SPATIAL-TEMPORAL VARIATION OF HEAVY METAL ELEMENTS CONTENT IN COVERING SOIL OF RECLAMATION AREA IN FUSHUN COAL MINE

Grid method is employed for sampling covering soil at the test field,whic h is reclamation area filled by coal mining wastes for cropland in th e Fushun coal mine,Liaoning Province,the Northeast China.The soil samp les are taken at different locations,inclu ding three kinds of covering soil,th ree different depths of soil layers a nd four different covering ages of covering soil.The s patial-temporal variation of heavy metal element content in reclamatio n soil is stud-ied.The results indicate that the co ntent of heavy metal elements is decreasing year after year;the determin ant reason why the content of heavy metal elemen ts at 60cm depth layer is higher than t hat at 30cm depth layer and surface is fertiliz-er and manure application;the metal elements mainly come from external environment;there is no metal pollut ion coming from mother material(coal mining wastes)in plough layer of covering soil.

Characteristics and Risk Assessment of Soil Heavy Metal Contents in Facility Agriculture of Guangxi

[Objectives]To study the characteristics of soil heavy metal contents in facility agriculture of Guangxi and analyze its risks.[Methods]The heavy metal content of 30 surface soil samples taken from facility agriculture in Guangxi was analyzed.The status of soil heavy metal pollution in facility agriculture of Guangxi was evaluated by the single factor index method,geo-accumulation index method and Hakanson potential ecological risk index method with reference to the soil background value in Guangxi.[Results]Compared with the soil background value in Guangxi,the over-limit rates of heavy metals cadmium,lead,arsenic,chromium,mercury,copper and zinc in soil samples were 56.67%,56.67%,16.67%,30.00%,50.00%,60.00%and 80.00%,respectively.Compared with the screening values of the Soil Environmental Quality-Risk Control Standard for Soil Contamination of Agricultural Land(for trial implementation)(GB15618-2018),the overlimit rates of the heavy metals cadmium,arsenic,copper and zinc in the surface soil of agricultural facilities in Guangxi were 56.67%,10.00%,16.67%and 23.33%,respectively.Except for the average content of soil cadmium exceeding the screening value,the evaluation content of the other six soil heavy metals did not exceed the screening value.According to the evaluation results of the single factor pollution index method,the surface soil arsenic and chromium of the agricultural facilities in Guangxi belonged to the clean level,lead,mercury,and copper belonged to mild pollution,and cadmium and zinc belonged to moderate pollution.According to the evaluation results of the geo-accumulation index,the lead,arsenic,chromium and mercury in the surface soil of the agricultural facilities in Guangxi belonged to the pollution-free level,while the cadmium,copper and zinc belonged to the mild-moderate pollution.According to the evaluation results of the potential ecological risk index method,the potential ecological risks of the heavy metals of lead,arsenic,chromium,copper and zinc in the soil of agricultural facilities in Guangxi belonged to low potential ecological risk level,and the potential ecological risks of cadmium and mercury belonged to moderate risk level.The potential ecological risk index(RI)of the seven heavy metals in the soil was 132.46,which belonged to moderate potential ecological risk.The largest contribution of soil heavy metals to the potential ecological risk index was cadmium and mercury.[Conclusions]Taking the soil of facility agriculture in Guangxi as the object,this paper studied the characteristics of heavy metal content in facility agricultural soil and its risk assessment,in order to provide a scientific basis for facility soil heavy metal risk prevention and control and provide safe technology for facility agriculture.

Evaluation on environmental quality for heavy metal elements of Xihe soil

According to "Environmental quality standard for soil" and using As,Cd,Cr,Cu,Hg,Ni,Pb,Zn elements as evaluation index,the author evaluated soil environmental quality in Xihe area of Shenyang.The results show that the soil in Xihe area is polluted rifely by heavy metal elements.The polluted areas are mainly distributed near the upstreams of Xihe River,Shenxin River and Shenliao irrigation canal.There exist large distinctions among the heavy metal elements to the pollution degree.Cd pollution area is the biggest and the most serious in pollution degree.

