Limits for High Organic Content

R. abronius is tolerant of substantial enrichment of sediment. Ten-day tests performed by Swartz et al. (1985) have shown that mean survival rates in samples of field-collected “clean” sediment with a total volatile solids content as high as 18% can be equivalent to that for control groups. Paine and McPherson (1991a) reported that 10-day survival rates of 89 to 92% were achieved when this species was held in a sample of field-collected sediment with a total organic carbon content of 10%, and that similar survival rates were found for uncontaminated sediment with a total organic content of 4%. Results for 10-day tests with field-collected sediment from 12 inlets off the west coast of the British Columbia mainland showed that sample survival rates (ranging from 35 to 88%) and total organic carbon content (ranging from 0.4 to 4.8%) were poorly correlated (R = 0.10) (Sullivan et al., 1998a).

No studies with formulated sediments are available which show the effect of elevated levels of organic carbon on the 10-day survival rate for this species. Studies with commercial formulations of silica sand (Tay et al., 1998) demonstrate that R. abronius can survive well for 10 days in the absence of any appreciable organic carbon content.

It is concluded that this species can tolerate samples of test material with a total organic carbon content of 18% or less. However, the upper limit that can be tolerated without affecting 10-day survival is not known. No application limit for total organic carbon seems necessary or appropriate.

Tolerance and Application Limits for Grain Size

The influence of sediment grain size on the 10-day survival rates for R. abronius in sediment toxicity tests has been considered in numerous studies. Most attention has focused on the influence of sediment fines (i.e., particles <0.063 mm), although the tolerance of this species to coarse-grained sediment has also been investigated (Lee, 1994; Tay et al., 1998).

Some studies have demonstrated high 10-day survival rates for R. abronius exposed to field-collected reference sediments with a high percentage of fines and a high percentage of clay. For instance, Swartz et al. (1985) reported a mean 10-day survival rate of 90% for R. abronius held in a sample of sediment comprised of 10% sand, 37% silt, and 53% clay (90% fines). Similarly, Long et al. (1990) found a mean 10-day survival rate of 91% for R. abronius held in a sample of field-collected sediment with 48.3% silt and 48.4% clay (i.e., 96.7% fines); and McLeay et al. (1991) noted 10-day survival rates of 81 to 91% for amphipods held in a sample of reference sediment with 99% fines. Conversely, McLeay et al. (1991) found reduced survival rates in another sample of reference sediment from a separate site with 99% fines. Sullivan et al. (1998b) reported a high (92%) 10-day survival rate for R. abronius held in a sample of field-collected sediment with 35% clay and 84% fines. Pinza et al. (1997) noted a mean 10-day survival rate of >90% when R. abronius were held in a sample of field-collected sediment comprised of 36% clay and 90% fines.

A number of studies have shown some reduction in 10-day survival rates when this species is held in fine-grained (predominantly silt and clay) field-collected reference sediment, or in commercial formulations of clay or silica sand:clay mixtures with a high percentage of fines. In a series of tests with various sand or clay formulations having markedly different grain size characteristics, Lee (1994) found that survival of R. abronius was highly negatively correlated (R = -0.82) with percent clay. Tay et al. (1998) demonstrated that, for this species, mean 10-day survival rates were reduced from a control value of 98% to ≤71% when sand:clay mixtures contained ≥22% clay. Similarly, Tay et al. (1998) found that a sample of reference sediment with 17% clay and 82% fines reduced survival to 75%. In 10-day tests with 12 samples of west coast sediments distant from and apparently unaffected by anthropogenic activities, Sullivan et al. (1998a) found that mean survival rates were <60% for four of seven samples with ≥90% fines; additionally, mean survival rates were <60% for five of eight samples with ≥40% clay.

Some (slight) reduction in tolerance of this species to very coarse-grained sand is evident from two series of studies with various sand:clay mixtures. Lee (1994) observed a slight reduction in mean 10-day survival from 90% (controls) to 84% for groups held in a commercial formulation (“silica sand no. 2") comprised of ~92% very coarse-grained (>1.0 mm) sediment. Tay et al. (1998) reported a similar finding for this mixture, with a mean survival rate of 77%.

