Metal bioaccumulation in plant leaves from an industrious area and the Botanical Garden in Beijing

The concentrations of Fe, Mn, Al, Zn, Pb, Ni, Cr, and As were measured in soils and leaves from 21 plant species growing on hills near the Beijing Steel Factory(BSF) and 17 plant species in the Beijing Botanical Garden(BBG). The results showed that soils from BSF were Zn contaminated according to the threshold of natural background of China. There was a metal contamination of the soils by Ni, and Cr in BSF comparing with those in BBG. The comparison between concentrations of metals in leaves from both sites indicated that, in general, accumulation of metals in the leaves of the same species was significantly different between the two sites. Even within the same locality each species accumulation of metals was significantly variable. The study aimed to screen landscape plants for the capacity to clean-up toxic metals in soils, and developed an overall metal accumulation index(MAI) for leaves and then categorized the MAI that can be applied broadly in the selection of species in polluted areas. To do this, the spectrum of MAI values were divided into four classes: strongly accumulated(SA or grade I), moderately accumulated(MA or grade II), intermediately accumulated(IA or grade III), and weakly accumulated(WA or grade IV). The results showed that elemental association between Fe, Al, Ni, and As was generally highly correlated with each other in the sampling sites. This may suggest their common biochemical characteristics. Generally, those species containing strong and moderate accumulation in both sites are considered including Vitex negundo, Broussonetia papyrifera, Ulmus pumila, and Rubia cordifolia. At BSF and other industrial sites with a similar ecosystem, strong and moderate accumulation species include Sophora japonica, Ampelopsis aconitifolia var. glabra, Platycladus orientalis, Wikstroemia chamaedaphne, Cleistogenes squarrosa, Grewia biloba, and in BBG, in addition Setaria viridis, Cotinus coggygria, Lespedeza floribunda, Rhamnus parvifolia, Lespedeza tomentosa.

Contamination and Ecological Risk Assessment of Heavy Metal in the Sediment of Turag River, Bangladesh: An Index Analysis Approach

Encroachment, disposal of untreated domestic and industrial wastewater and dumping of solid wastes have degraded the overall quality of the river Turag, which is located in Dhaka—the Capital City of Bangladesh. The present study investigated the extent of pollution of sediments of this river and analyzed the regional variability for the concentrations of Cr, Pb, Zn, Cu and Cd—all of concern because of their potential toxicity, using atomic absorption spectrophotometer. As per US EPA sediment quality guideline, metal concentrations ranged between Cd: 0.00 - 0.80, Cr: 32.00 - 75.50, Cu: 46.30 - 60.00, Pb: 28.30 - 36.40, and Zn: 94.60 - 190.10 mg/kg in the Turag river sediments. Cr, Cu, Zn belongs to moderately to highly polluted, Pb and Cd belongs to not polluted for Turag river. The heavy metals contamination in the sediments were also evaluated by applying Index of geo-accumulation (Igeo), contamination factor (Cf), pollution load index (PLI) etc. Toxicity characteristics leaching procedure (TCLP) test (US EPA 1311) for sediment samples have been performed also for metals (Pb, Cd, Cr, Cu and Zn) to determine the readily toxicity level of heavy metals. Sieve analysis of sediment performed in this study to determine the physical characteristic of sediment samples. The metal concentrations are well below the regulated level as per US EPA. This index can be complemented with the contamination index, which allows more site-specific and accurate information on contaminant levels. If the aim of work on contamination evaluation is to assess the overall contamination of a study area, the indices are highly appropriate.

Assessment of Heavy Metal Contamination in Sea Bed Sediment of the Bight of Bonny, Southern Atlantic Coast of Nigeria Using Index Model Analysis

