CAJ | 학술논문

选择天津北排污河灌区作为研究区域,调查了土壤和水稻总汞和甲基汞的含量及分布特征,评估污灌区稻米食用汞暴露风险,并对污灌区土壤-稻米甲基汞的影响因素进行了初步分析.结果表明,1.调查的29个污灌区稻田,土壤总汞含量为(367.04 ± 129.36) μg/kg,显著高于区域土壤Hg背景值73 μg/kg,甲基汞含量为(0.87 ± 0.77) μg/kg;水稻各部位总汞含量依次为稻叶 >稻根 >稻茎 >稻米,稻米总汞含量为(12.80 ± 5.14) μg/kg,甲基汞含量依次为稻米 >稻根 >稻茎 >稻叶,稻米对甲基汞具有很强的富集能力,甲基汞含量为(2.09 ± 1.20) μg/kg,甲基化率均值超过10%.污灌区稻米总汞每周摄入量为0.068~1.25μg/(kg·bw),甲基汞每周摄入量为0.0095~0.49μg/(kg·bw),污灌区稻米总汞及甲基汞暴露对居民健康风险总体仍在安全阈值内,但个别汞污染较严重地块甲基汞暴露风险值得高度关注.土壤甲基汞含量仅与土壤总汞含量及黏粒含量的相关性达到显著性水平,稻米甲基汞含量与土壤总汞含量、土壤甲基汞含量、稻米总汞含量及黏粒含量的相关性达到显著性水平.
선택천진북배오하관구작위연구구역,조사료토양화수도총홍화갑기홍적함량급분포특정,평고오관구도미식용홍폭로풍험,병대오관구토양-도미갑기홍적영향인소진행료초보분석.결과표명,1.조사적29개오관구도전,토양총홍함량위(367.04 ± 129.36) μg/kg,현저고우구역토양Hg배경치73 μg/kg,갑기홍함량위(0.87 ± 0.77) μg/kg;수도각부위총홍함량의차위도협 >도근 >도경 >도미,도미총홍함량위(12.80 ± 5.14) μg/kg,갑기홍함량의차위도미 >도근 >도경 >도협,도미대갑기홍구유흔강적부집능력,갑기홍함량위(2.09 ± 1.20) μg/kg,갑기화솔균치초과10%.오관구도미총홍매주섭입량위0.068~1.25μg/(kg·bw),갑기홍매주섭입량위0.0095~0.49μg/(kg·bw),오관구도미총홍급갑기홍폭로대거민건강풍험총체잉재안전역치내,단개별홍오염교엄중지괴갑기홍폭로풍험치득고도관주.토양갑기홍함량부여토양총홍함량급점립함량적상관성체도현저성수평,도미갑기홍함량여토양총홍함량、토양갑기홍함량、도미총홍함량급점립함량적상관성체도현저성수평.
Apaddy field is typical constructed wetland, where mercury (Hg) is easily methylated to methylmercury (MeHg). Due to long-term wastewater irrigation, a large area of farmlands, including paddy fields in Tianjin City, has been seriously contaminated with Hg. There is therefore an important question to be answered in our understanding as to the characteristics of total Hg (THg) and/or MeHg accumulations in rice from wastewater-irrigated areas and risk assessment for evaluation Hg exposure for the population by rice consumption. In this study, a field survey of mercury pollution in 29 paddy fields (soil and rice) from wastewater-irrigated areas around north discharged river in Tianjin city was conducted to evaluate the health risks of mercury to residents by rice consumption. The results showed that: 1. THg and MeHg concentrations in surveyed paddy fields were (367.04 ± 129.36) μg/kg and (0.87 ± 0.77) μg/kg, respectively, where the total mercury content of back soil was 73μg/kg. Analyses of the distribution of Hg species in different parts of rice plants from selected sampling locations shown that grain contained the lowest THg concentrations (12.80 ± 5.14) μg/kg, followed by stem < root < leaf. Contrary to THg, the highest concentration of MeHg was in grain (2.09 ± 1.20 μg/kg, %MeHg > 10%), followed by root > stem > leaf. This suggests that rice grain may preferentially accumulate MeHg compared to other parts of the plant. Observations clearly show that MeHg in the paddy soil could be more easily taken up and transferred to rice grain compared to THg. The probable weekly intake (PWI) of THg and MeHg for an adult population based on 60kg body weight (bw) in studied wastewater-irrigated area was 0.068~1.25 μg/(kg·bw) and 0.0095~0.49 μg/(kg·bw), respectively, which were all well below reference dose established by WHO (FAO) or U.S EPA. However, it was clearly manifest that there is a great concern of MeHg exposure risk for rice consumption around some highly Hg-contaminated areas. There were positive and significant correlations between soil MeHg concentrations and soil THg concentration, or clay contents in the collected soil samples. Similarly, significant positive correlations were also found between MeHg concentrations in brown rice and soil THg concentrations, or soil MeHg concentrations and soil clay contents. This study highlights the potential health risks of MeHg associated with cultivation and consumption of rice on the wastewater-irrigated areas.