A large number of man-made chemicals are present in the environment as pollutants and are capable of disrupting the endocrine system of animals and humans. Small-sized industry is an area where such chemicals are used and produced in abundance. There is no legislation governing the use, production and disposal of such chemicals, which studies have shown are posing a hazard to workers themselves and the surrounding communities. Run off water from seven sites in an area in Pretoria West, with significant numbers of small-sized industries, was screened for oestrogenicity, using the Recombinant Yeast Cell Bioassay (RCBA). Chemical analyses were done for the presence of endocrine disrupting chemicals (EOCs), including p-nonylphenol (p-NP), bisphenol A (BPA), phthalate esters, polychlorinated biphenyls (PCBs) and various organochlorine pesticides, including dichlorodiphenyltrichloroethane (DDT). The p-NP, PCBs and organochlorine pesticides were detected using a South African Bureau of Standards (SABS) in-house method: AM178 and the time of flight spectrometer, while the BPA and phthalates were detected using the CSIR Biochemtek Laboratory in-house GC-MS method: AM 186 based on the US EPA 8260 and the gas chromatography-mass spectrometer. The water tested positive for oestrogenic activity at all the sample sites and a significant amount of lindane, an organochlorine pesticide, was detected at one site. p-NP as well as phthalate esters were identified at different sites. No pattern or relationship could be established between the oestrogenic activity and the subsequent endocrine disrupting chemicals tested for. These EOCs in the water could pose a health risk for humans and animals. Further specific studies are needed to establish the possible sources of these contaminants, from industry and households. / Dissertation (MMed)--University of Pretoria, 2005. / School of Health Systems and Public Health (SHSPH) / Unrestricted