Sources Of Metals In Soils Research Articles

Effects of mining activities on the distribution, controlling factors, and sources of metals in soils from the Xikuangshan South Mine, Hunan Province.

In this study, we analyzed 53 topsoil samples from the Xikuangshan South Mine in Hunan Province to investigate the distribution characteristics of pH and the concentrations of selected metals to determine the controlling factors and identify their sources. Kriging interpolation, correlation analysis, principal component analysis, the index of the geoaccumulation index, and Hakanson's potential ecological risk were applied. The results show that the mean values of Pb, As, Cd, and Sb in the study area were larger than the background value of mountain soil in Hunan Province, and only the average Cr concentration was slightly lower than the background value. The spatial distributions of pH and five metals in the soil were very different, indicating that pH had no significant effect on the distribution of the metals. The wind, rivers, and land-use patterns in different regions of the study area may be the main reasons for their distribution patterns. The correlation component and principal component analysis revealed that Pb showed positive correlations with Cr and Cd, respectively, and Sb-As and Cr-Cd showed strong paired correlations. The cumulative proportion of the first two components accounted for 70.516% of the total variance, which suggests that mining activities are a major source of As and Sb, whereas Pb, Cr, and Cd were derived from natural and anthropogenic sources. The geoaccumulation index revealed that the major pollutants in the soils were mainly Cd, followed by Sb and As. The soils in the study area were moderately contaminated with Pb and lightly polluted by Cr. The ecological hazards of each metal in descending order were Cd > Sb > As > Pb > Cr. The index of the comprehensive potential ecological risk for metals indicated that the Xikuangshan South Mine is at or above a moderate ecological risk level, with an extremely strong potential for ecological risks posed by Cd and Sb. Integr Environ Assess Manag 2022;18:748-756. © 2021 SETAC.

Sources of heavy metals in soils in densely populated areas based on the UNMIX model

To estimate heavy metal sources in soils under the influence of a high-density population, the concentrations of heavy metals, namely, Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Hg, Pb, and Fe, were determined in 23 soil samples from different sites at Suzhou University campus. Factor analysis (FA) and source analysis were completed based on the UNMIX model; the results showed that the contents of Ni, Cu, As, Cd, and Hg in the samples are 40.06, 60.75, 25.03, 0.10, and 0.12 mg/kg, respectively, which are higher than their soil background values in China. Three factors were obtained, agricultural activities, natural pedogenesis, and domestic waste; these accounted for a total of 76.49% of the explained covariance. The results for the three sources calculated using the UNMIX model are consistent with the FA results. The contribution of these sources to heavy metals in soils of the study area was also calculated; the contribution rates were 5.01, 29.25, and 65.74%, respectively. In conclusion, heavy metals in soils in the study area are mainly inherited from the weathering of parent rock (source 3, 65.74%) and are affected by agricultural activities such as chemical fertilizer use (source 2, 29.25%), whereas the effects of domestic waste such as batteries (source 1, 5.01%) is weak.

Source apportionment and health risk quantification for heavy metal sources in soils near aluminum-plastic manufacturing facilities in northeast China

Identifying the source effect on heavy metals to human health risk is essential for devising and implementing restoration policies for polluted soils. For this purpose, eight heavy metals (As, Cd, Hg, Cr, Cu, Ni, Pb, and Zn) in soil profile samples (0–10, 10–20, 20–30, and 30–40 cm) collected in the area around aluminum-plastic manufacturing facilities (APMF) were determined. An absolute principal component score multiple linear regression (APCS-MLR) model supported by a health risk assessment (HRA) model was developed to determine the source apportionment of soil heavy metals and contribution rate of pollution sources to human health risk. Results showed significant accumulations of eight metals in the topsoil (0–20 cm), parent material, transportation, APMF, and agricultural practices were the four major contributing sources for heavy metals in soils, with average contribution percentages of 21.69%, 24.99%, 29.60%, and 14.25%, respectively. Carcinogenic risk factors for adults (1.23E-04) and children (1.32E-04) were found to be above the acceptable level (1E-06 to 1E-04). The health risk quantification results indicated that parent material, APMF, transportation, agricultural practices, and unidentified factors accounted for 55.76%, 14.48%, 12.09%, 10.13%, and 7.54% of the carcinogenic risk for children and adults. The adverse impacts of Cd, Zn, and Pb accumulations in soil coming from APMF activities were significant and need to receive more attention.

