For in situ remediation of groundwater contaminated by halogenated hydrocarbons Carbo-Iron®, a composite of microscale activated carbon and nano Fe0, was developed. Against the background of the intended release of Carbo-Iron into the environment in concentrations in the g/L-range, potential ecotoxicological consequences were evaluated in the present study (‘Oxidized Carbo-Iron causes reduced reproduction and lower tolerance of juveniles in the amphipod Hyalella azteca ’). The amphipod H. azteca was selected as a surrogate test species for functionally important groundwater crustaceans. Effects of Carbo-Iron on H. azteca were determined in acute and chronic tests: a 10-d acute test, a 7-d feeding activity test, a 42- and a 56-d chronic test.
In the acute toxicity test and the feeding activity test, Carbo-Iron had a significant effect on growth and feeding rate of H. azteca at the highest test concentration of 100 mg/L. In the chronic tests, the number of offspring was the most sensitive endpoint and significant effects were recorded at concentrations of 12.5 mg/L and above. Parental exposure to oxidized Carbo-Iron significantly exacerbated the acute effects of the nanocomposite on the subsequent generation of H. azteca by a factor >10.
The present study indicates risks for groundwater species at concentrations in the mg/L range. Carbo-Iron may exceed these effect concentrations in treated aquifers, but the presence of the pollutant might have impaired the quality of this habitat already. The benefit of remediation has to be regarded carefully against the risk of ecological consequences.
For additional information, see the publication in Aquatic Toxicology:
Weil, M., Meißner, T., Springer, A., Bundschuh, M., Hübler, L., Schulz, R., Duis, K. (2016). Oxidized Carbo-Iron causes reduced reproduction and lower tolerance of juveniles in the amphipod Hyalella azteca. Aquatic Toxicology 181, 94-103.
This work was funded by the German Ministry of Education and Research (project Fe-NANOSIT, FKZ 03X0082A, B, C and F).
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