Metal Contamination In Urban Soils Research Articles

Phytoremediation by trees as a nature-based solution for mitigating metal contamination in urban soils.

Trace metals in the environment are important pollutants affecting human health, particularly in urban areas worldwide. Phytoremediation as a nature-based solution (NBS) and environmentally friendly technology may decrease high concentrations of trace metals in urban soils, protecting public health (especially children) and contributing to urban sustainability. This study examined trace metal contamination of urban soils and trees in six cities in the Republic of Srpska (RS), Bosnia and Herzegovina (BiH) and investigated the potential of selected tree species for phytoremediation as a NBS for metal-polluted urban soils. Contamination of urban soils was assessed by quantifying the concentrations of 11 trace metals (B, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, and Zn). To estimate phytoremediation potential of urban tree species, concentration and bioconcentration factor of the 11 metals were quantified in leaves of three common and abundant tree species: Aesculus hippocastanum L. (horse chestnut), Platanus acerifolia Willd. (plane), and Tilia sp. (lime). The results showed that trace metal concentrations in leaf samples did not exceed toxicity threshold guideline values. Further assessments are needed to establish the true potential of the three species as NBS for urban soils.

Heavy Metal Contamination in Urban Soils: Health Impacts on Humans and Plants: A Review

This research looks at how the growth of cities and industries affects the levels of heavy metals in the soil, which can impact people's health. We find out where the pollution comes from, such as factories, car fumes, and improper waste disposal, by reviewing existing studies. We use different methods to test the soil for heavy metals and study how exposure to these metals in urban areas affects people's health. The evidence shows a connection between high levels of heavy metals in city soil and health problems like breathing issues, brain disorders, and overall toxicity in the body. We also explore how these metals get into the human body, highlighting the importance of understanding how they are available and the ways people are exposed. To deal with polluted city soils, we look at different ways to manage the soil and suggest sustainable methods to reduce heavy metal pollution. Our discoveries add to what we know about urban environmental health, emphasizing the need for actions to protect city residents. Ultimately, this study aims to give important information and insights to policymakers, city planners, and public health officials for managing and lessening the health risks linked to heavy metal contamination in urban soils.

Comprehensive human health risk assessment of heavy metal contamination in urban soils: insights from selected metropolitan zones

Introduction: This study aims to assess the extent of heavy metal contamination in urban soils in sixteen selected cities of Pakistan, encompassing the elements cadmium (Cd), lead (Pb), cobalt (Co), zinc (Zn), chromium (Cr), nickel (Ni), manganese (Mn), iron (Fe), and copper (Cu).Methods: The data utilized for this study was collected from online literature during the period 2005 to 2019. This study investigated potential threats to human health through a comprehensive analysis, considering standards such as Enrichment Factors (EF), Geo-accumulation Indices (Igeo), and Human Health Risk Assessment (HHRA).Results: Geo-accumulation Index results indicated varied risk intensities, with Cu, Pb, Co, Mn, and Fe exhibiting “no pollution” levels, while other elements show “moderate to extremely contaminated” values. EF analysis provided evidence of heavy metal presence, revealing a spectrum from “no pollution” to “moderate to extremely high pollution” for Cd, Zn, Cr, Ni, and Cu. The health risk assessment identified both carcinogenic and non-carcinogenic dangers for adults and children.Discussion: These findings highlighted the substantial contribution of identified sources such as industrial processes, vehicular emissions, sewage sludge, urban flooding, and the production and use of metallic materials that have elevated heavy metal levels in the urban soils. This established the link between urban industrial zones, human health, and long-term economic sustainability. This study provides essential guidance for decision makers to develop effective strategies for soil remediation, enhanced industrial practices, and regulatory measures to address heavy metal contamination in urban areas, ensuring the wellbeing and sustainable environmental quality management in cities.

