Concentrations and determinants of organochlorine levels among pregnant women in Eastern Spain

Persistent organic pollutants (POPs) comprise a large variety of toxic substances with ample distribution. While exposure to these toxins occurs mainly through diet, maternal POP levels may be influenced by certain sociodemographic, environmental, or lifestyle factors. This is important given that these substances may have adverse effects on fetal development. The aim of this study is to examine the sociodemographic, environmental, lifestyle, and dietary determinants of the levels of hexachlorobenzene (HCB), b-hexachlorocyclohexane (b-HCH), 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (4,4′-DDT), 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (4,4′-DDE), and polychlorinated biphenyls (PCB congeners 118, 138, 153, 180) measured in the blood of pregnant women participating in a mother-child cohort study conducted in Valencia (Spain).The study population consisted of 541 pregnant women who formed part of the INMA (Childhood and the Environment) cohort (2004-2006). POP levels were determined in blood taken during the 12th week of pregnancy with the aid of gas chromatography with electron capture detection. Sociodemographic, environmental, and dietary information was obtained from a questionnaire. Multivariate Tobit regression models were constructed in order to assess the association between POP levels and selected covariates.The results showed that all the women had detectable levels of at least one of these compounds while in 43% of the subjects, all eight compounds were detected. The compounds found in the greatest number of women were 4,4′-DDE (100%) and PCBs 153 and 180 (95%). The most important determinants of high POP levels were the mother's age, country of origin, increased body mass index, and number of weeks of breastfeeding after previous pregnancies. With regard to diet, 4,4′-DDT and 4,4′-DDE levels increased with the intake of meat, fruit, and cereal. PCB 153 levels increased with the intake of seafood. The levels of HCB, b-HCH, 4,4′-DDT, and 4,4′-DDE observed in this study were slightly higher than in other studies, whereas the PCB levels were similar.     

Persistent organochlorine compounds in fetal and maternal tissues: evaluation of their potential influence on several indicators of fetal growth and health

Some organochlorine compounds, such as polychlorinated biphenyls (PCBs), have a tendency to bioaccumulate in humans and predators at the top of the food chain. We have recently confirmed the transplacental transfer of these compounds and the present study has been designed on the same material with the aim of investigating their potential health effects on newborns from 70 pregnant women, resident in a Northern Italy industrial town. Organochlorine compounds [namely, p,p′-dichlorodiphenyltrichloroethane (p,p′-DDT), p,p′-dichlorodiphenyldichloroethene (p,p′-DDE), hexachlorobenzene (HCB), and PCBs] have been analyzed both in cord and maternal serum, placenta, and maternal subcutaneous adipose tissue by GC-MSD. p,p′-DDT levels in the adipose tissue resulted significantly (p < 0.05) related to birth length. Mothers of neonates born by preterm programmed caesarean delivery showed significantly (p < 0.005 for both) higher serum p,p′-DDE serum concentrations and p,p′-DDT levels in the adipose tissue, as compared to mothers delivering at term.     

河流底泥沉积物中五氯酚和六氯苯残留的同时测定

建立了冷冻干燥，超声波提取，弗罗里硅土固相萃取净化(Florisil SPE cleanup)，气相色谱-质谱(GC/MS)检测河流底泥沉积物中五氯酚（PCP）和六氯苯（HCB）残留的方法。方法加标回收率在91%~ 99%之间，相对标准偏差小于10%。检测五氯酚和六氯苯的方法检出限（干重）分别为0.038 3 μg/g、0.053 2 μg/g。应用该方法进一步研究了取样点底泥沉积物剖面PCP、HCB含量与总有机碳(TOC)的分布特征。由此推测TOC可能是PCP和HCB在底泥沉积物剖面中沿纵深向下层迁移的一个重要载体。     

Temperature effect on the elimination of pentachlorophenol,hexachlorobenzene and mirex by rainbow trout (salmo gairdneri)

The elimination rates of pentachlorophenol, hexachlorobenzene and mirex were estimated in rainbow trout that were held at 4, 12 and 18°C for 120 days following a single oral exposure. The results suggested temperature could become an important environmental variable in deriving a coefficient for the elimination component of a contaminant dynamics model. This response would be most applicable for those substances that are eliminated relatively rapidly, and those models that simulate the contaminant dynamics of fish in its natural environment.     

