The effects of environmental pollutants on human health are often subtle, long-term, sometimes transgenerational and difficult to measure even in long-term epidemiological studies in large populations. There is therefore a need for comprehensive research that monitors the concentration and distribution of toxic substances in humans. A number of persistent toxic substances are recognised as being responsible for adverse development and health effect in children. The growing foetus and newborn child are esp ecially sensitive to the toxic effects of many environmental pollutants, and several of them move from mother to foetus via the umbilical cord and to the child via mother's milk. Of particular concern are long-term, subtle effects that might influence rep roductive health, pregnancy outcomes, reduce defence against diseases, affect the children?s mental development, or increase the risk of cancer.Within this project we intend to obtain data on the current levels in mother?s blood and milk of DDT and othe r pesticides used for malaria vector control and/or in agriculture in Northern KwaZulu-Natal, to evaluate the exposure to foetuses and children of the target chemicals, and to investigate if their main source is the malaria control programme or agricultur e. We will take samples from areas where there is an active malaria vector control with DDT and other compounds and from areas where malaria vector control is not needed. In KwaZulu-Natal such areas are located quite close to each other and have essential ly the same conditions for agriculture and social life. We, therefore, expect to be able to distinguish between pesticide residues that are due to malaria control activities and those that have other sources, e.g., agriculture. The data will be compared w ith general medical history, reproductive outcome and child development. Ultimately the data can be used in policy decisions on appropriate malaria vector control procedures.