Spatial Analysis of Heavy Metal Contamination in Urban Soil: A Geographical Perspective on Distribution, Sources, and Human Health Impacts

Spatial Analysis of Heavy Metal Contamination in Urban Soil: A Geographical Perspective on Distribution, Sources, and Human Health Impacts

Assessment of Heavy Metal Contamination in Urban Soils of selected areas in Hilla City, Babylon, Iraq

Modern cities suffer from heavy metal pollution due to urban expansion and population increase. Heavy metals have a great impact on human health. The objective is to determine the contamination level of heavy metals Cr, Mn, Ni, Cu, Zn, As, Zr and Pb at industrial and residential in Hilla city. The mean concentration of Cr, Mn, Ni, Cu, Zn, As, Zr and Pb enrichment factors of the investigated industrial soils are 3.43, 0.74, 6.45, 3.95, 5.60, 3.44, 1.17 and 11.44, respectively. The means of Cr, Mn, Ni, Cu, Zn, As, Zr and Pb in residential soils are 3.30, 1.09, 11.40, 0.94, 2.08, 5.39, 0.9 and 3.6, respectively. The I-geo mean values of heavy elements in the industrial area may be ordered in the following: Mn> Pb> Ni> Zn> Cu> As> Cr> Zr. While in the residential area ordered Mn> Ni> As>Cr> Pb> Zn> Cu > Zr. Integrated Pollution Load Index categories results showed high contamination in industrial and residential areas. The main sources of heavy elements pollution in the study area has been regarded as anthropogenic sources.

Racial Disparities in the Heavy Metal Contamination of Urban Soil in the Southeastern United States.

(1) Background: Field monitoring data for addressing the disproportional burden of exposure to soil contamination in communities of minority and low socioeconomic status (SES) are sparse. This study aims to examine the association between soil heavy metal levels, SES, and racial composition. (2) Methods: A total of 423 soil samples were collected in the urban areas of eight cities across six Southern states in the U.S., in 2015. Samples were analyzed using inductively coupled plasma–mass spectrometry (ICP–MS) for eight heavy metals. The association was examined with mixed models with the log-transformed metal concentrations as the dependent variables and rankings of low-income or minority percentages as the explanatory variables. (3) Results: Model results showed that soil metal concentrations were significantly associated with rankings of poverty and minority percentages. The cadmium concentration significantly increased by 4.7% (p-value < 0.01), for every 10 percentiles of increase in poverty rank. For every 10 percentiles of increase in minority rank, the soil concentrations were significantly up (p-values < 0.01) for arsenic (13.5%), cadmium (5.5%), and lead (10.6%). Minority rank had significant direct effects on both arsenic and lead. (4) Conclusions: The findings confirmed elevated heavy metal contamination in urban soil in low-income and/or predominantly minority communities.

Distribution patterns and sources of heavy metals in soils from an industry undeveloped city in Southern China

The accumulations of heavy metals in urban soils are derived from natural parent materials and complex anthropogenic emission sources. This paper investigated metal contamination in urban soils at an industry undeveloped city (Haikou) in southern China, an ideal place to quantitatively assess the contribution of metals from different sources. The concentrations of most heavy metals in the urban soils of Haikou were much lower than their guideline values and that of those from other big cities in China. In contrast, the chemical speciation of metals in this study was similar to those from other cities. The spatial distributions of heavy metals and principal component analysis (PCA) revealed that basaltic parent materials, traffic emissions, and coal combustion were the main factors controlling the distribution of metals in the soils. The Pb isotope signatures of the Haikou soils were greatly different from those of the Beijing and Shanghai soils, but similar to those of the Guangzhou soils, suggesting the common sources of Pb in southern China cities. The results of ternary mixing model of Pb isotopes showed that the contributions of Pb from natural background, coal combustion and traffic emission sources were 5.3–82.4% (mean: 39.7 ± 21.1%), 0–85.7% (mean: 25.5 ± 24.6%), and 1.9–64% (mean: 34.8 ± 22.9%), respectively. This suggests that traffic emission is still the most important anthropogenic source of Pb in Haikou.

