Monitoring of the herbicide clomazone in environmental water samples by solid-phase extraction and high-performance liquid chromatography with ultraviolet detection

Abstract

SummaryEvaluation of a simple and rapid method for determination of cJomazone in environmental water samples, by high-performance liquid chromatography with ultraviolet detection, is described. After solid-phase extraction with Cl8 extraction cartridges clomazone was separated on a Cl8 column with 65:35 (v/v) methanol-water, pH 4.0, as mobile phase at a flow-rate of 1.0 mL min 1. After optimization of the extraction and separation conditions, the method was used for determination of clomazone residues in rivers and agricultural waters of the central region of the Rio Grande do Sul province. The results revealed that clomazone persists in agricultural water at least for 130 days, and was present in 90% of the river water samples analyzed.

The Impact of Herbicides on Benthic Organisms in Flooded Ricefields in Southern Brazil

“…After each collection, the labeled samples were taken for chemical analysis in the Group of Research Analyses of Residues and Pesticides laboratories of UFSM. The concentrations of herbicides were determined by means of High Performance Liquid Chromatography, with detection by the arrangement of diodes (HPLC -DAD), using methanol and water as the mobile phase and a C-18 column, according to the method described by Zanella et al (2002). The physical and chemical data were evaluated through a two-way ANOVA (time and treatment), and the means were compared by a t test (p<0.05).…”

Environmental Fate and Toxicology of Clomazone

“…The dissipation of clomazone from floodwaters was studied by Quayle et al (2006). When Quayle et al (2006) applied clomazone to small replicated rice plots at a rate of 0.5 L/ ha (i.e., as commercially (Zanella et al 2002).…”

Herbicides Persistence in Rice Paddy Water in Southern Brazil

“…It is stable at room temperatures for at least 2 years and it is also stable at 50 ºC for at least 3 months. The properties of clomazone indicates its potential for aquatic environmental pollution and has been detected in the majority of the water samples collected from rivers located close to irrigated rice fields in the South of Brazil (Zanella et al, 2002).…”

“…Herbicides are potential contaminants of environmental water because they are directly applied to the soil or irrigating water. Thus, they can be leached to the surface water and transported into the groundwater (Hatrík & Tekel, 1996;Zanella et al, 2002). According to specialized literature (Barceló & Hennion, 1997;Primel et al;Cabrera et al, 2008), a pesticide can pollute the aquatic environmental if its solubility in water is higher than 30 mg L -1 ; its K oc , organic carbon partition coefficient, is less than 300-500; its K H , Henry Law constant is less than 10 -2 Pa m 3 mol -1 , its soil half-life is longer than 2-3 weeks and its water half-life is longer than 25 weeks.…”

“…In Brazil some studies has been done until now to investigate the behavior and destination of herbicides in the systems related to the rice paddy fields in an attempt to evaluate the risk to the environment. (Zanella et al 2002;Noldin et al, 1997: Bortoluzzi et al 2006Marchesan et al 2007;Resgalla et al, 2007;Bortoluzzi et al 2007;Grützmacher et al 2008;Caldas et al 2009;Silva et al, 2009;Caldas et al 2010;Demoliner et al 2010;Marchesan et al 2010;Reimche, 2010).…”