Time filter

Source Type

He W.,Peking University | Chen Y.,Peking University | Yang C.,Peking University | Liu W.,Peking University | And 6 more authors.
Journal of Analytical Methods in Chemistry | Year: 2017

The organic contaminants, including polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs), are of priority concern because of their persistence, toxicity, and long-distance transportation in global environment. Their residues in a daily consumed fish (grass carp) pose potential threat to human health and aquatic ecosystems. The present study optimized an analytical protocol of microwave-assisted extraction (MAE), lip-removal by gel permeation chromatography (GPC), cleanup by solid phase cartridge (SC) or adsorption chromatography column (CC), and gas chromatography-mass spectrometry (GC/MS). Besides traditional statistical parameters, some indicators were calculated to judge the performances of extraction by various methods. The optimization experiment showed that n-hexane/acetone was the best MEA extraction solvent; an optimal fraction time of 10-39 min could simultaneously elute all the target chemicals in a single GPC run. Both CC and SC showed good recoveries. However, CC performed better than SC (p<0.05) for OCPs, and SC performed better than CC for PBDEs (p<0.05). We also emphasized the limitations and advantages of SC and CC and finally proposed SC as the promising cleanup method because of its low-cost materials, time-saving steps, being free of manual filling, and operation by automated SPE system. © 2017 Wei He et al.

Li C.,Beijing Academy of Agriculture and Forestry Sciences | Li C.,Beijing Municipal Key Laboratory of Agriculture Environment Monitoring | Chen J.,Beijing Academy of Agriculture and Forestry Sciences | Chen J.,Beijing Municipal Key Laboratory of Agriculture Environment Monitoring | And 8 more authors.
Science of the Total Environment | Year: 2016

The increased use of plastic film in greenhouse vegetable production (GVP) could result in phthalate ester (PAE) contamination in vegetables. However, limited information is currently available on their occurrence and associated potential risks in GVP systems. The present study documents the occurrence and composition of 15 PAEs in soil, plastic film, and vegetable samples from eight large-scale GVP bases in Beijing, China. Results showed that PAEs are ubiquitous contaminants in these GVP bases. Total PAE concentrations ranged from 0.14 to 2.13 mg/kg (mean 0.99 mg/kg) in soils and from 0.15 to 6.94 mg/kg (mean 1.49 mg/kg) in vegetables. Di (2-ethylhexyl) phthalate, di-n-butyl phthalate, and diisobutyl phthalate were the most abundant components, which accounted for > 90% of the total PAEs. This investigation also indicated that the widespread application of plastic film in GVP systems may be the primary source of these PAEs. The non-cancer and carcinogenic risks of target PAEs were estimated based on the exposures of vegetable intake. The hazard quotients of PAE in all vegetable samples were lower than 1 and the carcinogenic risks were also at acceptable levels for consumers. The data in this study can provide valuable information to understand the status of potential pollutants, specifically PAEs, in GVP systems. © 2016 Elsevier B.V.

Man Y.,Beijing Academy of Agriculture and Forestry Sciences | Man Y.,Risk Assessment Laboratory for Agro products Beijing | Man Y.,Beijing Municipal Key Laboratory of Agriculture Environment Monitoring | Liang G.,Beijing Academy of Agriculture and Forestry Sciences | And 8 more authors.
Chromatographia | Year: 2016

