Chloride – a precursor in the formation of volatile organochlorines by forest plants?

Two plants, a fern (Athyrium filix-femina) and a moss (Polytrichum commune Hedw.), both commonly occurring in Northern Temperate forests, were exposed in a laboratory study to a solution of 36Cl-chloride. The uptake of 36Cl-chloride by the plants was investigated and the emission of volatile chlorine 36 by the plants was determined. Furthermore, speciation of the emitted volatile organochlorine compounds (VOCls) was investigated. For the fern and the moss a rapid uptake of 36Cl-chloride was observed within a 1-h exposure period. The uptake rates for the fern and the moss, respectively, were 16 μg 36Cl-chloride g−1 fresh weight (FW) h−1 and 3.0 μg 36Cl-chloride g−1 FW h−1, respectively. The study also suggested that after uptake by the plants 36Cl-chloride is incorporated into VOCls, which were emitted by the plants into the atmosphere. Speciation analysis of the VOCls revealed the emission of chloroform, tetrachloromethane and 1,1,1-trichloroethane.