Artisanal Mining and Soil Quality in the Sudano-Sahelian Climate: Case of the Artisanal Mining Site of Yimiougou in Burkina Faso, West Africa

The majority of the population of Burkina Faso lives from agriculture and therefore depends on the land. The main objective of this study is to assess the quality of the soils in the area linked to artisanal mining activities. The methodology adopted consisted in sampling and characterizing the main types of soil. In order to assess the level of soil pollution by artisanal mining, parameters such as the geo-accumulation index (Igeo) and the contamination factor (CF) are calculated. A prediction of acid mine drainage (AMD) was also carried out on samples of mine tailings which are potential sources of pollution of these soils. The results obtained show that the soils in Yimiougou are of nil to low agronomic interest. The Igeo shows that for lead, copper, zinc and arsenic the levels found in the different morphological units are partly attributable to human action and specifically artisanal mining. The values of the contamination factor indicate contamination. Cobalt presents the lowest contamination. For cadmium, the different types of soil are moderately contaminated except for the FITLC type, which has a CF value of 0.50, therefore synonymous with low or absent contamination. The various morphological units studied are very heavily contaminated with zinc, copper, lead and arsenic. The pH and conductivity values indicate that the mine tailings samples are non-acidogenic, therefore not yet oxidized. As for the sulphide contents, they show that only samples S17, S22, S23 and S24 present values that are strictly above the threshold (0.3%) and therefore potentially acid-generating. The comparative study of the acid potential (AP) and the neutralization potential (NP) reveals that the neutralization potentials of the different samples are clearly higher than the acid potentials even for the samples which present a proven acidification potential (S17, S22, S23 and S24). These results show that the mine tailings have the natural capacity to neutralize any possible mine drainage, given the presence of acid-eating minerals such as the carbonates associated with the mineralization.

Growth, Metabolism and Yield of Rice Cultivated in Soils Amended with Fly Ash and Cyanobacteria and Metal Loads in Plant Parts

Soil amendment with fly ash（FA） and combined supplementation with N_2-fixing cyanobacteria masses as biofertilizer were done in field experiments with rice. Amendments with FA levels, 0, 0.5, 1.0, 2.0, 4.0, 8.0 and 10.0 kg/m2, caused increase in growth and yield of rice up to 8.0 kg/m2, monitored with several parameters. Pigment contents and enzyme activities of leaves were enhanced by FA, with the maximum level of FA at 10.0 kg/m2. Protein content of rice seeds was the highest in plants grown at FA level 4.0 kg/m2. Basic soil properties, p H value, percentage of silt, percentage of clay, water-holding capacity, electrical conductivity, cation exchange capacity, and organic carbon content increased due to the FA amendment. Parallel supplementation of FA amended plots with 1.0 kg/m2 N_2-fixing cyanobacteria mass caused further significant increments of the most soil properties, and rice growth and yield parameters. 1000-grain weight of rice plants grown at FA level 4.0 kg/m2 along with cyanobacteria supplementation was the maximum. Cyanobacteria supplementation caused increase of important basic properties of soil including the total N-content. Estimations of elemental content in soils and plant parts（root and seed） were done by the atomic absorption spectrophotometry. Accumulations of K, P, Fe and several plant micronutrients（Mn, Ni, Co, Zn and Cu） and toxic elements（Pb, Cr and Cd） increased in soils and plant parts as a function of the FA gradation, but Na content remained almost unchanged in soils and seeds. Supplementation of cyanobacteria had ameliorating effect on toxic metal contents of soils and plant parts. The FA level 4.0 kg/m2, with 1.0 kg/m2 cyanobacteria mass supplementation, could be taken ideal, since there would be recharging of the soil with essential micronutrients as well as toxic chemicals in comparative lesser proportions, and cyanobacteria mass would cause lessening toxic metal loads with usual N_2-fixation.

