Land cover change and its response to water level around Tonle Sap Lake in 1988–2020

The transboundary influence of environmental change is a critical issue in the Lancang-Mekong region. As the largest river-connected lake in the lower Mekong, the ecological change and influence of Tonle Sap Lake have received widespread attention and discussion, especially after 2008, when the hydrological regime of the Lancang-Mekong River mainstream underwent distinct changes. However, the linkage and coupling mechanism between the lake riparian environment and mainstream water level change a...     

珠江广州河段微表层与次表层水环境质量比较(英文)

The water quality in the surface microlayer(SML) and subsurface water(SSW) in the Guangzhou segment of Pearl River, a eutrophic urban river section in China, were analyzed. The spatial and temporal dynamics of nutrient concentrations, heavy metals and bacteria were examined from two sampling sites in monthly samples throughout 2010. The mean concentrations of total nitrogen, ammonia, nitrate and nitrite were higher than 7.0 mg/L, 3.1 mg/L, 1.1 mg/L and 0.3 mg/L, while total phosphorus and orthophosphate were 0.5 mg/L and 0.1 mg/L, respectively. These results indicated that the water quality was rich in minerals and eutrophic. The mean concentrations of Mn and Fe were higher than 0.013 mg/L; and Ni, Cr and Pb were higher than 0.001 mg/L. The mean concentrations were in the order of Mn Fe Ni Pb Cr. The concentrations of heavy metals in the Guangzhou segment were lower than the limit of the surface water quality standards in China and the World Health Organization(WHO), but higher than the median values in the world's freshwater. The density of bacteria ranged from 3.30×105 to 5.23×106 cells/mL, and the amount of cultivable heterotrophic bacteria ranged from 1.30×10 3 to 1.89×10 6 cfu/mL. Fecal coliform levels were beyond the V class of China water quality standard. The SML was enriched in nutrients, heavy metals and bacteria, with the maximum enrichment factor of 3.84 for nutrients, 8.00 for heavy metals, and 3.04 for bacteria, suggesting that the water quality of the SML of the Guangzhou segment of the Pearl River was more serious than in the SSW.     

湘江中下游农田土壤和蔬菜的重金属污染

A total of 219 agricultural soil and 48 vegetable samples were collected from the midstream and downstream of the Xiangjiang River（the Hengyang-Changsha section）in Hunan Province.The accumulation characteristics,spatial distribution and potential risk of heavy metals in the agricultural soils and vegetables were depicted.There are higher accumulations of heavy metals such as As,Cd,Cu,Ni,Pb and Zn in agricultural soils,and the contents of Cd（2.44 mg kg^-1 ）,Pb（65.00 mg kg^-1 ）and Zn（144.13 mg kg^-1 ）are 7.97,3.69 and 1.63 times the corresponding background contents in soils of Hunan Province,respectively. 13.2%of As,68.5%of Cd,2.7%of Cu,2.7%of Ni,8.7%of Pb and 15.1%of Zn in soil samples from the investigated sites exceeded the maximum allowable heavy metal contents in the China Environmental Quality Standard for Soils（GB15618-1995,Grade Ⅱ）.The pollution characteristics of multi-metals in soils are mainly due to Cd.The contents of As,Cd,Cu,Pb and Zn in vegetable soils are significantly higher than the contents in paddy soils.95.8%, 68.8%,10.4%and 95.8%of vegetable samples exceeded the Maximum Levels of Contaminants in Foods（GB2762-2005）for As,Cd,Ni and Pb concentrations,respectively.There are significantly positive correlations between the concentrations of Cd,Pb and Zn in vegetables and the concentrations in the corresponding vegetable soils（p〈0.01）.It is very necessary to focus on the potential risk of heavy metals for food safety and human health in agricultural soils and vegetables in the midstream and downstream of the Xiangjiang River,Hunan Province of China.     

