Tissue Concentrations of Chlordanes in Mice after Long-term Exposures to Technical Grade Chlordane at Indoor Air Levels

We determined concentrations of chlordanes (5 chlordane compounds and 2 metabolites) in tissues and organs of mice following a prolonged exposure to Chlordane (technical grade chlordane) at levels as low as those in indoor air. After exposure to 4.22 - 11.36 μg/m^3 Chlordanes (total of 5 compounds) in the air for 1 - 6 months, 6.44 - 13.00 ppm chlordanes (total of 7 compounds) were detected in mice (2 tissues and 6 organs). The adipose tissue among the 2 tissues / 6 organs examined contained the highest chlordanes. The ratio of the adipose tissue chlordanes to the liver chlordanes was approximately 5.6 times, followed by the muscle (0.9), lungs (0.4), kidneys (0.4), heart (0.3), spleen (0.2) and brain (0.1). In addition, trans-nonachlor, oxychlordane and heptachlorepoxide in chlordanes were at a high level. The level of Chlordane exposure (dose) and the level of chlordanes accumulation in each tissue or organ of the mice except for the heart were closely correlated (r = 0.9388 - 0.7130), and showed a linear relationship. The tendency of chlordanes accumulation in light of the linear relationship was adipose≫liver≧muscle. Thus, even with a low level of Chlordane in indoor air, chlordanes may be steadily accumulated in the bodies of human residents with prolonged exposure similarly. The present findings suggest that it is necessary to investigate the risk of organochlorine chemicals contamination in indoor air at prolonged exposure.