Residues and potential health risks of DDTs and HCHs in commercial seafoods from two coastal cities near Yangtze River Estuary

Effective removal matrix interferences by a modified QuEChERS based on the molecularly imprinted polymers for determination of 84 polychlorinated biphenyls and organochlorine pesticides in shellfish samples

A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedure combined with GC-MS/MS detection approach using a dynamic multiple reaction monitoring (DMRM) mode was successfully applied for the simultaneous analysis of 84 polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in shellfish samples. The novel molecular imprinted polymers (MIPs) were synthesized by precipitation polymerization and characterized by Scanning electron microscopy, Brunauer-Emmett-Teller, Fourier transform infrared spectra and adsorption experiment. The MIPs exhibited good adsorption capability to pigment coextractives in shellfish samples without the loss of analytes compared with other sorbents. Under optimal conditions, spiked experiments in sinonovacula, mussel, and clam at 10.0-100.0 μg/kg concentrations showed excellent recoveries ranging from 70% to 120% for all analytes with the relative standard deviations of <10%. The developed method showed good linearity with the correlation coefficient above 0.9980, and the limits of quantification were in the range of 0.01-9.02 μg/kg. The developed QuEChERS procedure combined with GC-MS/MS was successfully applied to 84 PCBs and OCPs residues detection in shellfish samples.

Microbial Degradation of Pesticide Residues and an Emphasis on the Degradation of Cypermethrin and 3-phenoxy Benzoic Acid: A Review

Nowadays, pesticides are widely used in preventing and controlling the diseases and pests of crop, but at the same time pesticide residues have brought serious harm to human's health and the environment. It is an important subject to study microbial degradation of pesticides in soil environment in the field of internationally environmental restoration science and technology. This paper summarized the microbial species in the environment, the study of herbicide and pesticides degrading bacteria and the mechanism and application of pesticide microbial degrading bacteria. Cypermethrin and other pyrethroid pesticides were used widely currently, while they were difficult to be degraded in the natural conditions, and an intermediate metabolite, 3-phenoxy benzoic acid would be produced in the degradation process, causing the secondary pollution of agricultural products and a series of problems. Taking it above as an example, the paper paid attention to the degradation process of microorganism under natural conditions and factors affecting the microbial degradation of pesticide. In addition, the developed trend of the research on microbial degradation of pesticide and some obvious problems that need further solution were put forward.

Biomagnification and enantiomeric profiles of organochlorine pesticides in food web components from Zhoushan Fishing Ground, China

Trophodynamics and chiral signatures of organochlorine pesticides (OCPs), including dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), and chlordanes in a food web from Zhoushan Fishing Ground, China, were studied. Residues of OCPs in all teleost fishes were within food safety levels. Strong positive correlations were found between trophic levels (TLs) and wet weight concentrations of target chemicals, with trophic magnification factors (TMFs) from 4.17 to 9.77. Lipid contents and TLs significantly correlated, which indirectly affect the bioaccumulation processes of OCPs. The consistently racemic EF values of α-HCH, as well as invariability of the relative proportions of HCH isomers in different marine species implied that HCHs in animals originate directly from the surrounding environment. However, in vivo biotransformation and/or elimination of o,p'-DDT cannot be precluded. TMFs of the individual enantiomers further suggest that the influence of achiral biotransformation is too minor to induce enantioselective biomagnification of chiral OCPs through the studied food web.

PCBs and OCPs in fish along coastal fisheries in China: Distribution and health risk assessment

PCBs and OCPs were analyzed in fish (bass) taken along Chinese coastal fisheries. In the bass muscle, PCB, DDT and HCH concentrations were in the range of 1.02-2.2ng/g, 0.44-1.74 and 2.84-106.11ng/gww, respectively. Spatial distribution showed that the concentrations of target contaminants in bass from south fisheries were in general much lower than those from north fisheries in China. The ratios of OCP congeners suggested that technical DDT was not the main input and a recent usage of lindane or old technical HCH residuals could be the source of HCHs. The OCC concentrations in liver (127-442.43ng/gww) from selected samples were 8-12 and 10-14 times higher than those in gills and muscles, respectively. Based on the maximum allowable fish assumption rate (CRlim and CRmm), it could cause human health risk, by consuming bass samples taken from highly contaminated fisheries including QD and ST.

Application of a multifunctional magnetic mesoporous material for seafood sample clean-up prior to the determination of highly chlorinated polychlorinated biphenyls

In this study, a highly effective clean-up adsorbent was developed for eliminating matrix interferences, especially main organochlorine pesticide residues during the determination of highly chlorinated polychlorinated biphenyls in seafood.