滇池水域重金属污染的历史追溯及生态风险评价

发布时间：2018-04-23 03:01

本文选题：滇池 + 重金属　；参考：《昆明理工大学》2016年硕士论文

【摘要】：重金属元素在全球范围内广泛的分布在水生生态环境中,环境中的重金属主要有自然来源及人为来源。重金属,如铅、锌、铜、镉和铬,是工业废水中常见的污染物,重金属污染已经成为一个全球性的环境污染问题。地球化学结构,采矿活动,金属冶炼、工业废物焚烧废物和城市污水排放都是水体中重金属污染物的潜在来源之一。由于重金属难以被降解,当汇集进入水体后,可沉降到沉积物中,甚至通过同化作用而进入水生动物中。重金属通过食物链中不断的积累,一旦在水生生物达到安全阈值,人类对水生动物的消费会造成毒性伤害。研究区域覆盖整个滇池,研究包括滇池8个点位(部分点位为国控水质监测点)的水体、表层沉积物和柱状沉积物,环滇池6个点位的野生鱼样。选择重金属(Pb、Zn、Cu、Cd和Cr)作为目标污染物质,研究其在滇池的污染特征。研究滇池水体、表层沉积物、柱状沉积物和3种当地野生鱼类(鲤鱼、鲫鱼和银白鱼)重金属元素的污染程度、分布特征、历史趋势、生物蓄积性并评估其潜在健康风险。这些结果有助于增加我们对滇池水、沉积物和一些特有野生鱼类的重金属污染的认识,具有明显的理论意义、社会价值、环境意义和应用价值。(1)通过对滇池8个点位水体及表层沉积物中重金属浓度进行分析,阐明了重金属在滇池水体及表层沉积物中重金属的浓度水平、分布特征。滇池水体及表层沉积物中普遍检出这5种重金属元素(Pb、Zn、Cu、Cd和Cr),且水体中浓度水平远低于表层沉积物中的浓度水平,表层沉积物中重金属的浓度普遍高于云南土壤背景值。水体和表层沉积物中重金属的浓度依次为ZnCrCuPbCd。各点位中,晖湾、宝象和罗家营采样点水样中重金属的浓度与其它5个采样点(观音山西、大渔乡、海口西、白鱼和滇池南)的差异性就不明娃,但多数金属的浓度依然较高。在这些点位发现较高的重金属浓度,与其临近昆明主城区,有大量的生活、工业污染排放有关。(2)研究了滇池8根柱状沉积物中重金属的浓度水平及污染特征,得到了5种重金属元素在滇池污染的历史数据。可以观察到各柱状沉积物内重金属浓度从底层到顶层呈现出先增加后平稳变动的趋势。结果揭示了滇池重金属的污染历史,从20世纪70年代末开始,重金属Pb、Zn、Cu、Cd和Cr的浓度有突然增加的趋势,此外,这些重金属的浓度从21世纪初到现在呈下降或者保持不变的趋势。总的来说,柱状沉积物中重金属浓度变化趋势反映了滇池重金属的污染情况,这主要与周边的主要城区(如昆明市主城区、晋宁县和呈贡区)人口数量增加、经济发展情况、城市化进程加快和相关环保政策实施有密切关系。(3)检测了滇池3种典型野生鱼类(鲤鱼、鲫鱼、银自鱼)的肌肉、肝脏和鳃中的重金属含量,阐述重金属在鱼类各组织中的浓度水平,讨论其生物富集情况及对暴露人群的潜在健康风险。各鱼样肌肉中重金属Pb.Zn.Cu.Cd和Cr含量分别为0.10-0.78 mg/kg、21.79-67.87 mg/kg、0.48-1.47 mg/kg、0.03-0.16 mg/kg和0.13-0.94 mg/kg,不超过政府规定的鱼类中重金属的限值,说明食用这3种鱼类相对是安全的。可以发现3种鱼类肌肉内重金属含量有银白鱼鲤鱼鲫鱼的顺序。另外,鲤鱼和鲫鱼的组织(肌肉、肝脏和鳃)中重金属含量,其富集能力呈现出肝脏鳃肌肉的规律。再分析重金属在3种鱼类体内的富集能力,通过计算出鱼类吸收重金属的生物浓缩因子(BCF),其范围为0.74到36.47,其顺序依次为ZnCdPbCuCr。计算3种鱼类重金属的目标危险系数(THQ)和危险指数(HI),其值多数都小于1。表明人类单一的消费其中一种鱼类而摄入体内的重金属元素其对人体的非致癌性健康风险较低,但消费鱼类造成的潜在健康风险依然不能被忽视,应该加强滇池湖泊的重金属污染防治工作。
[Abstract]:Heavy metals are widely distributed in the aquatic environment around the world. Heavy metals in the environment are mainly natural sources and human sources. Heavy metals, such as lead, zinc, copper, cadmium and chromium, are common pollutants in industrial wastewater. Heavy metal pollution has become a full sphere environmental pollution problem. Geochemistry structure, mining activities, Metal smelting, industrial waste incineration waste and urban sewage discharge are one of the potential sources of heavy metal pollutants in the water body. Heavy metals are difficult to be degraded. When they are collected into the water body, they can be deposited into the sediments and even enter into aquatic animals by assimilation. Heavy metals accumulate through the food chain, once in the water. Living organisms reach a safety threshold, human consumption can cause toxic damage to aquatic animals. The research area covers the entire Dianchi, including 8 points in Dianchi (part of the state controlled water monitoring point), surface sediments and columnar sediments, and wild fish at 6 points in Dianchi, selecting heavy metals (Pb, Zn, Cu, Cd and Cr) as an order. The pollution of Dianchi, the pollution of Dianchi water, surface sediments, columnar sediments and 3 kinds of local wild fish (carp, carp, and silver white fish) pollution, distribution characteristics, historical trends, biological accumulation and assessment of potential health risks. These results help to increase our effect on Dianchi. The understanding of heavy metal pollution of water, sediment and some special wild fish has obvious theoretical significance, social value, environmental significance and application value. (1) the concentration level of heavy metals in the water and surface sediments of Dianchi is clarified by analyzing the concentration of heavy metals in the water and surface sediments of 8 points in Dianchi. The 5 heavy metal elements (Pb, Zn, Cu, Cd and Cr) were found in the water body