【作者】 陈磊；

【导师】 花日茂； 储昭升；

【作者基本信息】 安徽农业大学 ， 环境科学， 2010， 硕士

【摘要】 沉积物既是水体污染物的储备库,又是水体主要的潜在污染源。水体沉积物中的酸可挥发性硫化物(AVS)易与重金属反应生成难溶的金属硫化物,从而控制沉积物中重金属的生物有效性,因此水体沉积物中重金属的生物有效性的研究成为当前热点问题之一。本文以北方洋河水库和南方的石臼湖、东钱湖和宜兴三氿四种不同类型水体沉积物作为研究对象,分别测定并分析了其沉积物中AVS、同步提取金属(SEM)和有机质等指标,运用AVS和SEM来判定沉积物中重金属的生物有效性,并初步探讨了AVS和SEM在平面和垂直方向上的分布特征及影响因素,主要得出以下研究结果:1.洋河水库表层沉积物中AVS浓度分布大体上表现为:春季,入库河流下游和水库中心区域沉积物中AVS浓度较高;秋季,该水库中心区域沉积物中AVS浓度较高。通过对春、秋两季表层沉积物中AVS浓度、有机质含量和氧化还原环境进行分析后发现,沉积物中有机质含量和其所在的氧化还原环境是影响AVS浓度分布的主要因素。2.洋河水库表层沉积物中SEM浓度波动秋季要大于春季。通过对采样点SEM浓度进行分析,发现采样点河.4和河.5SEM浓度较高;五种重金属中锌元素对SEM的贡献最大,镉元素对SEM的贡献最小。3通过对比洋河水库库区2个采样点AVS与SEM随深度的变化后发现:位于河流入库口处采样点(库.1)AVS的浓度随着深度的增加先增大然后迅速降低;水库中心最深的采样点(库.3)AVS的浓度是表层最高,随着深度的增加而逐渐降低。通过对两个采样点表层沉积物所在的氧化还原环境进行分析,得出:氧化还原环境的不同是造成两个采样点垂直方向上AVS浓度分布迥异的主要原因。两个采样点SEM浓度有随着深度的增加而逐渐降低的趋势。4.洋河水库10个采样点中,只有河.2采样点5>SEM-AVS>0,其他的9个采样点SEM-AVS则全部小于0。应用SEM/AVS进行评价,只有采样点河.2秋季时刚刚达到了对生物产生危害的阀值2.34;而其他的9个采样点在春秋两季SEM/AVS都远小于对生物产生危害的阀值。通过(SEM-AVS)/foc可以发现:10个监测点表层沉积物样品春秋两季(SEM-AVS)/foc都远远小于150μmol/g(OC)沉积物中重金属对底栖生物产生急性或慢性毒害的阀值。评价结果表明:该水库及入库河流绝大部分区域沉积物中的重金属生物有效性低。5.测定石臼湖、东钱湖和宜兴三氿表层沉积物中AVS和SEM,对数据分析后发现:石臼湖AVS平均浓度最高,东钱湖次之,宜兴三氿最低。通过对石臼湖、东钱湖和宜兴三氿表层沉积物中有机质含量和水深进行分析，发现：沉积物中有机质的含量是影响AVS浓度分布的主要因素。宜兴三氿沉积物中SEM平均浓度最高,石臼湖次之,东钱湖最低。通过对比石臼湖、东钱湖和宜兴三氿周边环境污染程度，发现重金属污染是影响SEM浓度分布的主要因素。6.测定石臼湖、东钱湖和宜兴三氿沉积物柱状样品，发现：三个湖泊AVS浓度变化趋势都是表层浓度较低,随着深度的增加逐渐升高,浓度达到最大后又逐渐降低。其中石臼湖AVS浓度峰出现相对其他湖泊要早。通过对比石臼湖、东钱湖和宜兴三氿垂直方向上有机质的含量变化，垂直方向上有机质含量的变化是影响AVS浓度变化的主要因素。石臼湖、东钱湖和宜兴三氿SEM浓度较低,变化趋势不明显,只有宜兴三氿在25cm处SEM浓度才大大升高。7.石臼湖7个采样点表层沉积物中SEM-AVS<0,其中的重金属不会对生物产生危害;东钱湖和宜兴三氿所有采样点5>SEM-AVS>0,其中的重金属可能会对水生生物产生危害。8.通过对比南北四种水体可以发现:沉积物中有机质含量和其所处的氧化还原环境是影响水体表层沉积物中AVS浓度分布的主要因素。表层沉积物中SEM浓度宜兴三氿要高于石臼湖、东钱湖和洋河水库，说明宜兴三氿沉积物中重金属污染程度要重于石臼湖、东钱湖和洋河水库。洋河水库和石臼湖垂直方向上SEM浓度较低并且变化趋势不明显,其重金属污染负荷较轻,东钱湖表层小于深层,重金属污染得到较好的控制,宜兴三氿表层浓度较低，深层较高，重金属污染较重。更多还原

