沿海某县级市农村土壤卫生状况及风险评估

发布时间：2018-01-18 11:33

本文关键词：沿海某县级市农村土壤卫生状况及风险评估　出处：《山东大学》2017年硕士论文　论文类型：学位论文

【摘要】：研究目的:随着科技的进步、现代化进程的加快,自然资源被人类过度开发利用、工业"三废"和生活污水任意排放、农药化肥过量使用,造成大量有毒有害物质进入生活环境,严重威胁着人类身心健康,环境污染已成为日益显著的全球性问题。土壤作为地球表面人类生活和发展的根本物质之一,其环境质量的好坏直接决定着农产品的产量和质量,其中的有毒有害物质并会通过生物富集、食物链放大作用危害公众健康。因此了解农村土壤环境质量状况,对加快优质农产品种植区域生产环境的建设,确保农产品达到卫生标准、降低人群健康风险水平具有重要意义。本研究通过监测沿海某县级市近年来农村土壤重金属铅、镉、铬含量、变化趋势以及土壤中蛔虫卵检出情况,根据检出结果客观评价该市农田土壤卫生状况,并利用已有的风险评估方法评估调查地区土壤潜在生态风险和人群健康风险。本研究结果将为卫生行政机构及政府相关部门制订政策及采取相应措施提供基础资料。方法:按照国家农村环境卫生监测方案及土壤监测技术规范要求,结合当地实际情况,检测土壤中蛔虫卵及重金属铅、镉、铬含量。将研究区按离矿区的距离分为矿区附近区(监测点距矿区10公里之内)和矿区远离区(监测点距矿区大于10公里)。2011-2016年,每年随机抽取20个行政村(包含矿区附近和矿区远离区),每村检测1份土壤,共120份。按照GB/T17141-1997《土壤质量铅、镉的测定-石墨炉原子吸收分光光度法》及HJ491-2009《土壤总铬的测定-火焰原子吸收分光光度法》方法分别测定土壤中铅、镉、铬元素含量;参照《粪便无害化卫生要求》(GB7959-2012)运用饱和硝酸钠溶液漂浮法测定土壤中的蛔虫卵数量。针对检测结果建立excel数据库并进行整理,运用spss20.0对检测结果统计分析。以《土壤环境质量标准》(GB 15618-1995)和该地级市农村土壤元素背景值为依据,借用单因子污染指数法、内梅罗综合污染指数法及Hakanson潜在生态危害指数法评价研究区矿区附近及远离矿区区域农村土壤质量状况,并运用国际机构推荐的人群健康风险模型评价当地居民土壤重金属污染经摄食途径和经皮肤接触引起的健康风险值。结果:(1)2011-2016年研究区土壤中蛔虫卵检出率在15%左右。(2)土壤pH均值为6.53,pH值小于6.5的占43.27%,大于7.5的仅占4.81%。(3)研究区土壤中铅、镉、铬的含量范围分别是12.60～81.60 mg/kg、0.05～1.09 mg/kg、40.60～147.00mg/kg;土壤中铅、镉元素具有一定的相关性(r=0.374,P0.01),且铬含量在监测期间有逐年升高的趋势(F=5.72,P0.01)。(4)矿区远离区土壤铅、镉元素具有一定的相关性(r=0.396,P0.01),而矿区附近土壤中铅、镉、铬这三种元素间不具有相关性(P0.05);对比显示矿区远离区铅含量低于矿区附近(P0.01)。(5)单因子污染指数法评价显示,矿区附近铅、镉属于轻度污染等级(指数分别为1.27和1.30),铬处于警戒限状态(指数为0.85);矿区远离区,镉属于轻度污染等级(指数为1.25),铅、铬元素污染处于警戒状态(指数分别为0.89和0.83)。内梅罗综合污染指数法分析显示矿区附近区域和远离区域都属于轻度污染(综合污染指数分别为1.10和1.06)。(6)Hakanson潜在生态危害指数法评价,铅、铬元素均属于无风险范围(指数均小于40);镉元素在2013年属于中度风险范畴(指数为82.44),其他年份属于轻度风险污染范畴(指数在40～80之间);且矿区附近铅生态危害指数高于矿区远离区(分别为8.17和5.71);三种元素对土壤的综合生态风险贡献率大小顺序依次是镉铅铬。(7)应用人群健康风险模型评价显示研究区土壤污染物经皮肤接触和摄食途径引起的总致癌性风险值均大于国际机构推荐的可接受水平上限1.0×10-4(成人为1.23×10-4,儿童为1.36×10-4)。儿童由摄食途径引起的非致癌性风险和致癌性风险均高于成年人,分别是成年人的8.13倍和2.71倍。结论:(1)研究区土壤存在蛔虫卵污染,但随着年份增加其污染情况变化不大。(2)研究区土壤受到铅、镉、铬不同程度的污染,镉的潜在生态危害贡献率最高;土壤pH偏酸性,可加重土壤中重金属溶出。(3)整个研究区土壤铅、镉元素可能来自同一污染源。(4)研究区土壤重金属污染的致癌性风险高于国际机构推荐的可接受水平范围上限。儿童经摄食途径引起的健康风险值高于成年人。
[Abstract]:Objective: with the progress of science and technology, accelerate the process of modernization of natural resources over exploitation of human beings, industrial wastes and sewage emissions, excessive use of pesticides and fertilizers, resulting in a large number of toxic and harmful substances into the environment, a serious threat to human health, environmental pollution has become a global problem increasingly significant. As the soil one of the basic material of human life and the development of the earth's surface, the environmental quality directly affects the yield and quality of agricultural products, including toxic and harmful substances and through biological enrichment and food chain amplification endanger public health. So understanding the soil environmental quality in rural areas, to accelerate the construction of high-quality agricultural products planting area production environment, to ensure that agricultural products meet health standards, has important significance to reduce health risk level. This study by monitoring a coastal county In recent years, the rural soil heavy metal lead, cadmium, chromium content, and the change trend of Ascaris eggs in the soil were, according to the detection results of objective evaluation of soil health status of farmland in the city, and the use of risk assessment methods for assessment survey of soil potential ecological risk and population health risks. The results of this study will provide the health administrative institutions and the relevant government departments to formulate policies and take corresponding measures to provide the basic data. Methods: according to the requirements of the health monitoring program of the national rural environment and soil monitoring technical specifications, according to the local actual situation, detection of Ascaris eggs in soil and heavy metals of lead, cadmium, chromium content in the study area. According to the distance from the area near the mine area (divided into monitoring point mining area and mining area within 10 kilometers) away from the area (monitoring point of mining area is more than 10 kilometers).2011-2016, 20 administrative villages were randomly selected from each year (including mine area and