Evidence for the Stepwise Behavioral Response Model (SBRM): the effects of Carbamate Pesticides on medaka (Oryzias latipes) in an online monitoring system

The Stepwise Behavioral Response Model (SBRM), which is a conceptual model, postulated that an organism displays a time-dependent sequence of compensatory Stepwise Behavioral Response (SBR) during exposure to pollutants above their respective thresholds of resistance. In order to prove the model, in this study, the behavioral responses (BRs) of medaka (Oryzias latipes) in the exposure of Arprocarb (A), Carbofuran (C) and Methomyl (M) were analyzed in an online monitoring system (OMS). The Self-Organizing Map (SOM) was utilized for patterning the obtained behavioral data in 0.1 TU (Toxic Unit), 1 TU, 2 TU, 5 TU, 10 TU and 20 TU treatments with control. Some differences among different Carbamate Pesticides (CPs) were observed in different concentrations and the profiles of behavior strength (BS) on SOM were variable depending upon levels of concentration. The time of the first significant decrease of BS (SD-BS) was in inverse ratio to the CP concentrations. Movement behavior showed by medaka mainly included No effect, Stimulation, Acclimation, Adjustment (Readjustment) and Toxic effect, which proved SBRM as a time-dependence model based on the time series BS data. Meanwhile, it was found that SBRM showed evident stress-dependence. Therefore, it was concluded that medaka SBR was both stress-dependent and time-dependent, which supported and developed SBRM, and data mining by SOM could be efficiently used to illustrate the behavioral processes and to monitor toxic chemicals in the environment.     

Multiresidue method for high-performance liquid chromatography determination of carbamate pesticides residues in tea samples

A multiresidue method was developed to determine 19 carbamate pesticides in tea samples. Optimizations of different parameters, such as the type of extraction solvents, clean-up cartridges, and elution solvents were carried out. The developed method used acetonitrile as extraction solvent, amino cartridge for adsorbents and acetone-n-hexane as the eluting solution. Nineteen carbamate residues were then analyzed by high-pressure liquid chromatography (HPLC) with fluorescence detector. The present results showed good linearity by correlation coefficients of more than 0.9999 for all analyses. Limits of detection and quantification varied from 0.0005–0.023 mg L^{? 1}, 0.008–0.077 mg L^{? 1}, respectively. Recoveries of sixteen carbamate pesticides ranged from 65% to 135% at the spiked level of 0.5, 1.0 and 2.0 mg L^{? 1}. The relative standard deviations were lower than 20% and coefficient of variations were lower than 15%. The results indicate that the proposed method provides an effective multi and trace level screening determination of carbamate pesticides residues for tea samples.     

Novel pipette-tip graphene/poly (vinyl alcohol) cryogel composite extractor for the analysis of carbofuran and carbaryl in water

A novel pipette-tip extractor of a graphene/poly (vinyl alcohol) cryogel (graphene/PVA) composite sorbent was prepared to preconcentrate carbamate pesticides in environmental water samples before analysis with a gas chromatograph-flame ionization detector (GC-FID). This novel pipette-tip extractor with the graphene/PVA sorbent exhibited a high porosity when observed through a scanning electron micrograph (SEM). Under optimal conditions, using only 1.0 mL of sample and 0.75 mL of eluting solvent, the developed method provided a wide linear range of 10–700 ng mL^?1 and 10–500 ng mL^?1 with limit of detection (LOD) of 6.40 ± 0.18 and 9.17 ± 0.34 ng mL^?1 for carbofuran (2,3-dihydro-2,2-dimethylbenzofuran-7-yl methylcarbamate) and carbaryl (1-naphthyl methylcarbamate), respectively. The pipette-tip extractor provided high extraction efficiency with high accuracy indicated, by good recoveries in the range of 74.5 ± 4.8% to 119.7 ± 1.6% and 76 ± 15% to 114 ± 19% for carbofuran and carbaryl, respectively. In addition, the fabrication procedure showed a good pipette-tip extractor-to-pipette-tip extractor reproducibility with a relative standard deviation of 1.3–9.8% (n = 5). When the developed pipette-tip extractor was applied for the extraction of carbofuran and carbaryl in surface water samples near vegetable plantation areas, 25.9 ± 8.2 ng mL^?1 of carbofuran was found, and carbaryl was also detected in concentrations that ranged from 45.0 ± 4.0 to 191 ± 13 ng mL^?1.     

