In the project ‘Iron-based nanoparticles and nanocomposite structures for removal of contaminants from groundwater and sewage’ (Fe-Nanosit), Carbo-Iron®, a nanocomposite for remediation of contaminated groundwater and Pd-doted magnetite and magnetite-zeolith for treatment of industrial wastewater were developed. Since no data on ecotoxicity of these particles were available, ecotoxicity of the nanocomposites was investigated using standard ecotoxicity tests. Suitable methods for application of the particles into the test systems were developed with special attention to the stability of the test suspensions. Apart from these modifications, the standard tests were suitable for investigating the ecotoxicity of the nanocomposites.
Substances that do not elicit (1) acute toxic effects at concentrations above 100 mg/L and (2) chronic toxic effects at concentrations above 10 mg/L are generally considered nontoxic. The results of the present project show that the studied nanocomposites are nontoxic or have a very low toxicity to the studied test organisms. Both magnetite-based nanocomposites are nontoxic: up to concentrations of 100 mg/L, no acute or chronic effects were observed in the zebrafish Danio rerio, the amphipod Hyalella azteca or the midge Chironomus riparius. In chronic tests with aged Carbo-Iron® and C. riparius, effects were observed at 100 mg/L. In a chronic test with H. azteca, Carbo-Iron® elicited effects on reproduction at concentrations ≥ 12.5 mg/L. Using microscopic analysis of the distribution of the nanomaterials in the organisms, the investigated particles were detected in the gut of the test organisms. However, no uptake of particles from the gut into the surrounding tissue was detected. In the test with D. rerio and Carbo-Iron, the composite had been excreted from the gut after a 4 day post-exposure period in control water.
For further information on the project results, see the following publications:
Weil, M., Meißner, T., Busch, W., Springer, A., Kühnel, D., Schulz, R., Duis, K. (2015). The oxidized state of the nanocomposite Carbo-Iron® causes no adverse effects on growth, survival and differential gene expression in zebrafish. Science of The Total Environment 530/531, 198-208. [read more]
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. [read more]
Weil, M., Mackenzie, K., Foit, K., Kühnel, D., Bundschuh, M., Schulz, R., Duis, K. (2019). Environmental risk or benefit? Comprehensive risk assessment of groundwater treated with nano Fe0-based Carbo-Iron®. Science of the Total Environment 677, 156-166. [read more]