Source identification and assessment of heavy metal contamination in urban soils based on cluster analysis and multiple pollution indices

To identify the sources and levels of contamination with anthropogenically derived heavy metals (HMs) for appropriate pollution control. We quantified anthropogenic influences with respect to HM pollution in soil, based on multiple pollution indices and cluster analysis derived from the results of an annual nationwide survey conducted in Korea. Contamination levels of HMs in soils were quantitatively evaluated using multiple pollution indices: contamination factor (CF), geo-accumulation index (Igeo), Nemerow’s integrated pollution index (NIPI), and pollution load index (PLI). Hierarchical cluster analysis was conducted to elucidate the correlations between HMs and contamination sources. A total of 2214 HM concentration data including six contamination sources were used to evaluate the pollution state of anthropogenic effects of HMs. The CFs for Zn and Cu revealed a broad enrichment of these HMs in all pollution sources. Scrap recycling sites (SRS) had the highest likelihood of pollutant distribution in soil surfaces. NIPI and PLI varied with the extent of anthropogenic activities or land use, especially in SRS, waste disposal sites (WDS), transport maintenance sites (TMS), and industrial sites (INS), and anthropogenic sources were divided into three discrete clusters: INS-TMS-LDS (land development sites), SRS-WDS, and vicinities of industrial sites (VIS). Our results confirmed that soil pollution indices combined with cluster analysis were useful to identify sources of anthropogenic HMs in urban soil, as well as to assess the levels of HM contamination.

Ecological risk assessment and source apportionment of heavy metal contamination in urban soils in Shiraz, Southwest Iran

Soil quality in urban areas is deteriorating globally due to diverse anthropogenic activities. This study assessed urban soils from Shiraz (SW Iran), a city with heterogeneous industrial activity and anthropogenic emissions. The objectives of this study were to (1) determine soil properties and concentrations of cobalt, chromium, iron and nickel and (2) assess the geoaccumulation index (Igeo), enrichment factor and pollution indices of the studied metals and their adverse impacts on environmental quality and human health. A total of 143 soil samples (0–20-cm depth) were collected from the study area, and multivariate analysis, including spatial mapping, was performed. The average concentrations of chromium and nickel exceeded the limits for residential/parkland/industrial soils according to Canadian guidelines, whereas the average cobalt concentration was less than that specified by Swedish and Canadian guidelines. A multivariate analysis (cluster analysis, Pearson correlation and principal component analysis) confirmed that the heavy metals had the same origin and that anthropogenic activities had a significant effect on the heavy metal contamination of the soil. Furthermore, the contamination factor and enrichment factor indicated that the soil samples were moderately to highly contaminated by nickel, chromium and cobalt, whereas Igeo indicated very high contamination in all soil samples tested. The potential ecological risk index and modified potential ecological risk index also indicated moderate to high ecological risk from the heavy metals in the urban soil samples.

Concentration, Spatial Distribution, Contamination Degree and Human Health Risk Assessment of Heavy Metals in Urban Soils across China between 2003 and 2019-A Systematic Review.

This study provides an overview of the studies of heavy metal pollution regarding As, Cd, Cr, Hg, Pb, Cu, Zn and Ni in the urban soils throughout 71 cities of China, based on data from online literature, during the period 2003–2019. The concentrations, spatial distributions, contamination degrees and health risks of heavy metals in the urban soils were evaluated. The results demonstrated that the mean values of eight heavy metals all exceeded the soil background values in China, and the kriging interpolation method showed that the hot-spot cities with heavy metal contamination in urban soils were mainly concentrated in the southwest, southcentral, southeast coast, northcentral and northwest regions of China. The geoaccumulation index (Igeo) indicated that Hg and Cd were at moderate contamination levels and that the levels of the other six metals did not appear contamination. The pollution index (PI) showed that Cd and Hg reached high contamination levels, and the other metals reached moderate contamination levels. The integrated pollution index (IPI) and potential ecological risk index (PRI) indicated that the integral urban soils in the study areas ranked high contamination levels and moderate ecological risk degree, respectively, and Cd and Hg should be labeled as priority metals for control in the urban soils around China. The human health risk assessments for the heavy metals indicated that ingestion was the dominant exposure pathway for having adverse effects on human health. The mean Hazard index (HI) values of eight heavy metals all showed that adverse effects on human health were unlikely, and the mean carcinogenic (CR) values of As, Cr and Ni for children and adults all suggested an acceptable carcinogenic risk to human beings. In addition, children exposed to these heavy metals faced more serious non-carcinogenic and carcinogenic health threats compared to adults. The results could provide valuable information for demanding the better control of heavy metal pollution and mitigation of the adverse effects on residents by environmental regulators in national urban regions.