In consideration of the evidence of some intolerance of R. abronius to a high percentage of fines, USEPA (1994a) has designated an application limit of <90% fines for this species. This application limit seems reasonable, and is adopted herein (see Table D.1 and Section 2.6). Additionally, a second application limit of <40% clay seems reasonable, and is to be applied as part of this reference method. Accordingly, test material with ≥90% fines and/or ≥40% clay content must not be used for a 10-day sediment toxicity test with R. abronius according to this reference method. Rather, another test species more tolerant of fine-grained sediment (e.g., Eohaustorius estuarius; see Appendix F) should be used, provided the application limits for this species are not exceeded. No application limit for very coarse-grained (i.e., >1.0 mm) material is necessary or appropriate for this species (Section 2.6).

Tolerance Limits for Ammonia

Sims and Moore (1995a) undertook a literature review for concentrations of ammonia in sediment pore water, as well as for known toxicity of ammonia to marine and freshwater invertebrates and fish. The authors concluded “The comparison of reported exposure and effects concentrations suggests significant potential for ammonia toxicity in dredged material bioassays”.

Tay et al. (1998) measured the tolerance of R. abronius to ammonia in both a 96-h “water-only” test and a 10-day “spiked sediment” test. In each instance, LC50s were calculated and expressed based on both measured total ammonia and calculated (Bower and Bidwell, 1978) un-ionized ammonia concentrations. Values derived for these tests are shown in Table D.1. Results show similar respective values (i.e., as total ammonia or un-ionized ammonia) for the 96-h “water-only ammonia” and 10-day “spiked sediment/porewater ammonia” tests.

Tay et al. (1998) found a 96-h “water-only” LC50 for total ammonia of 65.0 mg N/L. This value is identical to the water-only 96-h LC50 for total ammonia of 65 mg N/L reported by Kohn et al. (1994), and similar to the mean 96-h LC50 (n = 6) for total ammonia of 58 mg N/L reported by Pinza et al. (1997). The 96-h LC50 of 1.1 mg N/L for un-ionized ammonia calculated by Tay et al. (1998) is also similar to the value for un-ionized ammonia of 1.3 mg N/L given in Kohn et al. (1994). Other than those in Tay et al. (1998) (see Table D.1), no reports of 10-day LC50s for ammonia (total or un-ionized) were found in the literature reviewed for this species.

USEPA (1994a) presents R. abronius application limits for both total ammonia and un-ionized ammonia in sediment. These values, identified as “water column no-effect concentrations”, are <30 mg NH₃/L (= <24.7 mg N/L) as total ammonia, and <0.4 mg NH₃/L (= <0.3 mg N/L) as un-ionized ammonia (pH 7.7).

No application limits are imposed here for total or un-ionized ammonia in test materials (see Table D.1), inasmuch as the ammonia concentrations in samples under investigation might be elevated due to anthropogenic and/or natural causes, and might be an integral toxic component deserving of consideration using this species and test method.

Tolerance Limits for Hydrogen Sulphide

Hydrogen sulphide can be elevated in sediment pore water to levels toxic to amphipods and other benthic life (Sims and Moore, 1995b). Based on a literature review of measured porewater concentrations of hydrogen sulphide and its known toxicity to marine or freshwater organisms, these authors concluded “The comparison of reported exposure and effects concentrations suggests a strong potential for hydrogen sulphide toxicity in dredged material bioassays”. To date, however, no definitive data are available showing the limits of hydrogen sulphide in pore water or overlying water (i.e., results of “water-only LC50s) that R. abronius can tolerate.

Historical Control Performance

For more than a decade, many North American laboratories have undertaken numerous 10-day sediment toxicity tests and 96-h water only reference toxicity tests with this species. Mean 10-day survival rates in control sediment have routinely been ≥90% in the majority of instances. Additionally, the water only controls for reference toxicity tests have typically achieved ≥90% survival during 96-h exposures. Accordingly, minimum mean 10-day survival rates of ≥90% in control sediment, and 96-h survival rates of ≥90% in the control/dilution water used in reference toxicity tests, are considered to be readily achievable and suitable limits on which to base criteria for valid sediment and reference toxicity tests using R. abronius (see Sections 4.6 and 5).

Appendix E: Eohaustorius washingtonianus - Known Tolerance and Application Limits

Tolerance Limits for Reference Toxicant

Environment Canada’s Pacific regional laboratory has been undertaking “water-only” 96-h LC50 reference toxicity tests with each group of field-collected Eohaustorius washingtonianus used in 10-day sediment toxicity tests. Results for 29 tests performed from November 1994 to April 1997 have been plotted and summarized as warning limits (geometric mean ± 2 SD; Fennell, 1997) according to Environment Canada (1992) and Section 5 herein. These summary values (Table E.1) should help guide inexperienced laboratories in selecting an appropriate range of test concentrations for undertaking reference toxicity tests with this species; and are useful for comparative purposes. Similar tolerances of E. washingtonianus to cadmium, in 96-h “water-only” LC50s performed at other laboratories, have been reported elsewhere (Paine and McPherson, 1991b).