mining area Away from the area), each village detection 1 soil samples, a total of 120. According to GB/T17141-1997< soil quality determination of lead, cadmium - spectrophotometry > and HJ491-2009< soil total chromium determination of Pb in soil, respectively. Spectrophotometry method on Flame atomic absorption graphite furnace atomic absorption of cadmium, chromium element content; according to < excrement health requirements > (GB7959-2012) using saturated sodium nitrate solution number of Ascaris eggs in soil were determined. According to the test results of floating method to establish the Excel database and organize, using spss20.0 analysis of the statistical results. In "soil environmental quality standard" (GB 15618-1995) and soil element background value of the rural City on the basis of using the method of single factor pollution index, Nemero comprehensive pollution index method and Hakanson potential ecological risk index method in the evaluation of the study area near the mine and away from the soil quality status of rural mining area, and the use of International The soil heavy metal pollution evaluation of local residents health risk model by feeding ways and recommended by the health risk caused by skin contact. Results: (1) 2011-2016 in the study area of Ascaris eggs in the soil in the detection rate of about 15%. (2) the average soil pH value is 6.53, pH value of less than 6.5 accounted for 43.27%, more than 7.5 only 4.81%. (3) in the soil of lead, cadmium, chromium content range was 12.60 ~ 81.60 ~ 1.09 mg/kg, 0.05 mg/kg, 40.60 ~ 147.00mg/kg; soil lead, cadmium has certain correlation (r=0.374, P0.01), and chromium content in the monitoring period is increasing year by year (F=5.72, P0.01). (4) away from the mining area soil lead, cadmium has certain correlation (r=0.396, P0.01), and near the mine soil lead, cadmium, chromium has no correlation between these three elements (P0.05); comparison showed that the mining area away from the area near the mine below the lead content (P0.01 (5). Single) Show the evaluation factor pollution index method, mine near lead, cadmium belongs to light pollution levels (index were 1.27 and 1.30), Cr at warning state (index 0.85); from the mining area, belongs to the slight pollution level of cadmium (index 1.25), Pb, Cr pollution in a state of alert (index respectively. 0.89 and 0.83). The analysis showed that the area near and far from the mining area are all mild pollution Nemerow index (comprehensive pollution index were 1.10 and 1.06). (6) evaluation of potential ecological risk index method, Hakanson Pb, Cr are risk free range (index less than 40); cadmium is moderate the risk category in 2013 (82.44 index), the other year belongs to the low risk category (pollution index in 40 ~ 80); and lead mine near the ecological risk index is higher than that from mine area (8.17 and 5.71); three elements of comprehensive soil The ecological risk contribution rate of the order is cadmium lead chromium. (7) health risk assessment model of soil pollutants in study area showed people by skin contact and ingestion pathway caused by total carcinogenic risk values are greater than the standards recommended by the international agency for the upper limit of 1 x 10-4 (adult children is 1.23 * 10-4, 1.36 * 10-4) children caused by feeding ways of non carcinogenic risk and carcinogenic risk was higher than that of adults, adults are 8.13 times and 2.71 times. Conclusion: (1) the study area soil roundworm eggs pollution, but with increased year its pollution condition did not change. (2) the study area soil by lead, cadmium and chromium in different the degree of pollution and the potential ecological risk of CD contribution rate; soil acidic pH, can increase the dissolution of heavy metals in soil. (3) the study area of soil lead, cadmium may come from the same sources. (4) the study area of soil heavy metal pollution The risk of cancer is higher than the upper limit of the acceptable level recommended by the international agency. The risk of health risk caused by children's feeding channels is higher than that of adults.

【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R127

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