【Abstract】 Sediment is not only the reserve of pollutants, but also the potential source ofpollutants which has influence on environment.Recently. The acid volatile sulfides (AVS)in sediments are available for binding heavy metals by formatting insoluble metal-sulfidecomplexes, thereby controlling the bioavailability of heavy metal, so the issue of heavymetal bilavailability of aquatic sedinents is becoming one of the popular matters in theresearch of heavy metals in water environment.This study chooses Yanghe reservoir, Shijiuhu lake, Dongqianhu lake andYixingsanjiu lake as my research object. Acid volatile sulfide (AVS), the simultaneouslyextracted metals (SEM) and organic matters which are main physical and chemical indiceshave been analyzed and heavy metal bioavailability of sediments from these reservoir andlakes has been estimated by AVS and SEM. The features of plane distribution and verticaldistribution of AVS and SEM, along with influence factors have been preliminarilydiscussed discussed. Results have been obtained as follows:1. The vertical distribution regularity of AVS in sediments from Yanghe reservoir is asfollows: the areas of high concentration are the lower reaches of the river and the center ofthe reservoir in spring; it is only area of high concentration in the center of Yanghereservoir in autumn.Through correlation of AVS, OM% and anaerobic environmentalcondition in surface sediments in different seasons, the resultes shows the concentration ofOM% in sediments and anaerobic environmental condition have great influence on thevertical distribution of AVS.2. The fluctuation of SEM in surface sediments from Yanghe reservoir is higher inautumn than in spring. The concentration of SEM in surface sediment of He.4 and He.5 arehigh. As for the composition of SEM, the amount of Zn is the largest and Cd is thesmallest.3. Comparing with the features of AVS and SEM in sediments with different depth attwo separate locations in the reservoir, we obtained following results: The AVS peak isdeeper in sampling location of reservoir.1 than that in sampling location of reservoir.3.Tthemajor cause is that anaerobic environmental condition is different in two locations. Thevertical distribution of SEM is decreasing with depth in these sampling locations.4. In 10 samples, it is only river.2 that 5>SEM-AVS>0, and the other samples are allSEM-AVS<0. The data of AVS and SEM are analysised using SEM/AVS method. Theresults showed that: there is only river.2 reaches the Biology Damage Threshold in autumn; the data of SEM/AVS from other samples are much less than 2.34. Though the(SEM-AVS)/foc ,it is founded that the data of all samples are much less than the BiologyDamage Threshold. Our conclusion is that it is impossible for heavy metals from surfacesediment of the river and the reservoir to induce heavy metals toxicity.5. The concentration of AVS and SEM in surface sediments from Shijiuhu lake,Dongqianhu lake and Yixingsanjiu lake which are in the South have been analyzed. Theresult of experiments showed that the avaverge concentration of AVS from high to low isShijiuhu lake >Dongqianhu lake> Yixingsanjiu lake. It shows that the concentration ofOM% in sediments plays important role in the vertical distribution of AVS.The avavergeconcentration of SEM from high to low is Yixingsanjiu lake>Shijiuhu lake>Dongqianhulake.The centents of heavy metals in surface sediments has mainly influence on the verticaldistribution of SEM..6. Comparing with the features of AVS and SEM in sediments with different depth inthree lakes, we obtained following results: The AVS peak is deeper in sampling location ofDongqianhu lake and Yixingsanjiu lake than that in sampling location of Shijiuhulake.Tthe major cause is that the concentration of organic matter is different in these lakes.The vertical distribution of SEM is decreasing with depth in these sampling locations.Theresultes shows the concentration of organic matter in sediments has great influence on thevertical distribution of AVS with depth.The concentration of SEM is low and the verticaldistribution of SEM is decreasing with depth in these sampling locations.The concentrationof SEM increases remarkably at 25cm from sediments in Yixinsanjiu.7. In 7 samples from Shijiuhu, there are all SEM-AVS<0, the heavy metals in thesesediments are safe for limonitic organisms.The all samples from Shijiuhu lake andDongqianhu lake are all 5>SEM-AVS>0, it is possible for heavy metals from surfacesediment of these lakes to induce heavy metals toxicity.8. The concentration of organic matter in sediments and anaerobic environmentalcondition play important role in the vertical distribution of AVS.The avavergeconcentration of SEM in surface sediments from Yixingsanjiu lake are higher than that insurface sediments from Shijiuhu lake ,Yanghe reservoir and Dongqianhu lake, it showedthat the heavy pollution is seriouser in Shijiuhu lake, Dongqianhu lake and Yixingsanjiulake than that in Yanghe reservoir. The concentration of SEM in surface sediments ishigher than that in deep sediments from sample, the experiment shows that heavy metal pollution is increasing.更多还原