and surface sediments, and the concentration level of the water body was far lower than the concentration level in the surface sediments. The concentration of heavy metals in the surface sediments was generally higher than that of the Yunnan soil background value. The concentration of heavy metals in the water body and the surface sediments was ZnCrCuPbC in turn. The concentration of heavy metals in the surface sediments was ZnCrCuPbC. The concentration of heavy metals in the surface sediments was higher than that of the soil background value in the surface sediments. The concentration of heavy metals in the surface sediments was in turn as ZnCrCuPbC in the surface sediments. In the D. points, the concentration of heavy metals in water samples at Hui Wan, Bao Xiang and Luojia sampling point is different from other 5 sampling points (Guanyin Shanxi, big fishing village, Haikou West, white fish and Dianchi South), but the concentration of most metals is still high. Life, industrial pollution emission is related. (2) the concentration level and pollution characteristics of heavy metals in 8 columnar sediments in Dianchi are studied. The historical data of 5 heavy metal elements in Dianchi are obtained. It is observed that the heavy metal concentration in the columnar sediments is increased from the bottom to the top. The result is revealed. The pollution history of heavy metals in Dianchi, since the end of 1970s, the concentration of heavy metals Pb, Zn, Cu, Cd and Cr has a tendency to increase suddenly. In addition, the concentration of these heavy metals has declined from the beginning of twenty-first Century to the same trend. In general, the trend of heavy metal concentration in the columnar sediments reflects the pollution of heavy metals in Dianchi. The population increased mainly with the surrounding main urban areas (such as the main city of Kunming, Jinning and Chenggong), the economic development, the accelerated urbanization process and the implementation of the related environmental policies. (3) the heavy metal content in the muscles, liver and gills of 3 typical wild fishes (carp, carp, silver and fish) in Dianchi were detected. The concentrations of heavy metals in fish tissues were discussed, and their bioaccumulation and potential health risks to exposed populations were discussed. The contents of heavy metals Pb.Zn.Cu.Cd and Cr in the fish like muscles were 0.10-0.78 mg/kg, 21.79-67.87 mg/kg, 0.48-1.47 mg/kg, 0.03-0.16 mg/kg and 0.13-0.94 mg/kg, which did not exceed the weight of fish in the government. The limit value of the metal indicates that the 3 species of fish are relatively safe to eat. The heavy metal content in the muscles of 3 species of fish can be found in the order of silver carp and carp. In addition, the heavy metal content in the tissues of carp and carp (muscle, liver and Gill), its enrichment ability shows the law of the gill muscles of the liver. Then the heavy metal is analyzed in 3 species of fish. The enrichment capacity of the bioconcentration factor (BCF) of heavy metals absorbed by fish was calculated from 0.74 to 36.47, and the order of the sequence was ZnCdPbCuCr. to calculate the target risk coefficient (THQ) and risk index (HI) of 3 species of heavy metals in fish, and the value was mostly less than 1.. The risk of non carcinogenic health of the human body is low, but the potential health risks caused by consumer fish can not be ignored. The prevention and control of heavy metal pollution in Dianchi lake should be strengthened.

【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X524;X826

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