【作者】 石吉彬；

【导师】 袁晶；

【作者基本信息】 华中科技大学 ， 劳动卫生与环境卫生学， 2008， 硕士

【摘要】 铅、镉、铜、镍等重金属已广泛用于各种电子产品。大量淘汰的电子产品带来了新的环境问题。由于众多简易作坊以原始简陋的方法手工拆解电子垃圾,导致其中的有害物质如多溴联苯醚(Polybrominated Diphenyl Ethers, PBDEs)、多环芳烃(Polycyclic Aromatic Hydrocarbons, PAHs)和重金属进入大气,水体和土壤等环境介质,对健康构成潜在的威胁。已知铅、镉、铜、镍等重金属可经多途径侵入机体,损害机体的多个系统。例如,铅是以神经毒性为主的一种重金属元素且毒性很强,它可累及全身各系统,如造血系统、消化系统、心血管系统以及免疫系统。已知镉是确认的致癌物。当机体长期暴露镉后,不仅其肾脏功能受影响,而且其两性生殖系统功能也可受损。镍污染能引起人类呼吸系统的癌症。铜虽是人体的必需微量元素,但是机体过量暴露铜后,则可导致机体正常代谢失衡。近年,电子垃圾产生的环境问题已引起社会的广泛关注。但是有关电子垃圾污染物暴露人群可能的生物学效应研究的报导却十分有限。本研究选择我国南方某电子垃圾拆解地居民58名为暴露组,地理环境和生活习惯相近且无明显已知污染源存在的农业区居民80名为对照组,通过分析电子垃圾拆解地居民体内重金属暴露水平及其氧化应激水平、尿8-羟基脱氧鸟苷(8-Hydroxy-desoxyguanosine, 8-OHdG)水平和人外周血淋巴细胞双微核率,以反映电子垃圾污染环境中重金属污染的人群生物学效应。本文由两部分组成:第一部分:电子垃圾拆解地居民体内重金属水平与氧化应激指标的研究用石墨炉原子吸收法测定全血中铅,镉,镍,和尿样中铅,镉,镍,铜含量;火焰原子吸收法测定血清铜含量。用谷胱甘肽-S转移酶(glutathione S-transferases, GST)、谷胱甘肽(glutathione, GSH)、超氧化物歧化酶(superoxide dismutase, SOD)试剂盒检测血清GSH,GST,SOD等氧化应激指标。用电化学高效液相色谱法测定尿8-OHdG。结果发现:暴露组人群血铅(115.78μg/L)与尿铜(0.03μg/mgCr)的平均水平高于对照组(87.25μg/L, P<0.01; 0.02μg/mgCr, P<0.05),而血清铜(0.80μg/L)、血镍(7.58μg/L)与尿镉(0.001μg/mgCr)的平均水平则低于对照组(0.88μg/L, P<0.01; 13.55μg/L, P<0.01; 0.002μg/mgCr, P<0.05);暴露组血清GST活性(median=19.52 U/ml)和GSH含量(mean=205.39mg/L)显著高于对照组(mean=14.47U/ml, P<0.01;mean=193.32mg/L, P<0.05),而两组血清SOD活性和尿8-OHdG水平未见显著性差异(P<0.05)。提示电子垃圾拆解地居民有较高的铜暴露,但体内仅有铅的蓄积增加。对照组可能有尚未发现的因素引起了机体的氧化应激反应。第二部分:电子垃圾拆解地居民淋巴细胞双微核率及其影响因素的研究用淋巴细胞胞质阻滞双微核试验检测人群外周血淋巴细胞双微核率(micronucleated binucleated cells, MNed BNC)。结果表明:暴露组外周血淋巴细胞中位双微核率为4‰,高于对照组(1‰,P<0.01)。血铅水平与淋巴细胞双微核率之间呈正相关关系(r=0.204, P<0.05)。电子垃圾从业史是双微核率升高的危险因素,即有电子垃圾从业史者的双微核率升高的危险性是对照人群的6.7倍(P<0.01)。这可能是暴露人群接触较高铅导致其体内DNA的损伤。这一推测有待在大样本中证实。更多还原

