汉江中下游水体重金属时空分布及污染评价

为探明汉江中下游水体中重金属的污染状况,分别于2019年6月(丰水期)和2020年1月(枯水期)在汉江中下游选取20个监测断面采集水样,监测水体中Cu、Zn、Pb、Fe、Mn、As、Se和Cd 8种重金属的含量,分析汉江中下游水体中重金属污染的时空分布特征,并对水体重金属污染状况进行评价。结果表明:汉江中下游水体重金属污染以Fe、Mn为主,其他6种重金属浓度均满足地表水Ⅱ类水标准。汉江中下游水体中Fe和Mn含量沿程波动较大,二者变化规律基本一致。Fe和Mn含量最大值在支流竹皮河,其中Fe浓度超标4.63倍,Mn超标13%;此外,位于汉川市的S17断面Fe元素含量超标3.89倍。结合历史数据分析,发现近年来汉江中下游水体重金属含量总体呈上升趋势。评价结果表明,汉江中下游大部分水体水质良好,钟祥市和汉川市是汉江中下游重金属污染相对较重的两个城市,支流竹皮河的水体重金属污染问题需引起重视。     

煤矸石在动态淋滤作用下污染物释放规律研究

对新邱露天矿不同风化程度的煤矸石溶解释放污染物的规律进行了动态淋滤实验研究,结果表明:煤矸石溶解释放的主要污染组分为总硬度(以CaCO3计)、SO42-,Na+,TDS,F-,CODMn和总Fe等,淋滤液pH值基本在6.6~7.0之间,Cl-,Mn,Zn等少量,其他重金属和As等微量;煤矸石风化程度越高,溶解释放的无机盐类污染物量越多,新鲜混合煤矸石溶解释放出较高的F-,CODMn和总Fe;淋滤初期,淋滤液中主要污染组分质量浓度较高,溶出速率也较快;尤其是Na+溶解释放速率更快,以后随着降水量的增加,煤矸石中的污染物逐渐被降雨淋滤水量带走,淋滤液中各污染物质量浓度逐渐降低,煤矸石中污染物的淋溶释放呈指数曲线规律衰减;利用该衰减规律可定量预测煤矸石中污染物对土壤和地下水污染的强度。     

PHYSICAL AND PLANT COMMUNITY CONTROLS ON NITROGEN AND PHOSPHORUS LEACHING FROM IMPOUNDED RIVERINE WETLANDS FOLLOWING DAM REMOVAL

Dam removal has emerged as a critical issue in water resources engineering and management. Of particular concern in many regions of the USA is the effect of dam removal on downstream water quality and potential methods of decreasing sediment and nutrient loading to downstream reaches. Rapid revegetation of reservoir sediments has been suggested as a means of reducing the impact of dam removal, although little data exist about the role of vegetation in controlling the downstream release of sediment or nutrients. This study investigated an impounded riverine wetland complex on the Little River, North Carolina, before and after the removal of a low‐head dam. We quantified the leaching of interstitial nitrogen (N) and phosphorus (P) to the adjacent river channel during reservoir dewatering and, through experimental manipulations, isolated the difference between physical (soil) and biological (plant) controls on N and P leaching from dewatering impoundment sediments. We found that the rate and the quantity of N and P leaching from impounded dewatering sediment are predominately controlled by sediment porosity and specific yield. Although vegetation controls on N and P leaching were statistically significant during the first growing season following dam removal, vegetation is likely to be more important as a long‐term control on sediment and nutrient loads. Our results suggest that the initial release of N and P from a dewatered reservoir will be difficult to control but that vegetation may play an important long‐term role. Copyright © 2011 John Wiley & Sons, Ltd.     