Deciphering source contributions of trace metal contamination in urban soil, road dust, and foliar dust of Guangzhou, southern China

Trace metal contamination prevails in various compartments of the urban environment. Understanding the roles of various anthropogenic sources in urban trace metal contamination is critical for pollution control and city development. In this study, the source contribution from various contamination sources to trace metal contamination (e.g., Cu, Pb, Zn, Co, Cr and Ni) in different environmental compartments in a typical megacity, Guangzhou, southern China, was investigated using the receptor model (Absolute Principal Component Scores-Multiple Linear Regression, APCS-MLR) coupled with the Kriging technique. Lead isotopic data and APCS-MLR analysis identified industrial and traffic emissions as the major sources of trace metals in surface soil, road dust, and foliar dust in Guangzhou. Lead isotopic compositions of road dust and foliar dust exhibited similar ranges, implying their similar sources and potential metal exchange between them. Re-suspended soil contributed to 0–38% and 25–58% of the trace metals in the road dust and foliar dust, respectively, indicating the transport of the different terrestrial dust. Spatial distribution patterns implied that Cu in the road dust was a good indicator of traffic contamination, particularly with traffic volume and vehicle speed. Lead and Zn in foliar dust indicated mainly industrial contamination, which decreased from the emission source (e.g., a power plant and steel factory) to the surrounding environment. The spatial influence of industry and traffic on the contamination status of road dust/foliar dust was successfully separated from that of other anthropogenic sources. This study demonstrated that anthropogenic inputs of trace metals in various environmental compartments (e.g., urban soil, road dust, and foliar dust) can be evaluated using a combined APCS-MLR receptor model and geostatistical analysis at a megacity scale. The coupled use of APCS-MLR analysis, geostatistics, and Pb isotopes successfully deciphered the spatial influence of the contamination sources in the urban environment matrix, providing some important information for further land remediation and health risk assessment.

Assessment of heavy metal contamination in urban soil (Tuzla District, Istanbul, Turkey)

Assessment of heavy metal contamination in urban soil (Tuzla District, Istanbul, Turkey)

Vegetation reflectance spectroscopy for biomonitoring of heavy metal pollution in urban soils

Heavy metals in urban soils may impose a threat to public health and may negatively affect urban tree viability. Vegetation spectroscopy techniques applied to bio-indicators bring new opportunities to characterize heavy metal contamination, without being constrained by laborious soil sampling and lab-based sample processing. Here we used Tilia tomentosa trees, sampled across three European cities, as bio-indicators i) to investigate the impacts of elevated concentrations of cadmium (Cd) and lead (Pb) on leaf mass per area (LMA), total chlorophyll content (Chl), chlorophyll a to b ratio (Chla:Chlb) and the maximal PSII photochemical efficiency (Fv/Fm); and ii) to evaluate the feasibility of detecting Cd and Pb contamination using leaf reflectance spectra. For the latter, we used a partial-least-squares discriminant analysis (PLS-DA) to train spectral-based models for the classification of Cd and/or Pb contamination. We show that elevated soil Pb concentrations induced a significant decrease in the LMA and Chla:Chlb, with no decrease in Chl. We did not observe pronounced reductions of Fv/Fm due to Cd and Pb contamination. Elevated Cd and Pb concentrations induced contrasting spectral changes in the red-edge (690–740 nm) region, which might be associated with the proportional changes in leaf pigments. PLS-DA models allowed for the classifications of Cd and Pb contamination, with a classification accuracy of 86% (Kappa = 0.48) and 83% (Kappa = 0.66), respectively. PLS-DA models also allowed for the detection of a collective elevation of soil Cd and Pb, with an accuracy of 66% (Kappa = 0.49). This study demonstrates the potential of using reflectance spectroscopy for biomonitoring of heavy metal contamination in urban soils.