Comparative toxicity of some pesticides on human health and some aquatic species

Abstract

Inhibition studies have been carried on the hydrolysis reactions catalyzed by cholinesterases taken from electric eel, human and horse serums by Sevin, Aldrin and Malathion. Three esters of p‐nitrophenol have been used as substrates. The degree of inhibition has been used as a measure of the comparative toxicity of these pesticides on these cholinesterases.     

The sorption of Zectran on bottom sediments and peat moss

Abstract

A modified analytical method employed to determine the insecticide Zectran in natural waters frequently has resulted in erroneous data. The errors have been attributed to interferences from particulate matter in these waters. In order to evaluate analytical interferences due to sorption of Zectran on particu‐lates, a series of experiments was performed using bottom sediments and a peat moss in contact with aqueous solutions of Zectran at a pH value of 6.0 and 20°C.

Isotherm studies confirmed that Zectran sorption occurs in a direct relation to the amount of chemically oxidizable carbon present in the bottom sediments or peat moss. However, the extent of sorption was limited, which suggested that particulates may not be the primary interference in the modified analytical method.     

UPLC-MS/MS法分析土壤中氨基甲酸酯类农药残留的基质效应研究

采用加速溶剂萃取处理土壤样品,用超高效液相色谱串联质谱法测定样品中15种氨基甲酸酯类农药残留,方法在5.00μg/L～200μg/L范围内线性良好,检出限为0.3μg/kg～0.5μg/kg,加标回收率为78.9％ ～116％,6次测定结果的RSD为0.7％ ～15.7％.试验表明:不同地域的6种标准土壤对15种目标物...     

Highly efficient photodegradation of the pesticide metolcarb induced by Fe complexes

Here we show the efficient photoinduced degradation of the pesticide metolcarb, in less than 400 min, using iron(III) aquacomplexes and 365 nm light. The degradation is mainly due to the formation of hydroxyl radical. It was complete when molecular oxygen was present. The analytical study gives evidence for the primary formation of several byproducts formed from 1) the scission of the O–C bond, 2) the hydroxylation of the aromatic moiety and 3) the attack of the two methyl groups. Under prolonged irradiation and in aerated solutions, efficient mineralization was evidenced by the study of total organic carbon evolution as a function of irradiation time.     

Prospects and limitations of phytoremediation for the removal of persistent pesticides in the environment

The environmental problems that have arisen from the use of persistent pesticides in the past, and potential sources of further contamination have been discussed. The potential and limitations of phytoremediation for removal of pesticides in the environment have been reviewed. The enzymatic processes in plants that are known to be involved in phytodegradation of pesticides, and possibilities for enhancing them have also been discussed.     

固相萃取/高效液相色谱法测定地表水中氨基甲酸酯类农药

通过固相萃取法提取地表水中10种氨基甲酸酯类农药,萃取溶液经浓硫酸脱色,佛罗里硅土柱除杂,用柱后衍生高效液相色谱法测定.在5μg/L～500μg/L范围内,标准曲线线性关系良好,仪器检出限低于1μg/L,水样平均加标回收率为90.0%～101%,RSD为1.1%～9.2%.     

地表水中氨基甲酸酯农药及代谢物的快速、灵敏分析方法研究

利用固相萃取-超高效液相色谱/串联质谱,建立水样中痕量氨基甲酸酯农药及代谢物的分析方法.该方法在5min之内完成15种目标物的分析;加标回收率为80.4%～120.7%,相对标准偏差为0.7%～12.0%;检测限为0.005～0.2ng/L;在0.002～0.2μg/ml浓度范围内具有很好的线性.该方法具有快速、灵敏的特点.