Carbaryl [HRP]

Container aquatic habitats support a specialized community of macroinvertebrates (e.g. mosquitoes) that feed on microbial communities associated with decaying organic matter. These aquatic habitats are often embedded within and around agricultural lands and are frequently exposed to pesticides. We used a microcosm approach to examine the single and combined effects of two herbicides (atrazine, glyphosate), and three insecticides (malathion, carbaryl, permethrin) on microbial communities of container aquatic habitats. MiSeq sequencing of the V4 region of both bacterial and archaeal 16S rRNA gene was used to characterize the microbial communities of indoor microcosms that were either exposed to each pesticide alone, a mix of herbicides, a mix of insecticides, or a mix of all five insecticides. Individual insecticides but not herbicides reduced the microbial diversity and richness and two insecticides, carbaryl and permethrin, also altered the microbial community structure. A mixture of herbicides had no effect on microbial diversity or structure but a mixture of insecticides or all five pesticides reduced microbial diversity and altered the community structure. These findings suggest that exposure of aquatic ecosystems to individual pesticides or their mixtures can disrupt aquatic microbial communities and there is need to decipher how these changes affect resident macroinvertebrate communities.

This study is aimed to develop an electroanalytical methodology using a boron-doped diamond electrode (BDD) associated with experimental design in order to determine simultaneously and selectively carbendazin (CBZ) and fenamiphos (FNP) pesticides. In previous studies oxidation peaks were observed at 1.10 V (CBZ) and 1.20 V (FNP), respectively, with characteristics of irreversible processes controlled by diffusion of species (in pH 2.0 (CBZ) and pH 3.5 (FNP)) using a BR buffer 0.1 mol.L-1 as support electrolyte. The differences between the potentials for both pesticides, (about 100 mV) indicate the possibility of selective determination of FNP and CBZ. However, employing an equimolar mixture of analytes, the peaks overlap to form a single oxidation peak. Thus, we used a 34 full factorial design with four parameters to be analyzed in three levels, in order to obtain the optimized parameters for the separation of the peaks. The best separation conditions were pH 5.0, square wave frequency of 300 s(-1), pulse amplitude of 10 mV and scan increment of 2 mV. These parameters were used to obtain the calibration curves of CBZ and FNP. For CBZ the analytical curve was obtained in the concentration range of 4.95x10(-6) to 6.90x10(-5) mol.L-1 with good sensitivity and linearity (0.175 A/molL(-1) and 0.999, respectively). The limits of detection (LOD) and quantification (LOQ) were 1.6x10(-6) molL(-1) and 5.5x10(-6) molL(-1), respectively. For FNP the linear concentration interval was 4.95x10(-6) to 3.67x10(-5) molL(-1), with a sensitivity of 0,207 A/molL(-1) and linearity of 0.996. The LOD and LOQ were 4.1x10(-6) molL(-1) and 13.7x10(-6) molL(-1), respectively. Using these experimental conditions it was possible to separate the oxidation peaks of CBZ (E-p=1.08 V) and FNP (E-p=1.23 V). The electroanlytical method was applied in lemon juice samples. The recovery values were 110.0% and 92.5% for CBZ and FNP, respectively. The results showed that the developed method is suitable for application in foodstuff samples.