02216naa a2200217 a 450000100080000000500110000800800410001910000210006024501130008126000090019452013450020365000160154865000250156465000190158965300230160865300180163170000210164970000190167070000290168977302800171820375952017-07-19       1995    bl uuuu     u00u1 u    #d1 aHIRATA, R. C. A.  aGroundwater contamination risk by agricultural activity in São Paulo State (Brazil).h[electronic resource]  c1995  aSão Paulo State is well known for its diversified and intensive agricultural practices, which reach a high level of productivity,as seen from the widespread use of pesticides and fertilizers and high agricultural technology. It is estimated that 43.5% of the water demand in the State is for agriculture, whereas 31.8% is for industry and 24.7% for general public use (São Paulo, 1990). Approximately 85.2% of the São Paulo State area, equivalent to 20 595 700 ha, is devoted to agriculture. Although several cases of point source aquifer contamination from industrial activity, waste disposal and fuel tank leakages are known, the impact of agricultural activity has been little studied. Sources of diffuse groundwater contamination are difficult to characterize, because they correspond to large areas, requiring a large number of monitoring centres, and low-concentration of contaminants, almost always requiring careful methods of sampling and sophisticated and expensive analytical techniques. Regional hydrochemical studies of aquifers in São Paulo State, particularly sampling from wells in the Bauru Aquifer System, have detected high concentrations of nitrate originating from agricultural activity. There have not yet been any specific studies in Brazil of groundwater quality degradation resulting from the use of pesticides.  agroundwater  aÁguas Subterrâneas  aContaminação  aÁgua subterrânea  aContamination1 aRODRIGUES, G. S.1 aPARAIBA, L. C.1 aBUSCHINELLI, C. C. de A.  tIn: CHILTON, P.J.; JÉGAT, H.J.; STUART, M.E. (Ed.). Groundwater and agriculture: the interrelationship. Keyworth: British Geological Survey, 1995. 143p. (Technical Report WD/95/26). Proceedings of an International Seminar, Merida, Venezuela, 14-17 October 1992. p. 93 a 101.