Congener-distribution patterns and risk assessment of polychlorinated biphenyls,dibenzo-p-dioxins and dibenzofurans in Korean human milk

Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs) were analyzed by high-resolution gas chromatography/high-resolution mass spectrometry in human milk samples from an urban and an industrial area in Korea. All PCB congeners were analyzed to characterize the congener distribution as well as to evaluate the toxic equivalent quotient (TEQ) values and the total concentration. In homologue distributions of PCBs, two distinct patterns were found. The mean concentrations of PCDD/Fs and PCBs were 15.13 and 5.64 TEQ pg/g fat (based on WHO TEF, 1997), respectively. The contamination in Korean human milk is comparable to that found in other countries. From these results a daily intake of 60 TEQ pg/kg/day for an infant was estimated. The assumptions were that the infant breast feeds for 1 year, has an average body weight of 10 kg during this period, and ingests 800 g/day of human milk containing a mean concentration of 20.84 TEQ (PCDD/Fs) pg/g fat (based on primipara mothers).     

Congener-distribution patterns and risk assessment of polychlorinated biphenyls, dibenzo-p-dioxins and dibenzofurans in Korean human milk

Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs) were analyzed by high-resolution gas chromatography/high-resolution mass spectrometry in human milk samples from an urban and an industrial area in Korea. All PCB congeners were analyzed to characterize the congener distribution as well as to evaluate the toxic equivalent quotient (TEQ) values and the total concentration. In homologue distributions of PCBs, two distinct patterns were found. The mean concentrations of PCDD/Fs and PCBs were 15.13 and 5.64 TEQ pg/g fat (based on WHO TEF, 1997), respectively. The contamination in Korean human milk is comparable to that found in other countries. From these results a daily intake of 60 TEQ pg/kg/day for an infant was estimated. The assumptions were that the infant breast feeds for 1 year, has an average body weight of 10 kg during this period, and ingests 800 g/day of human milk containing a mean concentration of 20.84 TEQ (PCDD/Fs) pg/g fat (based on primipara mothers).     

Effects of copper chloride on formation of polychlorinated dibenzo-p-dioxins in model waste incineration

Combustion experiments in a laboratory-scale fluidized-bed reactor were conducted to elucidate the effects of copper chloride as a catalyst on polychlorinated dibenzo-p-dioxins (PCDDs) formation in municipal waste incineration. We used model wastes with and without copper chloride (CuCl₂ · 2H₂O), both of which contained polyvinyl chloride as a chlorine source. Combustion temperature was set to 900 °C, and the amount of air supplied was twice the stoichiometric ratio. The experimental setup was carefully planned to suppress the influences of experimental conditions except the waste composition. Results of these experiments showed that copper chloride in the waste increased the amount of PCDDs formed and made the homologue profile to shift towards the highly chlorinated species. Copper chloride contributes to the PCDDs formation by promoting chlorination, whereby the reaction is important in that organic matter is chlorinated directly by copper compounds. Copper chloride did not exert a great influence on the isomer distribution patterns of PCDDs, while there appeared a significant difference in the case of PCDFs. This points out the difference of the major formation mechanisms between PCDDs and PCDFs. PCDDs are less formed by the catalytic reactions from carbon/polycyclic aromatic hydrocarbons than PCDFs in our experimental conditions.     

水体中PCDD/Fs生物标示器的研究进展

水生生物体内PCDDs/Fs的累积作用是通过3种途径实现的,包括通过鳃和表皮从水中的直接摄入(生物富集),水中悬浮颗粒的摄取(吞入)和污染食物的消耗(生物放大)。鱼体内的PCDDs/Fs含量可以在一定程度上反映水体的PCDDs/Fs污染水平。但是,由于鱼体的生物-沉积物累积因子相当低,其作为生物累积标示的可能性仍有待进一步的研究。鱼体肝脏的总细胞色素P450、细胞色素P4501A、乙氧基试卤灵-O-脱乙基酶、超氧化物歧化酶和脂过氧化反应水平等指标都可作为水体PCDDs/Fs污染的较为敏感的生化生物标示器     

六六六热解废渣提取物对家兔皮肤的毒性

使用六六六热解废渣提取物对家兔进行了皮肤毒性试验。家兔皮肤经涂布提取物后,在涂布处及其他部位引起常有丘疹和小脓疱特征的痤疮型皮炎,与六六六热解生产多氯苯时暴露于其废渣烟尘中的工人所患氯疮相似。分析证明废渣中含有大量PCDDs和PCDFs,显然这是家兔皮肤反应和工人皮肤疾患的原因。引起家兔皮肤反应的最小涂布剂量为55μg混合物质,其中含2,3,7,8-TCDD约0.003μg。     

Detailed analysis of PCBs and PCDD/Fs impurities in a dielectric oil sample （ASKAREL Nr 1740） from an imported transformer in China