Tolerance and Application Limits for Salinity

Lee and Fennell (1995) reported the findings of a series of ten-day survival tests which were undertaken to determine the tolerance of E. washingtonianus to a range of concentrations of porewater salinity. Each assay was performed using dry Target^TM “superfine” (≤0.5 mm) sand and seawater with overlying salinity adjusted to values of 15‰, 20‰, 25‰, 30‰, 35‰, 40‰, and 45‰. Mean 10-day survival was not significantly different throughout the range 15 to 35‰; mean values within this range were 83 to 94% and no salinity-dependent trend was apparent. At salinities of 40‰ and 45‰, mean survival rates were significantly lower (i.e., 60% and 43%, respectively). No other studies are available which report the salinity tolerance of this species.

Based on the findings of Lee and Fennell (1995), it is evident that E. washingtonianus is tolerant of salinities ranging within 15 to 35‰. An E. washingtonianus application limit of 15 to 35‰ is specified here for porewater salinity (see Table E.1 and Section 2.6). Test material with porewater salinity less than 15‰ must be evaluated for toxicity using another suitable species which is more tolerant of low-salinity water (e.g., Eohaustorius estuarius; see Appendix F).

Tolerance Limits for High Organic Content

No studies with formulated sediments are available which demonstrate the effect of high organic carbon content on the 10-day survival rate for this species. Results for tests with uncontaminated reference sediments are also not enlightening in this respect, inasmuch as no reports are available which show 10-day survival rates for E. washingtonianus when exposed to samples with organic content greater than 5%. Studies with commercial formulations of silica sand (Tay et al., 1998) demonstrate that E. washingtonianus can survive well for 10 days in the absence of any appreciable organic carbon content.

Results for 10-day tests with “clean” reference sediment from 12 inlets off the west coast of the British Columbia mainland showed that sample survival rates (ranging from means of 10 to 95%) and total organic carbon content (ranging from 0.4 to 4.8%) were poorly correlated (R = 0.23) (Sullivan et al., 1998a). Sullivan et al. (1998a) found a high mean 10-day survival rate of 80% in a sample with 4.8% organic content. Similarly, Lee et al. (1995) noted E. washingtonianus survival rates as high as 80% in field-collected sediment with 4.5% organic content.

It appears that E. washingtonianus can tolerate samples of test material with a total organic carbon content of 5% or less, but the upper limit that can be tolerated without affecting 10-day survival is not known. No application limit for total organic carbon seems necessary or appropriate.

Tolerance and Application Limits for Grain Size

Two studies by Environment Canada researchers (Lee, 1994; Tay et al., 1998) have examined the influence of sediment grain size on the 10-day survival of E. washingtonianus. Each of these studies was undertaken using various mixtures or commercial formulations of silica sand and clay. The findings of Lee (1994) demonstrated that mean survival rates were decreased to 9% or 55% when this species was exposed to silica sand formulations with ~92% or ~27%, respectively, of very coarse-grained (i.e., >1.0 mm) sediment. Tay et al. (1998) also demonstrated that this species was intolerant of a high percentage of very coarse-grained sediment, inasmuch as mean 10-day survival was reduced from a control value of 98% to 60% when amphipods were held in “silica sand no. 2", comprised of ~92% very coarse-grained (i.e., >1.0 mm) sediment. Based on these findings, an E. washingtonianus application limit of <25% very coarse-grained sediment is to be applied as part of this reference method (see Table E.1 and Section 2.6). Accordingly, test material with ≥25% very coarse-grained (i.e., >1.0 mm) sediment must not be used for a 10-day sediment toxicity test with E. washingtonianus according to this reference method. Rather, another test species more tolerant of a high percentage of very coarse-grained sediment (e.g., R. abronius, E. estuarius, or A. virginiana; see Appendices D, F, and G) should be used.