The heavy metal contamination status of Bight of Bonny sea bed sediment was investigated. Sediment samples were collected from eleven locations grouped into three stations. The samples were analyzed to determine the heavy metals (Fe, Pb, Ni, Zn, Mn, Co, Cd, Cu, Cr) concentration using atomic absorption spectrophotometer. Index model analyses, such as geo-accumulation index (I-geo), Enrichment factor (EF), and Pollution load index (PLI) were used for pollution assessment of sea bed sediment. The most predominant heavy metals in the upstream sediment were Fe;13.57 ± 1.838 mg/kg, cobalt;7.987 ± 3.550 mg/kg, and Ni;1.020 ± 0.802 mg/kg, midstream sediment were Fe;8.554 ± 3.010 mg/kg, Co;8.520 ± 4.00 mg/kg, and Ni;1.140 ± 0.879 mg/kg, while the downstream sediment result had Fe;11.12 ± 3.825 mg/kg, Co;7.275 ± 1.700 mg/kg, and Cd;1.025 ± 0.159 /kg. The I-geo results indicate that Cu, Mn, Pb, Cr, Fe, Zn, Ni, and Co were in their background concentrations while Cd had I-geo > 3 which implies a moderately or heavily polluted environment. The EF indicates metal enrichment from anthropogenic sources for Co, Ni, Pb, Cd, Cu, and Cr while Fe and Mn predicate biogenic origin. The PLI of the heavy metals in the three sample stations of sea bed sediment was found to be generally low (<1). The Enrichment Factor and geo-accumulation index strongly suggest the Bight of Bonny sea bed sediment contamination by Cd from anthropogenic sources.

Does Embankment Improve Quality of a River? A Case Study in To Lich River Inner City Hanoi, with Special Reference to Heavy Metals

To Lich River (TLR) system receives wastewaters from a population of nearly two million people and 100 manufactories of five industrial zones in inner city Hanoi, Vietnam. To improve quality of TLR, the embankment was carried out in 1998 and finished in 2002, resulted in width of 20 - 45 m, depth of 2 - 4 m, and maximum water flow capacity of 30 m3/s. Water and sediment quality indices based on heavy metal concentrations were used to evaluate current river environment compared to that of pre-embankment. Mass balance model was employed to estimate total metal loads for specific river reaches, which corresponds to various types of wastewater discharged along the river. The results indicated that currently there is about284,000 m3sediment accumulated in TLR bed, which is under high contamination of Cr, Mn, Fe, Ni Cu, Zn, As, Cd, and Pb with a total of 7347 tons of all concerned metals. Domestic-discharged river reaches received much lower metal loads, roughly 8% - 28% compared to river reaches of both domestic and industrial inputs. Total load of all nine concerned metals at the end of TLR is161.7 kg/day, which is finally discharged to Nhue River at South Hanoi. Water quality was improved much right after finishing embankment, then it gradually deteriorated. Meanwhile, sediment quality became even much worse after embankment. Relative river quality index as equal weight for both water and sediment quality indices indicated that quality of TLR was not much improved after the embankment. It even became worse due to the urbanization in recent years.

Soil Heavy Metal Pollution and Health Risk Assessment of Abandoned Land in Coal Mining Areas in Xingren County

Total contents of heavy metals （ Pb, Cr, Cd, Hg, As, Cu, Zn, and Ni） in 68 soil samples were determined to evaluate the contamination level of soil from five coal mine areas in Xingren County, Guizhou province. The pollution levels of heavy metals were characterized by anthro- pogenic influence multiple, and the pollution of heavy metal in soil was evaluated using geo-accumulation index. Based on the health risk models recommended by the U.S. Environmental Protection Agency （ US EPA）, the health risks of heavy metals in the soils were assessed. The results showed that the abandoned land in the five coal mining areas were contaminated by heavy metals, and the order of pollution levels of eight heavy metals was As 〉 Pb 〉 Cu 〉 Hg 〉 Ni 〉 Cr 〉 Cd 〉 Zn. The soils suffered moderate-heavy pollution from As and Pb, and the contents of As and Pb in the soils were 13.16 and 4.76 times higher than the background values of Guizhou Province, followed by Cu, Hg and Ni , while soil pollution from Cr, Cd and Zn was mild. The order of non-caminogenic risks of the heavy metals in the soils was As 〉 Pb 〉 Cr 〉 Ni 〉 Cu 〉 Hg 〉 Cd 〉 Zn, and the non-carcinogenic dsk value of As was higher than that its threshold value 1, which indicated that As had a high potential health risk to adults and children. The order of carcinogen risks of the four heavy metals was As 〉 Cd 〉 Cr 〉 Ni, and the carcinogenic risk value of As was higher than its threshold value, indicating that As had a high carcinogenic risk to adults and children. The carcinogenic risk values of other three heavy metals （ Cd, Cr and Ni） were lower than the threshold value, so they had no carcinogenic risk to human health. Moreover, children were more sensitively affect- ed by heavy metals from the abandoned land. Therefore, the health of children in such areas should be paid more attention to. The HI value of the eight heavy metals to children was seven times higher than that to adults. The contribution rate of HQAs to HI was about 88%, and the contribution rate of CRA, to TCR was about 98%, so As was the most crucial factor influencing non-carcinogenic and carcinogenic dsk in the abandoned soils.