Heavy metal pollution from copper smelting during the Shang Dynasty at the Laoniupo site in the Bahe River valley,Guanzhong Basin,China

Heavy metal pollution is hazardous for the environment and human health. However,there are few studies of heavy metal pollution caused by historic metallurgical activity. The Laoniupo site in the Bahe River valley, Guanzhong Basin, China, was an important settlement of the Shang Culture(1600–1046 BCE). We studied two stratigraphic profiles at the Laoniupo site, which were used for measurements of magnetic susceptibility, heavy metal concentrations, and AMS ~(14) C ages to provide evidence of copper smelting activity at the site during the Shang Dynasty. The Nemerow Pollution Index and Geoaccumulation Index were calculated to assess the heavy metals record(Cu, Zn, Ni, Pb, Cr, and As) in the topsoil on the loess tableland. According to the Single Pollution Index, the topsoil was slightly polluted by As and unpolluted by Cu, Zn, Ni, Pb and Cr; according to the Nemerow Composite Pollution Index the topsoil was mildly polluted; and according to the Geoaccumulation Index, the topsoil was moderately polluted by As, slightly polluted by Cu, and unpolluted by Zn, Ni, Pb and Cr. The main cause of the heavy metal pollution in the topsoil is the presence of copper slag in the cultural layers that was disturbed by modern farming activity.     

上海市崇明岛农田土壤重金属的环境质量评价(英文)

The environmental quality of heavy metals (Pb,Cd,Cr,As,Hg) in agricultural surface soil of Chongming Island was assessed by national,local and professional standards based on a large scale investigation,in which 28 samples from vegetable plots,65 samples from paddy fields and 9 samples from watermelon fields were collected from whole island area. Results showed that the average concentration of Pb,Cd,Cr,As and Hg was 21.6 mg·kg-1,0.176 mg·kg-1,69.4 mg·kg-1,9.209 mg·kg-1 and 0.128 mg·kg-1,respectively. Compared with the background value of Shanghai City soil,except for Pb and Cr,all the other heavy metals average concentrations in Chongming Island agricultural surface soil exceeded their corresponding natural-background values. The concentrations of Cd,As and Hg were 33.0%,1.2% and 26.3% higher than the background value of Shanghai City,respectively. In addition,inverse distance interpolation (IDW) tool of GIS was also applied to study the spatial variation of heavy metals. The results indicated that most of agricultural soil quality was good,and the ratio of ecological,good soil,certified soil and disqualified soil were 1.26%,97.1%,1.47% and 0.12%,respectively. About 10.1%,85.7%,27.0%,55.4% and 55.2% soil samples exceeded the Pb,Cd,Cr,As and Hg background value of Shanghai City,respectively. Among these three land use type soils,vegetable soil was most seriously polluted by heavy metals,which is probably related to the over-application of pesticides. The annual deposition fluxes of Pb,Cd,As and Hg were 7736 μg.m-2.a-1,208 μg.m-2.a-1,2238 μg.m-2.a-1 and 52.8 μg.m-2.a-1,respectively. Crop straw burning was the important source of heavy metals of atmospheric deposition,and atmospheric deposition contributed a lot to heavy metals in agricultural soil in Chongming Island.     

基于GIS的土耳其国际保护区G(o)ksu河水质的调查与建模

Gksu Delta is an important wetland where the Gksu River reaches to sea in the eastern of the town Tasucu-Ice1. The delta is classified as a Wetland of International Impor-tance according to the Ramsar Convention on Wetlands of International Importance. The amount of fertilizers used in this area was 7200 tons in 2006. These pollutants affect the surface and groundwater quality negatively. The intensively used fertilizers and pesticides contain not only N- and P compounds but also some heavy metals. The contents of all pol-lutants in surface waters were determined for four different seasons between 2006 and 2008 and with these data a Geographic Information System (GIS) has been constructed by using Map Info. From the photometric heavy metal analysis, it is inferred that the excess concen-tration of Fe, Ni, Mn, Mo and Cu at some locations is the cause of undesirable quality for drinking purposes. The source of excess concentration of various heavy metals is the agri-cultural activities and fertilizers. It is determined that in all periods between 2006 and 2008 the heavy metals and other pollutants in the fertilizers and pesticides transported easily to river water with irrigation return flow. The organic pollutants, including COD, BOD, NH3 and NO3 followed the sharply increasing trends from Silifke city to Mediterranean Sea. The water quality of Gksu River is modeled and determined that the waste water discharge of 10,700 m3/day from Silifke city does not create a serious problem because of the high amount of flow rate of Gksu River.     