The studies with commercial formulations of sand, clay, or sand:clay mixtures by Lee (1994) and Tay et al. (1998) each demonstrate that E. washingtonianus is very intolerant of a high percentage of fine-grained (<0.063 mm) material. Lee (1994) found a mean 10-day survival rate of only 14% when this species was exposed to a formulation of 95% fines and 59% clay; and survival was 0% for a formulation with 99% fines and 84% clay. Tay et al. (1998) found that mean 10-day survival rates in sand:clay mixtures declined progressively with increasing clay content, from 43% survival for 22% clay (31% fines) to only 17% survival for 64% clay (99% fines).

A number of studies with “clean” field-collected reference sediments support the findings for commercial sand/clay formulations that this species is intolerant of a high percentage of fine-grained material. In 10-day tests with 12 samples of west coast sediments distant from and apparently unaffected by anthropogenic activities, Sullivan et al. (1998a) found that mean survival rates were ≤60% for seven of eight samples with ≥80% fines; additionally, mean survival rates were ≤60% for eight of ten samples with ≥30% clay. A reasonably-high negative correlation (R = -0.76) between % clay and mean percent survival was found for these sediments. Lee et al. (1995) compared data for mean percent survival of E. washingtonianus in 34 samples of reference or contaminated field-collected sediment, and found that all samples with clay content ≥20% (20 of 34) had ≤80% survival. Similarly, these data showed that all samples with ≥55% fines (i.e., particles <0.063 mm) had ≤80% survival. For these (Lee et al., 1995) data, survival rates were negatively correlated with clay content (R = -0.85).

Given the apparent intolerance of E. washingtonianus to a high percentage of fines, an E. washingtonianus application limit of <80% fines is designated here (see Table E.1 and Section 2.6). Additionally, a second application limit of <20% clay seems reasonable, and is to be applied as part of this reference method. Accordingly, test material with ≥80% fines and/or ≥20% clay content must not be used for a 10-day sediment toxicity test with E. washingtonianus according to this reference method. Rather, another test species more tolerant of fine-grained sediment (e.g., Eohaustorius estuarius; see Section 2.6) should be used, provided that grain size characteristics are within the application limits for this species.

Tolerance Limits for Ammonia

Sims and Moore (1995a) undertook a literature review for concentrations of ammonia in sediment pore water, as well as for known toxicity of ammonia to marine and freshwater invertebrates and fish. The authors concluded “The comparison of reported exposure and effects concentrations suggests significant potential for ammonia toxicity in dredged material bioassays”.

Tay et al. (1998) measured the tolerance of E. washingtonianus to ammonia in both a 96-h “water-only” test and a 10-day “spiked sediment” test. In each instance, LC50s were calculated and expressed based on both measured total ammonia and calculated (Bower and Bidwell, 1978) un-ionized ammonia concentrations. Values derived for these tests are shown in Table E.1. Results show similar respective values (i.e., as total ammonia or un-ionized ammonia) for the 96-h “water-only ammonia” and 10-day “spiked sediment/porewater ammonia” tests. No other studies are available which show the acute lethal tolerance of this species to ammonia.

No application limits are imposed here for total or un-ionized ammonia in test materials (see Table E.1), inasmuch as the ammonia concentrations in samples under investigation might be elevated due to anthropogenic and/or natural causes, and might be an integral toxic component deserving of consideration using this species and test method.

Tolerance Limits for Hydrogen Sulphide

Hydrogen sulphide can be elevated in sediment pore water to levels toxic to amphipods and other benthic life (Sims and Moore, 1995b). Based on a literature review of measured porewater concentrations of hydrogen sulphide and its known toxicity to marine or freshwater organisms, these authors concluded “The comparison of reported exposure and effects concentrations suggests a strong potential for hydrogen sulphide toxicity in dredged material bioassays”. To date, however, no definitive data are available which show the limits of hydrogen sulphide in pore water or overlying water (i.e., results of “water-only LC50s) which E. washingtonianus can tolerate.

Historical Control Performance

Environment Canada’s Pacific regional laboratory has undertaken 37 separate series of 10-day sediment toxicity tests and associated 96-h water only reference toxicity tests with E. washingtonianus since late 1994. Mean 10-day survival rates in control sediment averaged 94%, and were consistently ≥85% for each test; although 12.9% of the tests failed to achieve ≥90% control survival (Fennell, 1998). For the associated reference toxicity tests, all but 5.4% of the control groups achieved ≥85% survival; whereas 13.5% of these tests failed to attain ≥90% control survival (Fennell, 1998). Given this historical control performance, minimum mean 10-day survival rates of ≥85% in control sediment, and 96-h survival rates of ≥85% in the control/dilution water used in reference toxicity tests, are considered to be readily achievable and suitable limits on which to base criteria for valid sediment and reference toxicity tests using E. washingtonianus (see Sections 4.6 and 5).

