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Response of bacteria and meiofauna to iron oxide colloids in sediments of freshwater microcosms
Author(s) -
Höss Sebastian,
FrankFahle Béatrice,
Lueders Tillmann,
Traunspurger Walter
Publication year - 2015
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.3091
Subject(s) - ferrihydrite , microcosm , environmental chemistry , sediment , benthic zone , fluoranthene , chemistry , colloid , meiobenthos , environmental remediation , environmental science , contamination , ecology , biology , paleontology , phenanthrene , organic chemistry , adsorption
The use of colloidal iron oxide (FeOx) in the bioremediation of groundwater contamination implies its increasing release into the environment and requires an assessment of its ecotoxicological risk. Therefore, microcosm experiments were carried out to investigate the impact of ferrihydrite colloids on the bacterial and meiofaunal communities of pristine freshwater sediments. The effects of ferrihydrite colloids were compared with those of ferrihydrite macroaggregates to discriminate between colloid‐specific and general FeOx impacts. The influence of ferrihydrite colloids on the toxicity of sediment‐bound fluoranthene was also considered. At high concentrations (496 mg Fe kg −1 sediment dry wt), ferrihydrite colloids had a significant, but transient impact on bacterial and meiofaunal communities. Although bacterial community composition specifically responded to ferrihydrite colloids, a more general FeOx effect was observed for meiofauna. Bacterial activity responded most sensitively (already at 55 mg Fe kg −1 dry wt) without the potential of recovery. Ferrihydrite colloids did not influence the toxicity of sediment‐bound fluoranthene. Significant correlations between bacterial activity and meiofaunal abundances were indicative of trophic interactions between bacteria and meiofauna and therefore of the contribution of indirect food web effects to the observed impacts. The results suggest that the application of ferrihydrite colloids for remediation purposes in the field poses no risk for benthic communities, given that, with the exception of generic bacterial activity, any negative effects on communities were reversible. Environ Toxicol Chem 2015;34:2660–2669. © 2015 SETAC