Residues and dissipation kinetic of abamectin,chlorfenapyr and pyridaben acaricides in green beans (Phaseolus vulgaris L.) under field conditions using QuEChERS method and HPLC

Abstract

The current study estimated the dissipation rates of abamectin, chlorfenapyr and pyridaben acaricides in pods of green beans (Phaseolus vulgaris L.) under field conditions in Egypt. Pesticides were extracted and cleaned-up by QuEChERS method and were analyzed by HPLC. The dissipation of these acaricides followed the first order kinetics model with half-life (t_1/2) values 1.00, 3.50 and 1.50?days for abamectin, chlorfenapyr and pyridaben, respectively. The lowest residues, at different time intervals of field application rate of each pesticide, were observed with abamectin followed by pyridaben and then chlorfenapyr. Pre-harvest intervals (PHIs) were 10.00, 13.50 and 6.00?days for abamectin, chlorfenapyr and pyridaben, respectively and were below the established European maximum residue limits (EU MRLs) 10–14, 14–21 and 7–10?days after application, respectively. If the fresh pods will be consumed after harvest, it is expected that the presence of these pesticides in the food will have a negative impact on human health. Therefore, the elimination of the residues of these harmful pesticides must be carried out.     

Phytotoxicity and groundwater impacts of leaching from thermal treatment residues in roadways

The use of coal fly ash (CFA), municipal solid waste incinerator bottom ash (MSWIBA) and flue gas desulfurization residue (FGDR) in road construction has become very common owing to its economical advantages. However, these residues may contain toxic constituents that pose an environmental risk if they leach out and flow through the soil, surface water and groundwater. Therefore, it is necessary to assess the ecotoxicity and groundwater impact of these residues before decisions can be made regarding their utilization for road construction. In this study, the physico-chemical characteristics, leaching and phytotoxicity of these residues were investigated. Specifically, multivariate analyses were used to evaluate the contributions of the leaching constituents of the CFA, MSWIBA and FGDR leachates to the germination index of wheat seeds. B, Ba, Cr, Cu, Fe and Pb were found to be more toxic to the wheat seeds than the other heavy metals. Furthermore, the leached concentrations of the constituents from the CFA, MSWIBA and FGDR were below the regulatory threshold limits of the Chinese identification standard for hazardous wastes. Analyses conducted using a numerical groundwater model (WiscLEACH) indicated that the predicted field concentrations of metals from the CFA, MSWIBA and FGDR increased with time up to about 30 years at the point of compliance, then decreased with time and distance. Overall, this study demonstrated that the risks resulting from MSWIBA, CFA and FGDR leaching could be assessed before its utilization for road construction, providing crucial information for the adoption of these alternative materials.     

Fate and transport of the β-adrenergic agonist ractopamine hydrochloride in soil–water systems

The feed additive ractopamine hydrochloride was fortified at four concentrations into batch vials containing soils that differed in both biological activity and organic matter(OM).Sampling of the liquid layer for 14 days demonstrated that ractopamine rapidly dissipated from the liquid layer. Less than 20% of the fortified dose remained in the liquid layer after 4 hr,and recoveries of dosed ractopamine ranged from 8 to 18% in the liquid layer at 336 hr. Sorption to soil was the major fate for ractopamine in soil:water systems, i.e., 42%–51% of the dose at14 days. The major portion of the sorbed fraction was comprised of non-extractables; a smaller fraction of the sorbed dose was extracted into water and acetone, portions which would be potentially mobile in the environment. Partitioning coefficients for all soils suggested strong sorption of ractopamine to soil which is governed by hydrophobic interactions and cation exchange complexes within the soil OM. Ractopamine degradation was observed, but to mostly non-polar compounds which had a higher potential than ractopamine to sorb to soil. The formation of volatiles was also suggested. Therefore, despite rapid and extensive soil sorption,these studies indicated a portion of ractopamine, present in manures used to fertilize soils,may be mobile in the environment via water-borne events.     

铁铜内电解-膨润土组合工艺处理含铬废水

研究利用铁铜内电解工艺和膨润土吸附的联合作用,对含铬废水进行处理。含铬模拟废水首先经过铁铜内电解法装置,该出水再经膨润土吸附,以达到去除效果。并考察此组合工艺的各种影响因素。结果表明:(1)铁铜内电解预处理确定最佳反应参数为:铁铜用量之比为8:1,反应时间为100 min,pH值为3.0;(2)膨润土最佳吸附条件为:膨润土用量为2 g/l,反应时间为20 min;(3)在最佳反应条件下,对初始浓度分别为30 mg/l和60 mg/l的实际制革废水中的铬进行了处理,都取得较好的去除效果,其Cr(VI)去除率分别为99.54%和99.32%。     

