Soil heavy metal pollution, influenced by both natural and anthropogenic factors, significantly reduces environmental quality. In this study, Cr, Ni, Cu, As, Cd, and Pb in eight different land-use soils from Patuakhal...Soil heavy metal pollution, influenced by both natural and anthropogenic factors, significantly reduces environmental quality. In this study, Cr, Ni, Cu, As, Cd, and Pb in eight different land-use soils from Patuakhali District in Bangladesh were assessed. Concentrations of Cr, Ni, Cu, As, Cd, and Pb in soils were 1-87, 5-271, 4-181, 0-80, 0.2-24.0, and 5-276 mg kg-1, respectively, measured using an inductively coupled plasma-mass spectrometer. The enrichment factor, pollution load index (PLI), and contamination factor (CJ) of metal i were used to assess the ecological risk posed by metals in soils. The PLI ranged from 0.78 to 2.66, indicating baseline levels to progressive deterioration of soil due to metal contamination. However, C;of Cd ranged from 1.8 to 12.0, which showed that the studied soils were strongly impacted by Cd. Considering the severity of the potential ecological risk of a single metal, the descending order was Cd > As > Pb > Cu > Ni > Cr. Soils under all land uses showed moderate to very high potential ecological risk.展开更多
Crude oil spills have inflicted extensive disruption upon the Niger Delta ecosystem, resulting in crop loss and severe environmental damage. Such spills exacerbate heavy metal concentration within soil due to the pres...Crude oil spills have inflicted extensive disruption upon the Niger Delta ecosystem, resulting in crop loss and severe environmental damage. Such spills exacerbate heavy metal concentration within soil due to the presence of metallic ions. The Okpare-Olomu community has borne the brunt of crude oil pollution from illicit bunkering, sabotage, and equipment malfunction. This study targets an evaluation of ecological hazards linked to heavy metals (HMs) in crude oil impacted agriculturally soils within Okpare-Olomu in Ughelli South LGA of Delta State. In this study, 24 topsoil samples were obtained from areas affected by crude oil pollution;the heavy metal content was evaluated through atomic absorption spectrometry. The concentration ranges for HMs (mg/kg) in soil were: 24.1 - 23,174 (Cu);0.54 - 37.1 (Cd);9.05 - 54 (Cr);12 - 174 (Ni);18.5 - 8611 (Pb);and 148 - 9078 (Zn) at a soil depth of 0 - 15 cm. Notably, metal concentrations were recorded to be above permissible World Health Organization limits. Predominantly, Zn and Pb recorded higher heavy metal concentration when compared to other heavy metals analysed, notably at sampling points PT7 through PT24. Zinc and Pb contamination exhibited highly significant contamination factors, and contamination severity was evidenced across all sample points, signifying a grave risk level. Pollution load indices indicated pervasive extreme pollution levels. Geoaccumulation indices signaled moderate to strong pollution, mainly by Pb and Zn. Ecological risk assessments revealed variable levels of heavy metal contamination, from low to very high, with potential ecological risk reflecting markedly elevated levels. This study underscores the imperative for soil remediation to rectify ecological imbalances in agriculturally affected soil constituents.展开更多
Flashover of ice-covered suspension insulator string is one of the major problems for the transmission lines in power grid.As leakage current is one of the important characteristics to predict the flashover of suspens...Flashover of ice-covered suspension insulator string is one of the major problems for the transmission lines in power grid.As leakage current is one of the important characteristics to predict the flashover of suspension insulator string,measuring method and analysis of the leakage current are developed for ice-covered XWP_2-160 porcelain suspension insulator string in this paper.The waveform of the leakage current is perfectly recorded from the occurrence of micro-discharge to flashover,in which the process can be divided into four periods according to the evolution of the leakage current.There are different rising rates of the leakage current and various phenomena of arc discharge in different periods with the increase of the applied voltage,and the distortion on the leakage current waveform is detected because of the effect of arc discharge.A characteristic current(I_w)and a critical current(I_(FT))of flashover,two important parameters of the leakage current before ice-covered insulator string flashover,are defined for analysis of the leakage current characteristics of pre-flashover along the polluted insulator string covered with ice.Statistical experimental results show that the average values of I_w and I_(FT) are within the major distribution zones,and both currents can be used for predicting the icing flashover.The values of two important leakage currents are approximately constant at different contamination degrees,while the direct relationships between the critical currents and the contamination degrees are not found in this paper.展开更多