纳米零价铁/活性炭复合材料去除水中六氯苯的影响因素研究

本文主要研究纳米零价铁/活性炭材料对水中六氯苯(HCB)的去除能力和影响因素。吸附等温研究结果表明该材料对六氯苯的去除符合Langmuir吸附即化学吸附机理。对水中六氯苯和脱氯产物的分析证明纳米零价铁/活性炭对六氯苯的去除包括吸附和脱氯。溶液p H,水中常见阴阳离子的存在等因素都会影响六氯苯去除。低p H对去除有利,这主要是由于低p H对纳米零价铁的氧化过程有利,导致脱氯反应加快。低浓度的HCO-3、Cl-和SO42-能促进六氯苯的去除。这些离子在低浓度时能加快零价铁的腐蚀,对六氯苯的去除有利。而高浓度时则由于铁氧化物沉积会产生抑制作用。NO-3则与六氯苯发生竞争反应,导致六氯苯的去除随硝酸盐的浓度增加而降低。常见的阳离子如Mg2+对六氯苯的去除没有影响。Cu2+和Fe2+的存在不仅改变了溶液的p H,还对纳米零价铁的氧化还原特性有影响。但总体而言,Cu2+和Fe2+的存在对六氯苯的去除是有利的。     

百菌清中微量杂质六氯苯含量的液相色谱分析

采用液相色谱外标法对百菌清中六氯苯成分进行定量测定 ,该方法标准偏差0 0 0 0 4 ,平均回收率 10 0 0 1%。     

六氯苯处理技术研究进展

简述了六氯苯的结构及其理化性质,通过系统的文献查阅,总结了迄今为止六氯苯降解及去除方法的研究进展,指出在六氯苯污染控制和处理方面进一步研究的方向。     

六氯苯的环境危害及其污染控制

六氯苯是一种持久性有机污染物(POPs),具有长期残留性、生物蓄积性、半挥发性和高毒性,能够导致生物体内内分泌紊乱、生殖及免疫机能失调、发育紊乱以及癌症等严重疾病.详细介绍了环境中六氯苯的来源及其危害.并对目前国内外六氯苯环境污染的治理技术进行了综述.     

超声波提取植物性食品中六氯苯的研究

采用超声波提取一气相色谱法，对植物性食品中六氯苯含量进行了定量分析。研究结果表明；在一定的超声波处理条件下，六氯苯较稳定且降解比率很小：三种不同的提取方法（索氏、振荡和超声波）相比，以超声波提取法最优；最适宜的超声波提取条件为：超声波功率20W、提取温度35℃、提取时间60min、以石油醚一丙酮混合溶剂（1：1）为提取剂；本方法的平均回收率为90.80％、变异系数2．23％、检测限0．0001μg/g，可满足植物性食品中微量有机物定量分析要求。     

Electroreduction of hexachlorobenzene in protic solvent at Hg cathodes

The electrochemical reduction of hexachlorobenzene (HCB) to lower chlorinated benzenes has been studied in methanol solution. Differential pulse voltammetry at a sessile mercury drop cathode showed four reduction waves at E=–1.13, –1.33, –1.57 and –1.84V vs the standard hydrogen electrode, corresponding to sequential reduction to penta-, tetra-, tri- and dichlorobenzenes, respectively. The formation of these products was followed with time using a recirculating flow-through cell; the isomer distributions of the lower chlorinated benzenes were as predicted from a mechanism involving chloride elimination from radical anion intermediates. A maximum current efficiency of 60% was achieved in single-pass experiments in which the potential was controlled near the peak of the first reduction peak (–1.2V) and the initial concentration of HCB was 1mm.