Health risk assessment of heavy metal pollution in groundwater of a karst basin,SW China

To investigate the presence of metal elements and assess their health risk for the populace in the Nandong Underground River Basin(NURB),we conducted an analysis of eleven common heavy metals in the water body.A Health risk assessment(HRA)model was employed to analyze 84 water samples from the NURB.The detection results revealed the following order of heavy metals concentrations:Fe>Al>Mn>Zn>As>Cd>Pb>Cr>Ni>Cu>Hg.Correlation analysis indicated a certain similarity in material source and migration transformation among these eleven metal elements.Our study identified that the health risks for local residents exposed to metal elements in the water of NURB primarily stem from carcinogenic risk(10^(−6)–10^(−4)a^(−1))through the drinking water pathway.Moreover,the health risk of heavy metal exposure for children through drinking water was notably higher than for adults.The maximum health risks of Cr in both underground and surface water exceeded the recommendation standard(5.0×10^(−5)a^(−1))from ICRP,surpassing the values recommended by the Swedish Environmental Protection Agency,the Dutch Ministry of Construction and Environment and the British Royal Society(5.0×10^(−6)a^(−1)).The results of the health risk assessment indicate that Cr in the water of NURB is the primary source of carcinogenic risk for local residents,followed by Cd and As.Consequently,it is imperative to control these three carcinogenic metals when the water was used as drinking water resource.

Water Quality and Heavy Metal Monitoring in Water, Sediments, and Tissues of the African Catfish Clarias gariepinus (Burchell, 1822) from the River Nile, Egypt

Water quality of the river Nile and trace elements of the water, sediments and fish tissues were investigated in the current work. Eighteen different sampling points were selected along the whole course of the River Nile from its spring at Aswan to its estuaries at Rosetta and Damietta. Higher mean value of conductivity, alkalinity, chemical oxygen demand (COD), total organic carbon (TOC), ammonia (NH3), nitrate (NO3), total solid (TS), sulphate (SO4), chloride (Cl), orthophosphate were recorded in the water of Damietta and Rosetta branches comparing to other sites. Also trace metals in the water, sediments and tissues of Clarias gariepinus increased significantly (P Fe > Cu > Pb > Mn > Cr> Cd > Hg. In the gill tissues theses metals were accumulated in the following order Fe > Zn > Mn > Pb > Cr > Cu > Cd> Hg. The low accumulation of metals in muscle may be due to lack of binding affinity of these metals with the proteins of muscle. This is particularly important because muscles contribute the greatest mass of the flesh that is consumed as food.

Geochemical Characteristics of Heavy Metals in Riparian Sediment Pore Water of Songhua River, Northeast China

This study reports the geochemical characteristics of zinc (Zn), copper (Cu), lead (Pb), nickel (Ni), mercury (Hg), iron (Fe), and manganese (Mn) in the riparian sediment pore water of the Songhua River, Northeast China. In total, 36 pore water samples and 18 surface water samples from three typical sections were collected and analyzed in June 2009. Cluster analysis of heavy metals was performed to analyze the pollution sources of the metals. Results showed that Hg concentrations in the pore water were greater than those in the surface water, indicating a potential ability of Hg release from riparian sediment system to river water. However, concentrations of Fe and Mn in the surface water were greater than those in the pore water, demonstrating that the microenvironments of riparian and riverbed sediment systems were quite different. Variations of Zn, Cu, Pb and Ni between the surface and the pore water were different in each section. Most metals had similar horizontal and profile distribution characteristics in the three sections except for Zn and Ni. Hg, Fe and Mn concentrations in the pore water increased gradually with the increase in horizontal distance from water body, in contrast to this, Cu decreased, and Pb presented a fluctuating trend. With the increase in depth, Pb and Fe, Cu and Mn showed the same trends, and Hg showed a variable trend. The above distribution characteristics could mainly be attributed to the properties and the interactions of metals, pH and oxidation-reduction conditions, and the complex pollution sources and hydrologic regime in history. The probable sources of metals include the historical and ongoing discharge of industrial wastewater, mining activities, sewage irrigation for agricultural production, and atmospheric deposition from coal-fired plants.

THE RESEARCH ON THE DISTRIBUTION AND FORMS OF HEAVY METALS IN THE XIANGJIANG RIVER SEDIMENTS

In this paper, the contents and various forms of Cd, Cu, Zn and Pb in the sediments of the Xiangjiang River have been investigated. The presentation of this paper focuses on the various forms and characteristics of the heavy metals in the column sediments at Xiawan Port of Zhuzhou, which has been severely polluted by a metallurgical plant.The forms of the heavy metals discussed in this paper are: The concentration of the exchangeable forms of Cd, Cu, Zn and Pb, in the forms of carbonates and Fe/ Mn oxide in water, the combination of Cu with organic matter and form, and the proportion of the residue form at each section have been studied.