Assessment of Heavy Metal Sources in Soils from a Uranium-Phosphate Deposit Using Multivariate and Geostatistical Techniques

The quantification of heavy metal contents in soils and their sources are essential for contamination monitoring and the assessment of the potential risks to the ecosystems. This study aims to investigate the source of heavy metals and other elements in soils from a uranium-phosphate deposit using integrated multivariate and geostatistics techniques. For this, 50 soil samples in Itataia deposit, Northeastern, Brazil, were collected at 0–0.2-m depth for the determination of U, Fe, Al, Mn, Ti, Zn, Cu, Ni, Mo, Co, Cr, Cd, Pb, As, Se, V, B, and Zr. The Pb, Se, Ni, Cr, As, and Mo mean contents were closer or exceeded The Brazilian Environmental Council (CONAMA) prevention values for soils. Uranium content was about 500 times higher than the mean levels reported for Brazilian soils. The cluster analysis indicates three geochemical groups based on different contamination levels. The first principal component was associated with lithological origin, the second principal component may be related to anthropogenic sources, and the third and fourth principal components indicated a joined source (natural and anthropogenic), indicating different sources of contamination. Mo was not related to other heavy metals, being found independent in the area. The accumulation of heavy metals in soils is associated not only with the parent material but also with the minerals of the soil. In the area of study, calcareous soils favored alkaline conditions that influenced the dynamics of heavy metals. The multivariate and geostatistical analyses were able to provide preliminary information regarding the metal contents in soil for environmental management.

Baseline Monitoring of Elemental Contamination Levels in Soil Samples in Elebele Community, Bayelsa State, Nigeria

This study evaluated the physico-chemical properties of the soil and water in Elebele Community in Ogbia Local Government Area of Bayelsa State, Nigeria. Standard sampling and analytical methods were employed. The predominant soils of the region are mainly sandy-loam and clayey-loamy. The soil physico-chemical properties were in good status as they were not toxic. Soil particle size distribution (sand silt and clay) was observed as follows: sand content ranged between 50.6%-86.2% with a mean of 64.5% at the surface soil while the subsurface soil ranged between 35%-80.2% with a mean of 60.2%. Silt on the other hand ranged between 7.8%-36% and a mean of 25.1% at the surface and ranged between 12.8-49.6% and mean of 25.4% at the subsurface while clay ranged between 3.4%-16% and mean of 9.4% at the surface and also ranged between 7%-16% and mean value of the soil. However, the soil physical properties were relativity good for sustainability. Also, the metals studied were detected in all the sites. Generally the concentrations of the metals were highest at the top soils. This is expected since the top soil is the point of contact. The metal levels in all the sites were significantly higher than the levels observed in the control sites. Sources of heavy metals in soils like inorganic fertilizers and pesticides need to be controlled.

Multiple methods for the identification of heavy metal sources in cropland soils from a resource-based region

Examination of heavy metal sources in soils from a resource-based region is essential for source identification and implementation of restoration strategies regarding soil contamination. A total of 1069 samples were collected from cropland soils in the Baiyin District (Loess Plateau, Northwest China), a characteristically resource-based region to investigate the sources of arsenic (As), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), vanadium (V), and zinc (Zn). Source identification was analyzed by multiple methods including spatial deviation (SD), correlation analysis (CA), enrichment factor (EF), principal component analysis (PCA), geographic information system (GIS), and positive matrix factorization (PMF). The results showed the combined applications of PMF, GIS, and PCA were accurate, pragmatic, and effective for source apportionment. Three origins were identified and the contribution rates were calculated as follows: approximately 95% of As came from wastewater irrigation; 75, 88, 60, and 76% of Cr, Mn, Ni, and V were separately derived from natural origins; and 81, 93, and 70% of Cu, Pb, and Zn originated from industrial sources, respectively. Natural origins, industrial sources, and wastewater irrigation were the three main contributors of heavy metals to cropland soils in this region.

Analysis of metal(loid)s contamination and their continuous input in soils around a zinc smelter: Development of methodology and a case study in South Korea

Soil contamination due to atmospheric deposition of metals originating from smelters is a global environmental problem. A common problem associated with this contamination is the discrimination between anthropic and natural contributions to soil metal concentrations: In this context, we investigated the characteristics of soil contamination in the surrounding area of a world class smelter. We attempted to combine several approaches in order to identify sources of metals in soils and to examine contamination characteristics, such as pollution level, range, and spatial distribution. Soil samples were collected at 100 sites during a field survey and total concentrations of As, Cd, Cr, Cu, Fe, Hg, Ni, Pb, and Zn were analyzed. We conducted a multivariate statistical analysis, and also examined the spatial distribution by 1) identifying the horizontal variation of metals according to particular wind directions and distance from the smelter and 2) drawing a distribution map by means of a GIS tool. As, Cd, Cu, Hg, Pb, and Zn in the soil were found to originate from smelter emissions, and As also originated from other sources such as abandoned mines and waste landfill. Among anthropogenic metals, the horizontal distribution of Cd, Hg, Pb, and Zn according to the downwind direction and distance from the smelter showed a typical feature of atmospheric deposition (regression model: y = y0 + αe−βx). Lithogenic Fe was used as an indicator, and it revealed the continuous input and accumulation of these four elements in the surrounding soils. Our approach was effective in clearly identifying the sources of metals and analyzing their contamination characteristics. We believe this study will provide useful information to future studies on soil pollution by metals around smelters.

