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Title: Toxicity Reduction (and Identification) for Dredging Evaluations : Methods for Whole Sediment Elutriate Bioassays
Authors: Melby, Nicolas L.
Kennedy, Alan James, 1976-
Farrar, J. Daniel
Bednar, Anthony J.
Moore, David W.
Lehmann, Wade
Keywords: Dredging--Evaluation
Sediment transport
Toxicity testing
Publisher: Dredging Operations and Environmental Research Program (U.S.)
Environmental Laboratory (U.S.)
Series/Report no.: Technical Note (Dredging Operations and Environmental Research Program (U.S.));no.ERDC/TN DOER-R26
Abstract: Physical, chemical, and toxicological characterization of sediment may be required to evaluate dredged material (DM) under the Clean Water Act (CWA) or Marine Protection Research and Sanctuaries Act (MPRSA). When DM evaluations indicate potential for biological effects, it is useful to identify the likely causes of those effects to better inform test interpretation and/or management decisions (USEPA/USACE, 1991). For example, when a non-persistent substance, such as ammonia, is present at elevated levels that are sufficient to alone cause a toxicological effect in laboratory bioassays, it is logical to employ methods to reduce ammonia levels prior to conducting the bioassay to allow toxicological assessment for more persistent contaminants of concern. The primary objective of this Technical Note (TN) was to disseminate methods for conducting toxicity reduction/identification evaluations (TRE/TIE) to be used in select dredging evaluations. While previous documents have discussed the utility of TRE/TIE information for dredging management decisions, this TN provides more specific guidance. In practice, TREs for ammonia in elutriate toxicity tests may be most common and applicable. TRE methods serve as supplementary testing to standard whole sediment and sediment elutriate bioassays in which significant reductions in survival (or other endpoints) are observed, but the primary cause is unknown or suspected to be ammonia, hydrogen sulfide, or other non-contaminant related factors. Through sediment and elutriate manipulations, these methods can generate lines of evidence that a certain chemical class (or specific chemical compound or element when coupled with chemistry data) is primarily responsible for observed biological effects. The drivers of the biological effects may be narrowed to typical contaminants/classes; organic compounds, metals, ammonia, and/or sulfides (Ankley et al. 1992; Kreitinger et al. 2017). Application of the methods described herein is beneficial to align the type of data generated between different dredging projects, thus allowing greater consistency of robust, scientific data that feed management decisions.
Description: Technical Note
Gov't Doc #: ERDC/TN DOER-R26
Rights: Approved for public release; distribution is unlimited
Appears in Collections:Technical Note

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