Appendix F: Eohaustorius estuarius - Known Tolerance and Application Limits

Tolerance Limits for Reference Toxicant

Environment Canada’s Atlantic regional laboratory has been undertaking “water-only” 96-h LC50 reference toxicity tests with each group of field-collected Eohaustorius estuarius used in 10-day sediment toxicity tests. Results for ten tests, performed according to Environment Canada (1992) from November 1992 to May 1997, have been plotted and summarized as warning limits (geometric mean ± 2 SD; Doe, 1997). These summary values (Table F.1) should help guide inexperienced laboratories in selecting an appropriate range of test concentrations for undertaking reference toxicity tests with this species; and are useful for comparative purposes.

Other reports of findings for water-only reference toxicity tests using cadmium and E. estuarius are available in the literature. DeWitt et al. (1989) calculated a 96-h LC50 of 7.4 mg Cd/L; and Swartz et al. (1994) presented a value of 16.9 mg Cd/L. An interlaboratory study of the performance of 10-day sediment toxicity tests using this and other species of estuarine or marine amphipods, which involved eight laboratories and included a water-only toxicity test with cadmium by each, found a mean 96-h LC50 of 8.4 mg Cd/L for E. estuarius, with values for differing laboratories ranging from 4.8 to 11.2 mg Cd/L. These reported values are in keeping with those determined by Environment Canada’s Atlantic regional laboratory (see Table F.1).

Tolerance and Application Limits for Salinity

E. estuarius is a euryhaline species that is very tolerant of a wide range of salinities. DeWitt et al. (1989) found that mean survival rates were consistently >95% at all salinities tested, in a series of 10-day tests where groups of E. estuarius were exposed to control sediment with porewater salinity adjusted to values ranging from 2 to 28‰. A subsequent unpublished study cited in USEPA (1994a) has shown that this species can tolerate salinities up to and including 34‰.

USEPA (1994a) states that a “salinity tolerance range” of 2 to 34‰ is indicated for this species. For 10-day sediment toxicity tests, USEPA (1994a) has specified an “application limit” of 0 to 34‰ for the overlying water.

Based on the known salinity tolerance range for this species, an E. estuarius application limit of 2 to 35‰ is specified here for porewater salinity (see Table F.1 and Section 2.6).

Tolerance Limits for High Organic Content

No studies with formulated sediments are available which demonstrate the effect of elevated levels of organic carbon on the 10-day survival rate for this species. Studies with commercial formulations of silica sand (Tay et al., 1998) demonstrate that E. estuarius can survive well for 10 days in the absence of any appreciable organic carbon content. One study with a sample of field-collected sediment high in total organic carbon content (12.4%) showed that E. estuarius could tolerate this degree of enrichment (mean 10-day survival, 84%; Paine and McPherson, 1991a).

It is known that E. estuarius can tolerate samples of test material with a total organic carbon content of 12% or less; however, the upper limit that can be tolerated without affecting 10-day survival, is not known. No application limit for total organic carbon seems necessary or appropriate.

Tolerance and Application Limits for Grain Size

E. estuarius is tolerant of sediments with a wide range of grain size characteristics. Ten-day tests using a range of commercial formulations of silica sand, clay, or sand:clay mixtures with diverse grain sizes demonstrated that this species can show high survival rates in both coarse-grained and fine-grained sediments (Tay et al., 1998). For instance, the mean 10-day survival rate in a sample of 100% silica sand comprised of ~27% very coarse-grained material (i.e., particles >1.0 mm) was 87%. However, mean 10-day survival was somewhat lower (71%) when amphipods of this species were held in ~92% very coarse-grained (>1.0 mm) sediment. Based on these findings, an E. estuarius application limit of <90% very coarse-grained sediment is to be applied as part of this reference method (see Table F.1 and Section 2.6. Accordingly, test material with ≥90% very coarse-grained (i.e., >1.0 mm) sediment must not be used for a 10-day sediment toxicity test with E. estuarius according to this reference method. Rather, another test species more tolerant of a high percentage of very coarse-grained sediment (e.g., R. abronius or A. virginiana; see Appendices D and G) should be used.