【Abstract】 Heavy metals including lead, cadmium, copper and nickel, are widely used in various electronic products. Numerous obsolesced electronic products, so-called electronic-waste can cause serious environment problem. When primary dismantling and recycle methods were used in a few plants, certain pollutants such as PBDE, PHA and heavy metals in e-waste can enter environmental media atmosphere, water body and soil, and threaten human health.It is well known that, heavy metals (such as lead, cadmium, copper and nickel) exists in the environment and can invade into human body, through many ways, resulting the damages of multiple systems in the organisms. For instance, lead had a stronger toxicity in the nervous system, the hematopoietic system, the digestive system, cardiovascular system and immunologic system. Cadmium is a proved carcinogen. Its adverse effects include damages in not only the kidney function and but also the function of the reproductive system in organisms, when they were exposed to Cadmium. Nickel associates with cancer of the respiratory system. Although copper is an essential element in human body, however, excessive level of Cu can cause disorder in the metabolism of the body.Recent years, widely concern on environment pollution relating to e-waste has been attracted. However, limited data reported that the adverse effects of pollutants from e-waste on the populations. In the present study, we recruited 58 subjects (as the exposure group) from a decade-long e-waste recycling site in southeast China. Another 80 subjects from an agricultural area that was similar to the exposure site in environment and custom, but without known pollution resources were recruited to be control. To evaluate the biological effects of pollutants from the e-waste on the population, levels of heavy metals, the oxidative stress indicators and the urinary 8-Hydroxy-desoxyguanosine (8-OHdG) were analyzed. In addition, frequencies of the micronucleated binucleated cells (MNed BNC) in the studied subjects were determined as well.Levels of heavy metals and oxidative stress indicators among the populaitonlevels of the lead, cadmium and nickel in the whole blood samples, and levels lead, cadmium, copper and nickel levels in the urine samples were detected using the graphite furnace atomic absorption spectroscopy method. Serum copper level was determined using the flame atomic absorption spectroscopy method. Levels of glutathione S-transferases (GST) and superoxide dismutase (SOD) and glutathione (GSH) activity were anayzed using the commercial kits. Levels of 8-OHdG were determined by high performance liquid chromatograph-electrochemistry method.The results showed that in the exposed levels of blood Pb (115.78μg/L) and urinary copper (0.03μg/mgCr) were significantly higher than those of the control (blood Pb: 87.25μg/L, P<0.01; urinary Cu: 0.02μg/mgCr, P<0.05); In exposed levels of blood copper and blodd nickel (0.80μg/L, 7.58μg/L) and urinary cadmium (0.001μg/mgCr) were significantly lower, compared to the control (blood Cu: 0.88μg/L, P<0.01; blood Ni: 13.55μg/L, P<0.01; urinary Cd: 0.002μg/mgCr, P<0.05). Levels of serum GST (median: 19.52 U/ml) and GSH (mean±SD: 205.39±31.21mg/L) in the exposed were significantly higher than those in the control (median: 14.47U/ml, P<0.01; mean±SD: 193.32±37.62mg/L, P<0.05). But no significantly difference were observed between the groups in levels of urinary 8-OHdG and serum SOD (P>0.05).Our findings suggest that the residents who lived in the E-waste recycling site had higher exposure of Cu but an accumulation of only lead in their body was found. In the control there are some unknown factors may cause oxidative stress reactions. Frequencies of micronucleated binucleated cells in the peripheral lymphocytes and its correlative factorsThe frequencies of micronucleated binucleated cells (MNed BNC) in the peripheral lymphocytes among the studies subjects were determined using Cytokinesis-Block Micronucleus assay (CBMN). The results showed that the median frequency of MNed BNC in the exposed is 4‰, which was significantly higher than that (median: 1‰) of the control (P<0.01). A positive correlation between the blood lead level and the frequency of MNed BNC was found (r=0.204, P<0.05). We also found that the history of occupational exposure of dismantling E-waste was a risk factor for the elevated frequency of MNed BNC, because the frequencies of MNed BNC in the workers were 6.7 times that of the control (P<0.01)The findings indicated that the detected DNA damage in the workers may associate with their exposure of higher level of Pb in their bodies, which need to be validated in the larger populations.更多还原