A sensitive monoclonal antibody-based enzyme-linked immunosorbent assay for chlorpyrifos residue determination in Chinese agricultural samples

A monoclonal antibody-based competitive antibody-coated enzyme-linked immunosorbent assay (ELISA) was developed and optimized for determining chlorpyrifos residue in agricultural products. The IC(50) and IC(10) of this ELISA were 3.3 ng/mL and 0.1 ng/mL respectively. The average recoveries in six agricultural products were between 79.5% and 118.0%, with the intra-assay coefficient of variation being less than 8 %. The limit of detection for all tested products was 30 ng/g. To the best of our knowledge, this assay has the best specificity among all the published research on ELISAs for chlorpyrifos.     

Uptake and distribution of metals by water lettuce (<Emphasis Type="Italic">Pistia stratiotes</Emphasis> L.)

Background, aim and scope  

Water quality impairment by heavy metal contamination is on the rise worldwide. Phytoremediation technology has been increasingly applied to remediate wastewater and stormwater polluted by heavy metals.     

Polybrominated diphenyl ethers (PBDEs) and mercury in fish from lakes of the Tibetan Plateau

High mountains may act as cold traps for globally transported persistent organic pollutants (POPs) and mercury (Hg). In the present study, 60 fish samples were collected from eight alpine lakes across the Tibetan Plateau. Concentrations of polybrominated diphenyl ethers (PBDEs), total mercury (HgT) and methyl mercury (MeHg) were quantified in the fish muscle tissues to improve the understanding of pollution status and factors regulating the transport and fate of these contaminants on the Plateau. The results showed that lake-averaged ∑₁₄PBDEs concentration was between 0.09 ng g⁻¹ dw and 4.32 ng g⁻¹ dw, which was lower than those reported for European mountains. The total mercury concentration in individual fish ranged from 243 to 2384 ng g⁻¹ dw, and that of MeHg from 131 to 1610 ng g⁻¹ dw, which is much higher than those reported in other mountain fish. The spatial variation of PBDEs and mercury in the Plateau is largely controlled by the specific meteorological patterns.     

Analysis of pesticide residues using the Quick Easy Cheap Effective Rugged and Safe (QuEChERS) pesticide multiresidue method in traditional Chinese medicine by gas chromatography with electron capture detection

The Quick Easy Cheap Effective Rugged and Safe multiresidue method (QuEChERS) has been validated for the extraction of 15 organochlorine pesticides (OCPs) in completely different matrices of traditional Chinese medicine (TCM). The method employed a rapid, simple and cost-effective procedure. The spiking levels for the recovery experiments were 0.1, 0.5 and 2.0 mg kg⁻¹. Mean recoveries mostly ranged between 76.0% and 114.0% (96.0% on average), and relative standard deviations (RSD) were generally below 10% (4.72% on average). Based on these results, the methodology has been proven to be highly efficient and robust and thus suitable for monitoring the MRL compliance of a wide range of commodity. The contamination status of 15 OCPs on 80 different TCMs marketed in China, and a total of 400 samples were also performed using a previously validated method. 15 OCPs were benzene hexachloride (BHC, including α-BHC, β-BHC, γ-BHC, δ-BHC), hexachlorobenzene, heptachlor, heptachlor epoxide, aldrin, p, p′-DDE, p, p′-DDD, o, p′-DDT, p, p′-DDT, mirex, endrin, dieldrin. This study indicates that the proposed method is useful for analyzing OCPs in TCM.     

Biodegradation and bio-sorption of antibiotics and non-steroidal anti-inflammatory drugs using immobilized cell process