Heavy metal concentrations of agricultural soils and vegetables from Dongguan, Guangdong

A total of 118 of agricultural soil and 43 of vegetable samples were collected from Dongguan City, Guangdong, China. The spatial distribution, sources, accumulation characteristics and potential risk of heavy metals in the agricultural soils and vegetables were depicted in details by three different approaches, including total contents of eight metal elements in soils and vegetables, GIS maps and multivariate analysis of heavy metals in soils in the study. The results show that there are higher accumulation of heavy metals such as Cu, Zn, Ni, Pb, Cd and Hg in agricultural soils, and the contents of Pb (65.38 mg kg?1) and Hg (0.24 mg kg?1) are 1.82 and 2.82 times of the background contents of the corresponding heavy metals in soils of Guangdong Province, respectively. There are about 3.4% of Cu, 5.9% of Ni, 1.7% of Cd and 28% of Hg in all collected soil samples from all investigated sites which have overran the contents for heavy metals of the China Environmental Quality Standard for Soils (GB15618-1995, Grade Ⅱ). The pollution characteristics of multi-metals in soils are mainly reflected by Hg. There are different sources to eight metal elements in soils, Cu, Zn, Ni, Cr and As are predominantly derived from parent materials, and Pb, Hg and Cd are affected by anthropogenic activities. The spatial distribution shows that the Cu, Zn, Ni, Cr, Pb, As and Hg contents of agricultural soils are high in the west and low in the east, and Cd contents are high in the northwest, southeast and low in the southwest in Dongguan. The ratios of vegetable samples which Ni, Pb and As concentrations higher than the Maximum Levels of Contaminants in Foods (GB2762-2005) are 4.7%, 16.3% and 48.8%, respectively. The order of bio-concentration factors (BCF) of heavy metals in vegetables is Cd > Zn > Cu > As > Ni > Hg > Cr > Pb. It is necessary to focus on potential risk of heavy metals for food safety and human’s health from agricultural soils and vegetables in Dongguan City, Guangdong Province.     

色楞格河三角洲重金属季节和空间分布

In order to estimate the present-day pollution levels in the ecosystem of the Selenga River Delta and to monitor the changes caused by the discharge of household refuse and industrial wastes,as well as the functioning of the agricultural and stock farming,a comprehensive study of the water and bottom sediments in the main branches of the Selenga River Delta was carried out.This study has determined the concentrations of heavy metals in river water and bottom sediments in its delta.     

基于二元水循环的河流生态需水水量与水质综合评价方法——以辽河流域为例

In this article the meaning of the quantity and quality of environmental flows of river in dualistic water cycle is discussed,and compared with the meaning of unitary water cycle. Based on the analysis of the relationship between environmental flows of river re-quirements,the efficiency of water resource usage,the consumption coefficient,and the concentration of waste water elimination,the water quantity and water quality calculation method of the environmental flows of river requirements in dualistic water cycle is developed,and the criteria for environmental flows of river requirements are established,and therefore the water quantity-quality combined evaluation of natural river flows requirements are realized. Taking the Liaohe River as a model,the environmental flows of river requirements for Xiliao River,Dongliao River,mainstream Liaohe River,Huntai River and northeast rivers along the coasts of the Yellow and Bohai seas in unitary water cycle are calculated,each taking up 39.3%,63.0%,43.9%,43.3% and 43.5% of runoff respectively. Evaluated according to Tennant recommended flow,the results show that: except Xiliao River is "median",the rest are all upon "good",the Dongliao River is even "very good". The corresponding results in dualistic water cycle are that,the proportion of natural flows for each river is 57.5%,74.1%,60.8%,60.3% and 60.4%; while the combined evaluation results show that: considering "quantity",except Xiliao River,the rest rivers can all achieve the "quantity" criteria of the en-vironmental flows of river requirements,but if considering the aspect of "quality",only Dongliao River can reach the "quality" standard. By water quantity-quality combined evalua-tion method,only Dongliao River can achieve the criteria. So the water quality is the main factor that determines whether the environmental flows can meet the river ecosystem de-mands.     