Hybrid constructed wetlands for highly polluted river water treatment and comparison of surface-and subsurface-flow cells

A series of large pilot constructed wetland （CW） systems were constructed near the confluence of an urban stream to a larger fiver in Xi＇an, a northwestern megacity in China, for treating polluted stream water before it entered the receiving water body. Each CW system is a combination of surface- and subsurface-flow cells with local gravel, sand or slag as substrates and Phragmites australis and Typha orientalis as plants. During a one-year operation with an average surface loading of 0.053 m3/（m2.day）, the overall COD, BOD, NH3-N, total nitrogen （TN） and total phosphorus （TP） removals were 72.7% ~ 4.5%, 93.4% ＋ 2.1%, 54.0% ＋ 6.3%, 53.9% ~ 6.0% and 69.4% ：t： 4.6%, respectively, which brought about an effective improvement of the fiver water quality. Surface-flow cells showed better NH3-N removal than their TN removal while subsurface-flow cells showed better TN removal than their NH3-N removal. Using local slag as the substrate, the organic and phosphorus removal could be much improved. Seasonal variation was also found in the removal of all the pollutants and autumn seemed to be the best season for pollutant removal due to the moderate water temperature and well grown plants in the CWs.

基于SWAT模型污染防治措施对茫溪河水质改善影响研究

为了更好地开展茫溪河的污染防治,摸清茫溪河流域污染源贡献比例以及各种污防措施对水质改善效果十分必要。基于SWAT构建了茫溪河流域分布式水文和污染负荷模型,根据监测数据分析了茫溪河近年超标污染物,基于SWAT模型分析了茫溪河水质达标场景假设,包括污染源贡献率及生态补水、点源和面源等污染防治措施对水质改善的效果情况。结果表明,茫溪河流域超标项目集中在总磷和高锰酸盐指数;污染源中,面源相对于点源对高锰酸盐指数和总磷贡献率大些,特别是水土流失的贡献率最大,分别达到了42.8%和76.1%;生态补水对污染物浓度降低有一定影响,直排源和非直排源污染控制一定程度上使污染物浓度降低,达标率有所提升。基于SWAT模型的茫溪河水质达标场景分析对于推动水质改善具有积极的意义。

常州次级河流污染应急处理方式探讨——以安定河河道为例

孟河镇安定河是一条典型的黑臭水体,文章研究了该河道的水质情况,17个考核断面水质均不满足《地表水环境质量标准》(GB 3838—2002)Ⅳ类标准,主要污染因子为氨氮、总磷、总氮,超标率分别为100%、88%、100%。根据河道治理及排水需求,对河道进行应急处理,在河道两端及污染物汇入量较大处建设应急处理装置,处理工艺为反硝化(生物膜法)+活性污泥法+MBR(膜生物反应器)膜,出水直排河道;在河道沿线污水排入口设置截污井;河道污染严重区域设置河道曝气系统。结果表明,工程效果较好,化学需氧量(COD)去除率达90%以上,氨氮去除率达98%以上,河道水质由劣Ⅴ类提升到Ⅴ类、Ⅳ类。

北汝河饮水源地土壤重金属元素污染特征分析

为探讨北汝河襄城段饮水源地土壤重金属含量特征,采用单因子评价法、内梅罗综合污染指数法对饮水源地附近土壤中的重金属含量特征进行综合评价.结果表明:水源地污染主要受到Pb、Zn、Cu三种元素影响,Pb、Zn、As、Cu、Ni、Cr元素分别是环境背景值的1.34、1.03、0.87、1.36、0.70、0.97倍.研究区由Pb单因子污染指数最高是2.35,最低是0.71,处于轻度污染范围和清洁无污染范围.7个研究区中内梅罗综合污染指数最低为0.63,最大为3.06,2%土壤样品污染等级为安全,14%处于警戒线,60%属于轻度污染,6%属于中度污染,2%属于重度污染.7个研究区中Pb、Zn、As、Cu、Ni、Cr六种元素都有不同程度的超标,其中北汝河北岸土壤重金属Pb元素超标程度最高.

