Potential effects of food addition to sediment on

Authors: Philipp Egeler Kevin S Henry Caroline Riedhammer

Publish Date: 2010/01/22

Volume: 10, Issue: 3, Pages: 377-388

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Abstract

Standardized sediment toxicity assays often employ periodic additions of uncontaminated food to sustain energy and growth requirements of the test organisms Consequently selective feeding on this uncontaminated food may reduce exposure to sediment particles containing the test substance To address this issue some standard guidelines propose to add food to the sediment before spiking with the test substance to account for multiple exposure routes including ingestion of contaminated food The present study focused on the influence of different feeding regimens and compositions of the aqueous medium on water quality ammonia concentrations and test organism developmentLumbriculus variegatus Hyalella azteca and Chironomus riparius larvae were used as test organisms Ammonia production was investigated under different feeding regimens and test conditions as well as under the presence of a potential inhibitor of nitrification 44methylenedianilineAmmonia concentrations strongly depended on the feeding regimen and on the type of food An influence of 44methylenedianiline on test organisms or ammonia concentrations was not found at the tested level Independently of ammonia concentrations L variegatus were more sensitive to food type and less sensitive to medium composition than H azteca Ammonia levels emergence ratio and development rate of C riparius were not different under periodic feeding and single addition of Urtica Findings suggest that in case of a “sedimentincorporated” feeding regimen the time point of food addition to the sediment and careful pH control appear critical For H azteca and L variegatus an Urtica/cellulose mixture provides a balance between ammonia production and organism developmentThis article gives recommendations and caveats for conducting spikedsediment tests with a single addition of sedimentincorporated food The presented work also contributed to the development of two recently adopted OECD test guidelines related to sediment toxicity and bioaccumulation testing with endobenthic oligochaetesThe authors wish to thank the following persons Thomas Schupp Elastogran GmbH BASF Polyurethane Lemfoerde Germany Andreas Seidel Bayer Industry Material Science Leverkusen Germany and Bob West The Dow Chemical Company Midland MI USA for useful advice on study design and comments on the manuscript Norbert Caspers Bayer Industry Services Leverkusen Germany for comments on earlier versions of the manuscript Marika Goth Kerstin Kronenberger and Daniel Gilberg ECT Oekotoxikologie GmbH for assistance during test performance HansJoachim Schallnaß ECT Oekotoxikologie GmbH for statistical advice and three anonymous reviewers for helpful comments on the manuscript These studies were supported by the International Isocyanate Institute Inc The conclusions are those of the authors and not necessarily those of the Institute

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