Occurrence of Hexachlorocyclohexane (HCH) in Coffee Culture.

Soil and water samples collected from different places of coffee plantations at
Balehonnur. Karnataka State contained HCH residues ranging from 7 to 40
ppm in soils and 0.02 to 0.16 ppm in water. The cot1ee seeds revealed 0.003 to
0.1 pm HCH in most samples. The a isomer predominated in soils, followed by
the l'-HCH. Soil percolation studies in the laboratory using 35 em soil columns
indicated that 60-700/0 of the applied HCH remained in the top 5 em and
7-100/0 at 20-35 em at the end of 90 days. Only '20/0 was accounted for by run-off
from the column. Sorption studies in sandy loam and clay loam plantation soils
suggested that the HCH sorption was greater in clayey than in the other type
and that the rate of desorption was related to the type of the soil. Vertical
movement and sorption studies helped to expIaln the origin of residues in
coffee seeds and ground waters.