Evaluation of ecotoxicological effects of different coniferous wood treatments on two marine bioindicator species
T Marčeta, N Nesto, I Guarneri, D Tagliapietra, V Moschino
Coniferous wood panels (Picea abies) were treated with two concentrations of copper-based impregnating agent to increase its durability in marine and brackish environment. In order to assess the environmental compatibility of the treatments a laboratory experiment was conducted with two marine invertebrate species: bivalve Mytilus galloprovincialis and a gastropod Steromphala albida. The bioindicator organisms were maintained for 4 weeks in experimental tanks under semi-static condition at control (without wood panels), NTC (non-treated wood panels), CuI (wood panels treated with 0.033% Cu solution) and CuII (wood panels treated with 1% Cu solution) conditions. After 2, 8, 18 and 25 days, water samples were collected to analyze copper release over time. The presence of oxidative stress was evaluated through the determination of catalase and glutathione-s-transferase enzymes activity, the response to metal exposure through metallothionein levels and the presence of neurotoxic effects through acetylcholinesterase activity determination. For the evaluation of possible genotoxic effects in mussels, presence of micronucleus in hemocytes was evaluated, while physiological responses in mussels and behavioral endpoint in snails were evaluated with survival in air test and flipping test, respectively. CuII condition exhibited the highest toxicity and in both mussels and snails, mortality was significantly affected reaching 100% before the end of the experiment. Conversely, results of all biomarker analyses allowed to exclude toxic effects of NTC and CuI conditions on the two model species. Toxic effect observed in CuII are consistent with copper concentration that was above 200 and 400 ppb after 2 and 8 days of exposure respectively, while was below 50 ppb during all the experiment in the other tested conditions.
Keywords: softwood, Cu-based preservatives, biomarker, M. galloprovincialis, S. albida environmental compatibility