The Geochemistry of Heavy Metals in the Mudflat of Salinas de San Pedro Lagoon, California, USA

Sediment core samples were collected from the Salinas de San Pedro to assess the pollutant deposition processes in response to extensive human activities. Analysis of the sediment samples for heavy metals and some trace elements was conducted with ICP-OES for 20 sites showing enrichment for some of trace and heavy metals. The results demonstrated that heavy metal concentrations in mud varied greatly for each metal, with concentration values (mg/g) ranging from 1.05 - 4.8 (Al);0.003 - 0.011(As);0.001 - 0.005 (Cd);0.02 to 0.82 (Cr);0.085 - 0.47 (Cu);5.98 - 14.22 (Fe);0.06 - 0.19 (Mn);0.03 - 0.67 (Ni);0.05 - 0.38 (Pb);- 0.069 (Se);0.18 - 0.63 (Ti);0.040 - 0.091 (V) and 0.149 - 0.336 (Zn). The Index of Geo-accumulation factor showed highest values for Pb, Mn, As, and Cu. Enrichment factors >1for these elements suggest anthropogenic inputs for most metals. The bioavailability of metals in lagoon sediments has the potential to be highly dynamic with local waste and natural H2S discharge from existing fault line.

Assessment of Heavy Metals Pollution in Sediments from Ologe Lagoon, Agbara, Lagos, Nigeria

This study was carried out to assess the level of heavy metals pollution in Ologe Lagoon, Agbara, Lagos, Nigeria. The Lagoon receives effluents from industries in the Agbara Industrial Estate. Cored Soft sediments were retrieved from six random sampling points within the Lagoon and labeled (S1, S2, S3, S4, S5 and S6). Subsamples of the sediments were prepared and analyzed for heavy metal concentration. The result from the heavy metal analysis of the sediments shows that average concentration of Mn, Zn, Cr, Ni, Cr, Ni, Co, Cu and Pb in the samples was 278.1 ppm, 21.7 ppm, 14.2 ppm, 6.6 ppm, 6.4 ppm, 6.4 ppm and 4.4 ppm, respectively. The correlation between the heavy metals varies from 0.71 to 0.98 shows that they have a strongly positive degree of association which suggests that they are from the same source. The geo-accumulation values for Cu in all stations ranged between (1 - 2.8 ppm) and it can be deduced that the sediments are moderately to strongly polluted. Pb varies between 1 and 2.1 suggesting that the sediments are moderately polluted. Zn exhibits strong pollution levels with a range from 2.5 and 3.5 ppm. Co is moderately polluted with 1.5 - 2.4 while Mn shows the highest level of pollution in all stations with Igeo values ranging between 4.1 and 5.8. This study showed that the Lagoon accumulates heavy metals as a result of anthropogenic activities evident in the dumping of municipal, sewage, industrial waste in the environment and domestic activities such as auto mobile transportation and mechanic repair workshop. Based on sediment quality guidelines, the Ologe Lagoon level of pollution ranged from Cu > Pb > Zn > Ni > Co > Mn > Cr > Al with Mn having the highest level of pollution.