GIS and DEM based analysis of incision and drainage reorganization of the Buyuan River basin in the upper Lancang-Mekong of China since the Late Pleistocene

River incision and drainage reorganization have an important impact on the site selection of many major projects including city,road and others,and are the key issues of Quaternary environmental changes.Studies of river incision and river-network adjustment have traditionally been based on extensive field evidence,such as sediment age and beheaded river system.The Buyuan River basin is a large sub-basin of the upper Lancang-Mekong,with high mountains and extremely active erosion.The latter affects the preservation of the Quaternary period sediments leading to difficulties in understanding the main evolution characteristics of the basin.This study investigates differences in the equilibrium state of the longitudinal profile,infers incision rates,and evaluates drainage divide migration timelines using the stream-power incision model,the latest morphological dating,and Chi-plots(χ–z) based on digital elevation models(DEMs) on the GIS software platform.The final results show that two significant erosion base-level decreases occurred in the Late Pleistocene at least.The incision rate of the mainstream might have been 0–2.99 mm/yr since 100 ka BP and 0–3.28 mm/yr since 46 ka BP.The Chi-values across the divides suggest that space limited(or constrained) river reorganization and that there is no severe reorganization in the basin;the imbalance of traceable erosion only exists in local areas.The main driving force for the geomorphologic evolution of the Buyuan River basin is likely climate fluctuations rather than strong tectonic uplift since the Late Pleistocene.     

澜沧江河床沉积物重金属污染评价

河床沉积物是河流水体与泥沙环境中重金属的主要积存载体,能反映水环境的重金属污染状况。本文选取澜沧江为对象,通过对澜沧江干流西藏和云南境内22个河段的河床沉积物重金属测定分析,得到了8种主要的重金属元素(Cr、Mn、Ni、Zn、As、Pb、Cu和Co)的含量,并采用沉积物富集系数法与地质积累指数法分别对所测得沉积物的重金属污染程度进行了评价。结果表明:①澜沧江干流大部分河段污染情况并不明显,但在中游的旧州和功果桥河段,因该区域的地质金属背景值和支流沘江流域铅锌矿开采,地表的重金属元素被雨水冲刷到该河段,导致沉积物重金属富集现象明显,出现了轻度到较强度污染;②澜沧江流域受人为干扰的区域集中于中游与下游,部分河段(功果桥附近)Cu、Pb和Zn等元素呈轻度或偏中度污染;③大坝对河流的阻隔效应使得干流沉积物重金属污染呈现片段化分布,河流沿岸城市化等人类活动对附近河段沉积物重金属污染状况也有较明显的影响。     

澜沧江水系底沙重金属含量空间分布及其污染评价

流域内矿山开采引起的河流系统重金属污染是流域开发及资源利用过程中的主要环境问题之一.本研究选取澜沧江水系底沙沉积物为介质,考察其干流及11 条主要支流的5 种重金属元素铜(Cu)、砷(As)、铅(Pb)、锌(Zn) 和铬(Cr) 含量的空间变化,并综合采用了单因子指数法和潜在生态危害指数法评价澜沧江干支流底沙沉积物中重金属污染分布现状.结果显示: (1) 澜沧江水系自上游至下游,底沙重金属含量呈减弱趋势,但各支流重金属含量分布差异较大;(2) 单因子指数法评价结果表明,干流最上游的旧州断面因区域背景值较高而致使As、Pb 呈现重污染.支流黑惠江河口的As及勐戛河的Cu为重污染,沘江断面的Pb、Zn污染指数最大,属严重污染.其它干支流样点除了少数重金属元素有中度污染外,均为无污染状态;(3) 潜在生态危害指数法指出,干流旧州断面的As及支流沘江断面Pb 的E_rⁱ 值较高,其它各采样点值均未超出40,且各支流潜在生态危害指数(RI) 值均小于150,属于低潜在生态危害的范围.本研究对澜沧江干流及其主要支流底沙沉积物中重金属污染状况进行分析与评价,分析干流主要的污染来源及各支流主要污染物,为澜沧江干支流的污染治理提供科学依据.     

