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Water: Contaminated Sediments

Measurement Methods

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Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated Contaminants with Freshwater Invertebrates--Second Edition

Fact sheet; March 2000

We have published procedures for testing freshwater organisms in the laboratory to evaluate the potential toxicity or bioaccumulation of chemicals in whole sediments. This second edition updates methods originally published in 1994 (EPA/600/R-94/024). Toxicity methods are outlined for two organisms, the amphipod Hyalella azteca and the midge Chironomus tentans. Guidance is also provided for conducting bioaccumulation tests with the oligochaete Lumbriculus variegatus.

Background

Sediment contamination is a widespread environmental problem that can potentially pose a threat to a variety of aquatic ecosystems. Sediment functions as a reservoir for common chemicals such as pesticides, herbicides, polychlorinated biphenyls (PCBs) polycyclic aromatic hydrocarbons (PAHs), and metals such as lead, mercury, and arsenic. Contaminated sediments may be directly toxic to aquatic life (organisms found in the water column and in or near the sediment) or can be a source of contaminants for bioaccumulation (where a substance is taken up by an organism) in the food chain.

Why is EPA publishing methods for measuring the toxicity and bioaccumulation of sediment-associated contaminants?

In the past, assessment of sediment quality was limited to chemical characterizations. This type of analysis alone cannot always provide enough information to adequately evaluate potential adverse effects that occur from interactions among chemicals, or that result from time-dependent availability of sediment-associated contaminants to aquatic organisms. Therefore, determination of contaminated sediment effects on aquatic organisms may require the use of controlled toxicity and bioaccumulation tests.

What are the major revisions compared to the first edition published in 1994?

This second edition of the manual is a revision to the USEPA (EPA/600/R-94/024) document published in 1994. The second edition includes new methods for evaluating sublethal effects of sediment-associated contaminants utilizing long-term sediment exposures with the amphipod Hyalella azteca, and the midge Chironomus tentans. The long-term sediment exposures with H. azteca are started with 7 to 8 day old organisms. Effect endpoints measured for H. azteca include survival (measured on days 28, 35, and 42), growth (measured on days 28 and 42), and reproduction (measured as number of young/female from day 28 to 42). The long-term sediment exposures with C. tentans start with newly hatched larvae (< 24 hours old) with effect endpoints including emergence, reproduction, and hatching of the next (F1) generation (which requires about 60 days).

What is the applicability of these methods?

These methods provide consistent testing protocols for agency-wide use to evaluate risks and provide comparable data. They provide the basis for uniform cross-program decision making within the USEPA. Each program, however, retains the flexibility of deciding whether identified risks would trigger regulatory actions.

How do I obtain a copy of the methods manual?

Copies of the complete document, titled Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated Contaminants with Freshwater Invertebrates—Second Edition (PDF) (212 pp, 3.7MB, March 2000; EPA 600-R-99-064) can be obtained from the National Service Center for Environmental Publications, P.O. Box 42419, Cincinnati, OH., 45242 by phone at 1-800-490-9198 or on their web site at http://www.epa.gov/ncepihom/orderpub.html.

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