Risk Factor Assessment of Coal Mine Drainage Water on Surrounding Agricultural Soil: A Case Study at Barapukuria in Bangladesh

This study is performed to know the contamination level of heavy metals on the surrounding agricultural soils at the site of Barapukuria Coal Mine Company Limited (BCMCL). Total concentrations of eight heavy metals (Cu, As, Cd, Zn, Pb, Cr, Ni and Mn) were measured in that soil. To calculate the contamination level, the enrichment factor (EF), geoaccumulation index (Igeo) and Hakanson potential ecological risk index were done. Igeo values indicated that the study areas at all stations were suffering from moderate contamination with As. The results of enrichment factor revealed that soils in all stations were in extremely high enrichment condition by As metal. Under Hakanson potential ecological risk index, the contamination coefficient () and potential ecological risk index () were calculated. The degree of contamination at BCMCL area reflects moderate contamination. By considering the ecological risk index of a particular heavy metal, the order is as follows: Cd > As > Cu > Pb > Ni > Cr > Zn and Cd has the highest risk index and poses the greatest damage to the BCMCL area’s soil. EF, Igeo values and potential ecological risk index indicate that there is considerable As and Cd pollution, mainly caused by coal mine drainage water.

Application of face－graph in heavy metal pollution assessment in river sediment

On the basis of sedimentation principles and environmental chemical characteristics of heavymetal, combine international new methods-face graph on heavy metal pollution assessment withmulti-variable graph expression, the article made a synthetical assessment study on state of heavymetal pollution and potential ecological risk of Taizi River sediment in Benxi City reach. The re-sults of the study indicated that the state of heavy metal pollution of Taizi River in Benxi Cityreach is very serious, appropriate counter measures should be taken.

Pollution assessment of heavy metals along the Mekong River and dam effects

The resource development and changes of hydrological regime, sediment and water quality in the Mekong River basin have attracted great attentions. This research aimed to enhance the study on transboundary pollution of heavy metals in this international river. In this study, eight sampling sites were selected to collect the bed sand samples along the mainstream of the Mekong River. In addition, the contents of 5 heavy metal elements and their spatial variability along the mainstream of the river were analyzed. The geoaccumulation index （l^eo） and potential ecological risk analysis were employed to assess heavy metal pol- lution status in the mainstream of the Mekong River. The results show that the average con- tent of the heavy metal elements Zn is 91.43 mg/kg, Pb is 41.85 mg/kg, and As is 21.84 mg/kg in the bed sands of the Upper Mekong River, which are higher than those （Zn 68.17 mg/kg, Pb 28.22 mg/kg, As 14.97 mg/kg） in the Lower Mekong. The average content of Cr in the Lower Mekong is 418.86 mg/kg, higher than that in the Upper Mekong （42.19 mg/kg）. Luang Prabang has a very high Cr concentration with 762.93 mg/kg and Pakse with 422.90 mg/kg. The concentration of Cu in all of the 8 sampling sites is similar, except for in Jiajiu with 11.70 mg/kg and Jiebei with 7.00 mg/kg. The results of the geoaccumulation index reveal that contaminations caused by Zn and Pb while Pb and As are more than those by Zn in Upper Mekong. Cr is the primary pollutant in the Lower Mekong, especially at Luang Prabang and Pakse. Slight pollution with As also occurs in Pakse. The potential ecological risk index indi- cates that the potential ecological risk of heavy metals in the mainstream of the Mekong River is low. We argue that the pollution of water quality and contamination of heavy metals in bed sediment caused by mining of mineral resources or geochemical background values in the Mekong is not transmitted from the Upper to the Lower Mekong because of the reservoir sedimentation and dilution along the river.

Distribution and assessment of heavy metals in the surface sediment of Yellow River, China

Large amounts of heavy metals discharged by industrial cities that are located along the middle reach of Yellow River, China have detrimental impacts on both the ecological environment and human health. In this study, fourteen surface sediment samples were taken in the middle reach of the Yellow River. Contents of Zn, Pb, Ni, Cu, Cr, Cd, As were measured, and the pollution status was assessed using three widely used pollution assessment methods, including the single factor index method, Nemerow pollution index method and potential ecological risk index. The concentrations of the studied heavy metals followed the order： Zn 〉 Cr 〉 Cu 〉 Ni 〉 Pb 〉 As 〉 Cd. Nearly 50% of sites had Cu and Cr accumulation. The concentration of Cu at the Yiluo River exceeded the secondary standard value of the Environmental quality standard for soils. Comparison of heavy metal concentrations between this study and other selected rivers indicated that Cu and Cr may be the major pollutants in our case. The single factor index indicated that many samples were at high levels of pollution for Cu and Cd; the Nemerow pollution index indicated that the Yihe River, Luohe River, Yiluo River and Huayuankou were polluted. According to the results of potential ecological risk assessment, Cd in the tributaries of Luo River, Yihe River,and Yiluo River showed high risk toward the ecosystem and human health, Cd in Huanyuankou and Cu in Yiluo River showed a middle level of risk and other samples were at a low level of risk.

An assessment of trace metal pollution indicators in soils around oil well clusters

Due to the metallic ion constituents of crude oil,environmental levels of toxic metals are often exac-erbated when oil is spilt.Biseni community plays host to numerous oil production companies in Bayelsa state,Nigeria.However,the tendency for this clan to be flooded,particularly owing to its lowland fea-tures has continued to negatively impact on the environment.Sometimes,floods are accompanied by spilt residual oil that encroach living areas,thus leading to the contamination of open water bodies,underground water resources,and fish and crop farms.This study surveyed the impact of oil seepages from oil well clusters on the overall soil quality by applying trace metal pollution indicators.Trace metals were analyzed by atomic absorption spectrometry,and concentration ranged from 5893.0-6263.8 mg/kg,0.03e11.52 mg/kg,3.15e6.46 mg/kg,4.46e58.64 mg/kg,13.61e29.83 mg/kg,0.23e0.73 mg/kg,8.32 e20.69 mg/kg,and 4.24e9.31 mg/kg for iron,copper,nickel,lead,zinc,cadmium,chromium and cobalt respectively.Concentrations were within target limits stipulated by the Department of Petroleum Re-sources,Dutch standard limit and World Health Organization.Zinc and chromium showed the strongest correlation(r¼0.92,p<0.05)in the study area,whilst one-way ANOVA revealed equality(p>0.05)among the different sampling points.This is evidence that the field area is affected by similar contam-ination source.Whereas,the micro-pollutant metals depicted significant variability(p<0.05),probably due to the outlier concentration of iron.Overall,lead was the most contaminating metal,while location BNS2(0.3m)was the most considerably contaminated area.Enrichment factor revealed the anthropo-genic origination of lead.Index of geo-accumulation of lead ranged from moderate to heavy contami-nation,with lead recording very high contamination factor,and the degree of contamination depicting considerable risk,especially at the top soil.Pollution load index showed most contamination(moderately polluted)at BNS2.Quantification of contamination showed relative contamination for most locations,whereas potential ecological risk index mostly depicted low risk,apart from the exhibition of moderate risk of lead and cadmium at BNS2.Conversely,sum of pollution indices and risk index revealed low contamination and low risk respectively.