Biological test method for determining acute lethality of sediment to amphipods: front matter
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Abstract
A reference method for measuring the acute lethal toxicity of contaminated whole sediment to marine or estuarine amphipods is described in this report. Explicit instructions are provided for performing a static, 10-day lethality test in the laboratory, using samples of estuarine or marine sediment and one or more of the following species of amphipod crustaceans: Rhepoxynius abronius, Eohaustorius washingtonianus, Eohaustorius estuarius, and Amphiporeia virginiana.
This reference method follows and is built upon the generic (multipurpose) biological test method “Acute Test for Sediment Toxicity Using Marine or Estuarine Amphipods” published previously by Environment Canada (1992; EPS 1/RM/26). It is intended for use with samples of contaminated marine or estuarine sediment.
Specific conditions and procedures are stipulated that include instructions on obtaining, shipping, holding, and acclimating test organisms; acceptable procedures and conditions for transporting, storing, and manipulating samples of sediment to be used in the test; required physicochemical analyses of sediment and water; procedures and conditions to be followed in preparing for and conducting the test; criteria for acceptable performance and valid test results; measurements and observations to be made; required or recommended data analyses; guidance for interpreting test results; and minimum reporting requirements. Instructions on the use of reference toxicity tests are also provided.
Foreword
This is one of a series of recommended methods for measuring and assessing the aquatic biological effects of toxic substances or materials. Recommended methods are those that have been evaluated by Environment Canada (EC), and are favoured:
- for use in EC aquatic toxicity laboratories;
- for testing that is contracted out by Environment Canada or requested from outside agencies or industry;
- in the absence of more specific instructions, such as are contained in regulations; and
- as a foundation for the provision of very explicit instructions as might be required in a regulatory protocol or standard reference method.
The different types of tests included in this series were selected because of their acceptability for the needs of programs for environmental protection and management carried out by Environment Canada. These reports are intended to provide guidance and to facilitate the use of consistent, appropriate, and comprehensive procedures for obtaining data on the toxicity to aquatic life of specific test substances or materials destined for or within the aquatic environment. Depending on the biological test method chosen, substances or materials to be tested for toxicity could include samples of chemical or chemical substance, effluent, elutriate, leachate, receiving water or, where appropriate, sediment or similar particulate material.
Terminology
The following definitions are given in the context of this report. Additional definitions in the detailed companion document (Environment Canada, 1992; including October 1998 Amendments) also apply here.
Grammatical Terms
Must is used to express an absolute requirement.
Should is used to state that the specified condition or procedure is recommended and ought to be met if possible.
May is used to mean "is (are) allowed to".
Can is used to mean "is (are) able to".
Might is used to express the possibility that something could exist or happen.
General Technical Terms
Acclimation is physiological adjustment to a particular level of one or more environmental conditions such as temperature. The term usually refers to controlled laboratory conditions.
Compliance means in accordance with governmental permitting or regulatory requirements.
Estuarine (water) is from a coastal body of ocean water that is measurably diluted with fresh water derived from land drainage.
Marine (water) is from or within the ocean, sea, or inshore location where there is no appreciable dilution of water by natural fresh water derived from land drainage.
Monitoring is the routine (e.g., daily, weekly, monthly, quarterly) checking of quality, or collection and reporting of information. In the context of this report, it means either the periodic (routine) checking and measurement of certain biological or water quality variables, or the collection and testing of samples of sediment for toxicity.
Photoperiod is the duration of illumination and darkness within a 24-h day.
Pretreatment means treatment of a sediment sample, or portion thereof, before exposure of test organisms.
Terms for Test Materials or Substances
Clean sediment is sediment that does not contain concentrations of any substance(s) causing discernible distress to the test organisms or their reduced survival during the test.
Contaminated sediment is sediment containing chemical substances at concentrations that pose a known or potential threat to environmental or human health.
Control/dilution water is the water used for preparing a series of concentrations of a test chemical, or that used as overlying water in a sediment toxicity test or as control water in a water-only test with a reference toxicant. Control/dilution water is frequently identical to the test (overlying) water.
Control sediment is clean sediment which does not contain concentrations of one or more contaminants that could affect the survival or behaviour of the test organisms. Control sediment might be natural sediment from an uncontaminated site, or formulated (reconstituted) sediment. This sediment must contain no added test material or substance, and must enable an acceptable survival rate for the test organisms during the test. The use of control sediment provides a basis for interpreting data derived from toxicity tests using test sediment(s).
Dredged material is sediment and/or settled particulate waste (e.g., solids from the sea bed of a harbour or channel) that has either been dredged from a waterbody or is being considered for dredging and subsequent ocean disposal.
Overlying water is water placed over sediment in a test chamber or holding/acclimation chamber.
Pore water (also called "interstitial" water) is the water occupying space between sediment particles.
Reference sediment is a field-collected sample of presumably clean (uncontaminated) sediment, selected for properties (e.g., particle size, compactness, total organic content) representing sediment conditions that closely match those of the sample(s) of test sediment except for the degree of chemical contaminants. It is often selected from a site that is uninfluenced or minimally influenced by the source(s) of contamination but within the general vicinity of the site(s) where samples of test sediment are collected.
Reference toxicant is a standard chemical used to measure the sensitivity of the test organisms in order to establish confidence in the toxicity data obtained for a test material or substance. In most instances, a toxicity test with a reference toxicant is performed to assess the sensitivity of the organisms at the time the test material or substance is evaluated, and the precision and reliability of results obtained by the laboratory for that chemical.
Reference toxicity test is a test conducted using a reference toxicant in conjunction with a sediment toxicity test, to appraise the sensitivity of the organisms and the precision and reliability of results obtained by the laboratory at the time the test material is evaluated. Deviations outside an established normal range indicate that the sensitivity of the test organisms, and the performance and precision of the test, are suspect. A reference toxicity test with marine or estuarine amphipods is most often performed in the absence of sediment (i.e., as a water only test).
