On the use of tree leaves as bioindicators of the contamination of air by organochlorines in France

The possibility of using leaves from plane trees (Platanus vulgaris S.) as bioindicators of the pollution of air by organochlorines has been studied in Paris, the Paris region and throughout France. Extracts were obtained by mechanical shaking and analyzed by capillary column gas chromatography. Inter- and intraspecific variations in the concentrations of polychlorinated biphenyls are seen to show a factor 3. In these conditions contents throughout France can be considered homogeneous. This type of biomonitoring would then appear to be capable of discerning, on a continental scale, variations of a factor 10 in atmospheric concentrations. Air/leaf bioconcentration factors are around 10⁵ for PCBs and 10⁴ for lindane.