流域水环境污染综合治理措施研究

社会发展环节,随着工业规模的扩大,水环境的污染状况愈发严重,需要相关人员结合实际进行治理,从而实现环境保护的目标。但是在实际作业环节,流域水环境较为复杂,再加上污染类型较多,水环境的污染治理存在很大难度,制约了污染治理的效果。在实际作业环节,相关单位需要结合流域水环境的污染实际进行综合治理,以保证相关作业的落实。此背景下,流域水环境污染的解决就需要采用综合治理技术,全面地对污染状况进行治理,从整体上改善水环境污染状况。

Effects of in situ biological treatments on heavy metal release of urban river sediment

A typical fiver in Yangzhou City was used to study the effects of artificial aeration, eco-brick cover, biological packing cover, and low-sited plant floating beds on the release of heavy metals from urban river sediments. This work showed that 1） the Cr release rate was decreased by 50.3%-89.6%, with an average of 59.3%, thereby reducing the Cr pollution load to the overlying water by 36.6%-82.7%, with an average of 53.3%; 2） the Zn release rate was reduced by 21.0%-88.9%, with an average of 42.3%, and the Zn pollution load of the overlying water was reduced by 38.0%-67.1%, with an average of 55.0%; 3） the Cu release rate was reduced by 27.5%-91.0%, with an average of 55.3%, and the Cu load of the overlying water was reduced by 57.1%-83.7%, with an average of 71.7%; 4） the Pb release rate was reduced by 11.8%- 79.3%, with an average of 41.2%, and the Pb pollution load of the overlying water was reduced by -1.3%-70.7%, with an average of 29.8%. We also found that the effects of in situ biological treatments on the release of heavy metals were affected by the extent of sediment disturbance. For integrated applications, high-disturbance treatments should be combined with low-disturbance treatments to reduce the explosive release of pollutants caused by sediment disturbance during the treatment operation to achieve better overall treatment effects.

乡村振兴下农村河道水污染生物强化治理方法研究

农村河道水污染治理是推动乡村振兴可持续发展的重要途径,研究乡村振兴下农村河道水污染生物强化治理方法,改善农村河道水污染问题。乡村振兴下农村河道水污染治理具有改善河道流域整体状况、推动当地经济增长、美化人居环境的作用。生物强化技术通过自然筛选、商业菌剂、构建基因工程菌三种方式获取生物强化菌剂,通过生物强化菌剂的直接作用、共代谢作用以及基因水平转移作用治理农村河道水污染。选取某农村河道作为研究区域,验证生物强化技术可以有效降解农村河道水中的污染物,为乡村振兴提供良好的环境基础。

重金属废水处理技术研究进展

废水中的重金属具有难降解性、长期积累性、毒害性、代谢困难及隐蔽性等特点,对生态环境和人类健康都构成了风险。目前常用的重金属废水处理方法包括稀释法、化学沉淀法、混凝-絮凝法及吸附法,本文对这些方法的除重金属机理、应用优缺点及进展进行了详细介绍,指出其普遍存在运行成本高、处理不彻底、可能造成二次污染等问题。认为废水处理-重金属回收等联合处理技术才能够解决目前复合污染问题,并取得良好的经济和社会效益;还应加强水处理技术机理研究,同时完善重金属废水修复工艺,开发出适用于实际排放的重金属含量范围内废水处理技术。另外,需在易受污染区域建立长期的重金属废水环境检测生态站,为重金属废水修复提供基础保障;应注重水处理技术评价的环境效应,避免二次污染。

某地陈家沟河水中重金属元素时空变化及影响因素研究

河水重金属污染一直是环境污染防治领域的热点。秦岭某地石煤矿区陈家沟河水中重金属含量严重超标,但重金属来源不明,为污染治理带来困扰。为了查明陈家沟河水中重金属来源和时空变化情况,采集了2期河水、废弃石煤矿硐排水、废渣堆淋溶水等地表水样品,采用污染指数法、主成分分析法和Pearson相关性分析方法,研究河水中重金属污染程度、空间分布,并对河水中重金属来源进行了解析。研究表明,陈家沟源头河水(对照点)重金属含量可以达到地表水的Ⅰ类标准,中游受废弃石煤矿矿硐排水及废渣堆淋溶水的影响,河水中重金属含量显著升高,汇入干流前河水中重金属含量是对照点的3.5~312倍;河水中Cd、Cu、Zn、Ni、Mn等重金属元素同源,均来源于矿硐排水、废渣淋溶水。河水中重金属含量的空间分布与地质体、污染源分布以及河水pH、盐度等因素有关。研究结果可为陈家沟河水重金属污染防治提供科学依据。

