Leaching from CCA-impregnated wood to food, drinking-water and silage
F G Evans
During the last years The Norwegian Institute of Wood Technology (NIWT) has analysed different foodstuff for contamination by copper, chrome and arsenic from CCA-impregnated wood. There has been some interest for using CCA-impregnated wood in contact with food and drinking-water. Before giving their permission the Norwegian Health Authorities want results from experiments. NIWT therefore started three experiments with 1) analysing stock-fish dried on CCA-treated rack, 2) analysing rainwater collected from wooden roofing of CCA- impregnated boards and 3) leaching from CCA-impregnated grass silos: 1) The results shows very little contamination of the stock-fish. Eating the stock-fish will cause no health hazard. 2) After two years of exposure we still find arsenic and copper in the collected rainwater. The water should not be used as drinking-water. 3) In the grass silo we find an extreme leaching of copper, chrome and arsenic. After exposure for two seasons we find that 20-50% of the copper compound, 50-60% of the chrome compound and 80% of the arsenic compound has leached from the boards. Calculation shows, however, that there is no poisoning hazard for the cattle eating the silage, but the silo's durability may be reduced.