The genus Alternaria comprises ubiquitous pathogens and saprophytes. They can even grow at low temperature, so they are the main fungi responsible for the spoilage of various fruits, vegetables, grains and their products during long-distance transport and refrigerated storage. Alternaria mycotoxins are the secondary metabolite of the genus Alternaria. They can be divided into five main classes according to their chemical structures, including dibenzopyrone derivatives, tetramic acid derivatives, perylene derivatives, AAL toxins and miscellaneous structures. Alternaria mycotoxins are associated with many health effects because of their mutagenicity, teratogenicity and carcinogenicity, which can cause economic losses to agriculture and serious diseases in humans and animals. So far, there is still a lack of monitoring data on these contaminants of Alternaria mycotoxins. Moreover, there are still no statutory or guideline limits set for Alternaria mycotoxins in food and feed by regulatory authorities worldwide. Until now, many analytical methods have been developed for the detection and quantification of Alternaria mycotoxins. On the basis of briefly introducing the chemical structures and toxicities of Alternaria mycotoxins, this article provides an overview of the progress achieved in the detection techniques for Alternaria mycotoxins, focusing on the analytical methods of thin layer chromatography (TLC), gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS), liquid chromatography (LC), liquid chromatography-mass spectrometry (LC-MS), enzyme-linked immunosorbent assay (ELISA) and so on. Finally, the problems of these analytical methods and future development trends are discussed. © 2016 Springer-Verlag Berlin Heidelberg

Xu L.,Beijing Academy of Agriculture and Forestry Sciences | Xu L.,Beijing Municipal Key Laboratory of Agriculture Environment Monitoring | Lu A.,Beijing Academy of Agriculture and Forestry Sciences | Lu A.,Beijing Municipal Key Laboratory of Agriculture Environment Monitoring | And 7 more authors.
Ecotoxicology and Environmental Safety | Year: 2015

The accumulation status, sources and phytoavailability of selected metals in greenhouse vegetable production systems in peri-urban areas of Beijing were investigated. The mean concentrations of As, Cd, Cr, Hg and Pb in greenhouse soils were 8.44, 0.25, 69.0, 0.09 and 22.0mgkg-1, dw, respectively. According to principal component analysis, As, Cd, Cr and Hg are mainly from anthropogenic source, but Pb is likely from natural source. Metal concentrations in all vegetable samples were decreased in the order of Cr>As>Pb>Cd>Hg. Compared with root and fruit vegetables, leaf vegetables had relatively high concentrations and transfer factors of heavy metals, except for Cd. By including soil pH, OM and greenhouse soil metals, 10 empirical models were derived using stepwise multiple linear regression analysis to predict heavy metal concentrations in the edible parts of different vegetables. Among the different vegetable groups, the highest intakes of metals occurred through consumption of leaf vegetables for the two age groups, except for Cd. The HI value of the studied metals were all below 1, indicating that consumption of vegetables grown in greenhouse soils was of low risk to consumers in our study area. © 2015 Elsevier Inc.

Xu L.,Beijing Academy of Agriculture and Forestry Sciences | Xu L.,Beijing Municipal Key Laboratory of Agriculture Environment Monitoring | Cao S.,Beijing Academy of Agriculture and Forestry Sciences | Cao S.,Beijing Municipal Key Laboratory of Agriculture Environment Monitoring | And 4 more authors.
International Journal of Environmental Research and Public Health | Year: 2016

Agricultural soil is typically an important component of urban ecosystems, contributing directly or indirectly to the general quality of human life. To understand which factors influence metal accumulation in agricultural soils in urban ecosystems is becoming increasingly important. Land use, soil type and urbanization indicators all account for considerable differences in metal accumulation in agricultural soils, and the interactions between these factors on metal concentrations were also examined. Results showed that Zn, Cu, and Cd concentrations varied significantly among different land use types. Concentrations of all metals, except for Cd, were higher in calcareous cinnamon soil than in fluvo-aquic soil. Expansion distance and road density were adopted as urbanization indicators, and distance from the urban center was significantly negatively correlated with concentrations of Hg, and negatively correlated with concentrations of Zn, and road density was positively correlated with Cd concentrations. Multivariate analysis of variance indicated that Hg concentration was significantly influenced by the four-way interaction among all factors. The results in this study provide basic data to support the management of agricultural soils and to help policy makers to plan ahead in Beijing. © 2016 by the authors; licensee MDPI, Basel, Switzerland.

Loading Beijing Municipal Key Laboratory of Agriculture Environment Monitoring collaborators
Loading Beijing Municipal Key Laboratory of Agriculture Environment Monitoring collaborators