FATE AND ATMOSPHERIC CONCENTRATIONS OF ALPHA-HEXACHLOROCYCLOHEXANE AND GAMMA-HEXACHLOROCYCLOHEXANE IN QUEBEC, CANADA

The atmospheric concentration of lindane and a-HCH measured at Villero y (Quebec, Canada) are presented. Time-series and source-receptor reco gnition techniques permit us to point out that agricultural activities , namely, corn seeding, are mainly responsible for the atmospheric rel ease of lindane. About 350 000 ha of land are used for this crop activ ity in Quebec, and the period of seeding appears to be concomitant wit h the highest peak of atmospheric lindane. The relationship of lindane with temperature shows that desorption mechanisms are important proce sses in the atmospheric lindane buildup. This volatilization might com e from soil and might involve old as well as fresh lindane.