Removal of triclosan from water by sepiolite supported bimetallic Fe/Ni nanoparticles.

A simple and low-cost route to fabricate sepiolite-supported bimetallic Fe/Ni (Sep-Fe/Ni) nanoparticles was obtained by synchronous liquid phase reduction method. The as prepared composite was used to remove triclosan (TCS) from aqueous solutions. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Brunauer-Emmett-Teller (BET) analysis were used for characterization of the materials. As the supporting material, Sep dispersed Fe/Ni nanoparticles on its surface effectively and reduced the agglomeration phenomenon, providing more reactive sites. Sep-Fe/Ni had a large surface area of 90.5 m2/g, which was considerably higher than that of Fe/Ni (9.2 m2/g). Sep-Fe/Ni exhibited an enhanced TCS removal efficiency, as compared to the Fe/Ni and Sep materials. Operation factors, including the solution pH, initial TCS concentration, and material dosage, were investigated and found to be influential for TCS removal. The kinetic analysis indicated that the depletion of TCS in aqueous solutions conformed to the pseudo-first-order kinetic model under optimized conditions. The transformation pathway of TCS was studied in detail, revealing that the dechlorination of TCS by Sep-Fe/Ni is a stepwise reaction, namely from TCS to di-chlorinated intermediates, with the newly formed intermediate products also degrading into mono-chlorinated products by further reductive dechlorination. This study demonstrated that Sep-Fe/Ni is a promising reductant for TCS removal in water.

Polybrominated diphenyl ethers and polychlorinated biphenyls in mangrove sediments of Shantou, China: Occurrence, profiles, depth-distribution, and risk assessment.

Surface and columnar sediments were collected from four mangrove Wetlands in Shantou coastal areas of South China to investigate the level, distribution, possible sources and ecotoxicological risks of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs). Total concentration of 14 PBDEs (∑14PBDEs) and 41 PCBs (∑41PCBs) varied from 0.61 to 180 ng/g and 42-636 pg/g dry weight (dw) in surface sediments, respectively. The concentration of PBDEs was much higher than that of PCBs. Compared with other mangrove Wetlands around the world, PCBs levels in the studied area were relatively low, while the concentrations of PBDE were at higher level. Decabromodiphenyl ether (BDE-209) was the predominant PBDEs homologue in all sediment samples, indicating the extensive use of deca-BDE in this area. Penta-CBs and hexa-CBs were the main homologues of PCBs. Spatial variations showed that the concentration of PBDEs might be mainly affected by anthropogenic activities in specific sites of this region, whereas dry and wet deposition might be an important input source of PCBs in this area. Although accurate sediment chronology was not available, higher concentrations of PBDEs and PCBs were still found in some deeper sediment layers, suggesting that new input quantity tends to decrease with the increase of control. Risk assessment showed that penta-BDEs and deca-BDE may have potential negative ecological effects on the ecological of Shantou mangrove sediments, while the effects of PCBs can be neglected.

Assessment of exposure to polybrominated diphenyl ethers associated with consumption of market hens in Guangzhou.

To evaluate contamination by polybrominated diphenyl ethers (PBDEs) in market hens and human PBDE exposure via hen consumption in Guangzhou, hens were collected and their muscle, liver, fat, blood, yolk, and ingluvies tissues were analyzed for 13 PBDE congeners. The median highest concentration of ∑PBDEs was found in the ingluvies (5.30 ng/g lw), followed by the muscle (2.53 ng/g lw), with the lowest located in the yolk (0.09 ng/g lw). The concentrations of PBDEs in the muscle tissue of market hens in Guangzhou were at medium levels compared to others reported around the world. BDE-47, -153, -99, and -183 were the predominant congeners. The daily intake concentrations of PBDEs from hen muscle were estimated to range from 0.08 to 0.31 ng/kg/day in this study, with a Hazard Quotient (HQ) below 1.0. These results suggest that the health risk of PBDEs for the general population, through the consumption of market hens in Guangzhou, was generally low. However, the intake of PBDEs via food consumption may be one major exposure pathway for the general population of Guangzhou.

[Levels, Sources, and Health Risk Assessments of Heavy Metals in Indoor Dust in a College in the Pearl River Delta].