The tolerance of E. estuarius to commercial formulations of fine-grained material was shown by Tay et al. (1998) to be high, with mean survival rates of ≥82% for silica:clay mixtures with up to 57% clay and 79% fines. Some reduction in tolerance was evident, however, for a mixture with 64% clay and 99% fines, in which the mean survival rate was 74% (Tay et al., 1998).

Results for 10-day toxicity tests with E. estuarius exposed to 42 samples of uncontaminated field sediment showed a slight decline in survival rate with an increasing percentage of fines; although correlations of survival versus percent fines (R = -0.22) and survival versus percent clay (R = -0.25) were low (DeWitt et al., 1989). These tests, which included a high percentage of samples with >90% fines, showed an overall mean 10-day survival rate of 94.4%. Based on this and similar studies, USEPA (1994a) indicated that 10-day sediment toxicity tests with E. estuarius could be applied to sediments with a full range of grain size characteristics (unlike for R. abronius, for which an application limit of <90% fines was specified).

The E. estuarius application limit of “full range” (i.e., 0 to 100%) for percent fines presented in USEPA (1994a) seems reasonable without conflicting data, and is adopted herein (see Table F.1 and Section 2.6). Thus test sediments comprised of ≤100% fines may be included in 10-day sediment toxicity tests with this species. Given the findings by Tay et al. (1998) which demonstrate some reduction in survival of this species when exposed to commercial sand:silt:clay mixtures with a mean of 60% clay, an E. estuarius application limit of <70% clay is to be applied as part of this reference method. Accordingly, test material with ≥70% clay content must not be used in a 10-day sediment toxicity test with E. estuarius according to this reference method.

Tolerance Limits for Ammonia

Sims and Moore (1995a) undertook a literature review for concentrations of ammonia in sediment pore water, as well as for known toxicity of ammonia to marine and freshwater invertebrates and fish. The authors concluded “The comparison of reported exposure and effects concentrations suggests significant potential for ammonia toxicity in dredged material bioassays”.

Tay et al. (1998) measured the tolerance of E. estuarius to ammonia in both a 96-h “water-only” test and a 10-day “spiked sediment” test. In each instance, LC50s were calculated and expressed based on both measured total ammonia and calculated (Bower and Bidwell, 1978) un-ionized ammonia concentrations. Values derived for these tests are shown in Table F.1. Results for the respective values (i.e., as total ammonia or un-ionized ammonia) indicate somewhat greater tolerance of E. estuarius to ammonia in the 96-h “water-only” test, relative to that in the “spiked-sediment” test.

Tay et al. (1998) reported a 96-h “water-only” LC50 for total ammonia of 156 mg N/L. This value does not differ markedly from the 96-h water-only LC50 for total ammonia of 104 mg N/L determined for this species by Kohn et al. (1994), as well as that (i.e., 144 mg N/L) reported by Bailey et al. (1997). The 96-h LC50 of 2.2 mg N/L for un-ionized ammonia calculated by Tay et al. (1998) for E. estuarius is very similar to that (i.e., 2.1 mg N/L) calculated by Kohn et al. (1994), although somewhat higher than that (i.e., 0.8 mg N/L) determined by Bailey et al. (1997).

USEPA (1994a) presents E. estuarius application limits for both total ammonia and un-ionized ammonia in sediment. These values, identified as “water column no-effect concentrations”, are <60 mg NH₃/L (= <49.4 mg N/L) as total ammonia, and <0.8 mg NH₃/L (= <0.7 mg N/L) as un-ionized.

No application limits are imposed here for total or un-ionized ammonia in test materials (see Table F.1), inasmuch as the ammonia concentrations in samples under investigation might be elevated due to anthropogenic and/or natural causes, and might be an integral toxic component deserving of consideration using this species and test method.

Tolerance Limits for Hydrogen Sulphide

Hydrogen sulphide can be elevated in sediment porewater to levels toxic to amphipods and other benthic life (Sims and Moore, 1995b). Based on a literature review of measured porewater concentrations of hydrogen sulphide and its known toxicity to marine or freshwater organisms, these authors concluded “The comparison of reported exposure and effects concentrations suggests a strong potential for hydrogen sulphide toxicity in dredged material bioassays”. To date, however, no definitive data are available showing the limits of hydrogen sulphide in porewater or overlying water (i.e., results of “water-only” LC50s) that E. estuarius can tolerate.

