Treatment of wood with a mixture of copper, chrome and arsenic salts (CCA) is used to prevent the settlement of wood-boring invertebrates. The efficacy of treatment is due to toxicity to the borers, so there is concern that preservatives may have undesirable impacts on non-target biota.
This study aims to provide a realistic assessment of the hazard posed by the use of treated wood in coastal installations. Rates of leaching of CCA components will be measured at marine sites representing the range of conditions in European waters. The rate of release or sequestration of CCA components by soft rot fungi and lignolytic bacteria will also be measured. These data will be combined to predict the rate of leaching beyond the time limits of the project.
Impacts of CCA-leachate may occur at the wood-water interface, in the water column or in nearby sediments. Epibiotic forms provide evidence of effects at the wood preservative/seawater interface, where the flux of leachate is highest. The acute effects of this flux will be evaluated by monitoring settlement of epibiotic organisms, the chronic effects by measuring their growth rates. Chronic effects will also be monitored by measuring the impact on the physiology of Mytilus. Impact on planktonic organisms will be assessed by measuring effects of leachate on the behaviour of bivalve veligers. Toxicity testing methods for benthic organisms will be modified to reflect the particular needs of investigating the impact of wood preservatives. The possibility of uptake and storage of components of the CCA by epibiota will be investigated by chemical analysis. Surface grazers and filter feeders will be examined in order to investigate more than one possible mode of uptake.
Current and projected patterns of utilisation of treated wood in European waters will be assessed in order to provide a guide to the scale of the impacts measured in the experimental component of this project. The experimental work will provide the basis for a model of
preservative/wood/seawater/biota interactions capable of prediction of the environmental impact of CCA preservatives in planned construction such as harbours and marinas. An evaluation of the experimental procedures and findings will be used to recommend a protocol for predicting the environmental impact of new preservatives intended for marine use.
Call for proposalData not available
Funding SchemeCSC - Cost-sharing contracts
17390 La Tremblade
750 07 Uppsala
PO1 2DY Portsmouth