Chemometric evaluation of heavy metals distribution in wastewater irrigated soil of peri-urban area

Characterization of content and source of heavy metals in soils are necessary to establish quality standards on a regional level. In relation to this, two zones, (sampling zone-1) and (sampling zone-2) depending on nature and intensity of wastewater disposal along the peri-urban area of Peshawar, Pakistan were selected. Thirty-six samples of wastewater and topsoil each were collected to determine the content of Pb, Cr, Cd, Cu, Zn, Ni, Fe and Mn, and physico-chemical parameters like pH, electrical conductivity, total solids, total dissolved solids, total suspended solids, and organic matter. Analytical determinations were performed by atomic absorption spectroscopy after microwave sample digestion in acid solution. Chemometric techniques which include hierarchical cluster analysis, principal component analysis, correlation analysis, and tukey test were applied. Concentrations of physico-chemical properties in wastewater and soil were higher in sampling zone-2. Concentrations of six heavy metals in wastewater and two in soil exceeded permissible limits of World Health Organization (Guidelines for drinking water quality, 4th edition, 2011), European Union (Heavy metals in wastes, European commission on environment. http://ec.europa.eu/environment/waste/studies/pdf/heavymetalsreport , 2002). Hierarchical cluster analysis grouped eight heavy metals into two clusters for wastewater and five clusters for soils. Principal component analysis describes four factors possessing Eigenvalues greater than 1.0 and explained the cumulative total variance of 84% with factor 1, having positive loading of anthropogenic metals (Cd, Cu, and Ni). Significant correlation was found between anthropogenic metals like Ni and Cd in water and between Cu and Cr in soil. Further research in other agricultural lands in peri-urban region would improve the basis for proposing such soil quality standards.

Analysis of Heavy Metal Sources in Soil Using Kriging Interpolation on Principal Components

Anniston, Alabama has a long history of operation of foundries and other heavy industry. We assessed the extent of heavy metal contamination in soils by determining the concentrations of 11 heavy metals (Pb, As, Cd, Cr, Co, Cu, Mn, Hg, Ni, V, and Zn) based on 2046 soil samples collected from 595 industrial and residential sites. Principal Component Analysis (PCA) was adopted to characterize the distribution of heavy metals in soil in this region. In addition, a geostatistical technique (kriging) was used to create regional distribution maps for the interpolation of nonpoint sources of heavy metal contamination using geographical information system (GIS) techniques. There were significant differences found between sampling zones in the concentrations of heavy metals, with the exception of the levels of Ni. Three main components explaining the heavy metal variability in soils were identified. The results suggest that Pb, Cd, Cu, and Zn were associated with anthropogenic activities, such as the operations of some foundries and major railroads, which released these heavy metals, whereas the presence of Co, Mn, and V were controlled by natural sources, such as soil texture, pedogenesis, and soil hydrology. In general terms, the soil levels of heavy metals analyzed in this study were higher than those reported in previous studies in other industrial and residential communities.

Heavy metals distribution in the soils of Peshawar valley, Northern-Pakistan

Information about metals concentrations in soil profiles of Peshawar-Pakistan in relation to their parent material is in scarcity. The study was aimed to identify the source of metals in soils and to determine the level of depletion and enrichment. Twenty two soil profiles derived from alluvium, piedmont alluvium, loess and re-deposits loess underlain by quaternary sediments with their respective parent materials were sampled and analyzed for metals by AAS. The average value of Ca, Fe, K, Mg, Na was significantly greater (p<0.05) in piedmont soils than red Murree shales. Cadmium was found to be high in all soils than the parent material. There was no significant difference in total content of Cu in all soils. Total content of Cd, Cr, Mn and Zn was found to be significantly greater (p<0.05) in piedmont soils than alluvium and loess soils, similarly Ni and Pb were significantly greater (p<0.05) in loess soils than piedmont and alluvium soils. The concentrations of Cr, Pb and Zn were significantly greater (p<0.05) in the A horizon of piedmont and alluvium soils than B horizon. The total content of all trace elements except for Cd and Ni was found to be significantly greater (p<0.05) than the reported mean for world soils. There was no significant difference between total trace elements content except for Cd and Ni between soils and parent materials. Data suggested no depletion or enrichment in all metals. All metals were evenly distributed and derived from similar parent material of sedimentary origin. These values could be considered as baseline levels for comparison with soils contaminated due to anthropogenic activities. Key words: Soil series, depletion, enrichment, metals.