Spatial distribution of metal pollution of soils of Chinese provincial capital cities

This work describes the spatial distribution of metal concentrations, resulting environmental quality, and potential ecological risks using ArcGIS. The data were based on collecting the soil background and baseline values of eight metal elements (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in 31 Chinese provincial capital cities (PCCs) from published literatures 2005–2017. The following results were obtained in accordance with the integrated pollution index and the total potential ecological risk index: (1) The average concentrations of metals varied in relatively low degree in Chinese PCCs, while 10 and six PCCs were classified as having “severe” contamination and “moderate” risk, respectively. (2) Cd, Hg, Cu, Pb, and Zn were chosen as priority control metals; Beijing, Chengdu, Tianjin, Changsha, Shijiazhuang, Shenyang, Ji'nan, Changchun, and Xi'an were chosen as priority control PCCs, due to their higher pollution level and ecological risk of soils in comparison to other metals or PCCs. (3) A clear southeast/northwest boundary marked the urban soil metal pattern, which was aligned with the famous demographic, geological, and economic boundary known as the “Hu-line.” This finding suggests that metal contamination in urban soil was caused by both geochemical background and human activities. These results provide basic information that can assist to avoid further degradation of soil by preventing and monitoring metal contamination in China's PCCs. The study suggests that more attention should be focused on developing cities in western China and “The Belt and Road” when pursuing economic development.

Soil pollution indices conditioned by medieval metallurgical activity – A case study from Krakow (Poland)

The studied soil profile under the Main Market Square (MMS) in Krakow was characterised by the influence of medieval metallurgical activity. In the presented soil section lithological discontinuity (LD) was found, which manifests itself in the form of cultural layers (CLs). Moreover, in this paper LD detection methods based on soil texture are presented. For the first time, three different ways to identify the presence of LD in the urban soils are suggested. The presence of LD had an influence on the content and distribution of heavy metals within the soil profile. The content of heavy metals in the CLs under the MMS in Krakow was significantly higher than the content in natural horizons. In addition, there were distinct differences in the content of heavy metals within CLs. Profile variability and differences in the content of heavy metals and phosphorus within the CLs under the MMS were activity indicators of Krakow inhabitants in the past. This paper presents alternative methods for the assessment of the degree of heavy metal contamination in urban soils using selected pollution indices. On the basis of the studied total concentration of heavy metals (Zn, Pb, Cu, Mn, Cr, Cd, Ni, Sn, Ag) and total phosphorus content, the Geoaccumulation Index (Igeo), Enrichment Factor (EF), Sum of Pollution Index (PIsum), Single Pollution Index (PI), Nemerow Pollution Index (PINemerow) and Potential Ecological Risk (RI) were calculated using different local and reference geochemical backgrounds. The use of various geochemical backgrounds is helpful to evaluate the assessment of soil pollution. The individual CLs differed from each other according to the degree of pollution. The different values of pollution indices within the studied soil profile showed that LDS should not be evaluated in terms of contamination as one, homogeneous soil profile but each separate CL should be treated individually.

Magnetic signature and source identification of heavy metal contamination in urban soils of steel industrial city, Northeast China

Purpose Identifying the spatial distribution and degree of heavy metal contamination in the soils is required for urban environmental management. Magnetic measurement provides a rapid means of determining spatial distribution and degree of soil pollution and identifying various anthropogenic sources of heavy metals. The purpose of this study was to characterize the magnetic signature of heavy metal contamination and identify the sources of heavy metals in urban soils from steel industrial city.

Contemporary sources and levels of heavy metal contamination in urban soil of Broken Hill, Australia after ad hoc land remediation

This study used GIS-based and multivariate statistical approach to identify sources of Cr, Mn, Ni, Pb and Zn in urban soil surrounding a large Pb-Zn-Ag orebody. The results show that Mn-Pb-Zn-rich dust originating from the orebody and associated mining works has acted as an important contaminating source of topsoil metals. In contrast, Cr and Ni appear to be sourced naturally from weathering of parent materials. The calculation of contamination indices reflects a high level of Pb and Zn contamination in topsoil near the orebody and a moderate level of Mn contamination, while topsoil contamination with Cr and Ni is negligible.

Magnetic properties, microstructure and mineralogical phases of technogenic magnetic particles (TMPs) in urban soils: Their source identification and environmental implications

