Hexabromocyclododecane and tetrabromobisphenol A in sediments and paddy soils from Liaohe River Basin, China: Levels, distribution and mass inventory

Hexabromocyclododecane(HBCD) and tetrabromobisphenol A(TBBPA) are two kinds of brominated flame retardants and widely present in the environment and biota. The levels,spatial distributions and mass inventories of HBCD and TBBPA were investigated in sediments and paddy soils from the Liaohe River Basin in northeast China. The concentrations of ΣHBCD and TBBPA were in the range of not detected(nd) to 4.02 ng/g dry weight(dw) and 0.03 to 4.06 ng/g dw, respectively. γ-HBCD was dominated in sediments,while the abundance of α-HBCD was relatively high in paddy soils. The spatial distributions of HBCD and TBBPA in surface sediments and paddy soils indicated that the local point-input was their major source. The significant correlation between total organic carbon(TOC) contents and the HBCD levels suggested that TOC content also exerted an influence on the distribution of HBCD in sediments. Meanwhile, it was found that the irrigation with river water was not the major transportation pathway of HBCD and TBBPA in paddy soils. Based on the study, it was estimated that there were about 1.67 tons HBCD and 2.20 tons TBBPA deposited into sediments of the Liaohe River system every year. The total mass inventories of HBCD and TBBPA in sediments were far higher than that in paddy soils.     

The thermal transformation mechanism of chlorinated paraffins: An experimental and density functional theory study

The increasing production and usage of chlorinated paraffins(CPs) correspondently increase the amount of CPs that experience thermal processes. Our previous study revealed that a significant amount of medium-chain chlorinated paraffins(MCCPs), short-chain chlorinated paraffins(SCCPs) as well as aromatic and chlorinated polycyclic aromatic hydrocarbons(Cl-PAHs) were formed synergistically during the thermal decomposition of CP-52(a class of CP products).However, the transformation mechanisms of CP-52 to these compounds are still not very clear.This article presents a mechanistic analysis on the decomposition of CP-52 experimentally and theoretically. It was found that CP-52 initially undergoes dehydrochlorination and carbon chain cleavage and it transformed into chlorinated and unsaturated hydrocarbons. Cyclization and aromatization were the most accessible pathways at low temperatures(200–400°C), both of which produce mostly aromatic hydrocarbons. As the temperature exceeds 400°C, the hydrocarbons could decompose into small molecules, and the subsequent radical-induced reactions become the predominant pathways, leading to the formation of Cl-PAHs. The decomposition of CP-52 was investigated by using density functional theory and calculations demonstrating the feasibility and rationality of PCB and PCN formation from chlorobenzene. The results improve the understanding of the transformation processes from CP-52 to SCCPs and Cl-PAHs as well as provide data for reducing their emissions during thermal-related processes.     

Organochlorine compounds and polycyclic aromatic hydrocarbons in surface sediment from Baiyangdian Lake, North China： Concentrations, sources profiles and potential risk

Organochlorine pesticides(OCPs),polychlorinated biphenyls(PCBs),and polycyclic aromatic hydrocarbons(PAHs) were determined in nineteen surface sediment samples collected from Baiyangdian Lake and its inflowing river(Fuhe River) in North China.Total concentrations of OCPs,PCBs and PAHs in sediments ranged from 5.4 to 707.6 ng/g,2.3 to 197.8 ng/g,and 101.3 to 6360.5 ng/g,respectively.The levels of contaminants in Fuhe River were significantly higher than those in Baiyandian Lake.For hexachlorocyclohexane(HCHs) and dichlorodiphenytrichloroethanes(DDTs),α-HCH and p,p-DDT were predominant isomers;while for PCBs,PCB 28/31,PCB 40/103,PCB 60,PCB 101,and PCB 118 were predominant congeners.Possible sources derived from historical usage for OCPs and incomplete combustion fuel,wood,and coal and exhaustion of boats or cars for PAHs.Risk assessment of sediment indicated that sediments in Fuhe River were likely to pose potential biological adverse impact.     

