Revista Brasileira De Herbicidas 2002; 3(1): 75-81
Picloram residues and leaching in water in a sugar cane area
DOI: 10.7824/rbh.v3i1.376
The region of Ribeirão Preto, SP, Brazil, is located on the Guarani aquifer, the most important source of ground water in the South Central region of the country. The recharge area of this aquifer is located in the Espraiado watershed. The presence of sandy soi! and a sugar cane crop treated with pesticides makes the aquifer vulnerable to groundwater contamination. The herbicide picloram was among the pesticides used. To study its behavior, a gas chromatography analytical method for residue analysis was developed and picloram was measured during the years of 1996 until 1999. The movement also was evaluated with simulation using the software CMLS-94-“Chemical Movement in Layered Soils”. The gas chromatography analytical method resulted in a 98.0% correlation of the area in the graphics and the herbicide concentration, and indicated that it was highly effective. No residue of picloram was detected in water in any year from 1986 to 1989. The simulation model CMLS have indicated the leaching down to maximum depth of 8.2 m for “Areia Quartzosa cinza” (AQ-Cin) sandy soi!, 7.3 m for “Areia Quartzosa rosa” (AQ-Ros) sandy soil and 6.7m for “Areia Quartzosa amarela” (AQ-Ama) sandy soi!, followed by latossols “Latossolos Vermelho-Escuro” ( LE-Col, 5.7 m) and “Latossolos Vermelho-Roxo” (LR-Col, 5.3 m), indicating possibilities of picloram leaching.
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