羟基磷灰石在水体污染治理中的应用研究

羟基磷灰石具有良好的吸附性能和生物相容性,在水体污染治理中,羟基磷灰石是一种理想的环境友好型吸附剂。羟基磷灰石能够通过络合反应、溶解—沉淀作用以及离子交换反应对水体中的重金属、氮磷、有机物等污染物进行去除,在一定条件下,可以大幅降低污染物在水体中的含量,达到水体污染治理的目的。总结了羟基磷灰石不同的制备方法,介绍了羟基磷灰石吸附处理的机理和羟基磷灰石作为吸附剂在水体污染治理中的应用。

山区河道水环境综合治理探讨——以綦江区新盛河为例

为落实长江大保护战略,推进长江流域河道水环境治理,以綦江区新盛河作为研究对象,探讨了典型山区河道特征及问题,采用产排污系数法对各类入河污染源进行了估算分析,结果表明:新盛河入河污染总负荷分别为:COD_(Cr) 419.71t/a、NH_(3)-N 46.25t/a、TN 73.23t/a、TP 8.05t/a,生活污染是新盛河最大污染源,其次为农业面源污染和养殖污染,底泥内源污染、工业污染和地表径流污染对各种类型的污染负荷贡献率均相对较小。最后结合河道现状问题及治理目标从水安全、水资源、水环境、水生态、水景观、水管理等六大方面提出了针对性的水环境综合治理思路及措施建议。

螯合剂对矿山水体底泥中重金属提取效率研究

为实现矿山水体底泥重金属污染的绿色修复,利用EDTA、GLDA和MGDA等3种螯合剂在不同的条件下提取矿山水体底泥中的重金属Cd、Cu和Ni并分析其作用机理。研究采用分批提取、BCR提取等试验方法比较分析了EDTA、GLDA和MGDA等3种螯合剂和不同影响因素对矿山水体底泥中重金属提取效率的影响。研究结果表明,最佳淋洗时间因重金属元素及螯合剂种类而异,pH是螯合剂提取重金属效率的主要影响因素,螯合剂浓度的增加能显著提高重金属去除率,累计循环淋洗对重金属的去除效率提升不足5%。螯合剂去除矿山水体底泥中重金属是通过改变重金属的存在形态。在室温体系下,3种螯合剂最适使用条件为:EDTA与重金属离子摩尔比6∶1(淋洗时间16 h,pH=4),循环淋洗2次;GLDA与重金属离子摩尔比4∶1(淋洗时间8 h,pH=4),循环淋洗3次;MGDA与重金属离子摩尔比6∶1(淋洗时间8 h,pH=4),循环淋洗3次。在最适使用条件下,螯合剂对Cd的去除效果由大到小依次为EDTA、GLDA、MGDA,对Cu的去除效果由大到小依次为MGDA、EDTA、GLDA,对Ni的去除效果由大到小依次为MGDA、GLDA、EDTA。绿色螯合剂GLDA和MGDA可以替代传统螯合剂EDTA,提高成本效益和环境友好性。用Na_2S处理淋洗液后,重金属回收率可达95%以上,处理后淋洗液中重金属含量低于国家排放标准,可直接排放。研究结果可为螯合剂去除矿山水体重金属污染底泥提供理论支撑。

新型“船式”水体生态修复装置研究

本文综述了目前河流、湖泊水体污染及水体生态修复技术的现状,并重点介绍了新型水体生态修复装置。该装置将微孔曝气增氧、微生物菌剂释放、水生植物净化等技术集成为一体,可系统地进行水体生态修复,提高了净化效率,在河流、湖泊、坑塘及景观水体净化方面有很好的应用前景。

磁性纳米颗粒表面功能化修饰及其在污水处理中的应用进展

磁性纳米颗粒具有高比表面积、高表面能和高磁响应等特性,其作为磁性吸附剂载体在污水处理中有着巨大的应用潜力,但目前的制备工艺及成本尚难以达到污水处理工业化应用要求。在总结磁性纳米吸附材料改性方法的基础上,综述了功能化磁性纳米颗粒在去除含重金属、有机污染物、无机污染物等污水中的应用研究进展,并对未来的磁性纳米吸附材料研究方向提出了若干建议。

不同植物景观配置对河道污染水体的净化治理效果研究

经济快速发展的代价是环境污染,目前已提出多种针对污染水体的净化方法,但大部分不适用于中国国情,不具备高经济性,为此提出不同植物景观配置对河道污染水体的净化治理效果的研究分析,综合分析中国国情和河道污染情况,以生态浮床技术作为净化治理手段,探究不同植物景观配置下河道的化学需氧量、氮素、磷素污染参数值变化情况,并测量河道pH值治理前后的数值,得出在不同配置的净化效果。经实验结果表明,组合配置比单株植物的净化效果强,其中第3组水葫芦、再力花、慈姑以及水芹配置的净化效果最好。