Historical Control Performance

Canadian and U.S. laboratory personnel have undertaken numerous 10-day sediment toxicity tests and 96-h water only reference toxicity tests with this species. Mean 10-day survival rates in control sediment have routinely been ≥90% in the majority of instances. Additionally, the water only controls for reference toxicity tests have typically achieved ≥90% survival during 96-h exposures. Accordingly, minimum mean 10-day survival rates of ≥90% in control sediment, and 96-h survival rates of ≥90% in the control/dilution water used in reference toxicity tests, are considered to be readily achievable and suitable limits on which to base criteria for valid sediment and reference toxicity tests using E. estuarius (see Sections 4.6 and 5).

Appendix G: Amphiporeia virginiana - Known Tolerance and Application Limits

Tolerance Limits for Reference Toxicant

Since 1991, Environment Canada’s Atlantic regional laboratory has been undertaking “water-only” 96-h LC50 reference toxicity tests with each group of field-collected Amphiporeia virginiana used in 10-day sediment toxicity tests. Results for these tests (n = 18), performed at 10°C according to Environment Canada (1992), have been plotted and summarized as warning limits (geometric mean ± 2 SD; Doe, 1997). These summary values (Table G.1) should help guide inexperienced laboratories in selecting an appropriate range of test concentrations for undertaking reference toxicity tests with this species; and are useful for comparative purposes. No reports are available which show the tolerance of A. virginiana to cadmium in 96-h “water-only” LC50s performed at other laboratories.

Tolerance and Application Limits for Salinity

Wade and Doe (1992) investigated the tolerance of A. virginiana to differing salinities, in a series of 10-day “water-only” survival tests. Mean 10-day survival was 100% at test salinities averaging 30‰ and 25‰, and 80% at salinities averaging 20‰ and 15‰. Only two of ten animals (20%) survived a 10-day exposure to 11‰ salinity; all amphipods exposed to mean salinities of 5‰ or 0‰ died during the 10-day test. A. virginiana has also been collected from sites where the salinity of sediment pore water was as high as 35‰ (Doe and Jackman, 1998). No other studies are available which report the salinity tolerance of this species.

Based on the findings of Wade and Doe (1992) and Doe and Jackman (1998), it is evident that A. virginiana is tolerant of salinities ranging from 15 to 35‰, and intolerant of salinities <15‰.

An A. virginiana application limit of 15 to 35‰ is specified here for porewater salinity (see Table G.1 and Section 4.6). Test material with porewater salinity less than 15‰ must be evaluated for toxicity using another suitable species which is more tolerant of low-salinity water (e.g., Eohaustorius estuarius; see Appendix F).

Tolerance Limits for High Organic Content

No studies with formulated sediments are available which demonstrate the effect of elevated levels of organic carbon on the 10-day survival rate for this species. Results for tests with field-collected reference sediments are also not enlightening; no reports are available showing 10-day survival rates for A. virginiana when exposed to samples with organic content greater than 2%. Studies with commercial formulations of silica sand (Tay et al., 1998) demonstrate that A. virginiana can survive well for 10 days in the absence of any appreciable organic carbon content.

It is known that A. virginiana can tolerate samples of test material with a total organic carbon content of 2% or less; however, the upper limit that can be tolerated, without affecting 10-day survival, is not known. No application limit for total organic carbon seems necessary or appropriate.

Tolerance and Application Limits for Grain Size

Studies by Tay et al. (1998) have demonstrated that A. virginiana is very tolerant of coarse-grained sediment. In tests with differing formulations of silica sand, Tay et al. (1998) found a mean 10-day survival rate of 94% for a sample comprised of ~92% very coarse-grained (i.e., particles >1.0 mm) sediment. This species also survived well (mean 10-day survival, 95%) when held in 96.5% coarse-grained (i.e. particles > 0.25 mm) material (Tay et al., 1998). Given the high tolerance of this species to coarse-grained material, no A. virginiana application limit for very coarse-grained (i.e., >1.0 mm) material is necessary or appropriate (see Section 2.6).

