Risk assessment of surface water contamination by herbicide residues: monitoring of propanil degradation in irrigated rice field waters using HPLC-UV and confirmation by GC-MS

• Autor(a) principal: Primel,Ednei G.
• Data de Publicação: 2007
• Outros Autores: Zanella,Renato, Kurz,Márcia H.S., Gonçalves,Fábio F., Martins,Manoel L., Machado,Sérgio L.O., Marchesan,Enio
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532007000300014
• topic: propanil; degradation; rice fields; water analysis; herbicide residues

This study evaluates the degradation of the herbicide propanil and of its major degradation product, 3,4-dichloroaniline (3,4-DCA) in water from irrigated rice farming in the State of Rio Grande do Sul, Brazil. It also assesses the contamination risk of surrounding surface waters. After a solid phase extraction step, the concentration of both compounds was determined by high performance liquid chromatography with ultraviolet detection. Confirmation was conducted by gas chromatography-mass spectrometry. Concentrations of propanil in water samples varied from 0.1 to 3600 µg L-1. Propanil was degraded very rapidly to 3,4-DCA and high concentrations of this product were found, varying from 1.0 to 567.5 µg L-1 in water. The obtained half-life times for propanil in water under real conditions for the 2001, 2002 and 2003 harvests were 18.2, 12.5 and 12.2 h, respectively.