This project supports a dissertation research by Mrs. W. M. Tahseen of the Pakistan Council of Scientific and Industrial Research (PCSIR), Karachi, who is currently completing her doctoral work at the University of Illinois, Urbana, in collaboration with Dr. Larry Hansen, and Dr. David Schaeffer of that Univeristy. The research includes sampling of sites near chemical plants for pollutants in water, soil, plant and/or animal after establishing acute bioassay capability for the in-country field work, subjecting the obtained samples to organochlorine and elemental analysis and additional bioassays, carrying out of statistical analyses of the data, and developing site contamination maps displaying multiple toxic endpoint contours. Scope: The project involves two experienced U.S. toxocologist with a young Pakistani researcher with the backing of the main industrial research organization in Pakistan. The problem to be dealt with is critical in Pakistan and other growing Third World Countries and is also important to the U.S. This project meets the Science in Developing Countries' criteria for the dissertaion improvement by allowing the Pakistani graduate student to do field work in that country.