Environmental impact of PCP and NaPCP in the aquatic and atmospheric compartment
P Marchal, P Vasseur, G Ozanne
PCP and NaPCP were studied for their aquatic toxicity on bacteria, microalgae and daphnids and for their behaviour in the atmospheric compartment with a climatic chamber. Results of aquatic toxicity bioassays showed that toxicity was higher at low pH. This can be explained by the pKa value of 4.7 of PCP and the higher concentration of the non dissociated form of the pesticide at more acidic pH. Volatilization of pentachlorophenol was studied with wood samples treated with PCP in organic solvent or aqueous solution of NaPCP. Test procedures were investigated in a first step. It appears that a period of three weeks minimum after impregnation must be respected before sampling the wood specimens and that the ratio m²/m³ has to be in good agreement with the saturated vapor pressure concentration. These recommandations would imply improvement of some conditions of the French norm NF X 41-566. The release of pentachlorophenol from wood samples treated with PCP was much higher than with wood treated with NaPCP. The different behaviours of PCP and NaPCP suggest that these substances should be considered distinctly.