生物陶粒处理深圳水库水的试验研究

利用生物陶粒对深圳水库水进行了生物预处理现场试验研究,试验结果表明,生物陶粒能有效地降低水中的ＮＯ２－Ｎ、ＮＨ３－Ｎ、ＯＣ、浊度、色度、Ｍｎ和藻类,在工作滤速为４ｍ／ｈ,气水比为１：１的条件下平均去除率分别为９０．８％,８４％、２１．４％６２％、４７％、８９％和６８％,是解决水源水微污染问题有效的预单元工艺。     

Sulfur-containing amino acid methionine as the precursor of volatile organic sulfur compounds in algea-induced black bloom

After the application of methionine, a progressive and significant increase occurred in five volatile organic sulfur compounds (VOSCs): methanethiol (MeSH), dimethyl sulfide (DMS), dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS) and dimethyl tetrasulfide (DMTeS). Even in the untreated control without a methionine addition, methionine and its catabolites (VOSCs, mainly DMDS) were found in considerable amounts that were high enough to account for the water’s offensive odor. However, blackening only occurred in two methionine-amended treatments. The VOSCs production was observed to precede black color development, and the reaching of a peak value for total VOSCs was often followed by water blackening. The presence of glucose stimulated the degradation of methionine while postponing the occurrence of the black color and inhibiting the production of VOSCs. In addition, DMDS was found to be the most abundant species produced after the addition of methionine alone, and DMTeS appeared to be the most important compound produced after the addition of methionine+glucose. These results suggest that methionine acted as an important precursor of the VOSCs in lakes suffering from algea-induced black bloom. The existence of glucose may change the transformation pathway of methionine into VOSCs to form larger molecular weight compounds, such as DMTS and DMTeS.     

伊宁市饮用水源地水质变化动态趋势分析

根据近10年的监测数据，对伊宁市饮用水源地水质变化进行动态趋势分析，无显著变化。     

生物法合成纳米铁的研究进展

纳米铁颗粒的制备技术发展迅速,方法多种多样。生物法因其具有原料来源广,反应条件温和,产物纳米级颗粒不易团聚,以及有毒副产物少等特点,成为学者们争相研究的对象。对近几年国内外采用微生物、植物提取物等合成纳米铁材料的方法及机理进行了阐述,综述了纳米铁在环保领域的应用,并对今后深入研究生物法合成纳米铁的前景进行了展望。     

粉末活性炭-超滤膜处理黄浦江原水的研究

采用粉末活性炭与超滤膜联用技术处理黄浦江原水。试验表明．投加粉末活性炭不会造成膜过滤阻力的增加。粉末活性炭的投加量越多，膜过滤阻力也越小。粉末活性炭与膜联用能有效地提高有机物的去除效果。     

Spatial–temporal characteristics of haze and vertical distribution of aerosols over the Yangtze River Delta of China

Variation of haze events occurred in the Yangtze River Delta(YRD) of China, the characteristics of meteorological elements and the vertical distribution of aerosols during haze episodes were analyzed by utilizing data of ground observation, radiosonde and CALIPSO. The results illustrate that the frequency of haze events between 1981 and 2010 peaked in winter but bottomed out in summer and decreased from north to south in the YRD region, reaching at the lowest point in "low frequency center" — Shanghai. When haze happened, the most seriously affected area was 2–4 km above the ground and the concentrated range of total backscattering coefficient(TBC) that decreased with altitude was 0.8 × 10~(-3)–2.5 × 10~(-3) km~(-1)·sr~(-1). Particulate depolarization ratio(PDR) was less than 40%in a large part and 93% aerosols over the YRD area were regular particles, while the irregular ones concentrated on 2 km above the surface and the irregularity rose up but the diversity diminished when altitude increased. Color ratio(CR) was lower than 1.2 mostly at all altitudes and distributed asymmetrically above the ground. Nearly 80% aerosols under10 km were fine particles(CR 1.0) and 22.54% coarse particles(CR 1.0) clustered at 2–4 km. Large particles(CR 1.2) aggregated in lower troposphere massively yet relatively smaller ones gathered in middle and upper troposphere. In the YRD region, aerosols with more powerful capabilities were wider and less regular than the ones of Northwestern China.     

缺氧生物滤池-UASB处理垃圾渗滤液的中试研究

用缺氧生物滤池与UASB相串联的工艺对杭州市天子岭垃圾填埋场惨滤液进行了中试试验。通过实验，总结了缺氧生物滤池的挂膜特性及UASB起动的成功经验。最终的试验结果表明：出水COD、BOD、SS分别稳定在900mg／L、150mg／L、250mg／L以下，缺氧生物滤池对渗滤液具有很好的预处理效果，不仅能脱吸部分NH3、CO2、H2S，而且能提高它的可生化性，为UASB的高效运行创造了良好的条件。