Tests with both commercial formulations of fine-grained material and fine-grained field-collected sediment indicate that this species is intolerant of a high percentage of fines (i.e., particles <0.063 mm). Tay et al. (1998) found 10-day mean survival rates of ≤66% for replicate groups of A. virginiana held in commercial sand:silt:clay formulations comprised of ≥36% clay and 50 to 99% fines. Additionally, Tay et al. (1998) reported a 10-day mean survival rate of only 56% for replicate groups held in a field-collected reference sediment with 17% clay and 82% fines. Tests with field-collected sediment have demonstrated a somewhat greater tolerance of this species to certain samples with a high percentage of fines and/or a high percentage of clay (Doe, 1998). In consideration of all available data showing mean 10-day survival rates in formulated and field-collected sediment with differing but high percentages of fines and/or clay, and in keeping with the subsequent recommendation by Doe (1998), an A. virginiana application limit of <90% fines is designated here (see Table G.1 and Section 2.6). Additionally, a second application limit of <35% clay seems reasonable, and is to be applied as part of this reference method. Accordingly, test material with ≥90% fines and/or ≥35% clay content must not be used for a 10-day sediment toxicity test with A. virginiana according to this reference method. Rather, another test species more tolerant of fine-grained sediment (e.g., Eohaustorius estuarius; see Appendix F) should be used, provided that grain size characteristics are within the application limits for this species.

Tolerance Limits for Ammonia

Sims and Moore (1995a) undertook a literature review for concentrations of ammonia in sediment pore water, as well as for known toxicity of ammonia to marine and freshwater invertebrates and fish. These authors concluded “The comparison of reported exposure and effects concentrations suggests significant potential for ammonia toxicity in dredged material bioassays”.

Tay et al. (1998) measured the tolerance of A. virginiana to ammonia in both a 96-h “water-only” test and a 10-day “spiked sediment” test. In each instance, LC50s were calculated and expressed based on both measured total ammonia and calculated (Bower and Bidwell, 1978) un-ionized ammonia concentrations. Values derived for these tests are shown in Table G.1. Results show an appreciably greater tolerance of this species to ammonia (as total ammonia or un-ionized ammonia) in the 96-h “water-only” test, relative to that measured in the 10-day “spiked sediment/porewater ammonia” test (see Table G.1). This finding is inconsistent with those for R. abronius, E. washingtonianus, or E. estuarius, in which instances the tolerance of each of these species to ammonia in 96-h “water-only” and 10-day “spiked-sediment” tests was similar (see Appendices D, E, and F). No other studies are available which demonstrate the acute lethal tolerance of A. virginiana to ammonia.

No application limits are imposed here for total or un-ionized ammonia in test materials (see Table G.1), inasmuch as the ammonia concentrations in samples under investigation might be elevated due to anthropogenic and/or natural causes, and might be an integral toxic component deserving of consideration using this species and test method.

Tolerance Limits for Hydrogen Sulphide

Hydrogen sulphide can be elevated in sediment pore water to levels toxic to amphipods and other benthic life (Sims and Moore, 1995b). Based on a literature review of measured porewater concentrations of hydrogen sulphide and its known toxicity to marine or freshwater organisms, these authors concluded “The comparison of reported exposure and effects concentrations suggests a strong potential for hydrogen sulphide toxicity in dredged material bioassays”. To date, however, no definitive data are available showing the limits of hydrogen sulphide in pore water or overlying water (i.e., results of “water-only” LC50s) that A. virginiana can tolerate.

Historical Control Performance

Environment Canada’s Atlantic regional laboratory has completed 32 separate series of 10-day sediment toxicity tests with A. virginiana since March 1991. Mean 10-day survival rates in control sediment averaged 89.5%. Fourteen of the 32 tests (=44%) failed to achieve ≥90% control survival; and seven of the 32 tests (= 22%) failed to achieve ≥85% control survival. However, 29 of the 32 tests (= 91%) achieved ≥80% control survival (Doe and Jackman, 1998). Given this historical control performance, a minimum mean 10-day survival rate of ≥80% in control sediment is considered to be a readily achievable and suitable limit on which to base a criterion for a valid sediment toxicity test using A. virginiana (see Section 4.6).

In conjunction with the sediment toxicity tests using this species, Environment Canada’s Atlantic regional personnel have undertaken 27 separate 96-h water only reference toxicity tests with A. virginiana since June 1991. For these tests, the mean overall survival rate for the control groups was 97%. Twenty-two of the 27 tests (= 81%) had ≥95% control survival, and only one of the tests (= 3.7%) had <90% survival (Doe and Jackman, 1998). Given this historical control performance, a minimum 96-h survival rate of ≥90% is considered to be a readily achievable and suitable limit on which to base a validity criterion for a water only reference toxicity test using A. virginiana (Section 5).