Effect of selected pesticides and their ozonation by-products on gap junctional intercellular communication using rat liver epithelial cell lines

The non-genotoxic effects of two commonly used pesticides, 1,1-bis (p-chlor ophenyl)-2,2,2-trichloroethane (DDT) and malathion, and one widely used com mercial insect repellent N,N-diethy-m-toluamide (DEET) on gap junction inte rcellular communication (GJIC) were determined using a rat liver epithelial cell line. Malathion and DDT reversibly inhibited GJIC in a treatment time - and dose-dependent manner at non-cytotoxic doses, whereas, DEET did not i nhibit GJIC. Malathion was very reactive with ozone, while DEET and DDT did not react to any appreciable extent with ozone. The mixtures of ozonation products from malathion and DEET did not inhibit GJIC. The mixtures of ozon ation by-products formed From DDT inhibited GJIC, but to a lesser extent th an did DDT, itself. These results suggest that ozone can effectively remove malathion from solution without forming GJIC-toxic products, but is less e ffective in eliminating DEET and DDT from solution. (C) 2001 Elsevier Scien ce Ltd. All rights reserved.