Application of Pollution Indices in the Assessment of Heavy Metal Contamination of Surface Sediments of River Bonsa, Ghana

Heavy metal contamination of sediments is a major risk to ecological systems and human health. Not only do sediments influence the quality of the water column, but can be transferred to micro biota and fishes, ultimately ending up at higher trophic levels in the food chain though biomagnification. This study was carried out to assess the contamination levels of heavy metals in the sediments of river Bonsa. Ten sediment samples were taken along the river and analyzed for Copper (Cu), Lead (Pb), Manganese (Mn), Iron (Fe), Zinc (Zn), Cadmium (Cd), Chromium (Cr), Cobalt (Co), and Nickel (Ni) using Atomic Absorption Spectroscopy (AAS). Data analysis was accomplished by comparing the measured heavy metal concentrations to Australian and New Zealand Environment and Conservation Council (ANZECC) and National Oceanic and Atmospheric Administration (NOAA) fresh water sediment quality guidelines and by the computation of geo-accumulation indices and enrichment factors. The results show that apart from Ni which had two of its sample concentrations (at BS1 21.167 mg/kg and at BS2 29.374 mg/kg) exceeding the ANZECC lower limit (21 mg/kg) guideline for fresh water sediment, all other heavy metals recorded concentrations below the lower limits of their respective ANZECC standards. Out of the 10 samples analyzed, 7 recorded Mn concentrations above the NOAA ARC TEL. A one-sample t-test also showed that the mean concentrations of Cu, Pb, Cd, Zn, Ni, and Cr were significantly lower than their respective ANZECC threshold values and Fe concentration was also significantly lower than the NOAA threshold;however, there was no significant difference between Mn mean value and the corresponding NOAA guideline value. The assessment of heavy metal pollution was derived using the Enrichment Factor (EF) and geo-accumulation indices (I-geo). The computed enrichment factors indicated that all the heavy metals except Ni are from natural sources (i.e., EF < 1.5) signifying a degree of heavy metal depletion rather than enrichment. The sources of Ni were attributed to domestic waste disposal into the river at sampling points BS1 and BS2 as well as run offs from a nearby auto mechanic workshop. All the metals had I-geo values between 0 and 1 (0 < I-geo < 1) denoting unpolluted to moderately polluted sediments. Thus, in terms of heavy metals, the river is unpolluted. These findings are very important as it shows that river Bonsa has not yet been impacted as far as heavy metals are concerned and the data gathered may serve as baseline for future studies.

Contamination and Potential Risks of Heavy Metals in the Sediments of the Chari and Logon Rivers in N’Djamena, Chad

The pollution of sediments by inorganic pollutants requires particularly important attention because of their toxicity, their persistence in the environment and their bioaccumulation by animal and plant life. The pollution of sediments by inorganic pollutants requires particularly important attention because of their toxicity, their persistence in the environment and their bioaccumulation by animal and plant living beings. This study focuses on the pollution of sediments of the Chari and Logon rivers in the city of N’Djamena by heavy metals. The objective of this study is to evaluate the degree of contamination, the geo-accumulation index and the degree of the Pollutant Loading Index of some heavy metals (Pb, Cr, Cu, Mn and Cd) and iron in the sediments of the sampled sites. The average concentrations of heavy metals and iron in the sediments are: Pb (10.00 ± 00 μg/Kg to 126 ± 16.52 μg/Kg);Cr VI (0.13 ± 00 mg/Kg to 0.21 ± 00 mg/Kg);Cd (trace);Cu (0.08 ± 0.02 mg/kg to 3.23 ± 0.64 mg/kg);Fe (0.25 ± 0.00 mg/kg to 5.79 ± 0.00 mg/kg);and Mn (0.2 ± 0.00 mg/Kg to 1.1 ± 0.00 mg/Kg);in order of highest to lowest abundance: Fe > Mn > Cd > Cu > Cr VI > Pb for the Logon;Fe > Cu > Mn > Cd > Cr VI > Pb for the Chari and Fe > Mn > Cu > Cd > Cr VI > Pb for the Confluent. The contamination factors for all heavy metals range from no contamination to low contamination for the sediments analyzed. The geo-accumulation indices indicate that the sampled sites are not polluted. The same is true for Er and RI which confirm an absence of ecological risks in the analyzed sediments.

