典型电子垃圾拆解区居民多卤代芳烃的膳食暴露及其癌症风险评估

收集浙江典型电子垃圾拆解区和对照区的饮用水、蔬菜、豆类、米饭、鸡蛋、鱼、鸡肉和猪肉等8类食物样品共191个;采用GC/MS 5975B分析样品中23种PBBs,12种PBDEs和27种PCBs;评估当地居民的PHAHs膳食暴露现状及其癌症风险.结果表明,拆解区居民这三大类PHAHs的平均日摄入量是对照区的2~3倍,通过米饭摄入PHAHs的量占当地居民PHAHs总摄入量的48%以上.拆解区居民因食物摄入PHAHs的癌症风险(3.81×10-4)是对照区(1.50×10-4)的2倍多,其中二英类PCBs的风险值占总癌症风险的45%以上.通过米饭摄入PHAHs是主要的暴露途径,二英类PCBs是引起癌症风险的主要贡献因子,电子垃圾拆解释放出的PHAHs通过食物摄入进入居民体内引起的癌症风险要明显高于对照区.     

新型污染物卤代咔唑的环境行为及生态毒理效应

卤代咔唑(PHCs)是一类与多氯二苯并呋喃结构相类似的新型环境有机污染物.单种卤素取代的PHCs具有135个同系物.绝大多数PHCs不是人类合成化学品或工业品.虽然20世纪80年代即首次在环境中发现PHCs,但直到本世纪这类化合物才逐渐引起人们的关注.近年来,20余种PHCs在河流湖泊沉积物和土壤中被陆续检出.另外,PHCs具有类二噁英毒性、持久性和生物累积性.作为一类新型污染物,PHCs的环境行为研究目前相对较少.因此,了解PHCs的环境分布、来源和生态毒理效应对正确认识这类化合物的环境风险具有重要意义.本文综述了PHCs的环境分布、来源、分析方法和生态毒理效应,并对其未来的研究发展方向作了展望.     

红球菌-R04生物降解多卤代联苯的影响因素研究

研究了不同取代元素以及取代元素的数量、位置等因素对 Rhodococcus sp. R04降解多卤代联苯的影响.结果表明,联苯苯环第4位上的氢分别被氟、氯、溴以及甲基基团取代后降解率由高到低依次为4-FB>4-CB34-MB>4-BrB;当取代元素相同时,随着取代原子数目的增加,多卤代联苯降解率降低;当取代元素及取代原子数目相同时,不同位置的取代对卤代联苯的降解影响较大,特别是2,6位取代会强烈抑制关键酶对卤代联苯的催化降解,导致降解率降低.     

Abstracts to forthcoming papers

Soil and sediments collected at a former chlor‐alkali plant in coastal Georgia (United States), revealed the presence of PCDF concentrations as great as 82.3 ng/g, dry wt. PCDF congener profile in soil was typical of “chlorine pattern”; with elevated proportions of OCDF and HpCDF. Concentrations of PCDFs declined gradually by 44‐fold at a distance of about 500 m along the contamination gradient. Of PCDDs/DFs, 2,3,7,8‐substituted PCDFs accounted for 94–98% of the TCDD‐like activity, which declined by 25‐fold, corresponding with the reduction of total PCDF concentrations. Concentrations of PCDDs in sediments were as great as 17 ng/g, with an elevated contribution from OCDD. The magnitude of decline in PCDD concentrations with distance from the source was less pronounced than that for PCDFs. PBDDs and PBDFs were not detected. Polybrominated biphenyl ether (PBBE) and monobromo‐heptachloro dibenzo‐p‐dioxins and dibenzofurans (PXDDs/DFs) were found, though, at low concentrations. Their spatial distribution was similar to those of PCDDs.     

Relationships between exposure to polyhalogenated aromatic hydrocarbons and organochlorine pesticides and the risk for developing type 2 diabetes: a systematic review and a meta-analysis of exposures to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

A systematic review was performed to evaluate the association between environmental exposures to polyhalogenated aromatic hydrocarbons (PHAHs) and organochlorine (OC) pesticides and the risk for type 2 diabetes (T2D). Searches of EMbase, Google Scholar, Medline, and Scopus were performed. Reports were included if they were original human studies whose design included a control group and if the sample size was larger than 10 participants per group. The articles were excluded if the type of diabetes was unknown or Type 1. Odds ratios (OR), 95% confidence intervals (CI), and modified Naranjo scores for the effects of environmental contaminants were determined for each study. Of the 35 eligible studies, six were included in the meta-analysis; these focused specifically on 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Meta-analysis of these studies showed no significant increased OR for the development of T2D from exposure to TCDD. However, subgroup analysis showed significant elevated OR for the development of T2D if exposure is repeated and accompanied by exposure to other persistent pesticides (OR?=?1.48; 1.10–1.90) but a decreased odds for T2D with exposure resulting from accidental exposure (OR?=?0.46; 0.39–0.52). Our results suggest that there are significant risks of developing T2D in populations with recurring exposures to TCDD in concert with other persistent chlorinated pesticides. A mean Naranjo score of 2.0 was determined for all 35 articles; this score was 2.5 when examining only TCDD studies and 2.1 when examining studies that looked only at T2D. Each of these Naranjo scores suggests a possible association between the prevalence of T2D and exposure to PHAHs or OC pesticides.