The effect of water content on the persistence of 14C- lindane in Brazilian soils

The effect to the water content on the behaviour of 14C-lindane was determined under laboratory conditions in two soil samples from the state of Parana, differing in organic matter and clay content. In Brunizem soil, richer in organic matter, the rate of degradation of 14C-lindane, as measured by 14CO2 evolution, was twice under 3/3 field capacity and flooded condition as compared with 2/3 field capacity. The percentage of 14CO2 envolved from the Dark Red Latosol soil practically the same for the three levels of moisture content and about equal to the Brunizem soil at 2/3 field capacity. Although after 240 days of incubation with 14C-lindane about 5% of the applied activity could be extracted from both soils, between 20 to 36% of the parent radiocarbon was yet bound to the soils. The degradation of 14C-lindage into 14CO2, the volatization of 14C-lindage, and the radiocarbon probably lost as volatile metabolites were the main routes of dissipation of the insecticide from both soils. (Author)