黄河流域渭河支流泾河(崆峒段)河流表层沉积物重金属溯源解析

河流沉积物重金属污染问题日益突出,严重威胁流域生态系统健康。以黄河流域泾河崆峒段为研究区,采集91个河流表层沉积物样品,测定并分析沉积物As、Cd、Cr、Cu、Hg、Ni、Pb和Zn共8项重金属元素含量及其空间分布特征。采用地累积指数(I_(geo))和污染负荷指数(PLI)系统量化重金属污染特征,并联合应用自组织神经网络(SOM)模型、相关性分析和正定矩阵因子分解(PMF)模型定量解析沉积物重金属污染来源及其贡献率。结果表明:泾河崆峒段河流表层沉积物重金属含量的平均值高低依次为Cr(65.66 mg/kg)>Zn(55.63 mg/kg)>Ni(21.78 mg/kg)>Pb(17.50 mg/kg)>Cu(14.07 mg/kg)>As(10.94 mg/kg)>Cd(0.19 mg/kg)>Hg(0.032 mg/kg)。除Cd和Hg外,As、Cr、Cu、Ni、Pb和Zn含量的均值均低于甘肃省土壤背景值和黄土高原土壤背景值,且As、Cd和Cr含量的均值分别是中国水系沉积物背景值的1.22、1.46和1.22倍。沉积物重金属含量空间分布具有明显的差异性,所有元素高含量和污染相对较重的区域均分布于人类活动强烈和入河口周边流域,且Hg的空间异质性最强。Cd是泾河崆峒段亟需关注的首要污染元素,Hg、Pb、Cr和Zn存在局部污染,Cu、Ni和As为清洁无污染。沉积物重金属的富集可能受污水交通源、农业源、金属冶炼加工源、电镀制造工业源和自然源的共同影响,贡献率依次为33.33%、27.21%、11.02%、15.49%和12.95%。

黔中磷矿区土壤重金属污染及其生态风险评价

为评价黔中磷矿区土壤重金属污染风险,采用梅花布点法在磷矿区周边区域和无矿区不同地层天然土壤采集24件表层土壤样品,测定Cu、Pb、Zn、As、Hg、Se、Cd、和Cr含量,并采用内梅罗综合污染指数(NPI)、地累积指数(I_(geo))以及Hankanson潜在生态危害指数(RI)对磷矿区土壤重金属的污染程度和潜在生态风险进行评价。结果表明,黔中磷矿区土壤中Hg、Se、Cd、As、Pb、Zn和Cr等元素平均含量分别为贵州土壤背景值的37.58倍、24.40倍、19.26倍、18.09倍、2.67倍、2.17倍和1.78倍,各重金属富集特征明显,Cu元素平均含量未超过贵州省土壤背景值。研究区土壤中Hg、Se、Cd、As、Pb、Zn和Cr等元素NPI平均值介于4.59~69.32之间,处于重度污染水平,而Cr和Cu元素NPI平均值分别为1.89和1.21,处于轻度污染水平。研究区Hg元素I_(geo)平均值为4.45,处于严重至极重污染;As、Se和Cd元素I_(geo)平均值介于3.35~3.65之间,处于重度污染;Pb、Zn和Cr元素I_(geo)平均值0.21~0.44之间,处于未污染至中度污染水平,而Cu元素I_(geo)平均值为-0.83,显示其未受到污染。潜在生态风险评价结果表明,研究区土壤Hg元素处于极强生态风险水平,Cd处于强生态风险水平,Ad处于中等生态风险水平,而Cu、Pb、Zn和Cr均处于轻微风险水平。黔中磷矿区土壤RI平均值为2285.50,显示出极强生态风险,Hg是最主要的生态风险元素,应引起高度重视。

