典型重金属污染场地再利用风险评估及修复目标值研究

发布时间：2018-01-16 00:21

本文关键词：典型重金属污染场地再利用风险评估及修复目标值研究　出处：《安徽理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文以典型铬盐生产企业搬迁遗留重金属污染场地为研究对象,在对场地原有企业生产历史、原料产品、生产工艺与污染防治措施进行调查分析的基础上,通过监测布点、采样分析,评价了场地内土壤重金属环境质量,得出该场地的土壤污染特征和分布情况。应用前期所得数据对该场地展开生态风险评价与健康风险评价,筛选了4种可能对人体健康产生危害的污染物,计算场地再利用过程中的健康风险水平,并分别计算这些污染物的修复目标值。通过以上研究,得出了如下结论： 1.该重金属污染场地污染程度根据污染场地监测数据,利用污染指数法对场地中重金属污染程度进行评价。从监测结果判断,超标点位均在场地内。场地内重金属污染严重,场地内土壤样品中砷、铬、Cr(VI)、镍4种污染物均存在超标现象,未发现镉、锌、铜超标。土壤铬污染最为严重,同时Cr(VI)监测数据表明污染点位样品中Cr(VI)是该场地污染土壤中铬的重要存在形态；镍的污染程度次之,再次为砷污染。 2.场地污染分布情况原有企业的主要生产区域、铬渣堆场以及循环水池等典型产污环节处都属于重度污染区域。在所测土壤点位中,大多数点位的监测浓度变化符合随着采样深度的加深而降低的趋势,少数点位出现跳跃性,且都出现在1m以上。其跳跃性的原因可能是原有生产活动中对局部土壤进行翻土整理或者是由于企业搬迁过程中对土壤的扰动所致。砷、铬(三价铬和六价铬)以及镍的污染表现出同源性,即由原有生产经营活动所致,同时也存在个别点位出现波动性。究其原因可能是受地表径流或是人工扰动所致。 3.污染场地生态风险水平运用瑞典科学家Lars Hakanson提出的潜在生态风险危害指数法,对该场地进行生态风险评价,结果表明：从单个重金属的潜在生态危害角度来讲,金属铬的生态危害最大,其次为镍,再次为砷。所有监测样品中铜、锌、镉均为轻微生态危害。从总潜在生态危害角度来讲,生态危害指数总体上随深度增加而逐渐降低。表层、0.5m、1m的样品生态危害最大。 4.污染场地健康风险水平根据住宅用地情景,确定暴露人群为成人和儿童,结合重金属污染物在土壤环境中的行为特征,确定敏感人群主要的暴露途径为：经口摄入、经皮肤接触和经呼吸吸入三种途径。在综合参考了污染物的相关毒理学参数后,利用健康风险评价模型,对场地污染物的致癌风险及非致癌危害商进行评价,评价结果表明,致癌风险方面,六价铬的致癌风险最大,砷次之,镍最小。非致癌风险方面,砷的非致癌风险最大,六价铬次之,镍最小,铬不存在非致癌风险。 5.基于健康风险的土壤修复目标值以10-6和1作为可接受风险水平,应用健康风险评价模型进行计算,得出基于健康风险的土壤风险控制值,即污染修复目标值分别是：As:0.368mg·kg-1、Cr(Ⅵ):0.251mg·kg-1、Ni:90.6mg·kg-1。
[Abstract]:In this paper, the typical chromate production enterprises move left heavy metal contaminated sites as the research object, on the site of the original production history, raw materials, investigating and analyzing the production process and pollution control measures, monitoring, sampling and analysis, evaluation of the site of heavy metals in soil environmental quality, soil pollution characteristics and the distribution of the site the application of pre launch data. The health risk assessment and ecological risk assessment of the site, the screening of 4 kinds of pollutants may cause harm to human health, calculation of site utilization over the level of health risk in the process of repair, and target value. These pollutants were calculated through the above research, conclusions are as follows:
1. pollution degree of the heavy metal contaminated site
According to the contaminated site monitoring data, the evaluation of the extent of heavy metal pollution in the field using pollution index method. From the results of the monitoring judgment, exceed the standard point position in the field. In the field of heavy metal pollution serious, site soil samples of arsenic, chromium, nickel, Cr (VI) there are 4 kinds of pollutants exceed the standard phenomenon, not found in CD copper, zinc, chromium exceed the standard. The soil pollution is most serious, at the same time, Cr (VI) monitoring data show that the pollution point in the sample of Cr (VI) is an important form of the site soil pollution of chromium; nickel pollution degree, again for arsenic pollution.
2. site pollution distribution
The main production area of the original enterprise, chromium slag and circulating water tank and other typical pollution sources are belonging to heavy pollution area. In the measured soil sites, monitoring the change of concentration with most points decreased with the sampling depth increasing trend, a few points appear to jump, and have appeared in more than 1m the reason of the jump. May be finishing or turn the soil is due to the relocation of enterprises in the process of soil disturbance caused by the local soil. The original production activities of arsenic, chromium (chromium and chromium six) and nickel pollution showed homology, from the original production and operation activities. There are also some points a volatility. The reason may be affected by surface runoff or artificial disturbance caused by.
3. ecological risk level of contaminated site
The potential ecological risk of the Swedish scientist Lars Hakanson proposed the risk index method, ecological risk assessment of the site, the results showed that: from a single heavy metal potential ecological risk perspective, the biggest ecological hazards of chromium metal, followed by nickel, again for arsenic. All monitoring samples of copper, zinc and cadmium were slight ecological harm from the total potential ecological risk perspective, ecological risk index generally increases with depth and gradually decreased. The surface of 0.5m, the largest sample 1m. Ecological harm
4. health risk level of contaminated sites
According to the situation of residential, to determine the exposure for adults and children, combined with behavior characteristics of heavy metal pollutants in the soil environment, determine the sensitive population exposure pathways for the major: ingestion, inhalation and dermal contact by three ways. In reference to the comprehensive toxicological parameters of pollutants, the use of health a risk evaluation model of pollutants carcinogenic risk and non carcinogenic hazard quotient is evaluated, the evaluation results show that the risk of cancer, six chromium carcinogenic risk, arsenic of nickel is minimal. The non carcinogenic risk side, the largest non carcinogenic risk of arsenic, chromium six times, nickel chromium minimum. There is no non carcinogenic risk.
5. target value of soil remediation based on health risk
Taking 10-6 and 1 as acceptable risk level, the health risk assessment model was applied to calculate the soil risk control value based on health risk. The target values of pollution recovery were: As:0.368mg. Kg-1, Cr (VI): 0.251mg? Kg-1, Ni:90.6mg? Kg-1..

【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;X820.4

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