proposal# 9413565 PI - Akse This Small Business Technology Transfer (STTR) Phase I research project is concerned with the consequences of long term human exposure to elemental chlorine and chlorine containing organic compounds which is an issue of increasing public concern. Chlorine in the environment has been associated with such disparate phenomena as carcinogenesis, reductions in human sperm count, and increased fragility of egg shells in endangered avian species. More stringent regulation of the release into the environment of chlorinated species is anticipated. A major source of long term, low level exposure to chlorocarbons is through the public drinking water supplies. The most significant means of minimizing the associated health risks is the reduction of those chlorinated by-products caused by excess chlorination. This requires a continuous and detailed knowledge of chlorine levels throughout the drinking water distribution system so that more precise control of chlorine additions can be made. Such control will maintain antimicrobial activity while reducing unwanted disinfection by- products. This research project has commercial potential in the monitoring of chlorine levels on a continuous basis in drinking water systems.