Homolog and congener profiles of polychlori- nated biphenyls （PCBs）, polychlorinated dibenzo-p- dioxins （PCDDs） and polychlorinated dibenzofurans （PCDFs） in commercial PCBs formulations are useful information for the source appointment of PCBs contam- ination as well as the risk assessment caused by potential exposure. Dielectric oil （ASKAREL Nr 1740） in an imported transformer found in China was sampled and analyzed by isotope dilution technology using high resolution gas chromatography-high resolution mass spectrometry （HRGC/HRMS）. The detailed homolog and congener profiles of PCBs obtained were compared with those of known Aroclor formulations. High similarity in the homolog profile between the oil sample and Aroclor 1260was found, with the hexachlorinated and hepta- chlorinated biphenyls accounting for more than 80.2% of the total PCBs concentration. Severn indicator PCBs contribute about 30%, while 12 PCB congeners （i.e., # 153, #143, #168, #180, #149, #165, #138, #170, #190, #187, #174, #181） account for more than 50% of the total PCB concentrations. Total concentration ofPCDDs, PCDFs and dioxin-like PCBs （DL-PCBs） was found to be 740 ng TEQ/g, of which 620 ng TEQ/g came from DL-PCBs. The contribution of PCDDs to the total TEQ was neglectable. The concentration of PCDFs homologs follows the order of OCDF 〉 HxCDFs 〉 HpCDFs 〉 PeCDFs 〉 TeCDFs, which is in consistence with the previous study on Aroclor 1260. Three DL-PCBs congeners （i.e., #118, #156, #157） accounted for 77% of the total concentration of DL-PCBs, also they contribute 72% in the TEQ caused by DL-PCBs.     

Improvement of sampling and analytical methods for polychlorinated dibenzo‐p‐dioxins and dibenzofurans in environmental samples and its quantitative evaluation

Sampling of PCDDs/Fs in flue gas from a MSW incinerator was conducted using a modified apparatus of the 5 train method, which has been widely used for the sampling of PCDDs/Fs emission. In the atmosphere a high volume air sampler with special packings was used. Collection efficiencies of PCDDs/Fs were more than 98% for both samplers, using ¹³C₁₂—PCDD reference standard isomers. It was suggested that these sampling methods were adaptable for the measurements of PCDDs/Fs at sources and in the environment. To validate the applicability of existing methodologies on the PCDD/F determination, interlaboratory comparisons were undertaken. From high resolution GC/MS analysis, 2,3,7,8‐TCDD concentrations in reference ash samples were 0.052±0.013 ng/g as comparable results between the laboratories. In addition, the daily intakes of PCDDs/Fs for exposed persons in the MSW incineration facilities in Japan were estimated ranging of 0.053 to 0.28 pg/kg/day by the international toxic equivalent calculations.     

Development of dioxin toxicity evaluation method in human milk by enzyme-linked immunosorbent assay--assay validation for human milk

In this study, the development of a toxicity evaluation method for dioxins in human milk by enzyme-linked immunosorbent assay (ELISA) was reported. A total of 17 human milk samples were tested by ELISA and by gas chromatography/mass spectrometry (GC/MS) to assess whether the ELISA performed on samples obtained from primiparas could be considered as reliable enough for identifying a dioxins contamination in human milk. The concept of toxicity equivalent quantity (TEQ) screening was validated by comparing TEQ values for a set of human milk samples to the ELISA responses predicted for those samples. A fairly good correlation (r=0.920) between immunoassay and GC/MS was achieved for human milk. This ELISA should be useful for biological samples monitoring.     

Substance flow analysis of coplanar PCBs released from waste incineration processes

Previous reports have focused on the emission of coplanar polychlorinated biphenyls (Co-PCBs) which have a toxic mechanism similar to that of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/DFs) released from municipal solid waste (MSW) incineration. Such emissions accounted for a small percentage of all the dioxins (PCDDs/DFs and Co-PCBs) recorded at the toxicity equivalent (TEQ) level. There is, however, very little information about Co-PCBs, such as the quantities being released and their effect on overall environmental pollution. The aim of this research has been to clarify the substance flow of Co-PCBs from MSW incineration processes. The results reveal that whereas the input of Co-PCBs into the MSW incineration facilities in Kyoto City was 0.13–0.29 μg-TEQ per ton waste, the total output of Co-PCBs (the sum of Co-PCBs released from emission gas, fly ash, and bottom ash) was 4.9 μg-TEQ per ton waste. The total output was therefore found to be higher than the total input. Over 90% of the total PCBs were decomposed in the incineration process. In comparing the profiles of congeners and homologues, those in the MSW were found to be similar to those detected in the atmosphere and products containing PCBs, but different from those in the MSW incineration gas. Received: August 26, 1998 / Accepted: March 2, 1999     

典型再生铜冶炼厂周边土壤中PCDD/Fs、PCBs和PCNs的污染特征及健康风险评估

本研究同时测定了1家典型再生铜冶炼厂周边土壤中PCDD/Fs、PCBs和PCNs的含量,进而分析和评估了该冶炼厂对周边环境的影响和研究区域工人的健康风险.冶炼厂周边土壤中PCDD/Fs、PCBs和PCNs的含量范围分别为17.2~370、1.20~14.2和70.9~950 pg·g^-1.在冶炼厂附近（<300 m）的采样点检出了高含量的PCDD/Fs和PCNs,其含量随距离的增加呈指数型下降.源解析结果表明,再生铜冶炼厂对其周边300 m内土壤中PCDD/Fs和PCNs的含量和单体分布特征影响显著.此外,除再生铜冶炼厂外,周边土壤中PCDD/Fs的污染可能还受到历史使用五氯酚或五氯酚钠的影响.健康风险评估结果表明,工人暴露周边土壤中PCDD/Fs、PCBs和PCNs的非致癌和致癌风险均处于可接受水平范围内,经口摄入是最主要的暴露途径.虽然健康风险评估只考虑工人工作时间内对室外环境中这些污染物的暴露,两份土壤样品的致癌风险值已达到0.47×10^-6和0.15×10^-6（阈值10^-6）,值得关注.PCDD/Fs对总致癌风险（PCDD/Fs+PCBs+PCNs）的贡献率最高（96%）,是该区域需首要关注和控制的二英类化合物.