Derivation of soil Pb/Cd/As thresholds for safety of vegetable planting: A case study for pakchoi in Guangdong Province,China

Regional guidelines for soil heavy metals,in conjunction with specific crops,are proposed to better assess soil environmental quality.In this study,large amounts of soils with different levels of Pb/Cd/As pollution were collected in Guangdong Province,China,to carry out a pot experiment,which was closer to the actual situation and properties of the heavy metal contaminated soils.Taking the widely planted vegetable pakchoi as the research object,we analyzed the correlations between the Pb/Cd/As concentrations in pakchoi and the total or available soil Pb/Cd/As concentrations and established their optimal regression equations.And then,the total and available soil Pb/Cd/As thresholds for pakchoi were calculated according to the allowable Pb/Cd/As limits in pakchoi and were compared with the current soil assessment standards.Furthermore,a lot of paired vegetable-soil samples in field were collected and their pollution situations were assessed by both the current limit thresholds and the calculated thresholds.Obviously,it was more consistent to assess the Cd and As pollution situation of the vegetable and soil samples with the calculated soil thresholds than the current soil assessment thresholds.It further proved that it was necessary to explore the soil heavy metal thresholds for safety of vegetable in specific regions,which would be more scientific and practical to guide safety production of local agricultural products and effective utilization of soil resources.

Study on the proposed environmental guidelines for Cd, Hg, Pb and As in soil of China

This paper deals with the soil-environmental standard. According to the current situation of researching on the soil-environmental quality guideline at home and abroad, and on the basis of the foundations and principles of enacting the soil-environmental standard, the soil environment quality guideline values of Hg, Cd, Pb and As were suggested.

Emission control for precursors causing acid rain(V): Improvement of acid soil with the bio-briquette combustion ash

The bio-briquette technique which mixes coal, biomass and sulfur fixation agent and bio-briquettes under 3—5 t/cm 2 line pressure has aroused people's attention in view of controlling the air pollution and the acid rain. In this paper, the physicochemical properties of bio-briquette and its ash were investigated. And the acid soil was improved by the bio-briquette combustion ash, which contained nutritive substances such as P, N, K and had the acid-neutralizing capacity(ANC). The pH, EC, effective nutrient elements(Ca, Mg, K, P and N), heavy metal elements(Al, Cu, Cd, Cr, Zn and Mn) and acid-neutralizing capacity change of ash-added soils within the range of 0—10%, were also studied. Specially, when 5% bio-briquette combustion ash was added to the tested soil, the content of the effective elements such as Ca, Mg and K rose by 100 times, 7 times and twice, respectively. The total nitrogen also increased by about twice. The results showed the oxyanions such as that of Al, Cu, Cd, Cr, Zn and Mn were not potentially dangerous, because they were about the same as the averages of them in Chinese soil. It is shown that the ANC became stronger, though the ANC hardly increases in the ash-added soil. On the basis of the evaluation indices, it is concluded that the best mixture ratio is to add 2.5%—8% of the bio-briquette combustion ash to the tested soil.

Soil Pollution along Kalwa Bridge at Thane Creek of Maharashtra, India

The present investigation deals with the assessment of pollution status along the wetland of Thane Creek, which has been subjected to a lot of pollution from the Asia’s biggest Thane—Belapur Industrial Complex located at the south of Mumbai harbor along the west coast of India. This paper advocates habitat conservation and ecological studies with special reference to the physico-chemical characteristics and heavy metal pollution in the soil along the creek area. In the present investigation, the pH, electrical conductivity, bulk density, alkalinity and chlorinity values recorded were observed to be high during dry seasons and low during rainy season. The soil samples were also analyzed for their heavy metal contents like nickel, zinc, cadmium, copper, iron, arsenic and mercury. It was observed that, the concentration of these heavy metals increases gradually in dry seasons, followed by sharp decrease during rainy season. These heavy metals have a marked effect on the aquatic flora and fauna which through bio magnification enter the food chain and ultimately affect the human beings as well. The present experimental data on heavy metal pollution in soil samples collected along Kalwa bridge of Thane Creek points out to the need of regular monitoring of water resources and further improvement in the industrial waste water treatment methods. If the present conditions continue for a long period, the creek may soon become ecologically inactive.

Distribution and Mobility of Zn,Pb and Cd in a Sewage Sludge-Amended Soil

The distribution of the metallic trace elements (MTE) Zn, Pb and Cd in a sludge-amended soil and their partitioning in specific soil microystems are studied by comparing their contents in amended and control soils. This comparison is achieved at the metric scale of the bulk soil horizons and at the micrometric scale of the weathering microsites (weathering rock-forming minerals and their specific weathered products). The chemical analyses of the MTE in the bulk samples do not show any anthropic contamination of the amended soil with repeated sewage sludge spreading. The chemical analyses of the

