Occurrence of organochlorines (PCBs, pesticides) and herbicides (triazines, phenylureas) in the atmosphere and in the fallout from urban and rural stations of the Paris area.

The concentrations of organochlorines (PCBs, pesticides) and herbicides (triazines, phenylureas) were determined in the atmosphere. The total fallout in the Paris area in 1992 and in 1993 was measured. Fallout was investigated at two stations, urban and rural and the gaseous phase was studied at the rural one. PCB concentrations (0.3-4.9 ng/m3) and compositions in the atmosphere and in the fallout (20-520 ng/l) varied, according to the local emission, with the temperature and the direction of wind. Compared to our first results in 1986, there were no changes of pollution levels by organochlorines in that area. Pesticide concentrations in the atmosphere and in the fallout reached maximal values after the local agricultural treatments in spring. No phenylurea was detected in any of the gaseous or liquid samples. Lindane, atrazine and simazine were the main pesticides found. Their levels in the vapour phase, expressed as ng/m3, were: lindane 0.3-6.3, atrazine < 0.03-2, simazine < 0.03-3; in the fallout, expressed as ng/l they were: lindane 5-350, atrazine 5-380, simazine 5-650. In relative terms, the Parisian area is very small. No difference in the diversity and in the abundance of the micropollutants introduced by the atmosphere was observed between the rural and the urban stations. The pollution level of atrazine was close to that found in Europe and in North America, while the organochlorine and the simazine levels were higher.