The study on insecticide hexachlorocyclo-hexane (HCH) was of its own kind that covered all the four HCH manufacturing units in the country. Beta HCH was found to be a predominant isomer present in the blood samples of exposed workers. This is due to accumulation of Beta-HCH which is a stable isomer, has a long half-life and is almost non-biodegradable. Beta-HCH was found even in the serum samples of workers who had discontinued their jobs for several years. Therefore Beta-HCH is taken as the marker for cumulative exposure for HCH and lindane for immediate past exposure.
About 25% of serum samples of workers with significantly high levels of serum HCH residues showed circulating immune complexes(CIC) of IgG and 20% showed CIC of IgM whereas CIC of C3 and C4 were not detected. Electro cardiogram abnormalities such as Left Ventricular Hypertrophy (LVH), Left Anterior Hemiblock, Right Bundle Branch Block and Wolff Parkinson White Syndrome were reported for the first time. Increased activity of Lucine amino peptidase. 5-nucleotidase, and Gamma Glutamyl transpeptidase, Ornithine Carbamoyl Transpeptidase was also observed.