In this study one economically important Ramsar wetland system of India, Vembanad wetland system, is studied to determine the environmental pollution. Six surface sediment samples collected from two extreme zones of t...In this study one economically important Ramsar wetland system of India, Vembanad wetland system, is studied to determine the environmental pollution. Six surface sediment samples collected from two extreme zones of the wetland system were analyzed for heavy metals such as Copper, Zinc, Manganese, Cadmium, Lead, Nickel and Mercury. Highest metal concentration was found at industrial zone and lowest concentration was detected at southern upstream of the wetland system. The results showed that the pollution level is significant in the industrial zone. Comparison of the results with different sediment quality guidelines indicated ultra high degree of contamination in the industrial zone. The numerical value of degree of contamination, pollution load index, sum of toxic units, enrichment factor and geo-accumulation index confirmed the above fact. Based on National Oceanic and Atmospheric Administration guidelines, the health of the ecosystem was seriously impaired with frequent occurring of biological effects in the industrial zone. The percentage of heavy metal calculated with respect to the industrial zone as the base line and the correlation analysis with organic matter indicated that, mobility of the specific metal has higher impact on its concentration at the fresh water region of the wetland.展开更多
Sediments play an important role in elemental cycling in the aquatic environment;it can be sensitive indicator for monitoring contaminants in aquatic environments. The heavy metal prominence, the amount and different ...Sediments play an important role in elemental cycling in the aquatic environment;it can be sensitive indicator for monitoring contaminants in aquatic environments. The heavy metal prominence, the amount and different forms of phosphorous present in the surface sediments of Kavvayi Wetland, which is in the south west coast of India was studied and reported in this paper. A total number of 10 surface sediment samples were taken from various regions of Kavvayi Lake and were subjected to heavy metal analysis and also phosphorous fractionation. Phosphorous forms in the sediment samples were determined by the modified sequential extraction procedure and among the inorganic phosphorous pool;Fe and Al bound phosphorous constituted the major portion while the Ca-bound phosphorous constituted the minor part only. Higher concentration of organic phosphorous was also detected in all the samples. The sediment samples were analyzed for heavy metals such as Fe, Mn, Cu, Pb, Cd, Ni, and Zn and the results showed comparatively higher concentration than the background values. The degree of contamination for each station was determined. Sediment pollution load index (PLI) values of the studied area ranged from 0.39 to 2.55 which indicated that the wetland sediments were polluted. Multivariate statistical techniques were applied to evaluate and characterize the analytical data. Spatial distribution maps of phosphorous fractions and heavy metals would help to identify the pollution sources and vulnerable sites.展开更多
基金Prof. Dr. Mohammad Shams-Ud-Din (Vice Chancellor, PSTU), for his valuable suggestions, cooperation, and provision of funding to conduct this research
文摘Soil heavy metal pollution, influenced by both natural and anthropogenic factors, significantly reduces environmental quality. In this study, Cr, Ni, Cu, As, Cd, and Pb in eight different land-use soils from Patuakhali District in Bangladesh were assessed. Concentrations of Cr, Ni, Cu, As, Cd, and Pb in soils were 1-87, 5-271, 4-181, 0-80, 0.2-24.0, and 5-276 mg kg-1, respectively, measured using an inductively coupled plasma-mass spectrometer. The enrichment factor, pollution load index (PLI), and contamination factor (CJ) of metal i were used to assess the ecological risk posed by metals in soils. The PLI ranged from 0.78 to 2.66, indicating baseline levels to progressive deterioration of soil due to metal contamination. However, C;of Cd ranged from 1.8 to 12.0, which showed that the studied soils were strongly impacted by Cd. Considering the severity of the potential ecological risk of a single metal, the descending order was Cd > As > Pb > Cu > Ni > Cr. Soils under all land uses showed moderate to very high potential ecological risk.