塔里木河下游生态输水量转化分析

塔里木河下游大西海子水库以下河段自1972年至2000年发生的持续断流是绿色走廊生态劣变的主要原因。从2000年5月至2011年11月,塔里木河下游共进行了10次生态输水。本文利用输水期间的地下水监测资料,运用水均衡法对大西海子以下河段历次输水过程中的水量转化进行了计算,量化了河道水量的转化项与塔里木河下游地下水的恢复程度,揭示了塔里木河下游河道径流一补给转化一蒸腾耗散的水文过程,文中结论可为今后进一步优化输水方案、合理配置区域水资源以及植被的有序恢复提供科学依据。     

Role of the sediments of two tropical dam reservoirs in the flux of metallic elements to the water column

In tropical climates, the high rainfall and temperature, throughout the annual cycle, allow high leaching rates of metallic elements from the basin upstream, which accumulate in the reservoirs. However, the concentration of these elements in natural waters is usually lower than expected, due to the ease of adsorption and co-precipitation in solid phases. We have studied two tropical dam reservoirs in Brazil, Três Marias (Minas Gerais) and Tucuruí (Pará), with the aim of understanding the correlation between physical-chemical parameters of the water column, chemical and mineralogical characteristics of the accumulated material and the solubility, mobilization and precipitation of metals in reservoirs. Metals speciation performed in selected samples determined that metallic micronutrients are preferentially adsorbed or retained through precipitation/co-precipitation onto fine-size charged crystalline/amorphous Fe-oxides. Under the prevailing reducing and low pH conditions of the bottom reservoirs, some adsorbed metals (particularly Fe and Mn) are easily released from their metal bearing-phases and mobilized to the aqueous phase of sediments, which show high levels of soluble forms of these elements. However, the solubilization process and the release to the water column are not very extensive, as abundances of metals such as Fe, Mn, Zn and Cu in water are low, although increasing with depth.     

Mineralogical and geochemical investigation of sediment in the Snake River arm of the Dillon Reservoir, Summit County, Colorado, USA

Mineralogical and chemical analyses of sediment in the Snake River arm of the Dillon Reservoir provided insight into the transport and fate of trace metals in this system, which provides potable water to the city of Denver in Colorado. The sediments contain metal hydroxide precipitates and sorbed trace metals that formed upstream in the Snake River and in Deer Creek, Peru Creek and other tributaries. Iron and trace metal concentrations in the sediments reach a maximum about halfway down the 3.3 km arm, with their distribution probably controlled by physical processes acting on the settling of precipitates entering the arm from the mouth of the Snake River. The concentration of molybdenum is at background concentration near the mouth of the Snake River, increasing towards the centre of the reservoir, where values are 10 times greater, owing to contamination from the Ten Mile Creek and Blue River arms of the reservoir. The results of a sediment‐leaching experiment demonstrated that the relative ease of extraction with a decreasing pH value in the sediments is zinc > cobalt > copper > nickel > lead. Although most of the trace metals are low in concentration, or are strongly sorbed in the sediments, the relatively high concentration of zinc and its relatively high mobility make it a metal of potential concern in the reservoir.     

粤北大宝山矿废水中锌的环境地球化学

粤北大宝山铁多金属矿床的开发给周围环境带来了严重的危害。采选产生的酸性废水携带浸滤出的重金属离子流入横石河,严重影响矿区及其下游的生态环境。从尾砂、水体、河流底泥、土壤以及食用蔬菜探讨整个环境系统对锌的环境响应。结果表明,河流水中高锌含量直接源于尾砂,并受水体pH值的显著影响;河流底泥能够大量聚集水体中的锌,在pH值高时,相对稳定存在,当水体pH值降低时,锌会被再次从河流底泥中释放出来,形成河流二次污染;土壤中锌含量和土壤pH值有良好正相关关系;食用蔬菜中锌的高含量受土壤的锌总量决定,并受土壤pH值的影响,通过改善农业用灌溉水质,可以降低蔬菜重金属含量。     

Seasonal and spatial variations in major and trace elements in a regulated boreal river (Esse River) affected by acid sulphate soils

