Dissipation of the experimental aquatic herbicide fluridone from lakes and ponds

Abstract

The dissipation of the aquatic herbicide fluridone, l-methyl-3-phenyl-5-[3-trifluoromethyl)phenyl]-4(lJ/)-pyridinone, has been determined in experiments conducted in small ponds at three different geographic regions in the United States and in Gatun Lake of the Panama Canal. Fluridone dissipated rapidly from the water, with a half-life averaging 5 days. The dissipation was due in part to deposition on hydrosoil and uptake by aquatic plants, although evidence is presented to suggest photolysis as a

Fate of fluridone in sediment and water in laboratory and field experiments

“…It has also been tested for weed control in cotton (Webster et al, 1977). Studies on the disappearance of fluridone in aquatic systems have indicated that it has an average half-life of about 5 days in pond and lake waters (West et al, 1979;Muir et al, 1980). Dissipation of the herbicide in sediments and terrestrial soils under field conditions has been reported to be much slower than in water.…”

“…Dissipation of the herbicide in sediments and terrestrial soils under field conditions has been reported to be much slower than in water. In sediments half-lives ranging from about 3 month to greater than 12 months have been observed (West et al, 1979;Muir et al, 1980). In sediments half-lives ranging from about 3 month to greater than 12 months have been observed (West et al, 1979;Muir et al, 1980).…”

Determinação de resíduo do herbicida fluridone em peixe

“…As percentagens médias de recuperação foram de 71% para 100 µg kg -1 , 73% para 200 µg kg -1 , 65% para 400 µg kg -1 e 60% para 2.000 µg kg -1 . West (1978) e West et al (1979) obtiveram valores médios de recuperação maiores (89 e 87%, respectivamente), mas as variações das percentagens de recuperação em função das concentrações foram muito maiores nestes trabalhos (Tabela 1). As percentagens de recuperação obtidas no método desenvolvido são adequadas para matrizes complexas, que requerem diversas etapas de limpeza e purificação do extrato para extração do analito.…”

“…As etapas de limpeza de amostras e a utilização de colunas de florisil e cromatografia líquida com detector de UV visível também mostraram-se eficientes e de fácil execução, descontando-se a não-necessidade de derivatização do herbicida, fundamental para que o herbicida seja analisado por cromatografia gasosa (West, 1978;West et al, 1979).…”

“…As primeiras análises de fluridone em peixe foram realizadas por West (1978), West et al (1979) e West et al (1983), utilizando cromatografia gasosa e detector de captura de elétrons, após metilação da molé-cula.…”