Magnetic measurement is an effective method to determine spatial distribution and the degree of heavy metal pollution and to identify various anthropogenic sources of heavy metals. The objectives of this investigation are to characterize the magnetic properties, microstructure and mineralogical phases of technogenic magnetic particles (TMPs) in urban soils and to discuss their potential environmental implications. The TMPs are separated from the urban topsoils of Luoyang city, China. The magnetic properties, morphology, and mineral phase of TMPs are studied using mineral magnetic measurement, scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM/EDS), X-ray diffraction, and synchrotron–radiation-based microprobe. The content of TMPs in urban topsoils ranges from 0.05 to 1.95% (on average 0.32%). The magnetic susceptibility of TMPs ranges from 4559×10−8 to 23,661×10−8m3kg−1 (on average 13,637×10−8m3kg−1). Thermomagnetic and bulk X-ray diffraction analyses indicate that main magnetic minerals of TMPs are magnetite (Fe3O4) and hematite (α-Fe2O3). The morphology of TMPs observed by SEM includes three shape types: spherule, irregular-shaped, and aggregate particles. The size of spherical TMPs ranges from 30 to about 200μm, with the largest percentage of 30–50μm. Synchrotron–radiation-based microprobe (μ-XRF and μ-XRD) indicates that TMPs are enriched with heavy metals Pb, Cd, Zn, Cu, and Cr, which are incorporated into lattice or adsorbed on the surface of magnetite/hematite. The content of TMPs significantly relates with the Tomlinson Pollution Load Index (PLI) (R2=0.467), suggesting that it can be used as proxy indicator of degree of heavy metal contamination in urban soils. The magnetic properties, microstructure and mineralogical phases of TMPs can serve as the identification of pollution sources in urban soils.

Health risk assessment of heavy metal exposure in urban soil from Seri Kembangan (Malaysia)

Heavy metals in urban soils are associated with direct and indirect human health risks. This study examined bioavailability of heavy metal (Pb, Cd, Cr and As) in urban soil of Seri Kembangan (Malaysia) and their risks to human health. Bioavailability of heavy metal concentration (arsenic, lead, cadmium and chromium) were analysed by a simplified physiologically based extraction test. Both noncarcinogenic and carcinogenic risks were assessed using health index and total lifetime cancer risk, respectively. Average concentrations of bioavailability heavy metal were found in the order of Pb (2668.8 mg/kg) > Cr (74 mg/kg) > Cd (47.5) > As (13.75 mg/kg). For non-cancer, average hazard index values of heavy metal order were Pb(1.27) > Cr(0.11) > Cd(0.05). For As, total cancer risk values of Seri Kembangan urban soil (7.2E-6) were lower than the tolerable lifetime cancer risk for regulatory purposes (1E-5). Ingestion pathway is the most contributed pathway for both cancer and non-cancer risks. Land use type is found to be the main contributor which influences heavy metal exposure corresponding to health risk assessment output. Industrial areas were found to have hazard index values were lesser than residential areas in Seri Kembangan urban soil. Location areas in Seri Kembangan as near major roads with large amount of traffics were found to be more higher with HI more than 1, indicating high heavy metal contamination in urban soil due to vehicular emissions. This study has showed that realistic estimation of human health risk of heavy metal contamination in urban soils needs combination of land use type with bioavailability heavy metal concentration.

Use of an in vitro digestion method to estimate human bioaccessibility of Cd in vegetables grown in smelter-impacted soils: the influence of cooking.

Metal contamination of urban soils and homegrown vegetables has caused major concern. Some studies showed that cadmium (Cd) was among the most significant hazards in kitchen garden soils and prolonged exposure to this metal could cause deleterious health effects in humans. In general, most risk assessment procedures are based on total concentrations of metals in vegetables. The present study assesses human bioaccessibility of Cd in vegetables cultivated in smelter-impacted kitchen garden soils. Seven vegetables (radish, lettuce, French bean, carrot, leek, tomato, and potato) were considered. Using the UBM protocol (unified BARGE bioaccessibility method), the bioaccessibility of Cd was measured in raw/cooked vegetables. A considerable amount of Cd was mobilized from raw vegetables during the digestion process (on average 85% in the gastric phase and 69% in the gastrointestinal phase), which could be attributed to a high uptake of Cd during the growth of the vegetables. Most Cd is accumulated in the vacuoles of plant cells, except what is absorbed by the cell wall, allowing Cd to be released from plant tissues under moderate conditions. Cooking by the steaming process generally increased the bioaccessibility of Cd in French bean, carrot, and leek. For potato, few or no significant differences of Cd bioaccessibility were observed after the steaming process, while the frying process strongly decreased bioaccessibility in both phases. The estimation of metal bioaccessibility in vegetables is helpful for human health risk assessment.