In coastal areas of Finland, extensive artificial drainage of Holocene sulphide‐bearing marine and lacustrine sediments has resulted in development of acid sulphate (AS) soils (pH 2.5–4.5) over an estimated area of approximately 3000 km². During heavy rains and snow melting, these soils are flushed resulting in discharge of acidic and metal‐rich waters that strongly affect small streams. However, the total and precise effects in the important and large rivers are not well understood. In this study, the impact of AS soil occurrence and hydrological changes on water quality was determined in an important regulated boreal river (Esse River) having a catchment area of 2054 km² partially covered with AS soil (39 km²). Water samples, collected at five sites along the river during four carefully selected events, were analysed for pH, total organic carbon, conductivity and the following elements/anions: Al, Ba, Br, Ca, Cd, Cl^?, Co, Cr, Cu, Fe, K, La, Mg, Mn, Na, Ni, NO, Rb, Sc, Si, SO, Sr, Th, Y and Zn. There is a clear spatial correlation between AS soil occurrence and elevated element concentrations in the river water, especially when the conditions change from dry/warm (summer) to wet/cool (autumn). During the rains in autumn these soils are extensively flushed and concentrations of Co, La, Zn, Y, Mn and Al are increased between three and nine times towards the outlet. The buffering capacity of the river was, however, high enough to prevent a detrimental drop in pH. Another intriguing feature is substantially elevated concentrations of several potentially toxic metals (Cr, Cd, Cu) in the middle reaches in winter when the river is ice‐covered. Since no external source for this was found, we suggest an internal source operating by an as yet unknown mechanism. During baseflow in summer, the concentrations of several solutes reach minimum concentrations. Copyright © 2005 John Wiley & Sons, Ltd.     

1997-2017年泰国蒙河流域水环境时空变化分析

蒙河(Mun River)流域是泰国东北部重要农业区,也是湄公河主要支流。随着流域经济社会发展,流域水环境难以避免受到扰动,研究其时空变化特征对于该区域及湄公河中下游的水生态环境保护具有重要意义。基于泰国污染管制署1997-2017年水质监测数据,应用季节性Kendall检验法分析代表性水质指标含量的变化趋势,并采用水质指数(water quality index)法分析流域整体水环境的时空分异特征。结果表明:尽管蒙河流域水环境总体质量尚好,近20年来水质总体上无趋势性变化,但存在明显的年内季节性变化以及空间差异。各监测站点非汛期水质状况一般好于汛期,而流域下游水质往往好于上游。推测土壤侵蚀、养分淋溶和城镇化进程是影响流域水环境的重要因素。     

里运河底泥COD和NH3-N空间分布及对水质的影响

通过对里运河底泥中污染物质的含量分析,阐述了不同深度底泥中COD和NH3-N的空间分布特征,结果发现城区段底泥中COD和NH3-N的含量约为非城区段的2倍,表层(0~30 cm)和次表层(30~60 cm)底泥污染较深层(150~210 cm)污染严重,0~60 cm底泥中的COD和NH3-N平均含量分别是深层底泥COD和NH3-N的2.5和2.1倍。同时通过对表层底泥和对应断面水质的比较分析,得出了表层底泥中COD和NH3-N的含量与水质有较好的相关性(R=0.76,n=12),说明底泥中污染物质的释放在一定程度上已经影响了里运河的水质。     

塔里木河流域生态输水效益分析

塔里木河流域位于我国西北内陆干旱区,由人类活动引起的土地荒漠化、土壤盐碱化、湖泊萎缩及干涸及生物多样性减少等一系列生态问题日趋严重。为适应西部大开发战略,改善生态环境和水利基础设施建设,政府部门开始对塔里木河流域实施综合治理工作,自2000年到2013年5月底,已先后向塔里木河下游"绿色长廊"实施了14次生态输水。基于大量相关文献及塔河官网数据,分析博斯腾湖的输水作用、开都-孔雀河下泄水量变化、水头历次到达大西海子水库以下距离变化等。研究表明:①博斯腾湖出水量与孔雀河下泄水量成正相关,博斯腾湖对于大西海子水库下泄水具有重要作用;开都-孔雀河输水量呈逐年下降趋势,而阿克苏河等3源流和干流输水量逐步提高,但在枯水年份的下泄能力有待提高;②大西海子水库向下游累计下泄水量41.64×108m3,10次将水输到台特玛湖,台特玛湖水量显著增加,结束了塔里木河下游河道连续断流近30年的历史,有效改善了塔里木河下游的生态环境。     

浸提时间对城市污泥重金属浸出特性的影响

在研究含工业废水污泥中Zn、Cu、Pb、Cr、Mn、Ni含量的基础上,应用固体废物浸出毒性方法,以不同浸出时间对污泥中重金属的浸出特性进行了实验研究.结果表明:污泥中Mn和Zn含量较高,其次为Cu和Ni,而毒性较大的Pb和Cr含量较低.浸提时间对污泥中重金属的浸出具有重要影响,污泥中的Zn、Cu、Ni最大浸出浓度在8h时,而Fe和Mn随着浸提时间增加而增加;浸提时间对污泥中重金属浸出量的影响因该重金属的化学性质不同而存在较明显的差别,这可能与浸提过程中的吸附-解吸过程、络合-解离过程和溶解-沉淀/共沉淀等因素有关.     