牛栏江(昆明段)表层沉积物重金属时空分布特征与潜在生态风险评价

为探明牛栏江(昆明段)表层沉积物重金属污染特征,于3个水期(丰水期、枯水期、平水期)分别采集了流域内20个点位表层沉积物并测定了8种金属(Cu、Zn、Cr、Cd、Ni、Pb、Hg、As)含量,进行了水期和区域差异分析、潜在风险评价以及重金属来源解析。结果发现牛栏江(昆明段)沉积物重金属中Cd含量1.45 mg/kg和Hg含量0.23 mg/kg,分别是云南省土壤背景值(0.218 mg/kg和0.058 mg/kg)的6.7倍和4.0倍,表明Cd和Hg污染相对严重。地累积指数表明牛栏江(昆明段)3个水期均为Cd污染程度最高,Hg次之,平均污染等级分别达到了中度污染和偏中度污染。因此Cd和Hg是牛栏江(昆明段)表层沉积物重金属污染最主要的生态风险贡献因子,应予以重视。同时,潜在生态风险指数表明,丰水期和平水期潜在生态风险程度分布具有干流高于支流、下游高于上游和北部高于南部的空间特征。

Metal release/accumulation during the decomposition of Potamogeton crispus in a shallow macrophytic lake

Changes in metal concentrations in the litter of Potamogeton crispus were monitored during a consecutive 40-day in situ decomposition experiment using the litterbag method.The accumulation index was calculated and used to indicate the changes in the metals in litter.The results showed that the concentrations of Al,Cd,Cr,Fe,Mn,and Pb in litter increased significantly during the decomposition,while Cu and Zn concentrations decreased dramatically.Significant positive correlations were found between the concentrations of Al,Cr,Fe,and Mn and between Cu and Zn.Moreover,Cu and Zn both negatively correlated with Al and Fe.The remaining dry mass was negatively correlated with Al and Fe concentrations but positively correlated with Cu and Zn concentrations.Generally the accumulation index values of metals other than Al were less than one,indicating that the litter of P.crispus acted as a source of metals to the surrounding water body.Al was the only metal that showed continuous net accumulation in litter.The net accumulation of Fe and Mn in litter during the last 10 days of the experiment may indicate the precipitation of Feand Mn-oxides.It was estimated that 160 g/m^2（dry weight）P.crispus was decomposed in40 days.This was equivalent to releasing the following amounts of metals：0.01 mg Cd,0.03 mg Cr,0.71 mg Cu,0.55 mg Mn,0.02 mg Pb and 13.8 mg Zn into surrounding water,and accumulating 149 mg Al and 11 mg Fe,in a 1 m^2 area.

Accumulation and relationship of metals in different soil aggregate fractions along soil profiles

Different aggregates vary in their ability to retain or adsorb metals in soil.Five soil profiles were sampled from different soil horizons and grouped,and the concentrations of Al,Mg,Ca,Fe,Mn,Cd,Cu and Pb were determined in six sizes of aggregates(>2,2-1,1-0.6,0.6-0.25,0.25-0.053,<0.053 mm).Significantly high(p<0.05)structural stability indexes(SSI)and ag-gregate stability indexes(ASI)were recorded in the topsoil horizon,which may be attributed to the high soil organic matter(SOM)content in aggregates from topsoil.In addition,ASI and SSI were positively correlated(r=0.569,p<0.05)with each other,which indicated that the stability of soil aggregates could contribute to the structural stability of bulk soil.Moreover,accumulation factors(AF),principal component analysis(PCA)and Pearson's correlation co-efficients were used for metal element assessment.The results indicated that SOM was not a key factor affecting the accumulation of Ca,Mg,Al,Fe,Mn,Pb,Cd and Cu in soil aggre-gates.In general,AF values for metal elements in microaggregates(<0.25 mm)were high,which showed that metals preferred to accumulate in fine soil aggregates.The PCA and Pearson's correlation coefficients indicated that soil parent materials primarily controlled the distribution of Al,Ca,Fe,Mg and Mn,while materials derived from technogenic sources have important impacts on the distribution of Cd,Cu and Pb in soil aggregates along the soil profile.