上海市奉贤区农田土壤-农产品中的重金属含量特征和污染评价

为分析奉贤区农田土壤和农产品的重金属污染状况,采集粮田、菜田和果园3种作物的农田土壤及其对应农产品,分别测定土壤8种重金属元素(Hg、As、Cd、Cr、Pb、Cu、Zn和Ni)和农产品5种重金属元素(Pb、Cd、Cr、As和Hg)的含量特征,采用单项污染指数法、综合污染指数法、积累指数法和富集因子等方法对土壤-农产品中重金属元素进行污染风险评价,并将地统计学与因子分析相结合分析农田土壤重金属的空间分布特征。结果表明:与上海市土壤背景值相比,奉贤区农田土壤Hg、Cd、Cr、Zn和Ni的平均含量较高,分别是背景值的1.40、1.36、1.06、1.15倍和1.44倍。单项及综合污染指数值显示土壤重金属处于无污染水平;但Cd、Ni、Hg元素的积累指数值显示无-中度污染水平,其中有4.92%农田土壤处于Hg元素的中度污染。在空间分布上,Hg呈连片分布;As、Cd整体含量低,南北区域分布;Cr、Zn呈条带状分布,自南往北递增状态;Pb呈散点状分布;Cu元素整体含量高,呈东西梯度分布;Ni元素呈岛状分布。因子分析中,因子1包括Cu和Zn,因子2是Pb,因子3包括Cd、Cr,因子4是Ni,因子5是As和因子6是Hg。奉贤地区土壤重金属含量主要受到工业源、农业源、交通源和自然源影响较大,应加强污染源控制,降低风险水平。农产品样中的5种重金属均未超出标准限量值,单项及综合污染指数值显示农产品重金属属于清洁水平。经土样和农产品样中的重金属含量相关性分析,两者无相关,农产品对土壤重金属的富集因子较小。不同土地利用方式对土壤和农产品中重金属含量影响较大,菜地土壤和农产品对Cd较为敏感,吸收能力较强,而果园土壤和农产品对各重金属吸收总体较弱。在农业生产中可以根据作物吸收重金属特性来调整种植结构,以减轻重金属污染。综合来看,奉贤区土壤-农产品系统中重金属累积程度低,但局部农田土壤中重金属含量存在轻微污染,需引起重视。

电感耦合等离子体质谱法测定鲜河蚌肉水提物中5种元素含量

目的建立测定鲜河蚌肉水提物中铜(Cu)、砷(As)、镉(Cd)、汞(Hg)、铅(Pb)含量的电感耦合等离子体质谱(ICP-MS)法。方法采用微波消解法对样品进行前处理。采用ICP-MS法测定,等离子体射频功率为1550 W,等离子体气体流速为15.0 L/min,辅助气体(氩气)流速为0.90L/min,雾化气流速为1.05L/min,蠕动泵速为0.1r/s,采样深度为8 mm,调谐模式为No Gas模式,重复3次。结果Cu、As、Cd、Hg、Pb质量浓度分别在0~500 ng/mL、0~200 ng/mL、0~10 ng/mL、0~5 ng/mL、0~20 ng/mL范围内与仪器响应值线性关系良好(r≥0.9996,n=5),检测限分别为0.0205,0.0045,0.0008,0.0042,0.0051 mg/kg,定量限分别为0.0682,0.0149,0.0027,0.0141,0.0170 mg/kg;精密度、重复性试验结果的RSD均小于5%;平均加样回收率分别为99.60%,106.16%,108.93%,115.30%,103.40%,RSD分别为0.84%,6.03%,1.15%,3.56%,0.55%(n=6)。参考《药用植物及制剂外经贸绿色行业标准》,9批样品中的Cu、Hg、Pb均符合限量标准,As、Cd超标的样品分别有8批、2批。结论该方法操作简单,结果准确,可用于测定鲜河蚌肉水提物中Cu、As、Cd、Hg、Pb的含量。