Thirty indoor dust samples were collected from staff and study areas in a college in Foshan, and the As, Hg, Cd, Cu, Zn, Ni, Pb, and Cr contents were measured. The Spearman correlation coefficient, principal component analysis, and US EPA health risk assessment model were used to determine the sources and degree of pollution and the health risks. The results showed that the levels of the eight heavy metals were higher than the background values in Guangdong Province and the reported values in other Chinese cities, excluding Hg. The levels of the eight heavy metals were higher in the staff area than in the study area, but the difference was not significant. The eight heavy metals were derived from similar sources; Hg was mainly derived from outdoor anthropogenic sources, while the others were mainly derived from indoor anthropogenic sources. The daily non-carcinogenic exposure dose was in the following order:ingestion > dermal exposure > inhalation. Ingestion was the major pathway of heavy metal exposure from indoor dust. Except for Cr, the non-carcinogenic hazard indexes of ingestion and dermal exposure were taken from partial sample points > 1. All of the health risks were lower than the average risk thresholds of the heavy metals, and would not cause health risks to humans. Printers, copiers, instruments, and equipment were important sources of indoor pollution and risk sources of heavy metals. Thus, protective measures should be taken to reduce the risk of exposure.

Tissue distribution of decabrominated diphenyl ether (BDE-209) and its metabolites in sucking rat pups after prenatal and/or postnatal exposure.

Growing evidence has shown that decabromodiphenyl ether (BDE-209) can disrupt thyroid hormones and induce neurological and developmental effects, especially for the fetuses and neonates after prenatal or postnatal exposure. The present study was carried out to examine the effects of in utero and lactational exposure to BDE-209 on the absorption and tissue distribution of BDE-209 and its metabolites in offspring. Pregnant Sprague-Dawley rats were given daily oral doses of 5µmol/kg b.w. BDE-209 in peanut oil during gestational and lactational period or during lactational period only. BDE-209 and its debrominated congeners were analyzed in several maternal tissues, offspring carcass and neonatal tissues. The occurrence of polybrominated diphenyl ethers (PBDEs) and their time profiles in maternal blood, placenta and fetuses/sucking pups indicated that BDE-209 and its debrominated products can be transferred from mother to offspring via in utero or lactational exposure. Nona-BDEs were the predominant congeners in the analyzed pup tissues, and BDE-206 was the most abundant congener while BDE-197/204 was the major congener of octa-BDE. Then the contributions of transplacental and lactational transfer were compared for BDE-209 and its debrominated congeners. The levels of PBDEs in tissues of sucking pups of the in utero and lactational exposure group were much higher than those of only lactationally exposed group. BDE-197/204 was the debrominated congener with the most significant difference between these two groups and the pup brain was the tissue with the most significant difference of the levels of debrominated congeners. The results provide a basis for understanding the possible adverse effects caused by maternal transfer of BDE-209 during the critical periods of development of fetuses and sucking neonates.

Characterization of maternal transfer of decabromodiphenyl ether (BDE-209) administered to pregnant Sprague-Dawley rats.

To evaluate maternal transfer of decabromodiphenyl ether (BDE-209), Sprague-Dawley rats were given daily oral doses of 5 µmol/kgb.w. BDE-209 in peanut oil from gestation day (GD) 7 to postpartum day (PD) 4. BDE-209 was increased temporally in maternal blood, placenta, fetuses and neonates. Furthermore, more BDE-209 was found in neonate whole-body samples obtained during lactational period (PD 4) than in that of fetal whole-body samples during pregnancy GD 15 and 21. Overall an increase was observed over time for nona-BDE levels in maternal blood and placenta, but these congeners were decreased in fetuses or neonates. Slight changes were observed for octa-BDEs in both maternal blood and placenta while a significant decrease was observed in the fetuses or neonates for BDE-196 and 198/203. These results demonstrated that BDE-209 and its metabolites can transport to the placenta and milk, and eventually enter the fetuses and/or the neonates.

Simultaneous determination of 8-hydroxy-2'-deoxyguanosine and 5-methyl-2'-deoxycytidine in DNA sample by high performance liquid chromatography/positive electrospray ionization tandem mass spectrometry.

8-Hydroxy-2'-deoxyguanosine (8-OHdG) and 5-methyl-2'-deoxycytidine (5-mdC) are utilized as useful biomarkers not only for early diagnosis but also for the detection and assessment of high-risk individuals. In the present study, a sensitive and specific method was developed for simultaneous determination of 8-OHdG and 5-mdC in DNA by high performance liquid chromatography/positive electrospray ionization tandem mass spectrometry. The limits of quantification for 8-OHdG and 5-mdC were 80 and 40pg/ml, respectively. The calibration curves of 8-OHdG and 5-mdC were linear over the concentration range of 0.02-100ng/ml and the correlation coefficients were higher than 0.9990. The intra-day and inter-day relative standard derivative values were in the range of 0.70-7.47% for 8-OHdG and 1.07-7.06% for 5-mdC, respectively. The recoveries were 93.4-108.5% for 8-OHdG and 87.4-104.9% for 5-mdC, respectively. This method was validated by determination of the background levels of 8-OHdG and 5-mdC in calf thymus DNA, and satisfactory results were obtained.