Methodology using solid phase extraction and high performance liquid chromatography (SPE-C18/HPLC-DAD) was applied to pesticide determinations in ten water reservoirs in the semidarid region of northeastern Brazil. The validated method was suitable for determination of herbicides and insecticide in surface water. The recovery efficiency of atrazine, methyl-parathion and simazine was approximately 70%. The method also showed good linearity and selectivity with correlation coefficients (R) greater than 0.99. The limits of detection were below the maximum residue limits (MRLs) established by government agencies. Studied reservoirs showed presence of atrazine at mean levels from 7.0 to 15.0 µg/L. Simazine and methyl parathion were not detected during the period. The atrazine levels measured from this semiarid region are of the same magnitude as those found in regions with moderate to high agricultural activity. According to detected atrazine concentrations, the annual health risk to humans was insignificant. However, the control of herbicides is important to maintain the quality of water in the reservoirs of Ceará, Brazil.

No abstract

Pesticides compounds represent an important class of pollutants for food, soil and surface water resources. Thus, a simplified method using gas chromatography was used for determining five insecticide residues in fruit samples produced in Ceará State (Brazil). The insecticides were simultaneously extracted from the fruit samples with a mixture of water-methanol (1 : 1 %v/v) from lipid-containing crops and then reextracted with ethyl acetate. Cleanup by silica gel column chromatography was not necessary. The extracts were analyzed by GC-ECD. Analytical parameters, such as limit of detection (LOD), limit of quantification (LOQ), linearity, precision, and recovery were considered for the orange fruit. A sufficient recovery of 52.1, 57.0, 49.5, and 108.5% for parathion methyl, malathion, chlorpyrifos, and 2,4-dichlorophenol was found. The compounds 2,4-dichlorophenol, malathion, parathion methyl, and chlorpyrifos were found in all the fruit samples analyzed.