文摘Crude oil spills have inflicted extensive disruption upon the Niger Delta ecosystem, resulting in crop loss and severe environmental damage. Such spills exacerbate heavy metal concentration within soil due to the presence of metallic ions. The Okpare-Olomu community has borne the brunt of crude oil pollution from illicit bunkering, sabotage, and equipment malfunction. This study targets an evaluation of ecological hazards linked to heavy metals (HMs) in crude oil impacted agriculturally soils within Okpare-Olomu in Ughelli South LGA of Delta State. In this study, 24 topsoil samples were obtained from areas affected by crude oil pollution;the heavy metal content was evaluated through atomic absorption spectrometry. The concentration ranges for HMs (mg/kg) in soil were: 24.1 - 23,174 (Cu);0.54 - 37.1 (Cd);9.05 - 54 (Cr);12 - 174 (Ni);18.5 - 8611 (Pb);and 148 - 9078 (Zn) at a soil depth of 0 - 15 cm. Notably, metal concentrations were recorded to be above permissible World Health Organization limits. Predominantly, Zn and Pb recorded higher heavy metal concentration when compared to other heavy metals analysed, notably at sampling points PT7 through PT24. Zinc and Pb contamination exhibited highly significant contamination factors, and contamination severity was evidenced across all sample points, signifying a grave risk level. Pollution load indices indicated pervasive extreme pollution levels. Geoaccumulation indices signaled moderate to strong pollution, mainly by Pb and Zn. Ecological risk assessments revealed variable levels of heavy metal contamination, from low to very high, with potential ecological risk reflecting markedly elevated levels. This study underscores the imperative for soil remediation to rectify ecological imbalances in agriculturally affected soil constituents.
文摘Flashover of ice-covered suspension insulator string is one of the major problems for the transmission lines in power grid.As leakage current is one of the important characteristics to predict the flashover of suspension insulator string,measuring method and analysis of the leakage current are developed for ice-covered XWP_2-160 porcelain suspension insulator string in this paper.The waveform of the leakage current is perfectly recorded from the occurrence of micro-discharge to flashover,in which the process can be divided into four periods according to the evolution of the leakage current.There are different rising rates of the leakage current and various phenomena of arc discharge in different periods with the increase of the applied voltage,and the distortion on the leakage current waveform is detected because of the effect of arc discharge.A characteristic current(I_w)and a critical current(I_(FT))of flashover,two important parameters of the leakage current before ice-covered insulator string flashover,are defined for analysis of the leakage current characteristics of pre-flashover along the polluted insulator string covered with ice.Statistical experimental results show that the average values of I_w and I_(FT) are within the major distribution zones,and both currents can be used for predicting the icing flashover.The values of two important leakage currents are approximately constant at different contamination degrees,while the direct relationships between the critical currents and the contamination degrees are not found in this paper.
文摘In this study one economically important Ramsar wetland system of India, Vembanad wetland system, is studied to determine the environmental pollution. Six surface sediment samples collected from two extreme zones of the wetland system were analyzed for heavy metals such as Copper, Zinc, Manganese, Cadmium, Lead, Nickel and Mercury. Highest metal concentration was found at industrial zone and lowest concentration was detected at southern upstream of the wetland system. The results showed that the pollution level is significant in the industrial zone. Comparison of the results with different sediment quality guidelines indicated ultra high degree of contamination in the industrial zone. The numerical value of degree of contamination, pollution load index, sum of toxic units, enrichment factor and geo-accumulation index confirmed the above fact. Based on National Oceanic and Atmospheric Administration guidelines, the health of the ecosystem was seriously impaired with frequent occurring of biological effects in the industrial zone. The percentage of heavy metal calculated with respect to the industrial zone as the base line and the correlation analysis with organic matter indicated that, mobility of the specific metal has higher impact on its concentration at the fresh water region of the wetland.
文摘Sediments play an important role in elemental cycling in the aquatic environment;it can be sensitive indicator for monitoring contaminants in aquatic environments. The heavy metal prominence, the amount and different forms of phosphorous present in the surface sediments of Kavvayi Wetland, which is in the south west coast of India was studied and reported in this paper. A total number of 10 surface sediment samples were taken from various regions of Kavvayi Lake and were subjected to heavy metal analysis and also phosphorous fractionation. Phosphorous forms in the sediment samples were determined by the modified sequential extraction procedure and among the inorganic phosphorous pool;Fe and Al bound phosphorous constituted the major portion while the Ca-bound phosphorous constituted the minor part only. Higher concentration of organic phosphorous was also detected in all the samples. The sediment samples were analyzed for heavy metals such as Fe, Mn, Cu, Pb, Cd, Ni, and Zn and the results showed comparatively higher concentration than the background values. The degree of contamination for each station was determined. Sediment pollution load index (PLI) values of the studied area ranged from 0.39 to 2.55 which indicated that the wetland sediments were polluted. Multivariate statistical techniques were applied to evaluate and characterize the analytical data. Spatial distribution maps of phosphorous fractions and heavy metals would help to identify the pollution sources and vulnerable sites.