新疆奎屯河流域地下水砷超标原因分析

新疆奎屯河流域是我国大陆第一个地方性砷中毒的区域,然而在人类活动与自然条件下,对该区地下水砷超标的原因未得到清楚的解释.通过2017年在研究区采集地表水、地下水样品51组,分析了主、微量元素组分;2019年在典型的高砷区钻井2个孔,采集沉积物样品44组,分析了粒径、化学成分.结果表明,研究区地下水砷浓度范围为10～88...     

黑河干流中游地区耗水量变化的历史分析

黑河流域水资源极其匮乏，加之地区上的配置不均衡和中游地区水土资源的过度开发，导致黑河下游出现了严重的生态环境问题，已影响到我国北方广大地区生态环境质量，受到国家的高度重视和全社会的广泛关注。黑河水资源开发利用主要集中在中游地区，该区是全国重要的商品粮、蔬菜和经济作物生产基地之一，耗水量占流域耗水量的85％以上，是黑河的主要耗水区和径流利用区。利用黑河上游控制站莺落峡站和中游控制站正义峡站水文资料，分析了黑河中游耗水量的变化，结果表明：20世纪80年代以前黑河中游耗水量在4．4亿m^3左右，比较稳定；进入20世纪80年代以后，耗水量明显增加，80年代耗水量比70年代以前增加了1．97亿－2.49亿m^3;90年代耗水量又比80年代增加了1.64亿m^3左右；80年代以来流域耗水量呈明显增加的趋势，这是以人类活动影响为主的结果。     

降雨对沣河水质和污染特征的影响

通过对沣河降雨前后水质的监测,分析了沣河污染特征。结果表明:降雨形成的面源污染对沣河总氮负荷影响显著,硝氮和总氮在降雨过程中的变化有很好的相关性,硝态氮是沣河总氮污染的主要存在形式,其主要来自于农田和水土淋溶流失及城市地表径流的硝酸盐氮;非降雨时,农村排放的生活点源是引起沣河COD和氨氮水质污染的根本原因,降雨促使生活点源进入沣河,COD和氨氮在河流水质变化中有着很好的相关性,其污染主要来自于沣河流域城镇生活污水、工业废水、乡镇企业废水及高校生活污水。     

水泥+石灰复合改性膨胀土对水质的影响

对引江济淮试验工程弱膨胀土进行石灰改性、水泥改性、水泥+石灰复合改性,并制作三轴试样进行不同龄期(1 d、3 d、7 d、28 d)的养护,各龄期试样取出浸泡并分别在第1天、第3天、第7天、第28天提取浸出液检测其pH与Ca~+含量等,比较复合改性土浸出液与石灰改性、水泥改性土浸出液水质差别,并观察改性土三轴试样的浸水后完整性,探究复合改性能否降低土体对水质的影响。结果表明:复合改性土三轴试样浸出液的pH与Ca~+含量明显低于石灰改性土三轴试样浸出液;养护龄期为28 d的复合改性土对水质的影响也要低于水泥改性土。在实际工程中,应保障至少28 d的养护时间,并且在养护过程中杜绝浸泡或流水冲刷,保证养护质量。     