青海省湟水河西宁段重金属元素的污染和评价

湟水河是西宁市的重要河流。开展湟水河西宁段沉积物的重金属研究对西宁市的环境保护和生态建设具有重要意义。本次研究对湟水河西宁段表层泥质沉积和河水以及流域内的现代菜地表土和松树苗地表土的重金属含量进行了测定。同时,采用全新世以前的黄土、湟水河一级阶地的砂质沉积给出了西宁市自然状态下的重金属背景值。各类样品的重金属元素含量结果表明:1)自然状态下,Pb为29.5 mg/kg,As为15.6 mg/kg,Hg为0.01 mg/kg,Cd为0.18 mg/kg,Cr为31.1 mg/kg。2)河流表层泥质沉积的重金属含量平均值,Pb为45.2 mg/kg,As为7.8 mg/kg,Hg为0.02 mg/kg,Cd为0.48 mg/kg,Cr为48.8 mg/kg。3)总体上,河流表层泥质沉积、现代菜地表土和松树苗地表土的Cd、Pb、Hg、Cr均比自然状态下的背景值要高。4)湟水河西宁段已出现较明显的重金属污染,应控制Cd等重金属元素向河流中的排放。     

青海湖流域沙柳河下游沉积物中重金属污染风险评价

对青海湖流域沙柳河下游沉积物中As、Cd、Pb、V、Cr、Mn、Ni、Cu和Zn 9种重金属元素的含量进行了分析测定,采用污染系数、富集系数、地累积指数和潜在生态危害指数评估了其污染程度。结果表明：无论在横向还是纵向上,重金属元素含量均低于青海湖土壤背景值;重金属元素污染系数和富集系数均小于2,且大多数样品的值低于1（高于1者多为Cd、Cu、Ni、Zn,且具高值）;地累积指数均为负值（除QB-19中Cd和Cu分别为0.10和0.02）;潜在生态风险因子大多低于30,潜在生态危害指数大多低于70。沙柳河下游沉积物尚未出现重金属污染,具有低的生态风险,但该流域重金属的人为排放确实存在（主要是Cd、Cu、Ni、Zn等）,而且在近代排放更为显著。     

Contaminations of Heavy Metals in Surface Soils of Various Lands and Their Health Risks in Tianjin Qilihai Ancient Lagoon Wetlands,China

A total of 36 surface soil profiles were set at the wetlands in Qilihai Ancient Lagoon Wetlands,Tianjin,the surface soils of 0-20 cm depth were sampled at various use types of lands to provide information on the concentrations of heavy metals in the coastal wetlands.Total concentrations of arsenic(As),cadmium(Cd),copper(Cu),lead(Pb),chromium(Cr)and zinc(Zn)were determined using inductively coupled plasma atomic absorption spectrometry(ICP-AES)to address the pollution levels in the sampling sites.The results showed that the concentrations of Cd,Cu in the soils disturbed by human activities intensively,the Phragmites australis marshes,the farmland,the brushes decreased in turn;among the sites,the concentrations of As,Cd and Cu were the highest in the soil of build-up areas,while the concentrations of Pb and Zn were the higher in the soil of farmland.The mean concentrations of Cu,Cr,Cd,Pb,Zn and As in the soils of 0-20 cm depth were 38.74 mg/kg,83.52 mg/kg,0.19 mg/kg,34.27 mg/kg,121.7 mg/kg and 18.77 mg/kg,respectively.The contamination indices of As were on the high pollution level in the soils of farmland and disturbed by human activities intensively;the concentrations of Cd in the soils of the marshes and farmland were at the moderate pollution level,while that in the soil disturbed by human activities intensively was at high pollution level.The values of comprehensive contamination index demonstrated that the variation of As contents was the maximum in the soils,Cd pollution reached to a high level.Geoaccumulation index showed that As pollution was at moderate level,and Cd,Cu and Zn pollution were at slight level,and the Pb and Cr pollution wasn't found in the build-up areas.     

