2.采用同位素稀释-HRGC/HRMS-MID方法分析了烧结厂不同除尘系统中排放的烟尘和静电除尘器灰尘中的二噁英。结果显示，烧结过程中产生的二噁英主要来自台车的机头部分，是台车机头部分冷却区中从头合成（de novo synthesis）的结果。样品中的二噁英以PCDFs占优势为主要指纹特征：浓度最高的同系物依次为TCDFs和PeCDFs。并且，2,3,4,7,8–PeCDF对 WHO-TEQs的贡献最大，占总TEQ值的45%左右。
|Other Abstract||Release, distribution, and health risk of persistent organic pollutants (POPs), especial of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs), are becoming a major environmental concern in the world. Theses compounds are highly persistent, semi-volatile, bioaccumulative, and have the adverse effects including immune, endocrine, nervous and reproductive toxicities to humans and animals. According to the latest inventory of PCDD/Fs emissions, thermal metallurgical processes, such as sintering, open burning of E-waste, and secondary smelters of different metal, are the other major pollution sources. Therefore, the samples collected from sinter plant were analyzed to discuss the emission and profile of PCDD/Fs. Human or environmental samples collected from Luqiao area in Zhejiang province or Changjiang Estuary to evaluate the contamination status. The potential sources of these contaminants in those areas and their potential influence to the environment and human beings were also discussed. The major content and the results are as follows.
1. The method for simultaneous determination of PCDD/Fs, PCBs, and PBDEs by isotope dilution-HRGC/HRMS-MID was established based on method US EPA 1613B, 1668A, and 1614. It was validated using the reference materials, and applied for the analysis of environmental samples. All the recoveries are within the acceptable ranges specified in the US EPA standard methods.
2. The fly ash and electrostatic precipitator (ESP) dusts samples were collected from the sinter plant of Wuhan Iron & Still Group. The samples were analyzed for PCDD/Fs by HRGC/HRMS-MID according to US EPA 1613B method. The drying area in sinter belt was expected to be the main place to produce dioxins during sintering process by de novo synthesis. PCDFs congeners in the samples were dominant and it can be seen increasing with Cl atom (r2 = 0.98), the congeners of PCDFs were decreased. Among them, 2,3,4,7,8-PeCDF was found to constitute around 45% of the total WHO- toxic equivalent (TEQ) values in the samples.
3. Surface sediments and bivalves samples collected from the Changjiang Estuary were analyzed for PCDD/Fs by isotope dilution- HRGC/HRMS-MID. In the bivalves samples collected in the downstream near the sewage outlet of sinter plant in Baoshan Iron & Still Group, 2,3,4,7,8-PeCDF was found to be dominant congener and the main contributor to total WHO-TEQs. The waste from sinter plant was major source of PCDD/Fs in the Estuary. The biota-sediment accumulation factor (BSAF) values obtained showed that PCDD/Fs were apparently accumulated in the biota. European Community Authorities (ECA) has settled a maximum level of 4 pg WHO-TEQs/g fresh weight in fish muscle and fishery products. The PCDD/Fs in the bivalve samples in the estuary were higher than the ECA bench mark, and may have potential risk to the environment.
4. The environmental and human samples collected from Luqiao area, a typical E-waste dismantling area, were analyzed for PCDD/Fs, PCBs, and PBDEs by the simultaneous analysis using isotope dilution- HRGC/HRMS-MID technique. Comparing the results with those inform the other researches, the Luqiao area is considered as being highly polluted by PCDD/Fs, PCBs, and PBDEs. Their homologue and congener profiles in the samples demonstrated that high concentrations of PCDD/Fs and PBDEs were originated from open burning of E-waste, meanwhile dismantling of transformers and capacitors were main contributor for the contamination of PCBs. The results showed that the E-waste dismantling workers were exposed to high concentrations of PCDD/Fs, PCBs, and PBDEs.
5. Using 8-OHdG as a biomarker for DNA oxidative damage, the preworkshift and postworkshift urines samples were collected from male workers in the E-waste dismantling area. The results of 8-OHdG levels in preworkshift urines were 6.40 ± 1.64 µmol/mol creatinine, but the levels of 8-OHdG in postworkshift urines were found to be significantly higher up to 24.55 ± 5.96 µmol/mol creatinine (p < 0.05), that has even been close to the levels in the urine of cancer patients such as prostate cancer and bladder cancer. Therefore, it is expected that there is a high cancer risk from the DNA oxidative stress for those workers in the E-waste dismantling area, because they are exposed to the high concentrations of PCDD/Fs, PCBs, and PBDEs.
The results from this study provide scientific bases and technological support for the control of POPs release, environmental and human health risk assessment.|