Agricultural contaminat risk on groundwater quality in Brazil
1998
Hirata, R. (Universidade de Sao Paulo (Brazil). Instituto de Geociencias) | Jahnel, M. (Universidade de Sao Paulo (Brazil). Escola Superior de Agricultura "Luiz de Queiroz")
According to recent studies, 51 per cent of Brazilian population (147 million people) use groundwater for its needs. The public water and the self-supply (private wells) systems depend for 12 per cent and 42 per cent, respectively, on aquifers. Almost 36 million people, who live in rural zones, use groundwater for their water supply. The lack of information about water quality from wells countrywide, mainly in rural areas, does not allow the accurate determination of the water contamination problem caused by agriculture. The risk of groundwater contamination by agriculture was defined from analysis of agrochemical uses (fertilizers and pesticides) and the groundwater resource vulnerability. Because of the scale and the large area studied, a regional approach was developed. The vulnerable aquifer zones were associated with water demands. The contaminant load for each area was defined by the identification of crops, area of plantation, and by the more common pesticides and fertilizer formulations that were used in a specific agronomic year. The main objective of this study was to identify regional zones that present higher risk of groundwater contamination by agriculture. One of the highest risk areas in Brazil is in the State of Sao Paulo. It is the largest fertilizer (30.5 per cent) and pesticide (40 per cent) consumer in the country. Many of its pesticide demanding crops (citrus, cotton, coffee, sugar cane and annual crops) are on highly vulnerable aquifers. Parana (soya, cotton and corn), Rio Grande do Sul (soya, corn and tomato), Minas Gerais (potato, citrus and tomato) and Bahia (citrus, cotton and tomato) were other states that have presented high contamination risk.
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