北京市小麦籽粒的重金属含量及其健康风险分析

为评价北京市小麦重金属含量及其健康风险,采集北京市现有小麦种植区土壤和小麦籽粒对应样品68份,分析其重金属含量,并估算消费导致重金属摄入量。结果表明:北京市麦地土壤重金属As、Cd、Cr、Cu、Ni、Pb和Zn的平均值分别为7.46、0.165、37.8、20.3、24.2、14.3和70.1mg/kg,处于比较清洁水平。这说明小麦种植这种土地利用方式并不会导致土壤重金属升高。小麦籽粒中重金属含量,除Cr与食品卫生标准限值没有显著性差异外,其他元素均显著低于相应标准限值。普通人群通过小麦制品消费,As、Cd、Cr、Cu、Ni、Pb和Zn的摄入量分别为0.005、0.004、0.136、0.994、0.041、0.024、4.75mg/人 · d。北京小麦种植的主要4个区中,顺义产小麦的Cr、Cu、Ni和Pb导致的重金属摄入量高于其他3个区,房山产小麦导致的重金属摄入量最低。对于普通人群而言,通过小麦和蔬菜摄入重金属没有明显风险。     

海南省五指山土壤中的重金属元素含量

海南省地处热带地区，山地面积占25．4％，五指山是海南山地的核心，也是海南最高峰，从下而上依次分布着砖红壤、赤红壤、黄壤、灌丛草甸土。五指山土壤普遍遍缺，而Zn、Ni、Pb、Cd、Cr、Co含量属正常值。在成土过程中，Cd有一定积累，其他元素有明显淋溶。在自下而上的垂直带谱中，Zn、Co含量呈现递减，Cd则相反，Ni、Pb、Cu、Cr含量呈现波浪式变化。气候因素是影响五指山土壤重金属元素含量及分布的主导因素。     

西溪湿地土壤重金属分布特征及其生态风险评价

测试和研究了杭州西溪湿地土壤中铜(Cu)、锌(Zn)、铅(Pb)、镉(Cd)、汞(Hg)、砷(As)和铬(Cr)的含量与分布特征,采用内梅罗综合污染指数和Hakanson潜在生态危害指数法对湿地土壤重金属污染环境质量和潜在生态风险进行了评价。结果表明,西溪湿地土壤表层7种重金属平均含量的质量比分别为36.8 mg/kg(Cu)、91.5 mg/kg(Zn)、39.2 mg/kg(Pb)、0.23 mg/kg(Cd)、0.19 mg/kg(Hg)、6.3 mg/kg(As)和64.9 mg/kg(Cr)。由于受各种人为作用的影响,与浙江省土壤背景值相比,Cu、Pb、Cd和Zn在湿地土壤中的积累较大,有3个采样点[菜地、芦苇(Phram ites austrlis)滩地和靠马路的居民区]土壤中的Cd含量超过《土壤环境质量标准》(GB15618-1995)标准值的二级标准(pH<6.5)。湿地土壤重金属污染环境质量和生态风险评价结果显示,内梅罗综合污染指数平均值为1.73,多种重金属潜在生态风险指数平均值为114.6,说明总体上西溪湿地土壤重金属污染及其潜在生态风险为轻微级。最后,讨论了西溪湿地公园土壤重金属的可能来源,对比了重金属污染评价中不同评价标准和评价方法的差异性。     

沅江下游入湖段河床沉积物重金属污染特征

对沅江入湖沉积物进行钻探取样,利用等离子质谱仪（ICP-MS）对沉积物重金属进行分析。结果表明：重金属Ba、Sc、V、Th、U、Cu、Co、Ni、Cr等在沉积物中含量变化相对稳定,分布相对均匀;而Mn、Zn、Pb、Mo、Cd、Tl、Bi等重金属的含量变化大,分布不均匀。重金属含量柱状剖面变化特征及富集系数（EF值）的计算结果显示：沉积物中Cd达显著富集,而Sc、V、Mn、Pb、Bi等为中等富集程度。沉积物中存在3个重金属富集层,即中下部Pb、Tl、Bi富集层;中上部Pb、Cr、Ni、Cu富集层;浅表部V、Cr、Mn、Ni、Cu、Zn、Pb、Cd、Tl、Bi等多种重金属富集层。地累积指数（I_geo）和综合富集指数（EI）评价结果显示：沅江入湖沉积物重金属污染程度自河床深部向浅部,污染程度趋于增强,污染元素组合趋于由Pb-Bi的单一元素组合向由V-Cr-Mn-Ni-Cu-Zn-Pb-Cd-Bi组成的复合元素组合变化。且自上游向下游,沉积物重金属污染程度趋于降低。这种重金属污染空间变化特征与区域人为活动有关,值得进一步研究。