干旱区绿洲农田土壤重金属含量高光谱反演

对新疆渭库绿洲土壤样本的As、Hg、Pb、Cr、Zn和Cu共6种重金属含量与高光谱关系进行分析,基于逐步回归方法筛选出特征波段,采用地理加权回归(GWR)和普通最小二乘法回归(OLS)构建土壤重金属的高光谱反演模型.结果显示:1)研究区的6种重金属元素含量存在一定的差异,土壤中的平均重金属含量依次为Zn>Pb>Cr>Cu>As>Hg,均未超过国家土壤背景值.研究区的Pb平均含量高于当地(新疆)土壤背景值,即研究区表土层中的Pb元素明显富集;2)不同的光谱变换使土壤重金属的光谱特征均得到了增强,但强度有所差异,经过二阶微分变换(SD)和一阶立方根微分变换(CRFD)的土壤光谱相对于原始光谱增强最显著;3)从模型验证来看,在反演6个土壤重金属元素含量时,GWR的R^(2)高于OLS,其中Zn的R^(2)接近0.8,Cu的R^(2)接近0.6,表明模型有一定预测能力,而As、Hg、Pb和Cr的R^(2)均依然低于0.5,模型预测能力并不理想;4)两种模型预测的6种土壤重金属含量的空间分布表现出一定的空间差异性.其中,As元素空间分布差异在这两种预测模型中最大,而其余5种重金属元素Hg、Pb、Cr、Zn和Cu的分布则较为均匀.通过高光谱反射率估算土壤重金属元素含量,实现了干旱区绿洲农田土壤重金属元素含量的高效快速反演,为干旱区绿洲农田土壤重金属元素含量动态监测提供了可靠的技术支撑.

有机肥与化肥配施对夏播玉米产量和土壤肥力的影响

为探索有机肥与化肥配施对全株玉米产量和土壤肥力的影响,以乐玉1号玉米为试材,通过田间试验,设置不施肥(CK)、全部化肥(HF)、牛粪单施(N1)、牛粪替代20%化肥(N2)、牛粪替代30%化肥(N3)、羊粪单施(Y1)、羊粪替代20%化肥(Y2)、羊粪替代30%化肥(Y3)共8个处理,测定全株玉米干草产量、氮磷钾素积累量和重金属含量以及土壤理化性质等相关指标。结果表明,Y2和Y3处理的全株玉米干草产量和氮磷钾积累量优于其他处理;N2处理的Cu积累量和Y1处理的Zn积累量最高;0~20cm土层以N3处理的有机质、速效磷、铵态氮、硝态氮和阳离子交换含量最高。可见,低总氮水平下,羊粪替代20%和30%化肥处理对全株玉米生长及养分积累有积极作用,牛粪替代30%化肥改良土壤肥力效果较好。

海南琼中岩-土体系重金属迁移特征及表土环境质量评价

地球关键带和土壤重金属污染是当今研究的前沿与热点,岩-土体系是地球关键带的重要组成部分。目前海南岛针对不同成壤母质岩-土体系的详细研究较少,并且重金属亟需基于新标准进行评价。为了查清岩-土体系中重金属元素迁移特征及污染状况,本文以海南岛琼中3个土壤垂向剖面及7115件表层土壤样品为研究对象,采用电感耦合等离子体质谱/发射光谱法(ICP-MS/OES)和原子荧光光谱法(AFS)等分析方法,测定岩石和土壤中Cu、Pb、Zn、Cr、Ni、Cd、As和Hg共8种重金属元素含量,利用土壤环境质量农用地土壤污染风险管控标准、内梅罗指数法和潜在生态危害指数法定量评价了表层土壤样品重金属污染状况及生态风险。结果表明,①海南岛琼中二长花岗岩岩-土体系中,不同重金属元素表现出明显的分异特征,Cu、Pb、Zn、Cr、Ni、Cd元素以亏损为主,As元素以富集为主,Hg元素则表现出不同的富集或亏损特征,As、Hg元素尤其富集在表层。②琼中绝大多数表层土壤中重金属元素含量低于土壤环境质量农用地土壤污染风险筛选值,土壤污染风险低。③以琼中和海南岛背景值为评价标准时,应关注Cr、Ni和As污染以及Hg、As和Cd的生态危害。以土壤环境质量为评价标准时,研究区表层土壤的环境质量总体清洁,生态风险较弱。

