贵州省典型铅锌矿区居民血液总汞和甲基汞暴露及健康风险模型预测评估

汞是铅锌矿石的常见伴生元素，铅锌冶炼活动会给当地居民带来潜在汞暴露风险.为了解铅锌矿区居民血液汞暴露及健康风险，选择贵州省赫章县为研究区域，以贵阳市为对照区，分别采集居民血液样品418和118份，利用冷原子荧光法测定其总汞和甲基汞含量，结合年龄和性别分析血液总汞与甲基汞含量特征，估算育龄期妇女头发甲基汞含量并进行甲基汞暴露致新生儿IQ（智商）损失评估，利用单区室PBPK（生理药代动力学）模型预测居民甲基汞ADI（日均摄入量）.结果表明:①铅锌矿区（赫章县）和对照区居民血液总汞含量几何均值分别为（3.11±5.05）和（1.83±1.19）μg/L，范围分别为0.63~54.26和0.46~11.88 μg/L，分别有21.5%和0.85%的血液样本总汞含量超过人体血液总汞安全限值（5.8 μg/L）.②铅锌矿区成年居民和0~6岁儿童血液总汞含量分别为（2.80±3.85）和（2.49±2.08）μg/L，分别有77和7人血液总汞含量超过5.8 μg/L，超标率分别为24.37%和10.61%，存在潜在总汞暴露风险.③斯皮尔曼相关性分析显示，铅锌矿区居民血液总汞和甲基汞含量分别与年龄（R=0.108，P < 0.05）和性别（R=-0.185，P < 0.05）相关，老年人较其他年龄段人群总汞暴露的风险更高，其血液总汞含量达（5.29±5.03）μg/L；男性血液甲基汞含量〔（0.24±0.32）μg/L〕高于女性〔（0.18±0.22）μg/L〕.④蒙特卡洛模型模拟结果显示，铅锌矿区和对照区育龄妇女头发甲基汞平均含量分别为（0.07±0.11）和（0.11±0.13）mg/kg，范围分别为0~11.81和0~5.74 mg/kg，其中铅锌矿区2.27%的育龄期妇女头发甲基汞含量超过发汞临界值（0.58 mg/kg），导致IQ评分为70~70.18分范围内的约0.05%的婴儿从IQ正常转变为MMR（轻度智力低下）.⑤单区室PBPK模型预测表明，铅锌矿区和对照区居民甲基汞日均摄入量分别为（0.005±0.006）和（0.007±0.008）μg/kg，分别有0.082%和0.013%的居民甲基汞日均摄入量超过RfD（参考剂量值，0.1 μg/kg）.研究显示:铅锌矿区成年居民和0~6岁儿童血液总汞含量高于国内其他地区，男性血液甲基汞含量明显高于女性；铅锌矿区约2.27%的育龄期妇女头发甲基汞含量超过发汞临界值，可致IQ评分在70~70.18分范围内的约0.05%的婴儿从智力正常转变为MMR；铅锌矿区居民甲基汞非致癌风险高于对照区. 

Total Mercury and Methyl Mercury in Blood of Inhabitant and Their Associated Modelling Prediction Evaluation in Typical Lead-Zinc Mining Region,Guizhou Province,China

Mercury (Hg) is a common element in lead-zinc ores. Lead-zinc smelting activities cause potential Hg exposure risks to the local residents. To understand the blood Hg exposure of residents in typical lead-zinc mining area in Hezhang County and in the control area in Guiyang City, approximately 418 and 118 blood samples were collected. Total mercury (THg) and methylmercury (MeHg) were determined using cold vapor atomic fluorescence spectrometry (CVAFS). Based on the estimated MeHg concentration in the hair of childbearing age women, assessment of newborns IQ loss related to prenatal MeHg exposure was conducted. At the same time, single-compartment pharmacokinetic (PBPK) model was employed for predicting residents' average daily intake (ADI) of MeHg. The results indicated: (1) The geometric mean values of blood THg in the lead-zinc mining and control areas were (3.11±5.05) and (1.83±1.19)μg/L, and the ranges were 0.63-54.26 and 0.46-11.88 μg/L, respectively. These values exceeded the safety limit of 5.8 μg/L in human blood by approximately 21.5% and 0.85%, respectively. (2) The blood THg of adults and children aged 0~6 in the lead-zinc mining area was (2.80±3.85) and (2.49±2.08)μg/L, respectively, of which 77 (24.37%) and 7 (10.61%) people exceeded 5.8 μg/L. The exceeding rate was 24.37% and 10.61%, respectively, implying a potential exposure risk. (3) Spearman's correlation analysis showed that blood THg and MeHg in the lead-zinc mining area were significantly correlated with age (R=0.108, P < 0.05) and gender (R=-0.185, P < 0.05). Compared with other age groups, the elderly with an average THg of (5.29±5.03)μg/L was at the greatest risk of THg exposure in the lead-zinc mining area. The MeHg concentration in the blood men was (0.24±0.32)μg/L, which was higher than the concentration of (0.18±0.22)μg/L in women. (4) Monte Carlo simulation result showed that the average women hair MeHg concentrations of childbearing age in the lead-zinc mining and the control areas were (0.07±0.11) and (0.11±0.13)mg/kg, and the range were 0-11.81 and 0-5.74 mg/kg, respectively, with approximately 2.27% women of childbearing age in the lead-zinc mining area exceeding the threshold of hair MeHg 5.8 mg/kg, causing a shift of approximately 0.05% of infants in the IQ range of 70-70.18 points into the mild mental retardation range (MMR). (5) The single-compartment PBPK model showed that MeHg ADIs in the lead-zinc mining area and control area were (0.005±0.006) and (0.007±0.008)μg/kg, respectively, which exceeded the reference dose (RfD) of 0.1 μg/kg by approximately 0.082% and 0.013%, respectively. It concluded that the blood THg concentrations of adults and children aged 0-6 in the lead-zinc mining area exhibited higher levels than that of other domestic areas, and blood MeHg concentrations of men was significantly higher than that of women. Approximately 2.27% of childbearing aged women in the lead-zinc mining area exceeded the threshold of hair MeHg, causing a shift of approximately 0.05% of infants in the IQ range of 70-70.18 points into the MMR. The non-carcinogenic risk exposure of the residents in the lead-zinc mining area to MeHg was higher than that in the control area.