Photochemical activation of chloroethenes leading to destruction of photosynthetic pigments

Abstract

All major photosynthetic pigments in spruce needles (Picea abies) are rapidly destroyed when the latter are UV-irradiated in the presence of tri-or tetrachloroethene at concentrations about 10-fold higher than those present in the lower atmosphere of industrialized countries. Uptake of chlorocarbons by spruce needles is fast, and the partition coefficients between the lipophilic compartments, such as the cuticle and cellular lipid membranes, and air are high. Volatile halogenated hydrocarbons are therefore suspected of being initiators of a phytotoxic phenomenon usually referred to as new forest decline. In conjunction with the fact that they seem to be preferentially deposited along the western slopes of mountain ranges receiving high precipitation, the phenomena preported here may indicate the initiation of a severe ecotoxicological manifestation by these widely used compounds.