Adsorption, transport and degradation of fipronil termiticide in three Hawaii soils

Abstract

BACKGROUND: The behavior of the termiticide fipronil in soils was studied to assess its potential to contaminate ground and surface water. This study characterizes (1) adsorption of fipronil in three different soils, (2) transport of fipronil through leaching and runoff under simulated rainfall in these soils and (3) degradation of fipronil to fipronil sulfide and fipronil sulfone in these soils. RESULTS: The adsorption experiments showed a Freundlich isotherm for fipronil with Koc equal to 1184 L kg−1. In the leaching experiments, the concentration of fipronil and its metabolites in leachate and runoff decreased asymptotically with time. The concentration of fipronil in the leachate from the three soils correlated inversely with soil organic carbon content. The degradation experiment showed that the half‐life of fipronil in the soils ranged from 28 to 34 days when soil moisture content was 75% of field capacities, and that 10.7–23.5% of the degraded fipronil was transformed into the two metabolites (fipronil sulfide and fipronil sulfone). CONCLUSION: Fipronil showed large losses through leaching but small losses via runoff owing to low volumes of runoff water generated and/or negligible particle‐facilitated transport of fipronil. The half‐life values of fipronil in all three soils were similar. Copyright © 2011 Society of Chemical Industry

Pesticide sorption and leaching potential on three Hawaiian soils

“…In terms of soil characteristics, organic carbon (OC) content, clay content, clay mineralogy, and pH are known to affect the immobilization and degradation of pesticides (Barriuso et al, 1992;Hiller et al, 2008;Koskinen and Harper, 1990). The oxide character and content can also be influential, particularly in tropical soils such as those found in Hawaii (Assis et al, 2011;Shuai et al, 2012).…”

Leaching patterns of fipronil in 3 kinds of soil in Hainan province, China

“…Fipronil was easier degraded than its metabolites in soils (Shuai et al, 2012;Spomer and Kamble, 2010). Our results found that Fipronil as an effective pesticides wound not cause earthworms death resulting in the reduce densities of earthworms in deep soil.…”

Recovery of Imidacloprid from Leachate and Soil

“…The measurements of pesticide residue in soil might not adequately predict long-term insecticidal efficacy, because they do not consider all the complex biotic and abiotic interactions that can have deleterious effects on the termiticides. Abiotic and biotic reactions (hydrolysis, photolysis, and oxidation) of insecticides designated for termite control have been documented (Austin 1999, Baskaran et al 1999, Kamble and Saran 2005, Shuai et al 2012. Other factors affecting efficacy of a termiticide are susceptibility and behavioral reaction of the termites to the chemical.…”