Metals Contamination in Soils and Vegetables in Metal Smelter Contaminated Sites in Huangshi, China

This study investigated the source and magnitude of metal contamination in soils and vegetables collected in the vicinity of the Daye smelter, China. Results showed that soils and vegetables were heavily contaminated by cadmium (Cd) and lead (Pb). The average levels of Cd and Pb in vegetables were 0.21 and 3.28 mg/kg fresh weight, respectively. Community Bureau of Reference (BCR) operational speciation analysis indicated that the source of metals in soils probably resulted from sewage irrigation and contaminated sediment. Transfer and correlation coefficients were also calculated to evaluate the bioavailability of metals to vegetables. This investigation highlights the potential risk to local residents via consumption of vegetables.

PIXE, 252Cf-PDMS and radiochemistry applied for soil and vegetable analysis

The aim of this work is to identify the elements present in vegetables and soils using PIXE (particle induced X-rays emission) and 252Cf-PDMS (252Cf plasma desorption mass spectrometry) techniques in order to estimate the possible influence of soil and agricultural techniques in the metal absorption by the vegetables. In this work, metal concentrations were evaluated in soil and vegetable samples from several regions, where different agricultural techniques were employed. Si, Zr, Ce, Th, Sc and Pb identified in the soil samples were not biologically available. Ga, Ge, As and Br identified in the tubercles indicate that spray pesticide used on the vegetable leaves was absorbed by them. 232Th and 238U present in the soil were not absorbed by the vegetables. The airborne particles from anthropogenic sources (as CFn, VCn) were absorbed by the vegetables. Compounds from mineral sources present in soil as V+, VCO3, HPO4, Cr+, CrOH+, Mn+, FeH+, Fe(OH)n and in the bioorganic compounds as N+, Ca(CN)n+ and CnH+ were identified in vegetables. The metal absorption by the vegetables is not dependent of the metal concentration in soil. Different tubercles cultivated in the same soil show similar metal absorption. The exogenous contributions such as the elements present in water irrigation, pesticides, fertilizers and airborne particles deposited on leaves can be absorbed by vegetables. The absorption by the roots depends on the chemical compound of the elements. The use of pesticide sprays and air pollution can cause more contamination in the vegetables than in soil. The use of this methodology allows the identification of possible sources of metals in soils and in vegetables and the metal speciation.

Multivariate statistical and GIS-based approach to identify heavy metal sources in soils

The knowledge of the regional variability, the background values and the anthropic vs. natural origin for potentially harmful elements in soils is of critical importance to assess human impact and to fix guide values and quality standards. The present study was undertaken as a preliminary survey on soil contamination on a regional scale in Piemonte (NW Italy). The aims of the study were: (1) to determine average regional concentrations of some heavy metals (Cr, Co, Ni, Cu, Zn, Pb); (2) to find out their large-scale variability; (3) to define their natural or artificial origin; and (4) to identify possible non-point sources of contamination. Multivariate statistic approaches (Principal Component Analysis and Cluster Analysis) were adopted for data treatment, allowing the identification of three main factors controlling the heavy metal variability in cultivated soils. Geostatistics were used to construct regional distribution maps, to be compared with the geographical, geologic and land use regional database using GIS software. This approach, evidencing spatial relationships, proved very useful to the confirmation and refinement of geochemical interpretations of the statistical output. Cr, Co and Ni were associated with and controlled by parent rocks, whereas Cu together with Zn, and Pb alone were controlled by anthropic activities. The study indicates that background values and realistic mandatory guidelines are impossible to fix without an extensive data collection and without a correct geochemical interpretation of the data.

Drilling Fluids and Reserve Pit Toxicity

Drilling fluids are now classified as exempt under the Resource Conservation and Recovery Act (RCRA) hazardous waste laws. Since 1986, however, the U.S. Environmental Protection Agency (EPA) has been studying reserve pit contents to determine whether oilfield wastes should continue under this exemption. Concerns regarding reserve pit contents and disposal practices have resulted in state and local governmental regulations that limit traditional methods of construction, closure, and disposal of reserve pit sludge and water. A great deal of attention and study has been focused on drilling fluids that eventually reside in reserve pits. In-house studies show that waste from water-based drilling fluids plays a limited role (if any) in possible hazards associated with reserve pits. Reserve pit water samples and pit sludge was analyzed and collated. Analyses show that water-soluble heavy metals (Cr, Pb, Zn and Mn) in reserve pits are generally undetectable or, if found in the total analysis, are usually bound to clays or organics too tightly to exceed the limitations as determined by the EPA toxicity leachate test. The authors' experience is that most contamination associated with reserve pits involves high salt content from produced waters and/or salt formations, lead contamination from pipe dope, or poorly designedmore » pits, which could allow washouts into surface waters or seepage into groundwater sources. The authors' analyses show that reserve its associated with water-based drilling fluid operations should not be classified as hazardous; however, careful attention attention should be paid to reserve pit construction and closure to help avoid any adverse environmental impact.« less