Mercury-Contaminated Sediments Affect Amphipod Feeding
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A 125-mile reach of the South River, Virginia, was contaminated with mercury during the first half of the 20th century. As increased concentrations of mercury have persisted, researchers have carefully studied its distribution in the river biota and estimated associated risks. The present study evaluated the influence of mercury on feeding rate and uptake by the amphipod Hyalella azteca. The test organisms were exposed for 7 days with leaf discs to reference and contaminated field sediment during the preliminary experiment and additionally to Sedimite (a commercial mercury-sequestering agent) amended sediments during the final experiment. The preliminary experiment demonstrated a decreased feeding rate (approximately 35%) of H. azteca in sediment from a contaminated site relative to sediment from a reference site. The test design of the final experiment took advantage of the knowledge gained in the preliminary experiment by increasing the number of replicates, which decreased the type II error rate. First, the results of the final experiment confirmed the results of the preliminary experiment by again demonstrating differences in the feeding rate of approximately 35% between reference and contaminated sediment. Second, the results indicated a lower feeding rate in reference sediment in the presence of Sedimite. Third, an opposite tendency, although not significant, was apparent for Sedimite-amended contaminated sediment. Thus, Sedimite appears to decrease sediment quality, whereas this conclusion is based on the feeding rate of H. azteca. However, Sedimite and its value as a mercury-sequestering agent requires further evaluation.
KeywordsMercury Leaf Disc Mercury Concentration Test Organism Final Experiment
The authors acknowledge three anonymous reviewers for their valuable comments on an earlier version of this publication.
- Altman DG, Machin D, Bryant TN, Gardner MJ (2000) Statistics with confidence, 2nd ed. Br Med J BooksGoogle Scholar
- Bousfield EI (1958) Fresh-water amphipod crustaceans of glaciated North America. Can Field Nat 72:55–113Google Scholar
- Bundschuh M, Zubrod JP, Schulz R (submitted) The functional and physiological status of Gammarus fossarum (Crustacea; Amphipoda) exposed to secondary treated wastewater. Environ PollutGoogle Scholar
- Lee L (2009) NADA: Nondetects and data analysis for environmental data. R package version 1.5-2. Available at: http://CRAN.R-project.org/package=NADA. Accessed 18 March 2010
- Lemon J, Bolker B, Oom S, Klein E, Rowlingson B, Wickham H, et al. (2009) Plotrix: Various plotting functions. R package version 2.7-2. Available at: http://CRAN.R-project.org/package=plotrix. Accessed 21 March 2010
- Maltby L, Clayton SA, Wood RM, McLoughlin N (2002) Evaluation of the Gammarus pulex in situ feeding assay as a biomonitor of water quality: robustness, responsiveness and relevance. Environ Toxicol Chem 21:361–368Google Scholar
- Menzie CA (2010) Combining engineering and biology in a low-impact in situ treatment system for sediments: Application to mercury. Available at: http://www.menziecura.com/. Accessed 28 September 2009
- Neumann PTM, Borgmann U, Norwood W (1999) Effect of gut clearance on metal body concentrations in Hyalella azteca. Environ Toxicol Chem 18:976–984Google Scholar
- Perneger TV (1998) What’s wrong with Bonferroni adjustments? Br Med J 316:1236–1238Google Scholar
- R Development Core Team (2009) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. Available at: http://www.R-project.org. Accessed 19 March 2010