基于SPA-BPNN的成都市天府新区东部土壤As含量高光谱估测建模

为明确成都平原城市边缘带土壤中重金属As含量,以四川省成都市天府新区东部为研究区,对土壤原始高光谱数据进行一阶微分(FD)、二阶微分(SD)、去包络线(CR)和标准正态变换(SNV)处理,利用皮尔逊相关系数(PCC)和连续投影算法(SPA)筛选出最佳变换光谱的特征波段,分别建立偏最小二乘(PLSR)、极限学习机(ELM)、随机森林(RF)和BP神经网络(BPNN)4种回归模型,利用高光谱数据进行土壤重金属As含量估测并进行精度验证。结果表明,经去包络线一阶微分(CR-FD)变换的光谱与土壤重金属As含量相关性显著提升,由0.473提高到0.848;无论是基于PCC还是SPA算法筛选出的特征波段,非线性模型的拟合度以及预测精度均高于线性模型;相对于PCC算法,利用SPA算法筛选的特征波段建立的模型预测精度明显提升,PLSR、ELM、RF、BPNN模型验证集的决定系数(R2)分别为0.786、0.847、0.856、0.942。因此,以SPA算法筛选出的光谱波段作为自变量构建的BPNN模型(SPA-BPNN)是研究区内As含量的最优估测模型。

猪场沼液还田对土壤和植物重金属含量的影响

还田消纳是猪场沼液资源化利用的主要方式。由于沼液中含有多种金属元素,过量浇灌会引发土壤重金属污染。目前,关于猪场沼液对耕地土壤和植物重金属污染特征的影响及其影响因子的研究还不够深入。在广西生猪养殖区,选取了4种不同耕地利用类型(叶菜类、果树类、饲草类、药草类)和14个样地,就不同沼液浇灌强度对土壤与植物重金属的影响规律及其影响因子进行研究。结果表明:在14个样地0~40 cm表层土壤中,重金属Cu、Zn、Cd的输入强度最大,且其含量和土壤pH变化和与沼液浇灌总量呈显著(p<0.05)正相关;在4种耕地类型中,杂交象草和空心菜的可食用部分Cu、Zn、Cd、Pb、Cr含量与沼液浇灌总量呈显著正相关;在沼液还田中,由于Cu、Zn的输入强度大,而植物对其的富集系数又较低,因此土壤中Cu、Zn积累较快;浇灌沼液对叶菜类和果树类的主要污染风险是Pb和Cd,而对杂交象草的污染风险较小。

荒漠草原不同重金属污染对牛枝子叶片—土壤生态化学计量特征的影响

探究荒漠草原牛枝子(Lespedeza potaninii)在不同重金属污染梯度下的生长状况,通过其不同重金属污染梯度下牛枝子叶片及土壤中碳(C)、氮(N)、磷(P)含量的变化以及对其他土壤理化性质的变化,明确在不同重金属污染梯度下牛枝子对养分的利用状况、生态适应策略。结果表明:在不同污染梯度下牛枝子叶片总C含量变化差异不明显,牛枝子叶片全N、全P含量呈先上升后下降的趋势。土壤总C、全N、全P含量在对照组CK下最高,随着重金属污染梯度的升高整体呈下降的趋势,随着重金属污染梯度的升高,土壤速效P、速效K、电导率整体上呈先上升后下降的趋势,土壤碱解氮整体呈下降趋势,土壤pH变化不显著。牛枝子叶片全N与全P与土壤总C呈极显著正相关(P<0.01),土壤总C与土壤全N、土壤C/N、C/P、N/P表现出极显著正相关(P<0.01)。在低浓度重金属下促进植物吸收营养元素,但过了其承载的重金属浓度时就会阻碍植物对营养元素的吸收。

河北省张北地区土壤和莜麦重金属含量及健康风险研究

为探讨河北省张北地区土壤和莜麦中重金属元素含量及健康风险,选择17个适宜采样点进行表层土壤和莜麦籽实样品的采集,通过单因子污染指数法、综合污染指数法和富集系数分别对土壤质量和重金属元素从土壤向莜麦迁移能力进行研究。结果表明:研究区土壤和莜麦中重金属含量远低于国家标准,品质安全健康;区内重金属元素在土壤-莜麦系统中富集能力为Zn>Cu>Ni>Cd>As>Pb>Cr=Hg, Ni、Cu和Zn的富集系数远高于Cr、As、Cd、Hg、Pb, Cd迁移能力很弱,As、Pb几乎不发生迁移,Cr、Hg不发生迁移。