湿式提砷法在处理工业废水及废渣中的应用

采用硫化法去除冶金工业酸性废水中的砷．除砷形成的含砷（ 主要成分 As₂S₃） 废渣用浓硫酸处理,废渣中的砷元素以 As₂O₃ 形式回收,纯度达99.4 ％ ,同时回收副产物硫磺等．试验结果表明,该方法的化学反应速度快,工艺过程稳定,砷的总回收率达95 ％ 以上,除砷效率可达99.99 ％ ．     

宁波市鄞州区农作物农药残留现状与控制对策

对鄞州区种植的稻谷、叶菜类、水果类、豆类、茄果类和块茎类农产品按月进行了411个批次抽样,按照国家相关规定对22个农药项目进行了检测。检测结果发现样本农药项目检出率为0.3%,农产品农药残留合格率97.82%,农药残留检出项目中88.89%是杀虫剂。超出农药残留标准的样本主要是5-10月的青菜,叶菜类超标样本率达到3.72%。农药残留超标样本在平原、滨海地区种植散户中有发现,而在山区各规模农户中均有发现。小学文化程度农户样本农药残留超标率高达4.50%,是大学文化程度农户样本农药残留超标率的6.16倍。为了降低鄞州区农作物农药残留率,提出5方面的控制对策。     

通过式固相萃取/超高效液相色谱-串联质谱法测定蔬菜中18种农药残留

建立了超高效液相色谱-串联质谱(UPLC-MS;MS)快速测定蔬菜中18种农药残留的方法.样品经乙腈提取后,经Oasis PRiME HLB固相萃取柱净化,采用ACQUITY UPLC HSS T3 C18(50 mm×2.1 mm,1.8μm)色谱柱进行分离,以0.1%甲酸水溶液和乙腈作为流动相进行梯度洗脱.采用电喷雾电离源、正离子模式下以多反应监测(MRM)进行定性和定量分析.结果表明,18种农药在0.5—50μg·L^-1范围内线性关系良好(r2>0.995),方法最低检出限为0.4—1.5μg·kg^-1,最低定量限为1.4—5.0μg·kg^-1.在韭菜、芹菜、番茄、白菜基质中,5、10、50μg·kg^-1添加水平下的加标回收率为60.2%—126.9%,相对标准偏差(RSD)为0.4%—21.6%(n=3).     

Measurement of residues of benomyl and mancozeb pesticides in shrub and nonshrub cucumbers sampled from different regions of Mazandaran province (Iran)

Farmers use mancozeb against cucumber pests, such as Perono spoxa, in large amounts without consideration of potential chronic human health hazards resulting from pesticide accumulation in food and fruits. Considering the necessity of food for humans and importance of fruit in daily diet, as well as the determination of pesticide residues in food and fruits as mandated by WHO and FAO, the residues benomyl and mancozeb, the most prominently used pesticides in Iran, were measured. In this study cucumbers from 76 sample regions were used. Data showed that the amounts of benomyl was related to the type of cucumber in the regions, but there was no significant relationship between the amount of mancozeb and type of cucumber.     

Influence of manufacturing process on the residues of certain fungicides used on tea

Green tea shoots which were sprayed with fungicides such as hexaconazole, propiconazole, carbendazim, and tridemorph were collected from tea bushes after 24 h of fungicide application to study the effect of manufacturing process on the residues. Significant loss of residues was noted at each stage of the manufacturing process. The total loss in residues upon manufacturing of these fungicides ranged from 12.20% to 57.14%. Among the various influential factors that determine the loss of residues, vapor pressure of the fungicides was most prominent in the contribution to residue loss. A high vapor pressure of the fungicide tridemorph amounted to a residue loss of 57.14%, while the low vapor pressure of the other three fungicides caused a loss of less than 22.22%.     

Effects of benzo(a)pyrene on blood components,tumor markers,and oxidative status in mice

This study was carried out to investigate the effect of long-term exposure to benzo(a)pyrene (B(a)P) in mice. Hemogram, tumor markers, oxidative status, and B(a)P residues in liver tissue were evaluated. Sixty albino Swiss mice were randomly distributed equally into three groups; the control was given 0.1?mL corn oil once a week for 8 weeks. The other two groups were given 20 and 40?mg B(a)P per kg body weight once a week orally for the same period. B(a)P-treated mice suffered from depression and ascites, and macrocytic normochromic anemia was recorded at the 16th and 30th week. There was marked leukocytosis with lymphocytosis at the early stage of the experiment, followed by leukopenia, lymphopenia, and neutropenia at the end of the experiment. Monocytes and arginase activity were elevated throughout the experiment. Alpha feto-protein was detected only in the experimental groups in the 30th week of the experiment. A marked increase in lipid peroxides associated with a decrease in reduced glutathione and glutathione-S-transferase (GST) activity was observed in liver homogenate of the B(a)P-exposed animals. Residues of B(a)P were detected in liver tissue with a concentration parallel to the B(a)P dose level. In conclusion, B(a)P caused abnormal changes in the hemogram, evidence of tumor formation through B(a)P-induced oxidative stress, and it was accumulated in the liver tissue of mice.