In the present study, the removal mechanisms of four antibiotics (sulfamethoxazole, sulfadimethoxine, sulfamethazine, and trimethoprim) and four non-steroidal anti-inflammatory drugs (acetaminophen, ibuprofen, ketoprofen, and naproxen) in immobilized cell process were investigated using batch reactors. This work principally explores the individual or collective roles of biodegradation and bio-sorption as removal routes of the target pharmaceuticals and the results were validated by various experimental and analytical tools. Biodegradation and bio-sorption were found as dominant mechanisms for the drug removal, while volatilization and hydrolysis were negligible for all target pharmaceuticals. The target pharmaceuticals responded to the two observed removal mechanisms in different ways, typically: (1) strong biodegradability and bio-sorption by acetaminophen, (2) strong biodegradability and weak bio-sorption by sulfamethoxazole, sulfadimethoxine, ibuprofen and naproxen, (3) low biodegradability and weak bio-sorption by sulfamethazine and ketoprofen, and (4) low biodegradability and medium bio-sorption by trimethoprim. In the sorption/desorption experiment, acetaminophen, sulfamethoxazole and sulfadimethoxine were characterized by strong sorption and weak desorption. A phenomenon of moderate sorption and well desorption was observed for sulfamethazine, trimethoprim and naproxen. Both ibuprofen and ketoprofen were weakly sorbed and strongly desorbed.     

Atmospheric particle characterization, distribution, and deposition in Xi'an, Shaanxi Province, Central China

Physical characterization and chemical analysis of settled dusts collected in Xi’an from November 2007 to December 2008 show that (1) dust deposition rates ranged from 14.6 to 350.4 g m⁻² yr⁻¹. The average deposition rate (76.7 g m⁻² yr⁻¹) ranks the 11th out of 56 dust deposition rates observed throughout the world. The coal-burning power was the major particle source; (2) on average (except site 4), ∼10% of the settled dusts having size <2.6, ∼30% having size <10.5, and >70% having size <30 μm; (3) the concentrations for 20 out of 27 elements analyzed were upto 18 times higher than their soil background values in China. With such high deposition rates of dusts that contain elevated levels of toxic elements, actions should be taken to reduce emission and studies are needed to assess the potential impacts of settled particles on surface ecosystem, water resource, and human health in the area.     

ZnO/LixNi1-xO光催化降解甲基橙的研究

采用溶胶凝胶法制备LixNi1-xO和ZnO粉体,利用球磨法制备ZnO/LixNi1-xO复合粉体,以紫外光为光源,通过降解甲基橙,研究了锂掺杂及n-p复合对氧化镍的光催化性能影响。结果表明：当投放量为0.1 g/L,x≤0.075（摩尔分数）的锂掺杂氧化镍均比未掺杂氧化镍的光催化活性高。当锂掺杂摩尔分数为0.025,投放量为0.4 g/L时锂掺杂氧化镍的光催化活性最佳,甲基橙最高降解率达到93.1%。当ZnO/Li0.025Ni0.975O在质量比为1∶1,投放量为0.2 g/L时光催化活性最佳,甲基橙最高降解率达到98.1%。     

间歇浸取对废物水泥窑共处置产品中Cr和As释放的影响

研究间歇浸取条件下废物水泥窑共处置产品中重金属Cr、As的释放,对水泥产品在实际应用中的环境安全性评价有重要意义.通过模拟煅烧实验制取含Cr和As的水泥熟料,并制取混凝土样品,采用pH影响实验和扩散浸出实验,研究了混凝土中Cr和As的溶解特性及其间歇浸取对混凝土中Cr和As释放的影响.结果表明,浸取方式对浸取液pH有较...     

凹凸棒土的氨氮吸附性能研究

在以氨氮去除率为指标,在振荡时间60 min,振荡温度25℃,振荡速度140r/min的条件下发现凹凸棒土的最佳投加量2.5 g;添加凹凸棒土可以加强SBR生物系统去除氨氮的能力;拟合凹凸棒土吸附氨氮的等温线方程符合Freundlich吸附模型.     

烧结脱硫灰制备蒸压加气混凝土砌块的研究

研究了烧结烟气半干法脱硫灰复掺粉煤灰、水渣/水泥,辅之外加剂,制备蒸压加气混凝土砌块的可行性.实验结果显示,当脱硫灰掺入量25%,粉煤灰掺入量45%,水渣和水泥掺入量均15%,铝粉掺入量0.04%,水料比0.6,稳泡剂掺入量0.0012%,烧碱掺入量1%,无需额外添加石膏,采用蒸压养护12.5 h(其中抽真空时间为0....