Sediment is natural particulate material, which has been transported by water and deposited on the sea floor. The term can also describe a substrate that has been experimentally prepared (formulated) using selected particulate material (e.g., sand of particular grain size, bentonite clay, etc.) and within which the test organisms can burrow.
Solid-phase sediment (also called whole sediment) is the intact sediment used to expose the test organisms; not a form or derivative of the sediment such as pore water or a resuspended sediment.
Stock solution is a concentrated solution of the substance to be tested. Measured volumes of a stock solution are added to dilution water to prepare the required strengths of test solutions.
Substance is a particular kind of material having more or less uniform properties.
Test sediment is a field-collected sample of solid-phase sediment, taken from a site thought to be contaminated with one or more chemicals, and intended for use in the toxicity test with amphipods. In some instances, the term also applies to any solid-phase sample (including control sediment, reference sediment, or dredged material) used in the test.
Test water is the water placed over the layer of sediment in the test chambers, i.e., overlying water. It also denotes the water used to manipulate the sediment, if necessary (e.g., for wet sieving of control sediment or for sieving the contents of each test chamber at the end of the test), and that used as control/dilution water for water only tests with a reference toxicant.
Statistical and Toxicological Terms
Acute means within a short period (seconds, minutes, hours, or a few days) in relation to the life span of the test organism.
Control is a treatment in an investigation or study that duplicates all the conditions and factors that might affect the results of the investigation, except the specific condition that is being studied. In an aquatic toxicity test, the control must duplicate all the conditions of the exposure treatment(s), but must contain no added test material or substance. The control is used to determine the absence of measurable toxicity due to basic test conditions (e.g., temperature, health of test organisms, or effects due to their handling).
Endpoint means the variable(s) (i.e., time, reaction of the organisms, etc.) that indicate(s) the termination of a test, and also means the measurement(s) or derived value(s) that characterize the results of the test (e.g., mean percent survival, LC50).
LC50 is the median lethal concentration, i.e., the concentration of substance or material in sediment (e.g., mg/kg) or water (e.g., mg/L) that is estimated to be lethal to 50% of the test organisms. The LC50 and its 95% confidence limits are usually derived by statistical analysis of mortalities in five or more test concentrations, after a fixed period of exposure. The duration of exposure must be specified (e.g., 96-h LC50 for a water only reference toxicity test, or 10-day LC50 for a sediment toxicity test with marine or estuarine amphipods).
Lethal means causing death by direct action. Death of amphipods is defined as the cessation of all visible signs of movement or other activity (e.g., a pleopod twitch) indicating life.
Lethality means causing death.
Static describes toxicity tests in which test solutions or overlying water are not renewed during the test.
Toxicity is the inherent potential or capacity of a material or substance to cause adverse effect(s) on living organisms. The effect(s) could be lethal or sublethal.
Toxicity test is a procedure for determining the effect of a material (e.g., dredged sediment) or substance (e.g., a reference toxicant) on a group of selected organisms of a single species (e.g., Eohaustorius estuarius), under defined conditions. An aquatic toxicity test usually measures either (a) the proportions of organisms affected (quantal; e.g., % survival) or (b) the degree of effect shown (graded or quantitative; e.g., growth), after exposure to a specific test material or substance.
Acknowledgements
This reference method was written by D. McLeay (McLeay Environmental Ltd., Victoria, BC). The report is based on, and is a companion to, Environment Canada’s generic (multipurpose) biological test method for measuring sediment toxicity using marine or estuarine amphipods (Environment Canada, 1992; EPS 1/RM/26), which includes but is not restricted to those species required for use herein.
R. Scroggins (Method Development and Application Section, Environmental Technology Centre, Environment Canada, Gloucester, ON) and J. Osborne (Marine Environment Division, Environment Canada, Hull, PQ) acted as Scientific Authorities and provided technical input and direction throughout the work. Members of the Inter-Governmental Aquatic Toxicity Group (IGATG, Appendix A) participated in the development and review of this report and are thanked accordingly. Members of Environment Canada’s regional and headquarters offices (Appendix B) are also thanked for their support.
Special acknowledgement is made of the many useful comments provided by each member of the Scientific Advisory Group responsible for scientific input and advice during the development and review phases related to the preparation of this report. This team of advisors included: Dr. P. Chapman (EVS Environment Consultants, North Vancouver, BC), Ms. C. Côté (Beak Consultants Ltée., Dorval, PQ), Mr. K. Doe (Environment Canada, Moncton, NB), Ms. M. Fennell (Environment Canada, North Vancouver, BC), Ms. C. Harris (Harris Industrial Testing Services Ltd., Hants County, NS), Ms. E. Jonczyk (Beak Consultants Ltd., Brampton, ON), Ms. D. Lee (B.C. Ministry of Environment, Lands and Parks, Surrey, BC), Ms. C. McPherson (EVS Environment Consultants, North Vancouver, BC), Ms. M. Murdoch (Jacques Whitford Environment Ltd., St. John’s, NF), Ms. L. Porebski (Environment Canada, Hull, PQ), Mr. P. Riebel (P. Riebel and Associates, Baie-d’Urfé, PQ), Ms. J. Stewart (EVS Environment Consultants, North Vancouver, BC), Ms. D. Sullivan (Environment Canada, North Vancouver, BC), Dr. K.-L. Tay (Environment Canada, Dartmouth, NS), and Mr. G. van Aggelen (Environment Canada, North Vancouver, BC). Appendix C provides complete affiliations and points of contact for each member of this Scientific Advisory Group, and for the Scientific Authorities and Consultant.
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