Wang Yawei

Concentrations, profiles and gas-particle partitioning of PCDD/Fs, PCBs and PBDEs in the ambient air of an E-waste dismantling area, southeast China

Polychlorinated diebenzo-p-dioxins (PCDDs), polychlorinated diebenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were monitored in the ambient air of Taizhou, an E-waste dismantling area of southeast China to evaluate their concentrations, profiles and gas-particle partitioning. The ΣPCDD/Fs concentrations ranged from 2.91 to 50.6 pg/m3, with an average of 14.3 pg/m3. The I-TEQs for PCDD/Fs were in the range of 0.20–3.45 pg/m3, with an average of 1.10 pg/m3. The ΣPCBs concentrations and TEQs ranged from 4.23 to 11.35 ng/m3, 0.050 to 0.859 pg(TEQ)/m3, respectively. The concentrations of ΣPBDEs ranged from 92 to 3086 pg/m3, with an average of 894 pg/m3. The pollution levels of PCDD/Fs, PCBs and PBDEs were higher than other urban sites, which may be associated with the E-waste dismantling activities. The PCDD/Fs were found exclusively in the particle phase whereas PCBs distributed dominantly in the gas phase. The gas-partilce partitioning was also assessed by correlating the gas-particle partition coefficient (Kp) with the subcooled liquid vapor pressure (PL0). The measured particulate sorptions of PCDD/Fs, PCBs and PBDEs were compared with the predictions from Junge-Pankow model and Koa absorption model. The Junge-Pankow model well estimated the particulate fractions of PCBs. However, it underestimated the sorptions of PCDD/Fs and overestimated the fractions of PBDEs. The predicted particulate fractions of PCDD/Fs and PCBs from Koa model fitted well with the measured data.

Multivariate analysis of sludge disintegration by microwave-hydrogen peroxide pretreatment process.

Microwave irradiation (with H2O2) has been shown to offer considerable advantages owing to its flexible control, low overall cost, and resulting higher soluble chemical oxygen demand (SCOD); accordingly, the method has been proposed recently as a means of improving sludge disintegration. However, the key factor controlling this sludge pretreatment process, pH, has received insufficient attention to date. To address this, the response surface approach (central composite design) was applied to evaluate the effects of total suspended solids (TSS, 2-20 g/L), pH (4-10), and H2O2 dosage (0-2 w/w) and their interactions on 16 response variables (e.g., SCODreleased, pH, H2O2remaining). The results demonstrated that all three factors affect sludge disintegration significantly, and no pronounced interactions between response variables were observed during disintegration, except for three variables (TCOD, TSSremaining, and H2O2 remaining). Quadratic predictive models were constructed for all 16 response variables (R(2): 0.871-0.991). Taking soluble chemical oxygen demand (SCOD) as an example, the model and coefficients derived above were able to predict the performance of microwave pretreatment (enhanced by H2O2 and pH adjustment) from previously published studies. The predictive models developed were able to optimize the treatment process for multiple disintegration objectives.

The research of human exposure to polybrominated diphenyl ethers and perfluoroocatane sulfonate

As two kinds of emerging chemicals, the pollution of polybrominated diphenyl ethers (PBDEs) and perfluoroocatane sulfonate (PFOS) has been becoming a global environmental problem. Also, research of the transport, transfer, bioaccumulation in organism, and toxicology of these two kinds of pollutant is a hotspot in environmental sciences now. In this paper, we summarize and critically review the status and progress of PBDEs and PFOS exposure to human beings. Further, data analyses based on statistical methods are done to study the characters of PBDEs and PCBs concentrations in different regions in the world.

Contamination trends of polybrominated diphenyl ethers, organochlorine pesticides and heavy metals in sediments from Dagu Drainage River estuary, Tianjin

Concentrations of polybrominated diphenyl ethers (PBDEs), organochlorine pesticides (OCPs) and heavy metals in two sediment cores, taken from the Dagu Drainage River, were determined. The contamination trends of these three kinds of compounds were obtained. The results showed that concentrations of PBDEs increased in recent years; there were new contamination sources for OCPs in this area; contamination levels of heavy metals had no significant change in the last several years. Comparing the results of these two cores, erosion and dilution of seawater had different effects on the transportation of these compounds.

Advances on environmental mass spectrometry for emerging contaminants

With the rapid development of instrument science and technology, mass spectrometry and its hyphenation technique is being used pervasively in environmental analysis at such a unprecedened speed, scale and depth. Their application in environmental monitoring has been or is being become the work practices of the day-to-day. In recent years, some high resolution mass spectrometry and their hyphenation with chromatography, especially high resolution chromatography, have played a more and more important role in accurate determination of targeted emerging contaminants and nontarget screening analysis of their metabolites and transformation products, which is vital to elucidate the environmental fate of emerging contaminants. This paper summarized the advances on the study of environmental mass spectrometry and their hyphenation technique with gas chromatography and liquid chromatography for the analysis of emerging contaminants, and the great concern about application of the high resolution mass spectrometry in environmental analysis was emphasized. The future developing perspectives were also presented.