Oxidized Carbo-Iron causes reduced reproduction and lower tolerance of juveniles in the amphipod Hyalella azteca.
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 intended release of Carbo-Iron into the environment in concentrations in the g/L-range, potential ecotoxicological consequences were evaluated in the present study. The nano Fei0in Carbo-Iron acts as reducing agent and is oxidized in aqueous systems by chlorinated solvents, groundwater constituents (e.g. dissolved oxygen) and anaerobic corrosion. As Carbo-Iron is generally oxidized rapidly after application into the environment, the oxidized state is environmentally most relevant, and Carbo-Iron was used in its oxidized form in the ecotoxicological tests. The amphipod Hyalella azteca was selected as a surrogate test species for functionally important groundwater crustaceans. Effects of Carbo-Iron on H. azteca were determined in a 10-d acute test, a 7-d feeding activity test and a 42-d chronic test. Additionally, a 56-d life cycle test was performed with a modified design to further evaluate effects of Carbo-Iron on adult H. azteca and their offspring. The size of Carbo-Iron particles in stock and test suspensions was determined via dynamic light scattering. Potential uptake of particles into test organisms was investigated using transmission and scanning electron microscopy. At the termination of the feeding and acute toxicity test (i.e. after 7 and 10 d of exposure, respectively), Carbo-Iron had a significant effect on the weight, length and feeding rate of H. azteca at the highest test concentration of 100mg/L. While an uptake of Carbo-Iron into the gut was observed, no passage into the surrounding tissue was detected. In both chronic tests, the number of offspring was the most sensitive endpoint and significant effects were recorded at concentrations ≥50mg/L (42-d experiment) and ≥12.5mg/L (56-d experiment). 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 has most likely impaired the quality of this habitat already. The benefit of remediation has to be regarded against the risk of ecological consequences with special consideration of the observed increasing sensitivity of juvenile H. azteca.
ECT Oekotoxikologie GmbH, Böttgerstrasse 2-14, 65439 Flörsheim, Germany. Electronic address: m.weil@ect.de.
Mirco
M
Weil
Fraunhofer Institute for Ceramic Technologies and Systems, Winterbergstrasse 28, 01277 Dresden, Germany. Electronic address: tmeiss@gmx.net.
Tobias
T
Meißner
Dresden University of Technology, Budapesterstrasse 27, 01069 Dresden, Germany. Electronic address: armin.springer@nano.tu-dresden.de.
Armin
A
Springer
Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden; Institute for Environmental Sciences, University of Koblenz-Landau, Forststrasse 7, 76829 Landau, Germany. Electronic address: mirco.bundschuh@slu.se.
Mirco
M
Bundschuh
ECT Oekotoxikologie GmbH, Böttgerstrasse 2-14, 65439 Flörsheim, Germany. Electronic address: lydia.huebler@gmail.com.
Lydia
L
Hübler
Institute for Environmental Sciences, University of Koblenz-Landau, Forststrasse 7, 76829 Landau, Germany. Electronic address: schulz@uni-landau.de.
Ralf
R
Schulz
ECT Oekotoxikologie GmbH, Böttgerstrasse 2-14, 65439 Flörsheim, Germany. Electronic address: k-duis@ect.de.
Karen
K
Duis
D033304:Amphipoda / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D000818:Animals; D002606:Charcoal / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000737:chemistry / Q000633:toxicity; D010084:Oxidation-Reduction; D010316:Particle Size; D012098:Reproduction / Q000187:drug effects*; D023382:Toxicity Tests, Acute; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000633:toxicity*
D014874:Water Pollutants, Chemical; D002606:Charcoal; D007501:Iron
Environmental risk; Groundwater remediation; Iron-based nanomaterial; Nanocomposite