贵州某煤矸石堆场重金属迁移研究

煤矸石含多种重金属,对周边耕地存在一定污染风险。以贵州某煤矸石堆场周边土壤为研究对象,通过消解法对重金属进行溶出,利用原子吸收法测定重金属含量。结果发现,Pb、Cu、Cd、Zn和Cr的质量分数(mg/kg)分别为24.735~73.22、67.2~239.28、6.40~9.97、60.96~104.70和13.33~41.67。沿着边坡海拔降低方向、下风向和山积水沟渠方向上,重金属均发生有规律迁移。最后,通过地质积累指数(I_(geo))判定:Cd为轻度污染,Cu为轻度污染到中强度污染,部分点位Pb达到重度污染和非常严重污染程度。

湛江湾海域沉积物重金属污染特征及来源研究

测定了2021年4月采集的湛江湾海域的10份沉积物样品中的7种重金属(Cd、Cr、Cu、Hg、As、Pb和Zn),并对其主要来源和生态风险进行了分析和探讨。结果显示:Cu、Zn、Cr和As的含量符合一类海洋沉积物标准,而Cd超标率最高。通过地累积指数和污染负荷指数的分析,发现Cd的污染程度最为严重,其次是Hg和Pb,而Cu、As、Zn和Cr的污染程度较低。溯源分析显示,湛江湾重金属的主要来源包括船舶排放、水产养殖排污、工业排污、生活垃圾和农业源。潜在生态风险系数评价表明,湛江湾的重金属污染具有较强的生态风险,其中Cd和Hg是关键的潜在生态风险因子。

北京市昌平区南口镇土壤重金属污染风险评估及来源分析

采集昌平南口镇473件表层土壤样品,收集65件土壤样品(1970年采集的),测试土壤中砷(As)、镉(Cd)、铜(Cu)、铬(Cr)、汞(Hg)、铅(Pb)、镍(Ni)、锌(Zn)等8种重金属元素及三氧化二铝(Al_(2)O_(3))、二氧化硅(SiO_(2))和三氧化二铁(Fe_(2)O_(3))等地球化学指标。采用多种污染评价方法和统计学方法,运用Pearson相关性分析和主成分分析,评估土壤重金属污染风险,分析污染来源。结果表明:重金属Cd含量普遍较高,超筛选值点位较广,Pb、Hg、Cr、Ni、Cu、Zn存在个别点位超筛选值的情况;Cd、Hg、Pb、Zn存在轻微及以上污染点位,Pearson相关性分析和主成分分析显示Cd、Hg、Zn来源相近;Cd和Zn的人为贡献率在1970—2021年间增长明显,且平均值明显高于北京地区背景值,表明研究区可能存在一定的人为污染。

沙河底质沉积物重金属污染评价及潜在风险分析

为综合评价与分析沙河底质沉积物中的重金属污染状况及其潜在生态风险,选取了沙河6个代表性站点,通过野外调查、样品采集和实验室分析,对底泥中的重金属元素汞(Hg)、镉(Cd)、锌(Zn)、铜(Cu)、铅(Pb)和砷(As)进行了测定,并引入地质累积指数法和潜在生态风险指数法对污染程度和生态风险进行了评估。结果显示,沙河沉积物中重金属含量自上游至下游逐渐降低,主要污染元素为Hg、Cd和Zn。地质累积指数分析表明,Hg在上游区域为中度污染,而其他重金属元素如Cu、Pb和As未发现明显污染。潜在生态风险指数分析表明,沙河上游区域的生态风险高于下游,尤其是G1点位,其重金属的潜在生态风险指数远高于其他点位,这与Hg的高含量和高毒性有关。

重金属低积累玉米品种的稳定性和环境适应性分析

选择当地大面积推广的5个玉米品种:正红311(1)、成单30(2)、川单428(3)、隆单8(4)和川单418(5),种植于四川射洪县玉米示范区的7个试点,通过AMMI模型研究品种和环境交互效应对玉米籽粒积累重金属能力的影响,旨在获得对重金属吸收具有低积累性和环境适应性较好的玉米品种。结果表明,Cu的品种效应(SS,平方和)占总效应的77.6%,玉米籽粒低积累Cu的性状有很高的重现性;而As、Hg、Pb、Zn、Cr5种重金属元素品种与环境交互效应同品种、环境效应比较占主导作用,分别为63.4%、74.3%、50.3%、69.2%和57.5%。通过双标图分析,比较了不同玉米品种籽粒富集重金属能力的大小和稳定顺序。AMMI模型为研究品种×地点交互效应对作物积累重金属能力的影响和评价品种稳定性提供了较好的分析方法,对于低重金属积累品种的准确筛选和成功应用具有重要意义。