新疆巩乃斯河水中微量重金属元素的特征分析

对河流中微量重金属元素含量和来源的鉴别是准确、有效控制和预防污染的基本前提。通过对巩乃斯河水样进行分析,初步探讨了河流重金属元素的含量及来源。结果表明:水体中重金属元素Pb、Cr、Cu、Fe等的含量因采样断面的不同而相差悬殊,所测重金属的含量都符合国家地表水环境质量标准中Ⅰ类水标准。通过主成分分析发现河流中金属元素分为2个主要来源:第一主成分为矿物岩石的自然风化、侵蚀过程及工农业排污,其贡献率为63.43%;第二主成分为河流沉积物中金属的迁移、转化,其贡献率为26.11%。其中Pb、Cr、Cu、Fe和Ni主要受第一主成分控制;Mn和Ni主要受第二主成分控制;Cd则是受第一主成分和第二主成分共同支配。     

Fate,Transport and Effects of Pollutants Originating from Acid Mine Drainage in the Olifants River,South Africa

Concentrations of pollutants were measured in water, sediment and algal samples collected along a longitudinal gradient from a stretch of the Olifants River, South Africa, that receives acid mine drainage (AMD) from the Klipspruit River. The effects of AMD were determined through macroinvertebrate biotic indices (SASS5) and multivariate analysis of macroinvertebrate communities. The acidic Klipspruit River caused increased concentrations of total Al, Fe and Mn in the Olifants River. Upon mixing of the Klipspruit with that from the alkaline Olifants River, Al and Fe precipitate rapidly, leading to lower concentrations in the dissolved phase and higher concentrations in the suspended phase and in sediment at sites in close proximity to the confluence. Similarly, filamentous algae accumulated high concentrations of Al, Fe and Zn immediately after the confluence. Mn remains in the dissolved phase, and sediment and algal concentrations increase with increasing distance downstream. Metal speciation analysis indicate that Al is rapidly converted from more toxic forms (e.g. Al³⁺ and Al(OH)²⁺) to less toxic forms (e.g. Al(OH)₃(aq) and Al(OH)^4?). In contrast, Mn remains in the soluble Mn²⁺ form. Macroinvertebrate metrics and community structure showed clear signs of deterioration in water quality in the Olifants River downstream of the point of AMD input. While total TDS concentrations at all sites fall within ranges likely to affect macroinvertebrates, the relative composition of major ions changes as a result of AMD input, which may also account for the observed changes in macroinvertebrate communities. Further downstream, the Wilge River discharges into the Olifants River and significantly improves water quality downstream of the confluence. Future mining and development activities in the Wilge catchment should be carefully managed and monitored so as to ensure sufficient flows of acceptable quality to prevent further deterioration of water quality in the Olifants River and downstream reservoirs. Copyright © 2014 John Wiley & Sons, Ltd.     

哈尔滨浅层地下水污染现状及影响因子分析

为查明人类活动驱动下的哈尔滨市浅层地下水污染现状及主要影响因子,利用松嫩平原地下水污染调查评价项目的数据,对浅层地下水主要化学特征进行了简单的描述。在此基础上,采用单因子污染指数法与内梅罗综合指数法对地下水污染现状进行评价,最后利用统计分析软件SPSS对采样点进行聚类分析。结果表明:研究区浅层地下水水化学类型以Ca-HCO_3、Ca-Cl-HCO_3、Ca-SO_4-HCO_3型水为主,水化学作用以溶滤和人类活动混合作用为主;地下水污染属于区域性污染,以轻度污染为主;除Fe、Mn以外,主要污染指标还有总硬度、TDS、p H、NO_-3、NH+4、Cl-、SO_2-4、As。Fe、Mn含量超标主要是受原生地质环境影响;研究区地下水污染的主要污染源为工业污染、农业污染、生活污染及地表水补给污染,人类活动主要影响水体的总硬度、TDS、p H、NO_-3、NH+4、Cl-、SO_2-4、As、总磷。     

里运河底泥CODCr和NH3-N释放对水质的影响实验

通过利用长江水体作为上覆水的里运河表层底泥的释放实验研究，分析了表层底泥中CODCr和NH3—N在静置和3种扰动条件下的释放规律，结果发现城区段底泥中CODCr和NH3—N的释放强度大于非常区段，底泥孔隙水与上覆水之间的浓度梯度增大促进了底泥中污染物质的更快更多地释放。同时得出了各个断面表层底泥中CODCr，和NH3-N的释放强度，在扰动条件下的释放强度远大于静置条件下的释放强度，底泥中污染物质的释放可能会在一定程度上影响里运河将来的调水水质。