Spatial distribution of potentially toxic elements in urban soils of Abbottabad city, (N Pakistan): Evaluation for potential risk

Investigation of heavy metals uptake in root-shoot of native plant species adjoining wastewater channels

Metal pollution in water, soil, and vegetation is an emerging environmental issue. Therefore, this study investigated the abundance of heavy metals (HMs) within roots and shoots of native plant species i.e., Bromus pectinatus, Cynodon dactylon, Poa annua, Euphorbia heliscopa, Anagallis arvensis, and Stellaria media grown in the adjoining area of municipal wastewater channels of a Pakistani city of Abbottabad. HMs concentrations (mg L-1) in municipal wastewater were: chromium (Cr) (0.55) > nickel (Ni) (0.09) > lead (Pb) (0.07) > cadmium (Cd) (0.03). Accumulation of HMs in both roots and shoots of plant species varied as B. pectinatus > C. dactylon > P. annua > E. heliscopa > A. arvensis > S. media. Irrespective of the plant species, roots exhibited higher concentrations of HMs than shoots. Higher amount of Cr (131.70 mg kg-1) was detected in the roots of B. pectinatus and the lowest amount (81 mg kg-1) in A. arvensis, Highest Cd concentration was found in the shoot of B. pectinatus and the lowest in the E. heliscopa. The highest concentration of Ni was found in the roots of S. media (37.40 mg kg-1) and the shoot of C. dactylon (15.70 mg kg-1) whereas the lowest Ni concentration was achieved in the roots of A. arvensis (12.10 mg kg-1) and the shoot of E. heliscopa (5.90 mg kg-1). The concentration of HMs in individual plant species was less than 1000 mg kg-1. Considering the higher values (> 1) of biological concentration factor (BCF), biological accumulation co-efficient (BAC), and translocation factor (TF), B. pectinatus and S. media species showed greater potential for HMs accumulation than other species. Therefore, these plants might be helpful for the remediation of HM-contaminated soil.

Ethnobotanical, ecological and health risk assessment of some selected wild medicinal plants collected along mafic and Ultra Mafic rocks of Northwest Pakistan

The current study investigated wild plant resources and health risk assessment along with northern Pakistan's mafic and ultramafic regions. Ethnobotanical data was collected through field visits and semi-structured questionnaire surveys conducted from local inhabitants and healers. Six potentially toxic elements (PTEs) such as lead (Pb), cadmium (Cd), nickel (Ni), chromium (Cr), manganese (Mn), and zinc (Zn) were extracted with acids and analyzed using atomic absorption spectrophotometer (AAS, Perkin Elmer-7000) in nine selected wild medicinal plants. Contamination factor (CF), pollution load index (PLI), estimated daily intake (EDI), target hazard quotient (THQ), and hazard index (HI) were used to determine the health risk assessment of the studied medicinal plants. The results showed that the selected medicinal plants were used for the treatments of cough, joint swelling, cardiovascular disorders, toothaches, diabetes, and skin pimples by the local inhabitants due to their low-cost and easy accessibility. The concentrations of Pb (3.4-53 mg kg-1), Cd (0.03-0.39 mg kg-1), Ni (17.5-82 mg kg-1), Cr (29-315 mg kg-1), Mn (20-142 mg kg-1), and Zn (7.4-64 mg kg-1) in the studied medicinal plants were found above the safe limits (except Zn) set by WHO/FAO/USEPA (1984/2010). The Pb contamination factor was significantly (p < 0.05) higher in A. modesta (7.84) and D. viscosa (6.81), and Cd contamination factor was significantly higher in C. officinalis (26.67), followed by A. modesta (8.0) mg kg-1. Based on PTE concentrations, the studied plants are considered not suitable for human consumption purposes. Pollution load index values for A. modesta, A. barbadensis, A. caudatus, A. indica, C. procera (2.93), D. viscosa (2.79), and C. officinalis (2.83), R. hastatus (3.12), and Z. armatum were observed as 1.00, 2.80, 2.29, 2.29, 2.93, 2.79, 2.83, 3.12 and 2.19, respectively. Hazard index values were in order of R. hastatus (1.32 × 10-1) ˃ C. procera (1.21 × 10-1) ˃ D. viscosa (1.10 × 10-1) ˃ A. caudatus (9.11 × 10-2) ˃ A. barbadensis (8.66 × 10-2) ˃ Z. armatum (7.99 × 10-2) ˃ A. indica (6.87 × 10-2) ˃ A. modesta (5.6 × 10-2) ˃ C. officinalis (5.42 × 10-2). The health risk index values suggested that consumption of these plants individually or in combination would cause severe health problems in the consumers. Pearson's correlation results showed a significant correlation (p ≤ 0.001) between Zn and Mn in the studied medicinal plants. The current study suggests that wild medicinal plants should be adequately addressed for PTEs and other carcinogenic pollutants before their uses in the study area. Open dumping of mining waste should be banned and eco-friendly technology like organic amendments application should be used to mitigate PTEs in the study area.

A 20-year shift in China's sewage sludge heavy metals and its feasibility of nutrient recovery in land use

Recycling resources from wastewater is even more important for developing a more sustainable society. Disposing sewage sludge, which accumulates most pollutants and resources in sewage, is the main challenge in wastewater pollution control and resource utilization. Heavy metals (HMs) are the greatest constraint limiting the application of sewage sludge to land as a sustainable use of this material. We conducted a meta-analysis of the concentrations of HMs in Chinese sewage sludge by combining data from studies published from 2000 to 2019 (N = 8477). Over this period, the reported concentrations of HMs in sewage sludge declined in three stages (a fluctuating stage, a slight decrease stage, and a rapid and stable decrease stage). The results revealed that economic development and environmental policy implementation were the main factors mitigating HM pollution in sewage sludge in China. Moreover, if environmental regulations were strengthened and HM pollution-mitigation strategies were made consistent, such that the proportion of sewage sludge applied to land in China could be increased from 18.6% to 48.0% (the proportion applied to land in the United States), the ecosystem services analysis showed that huge ecological-economic benefits could be realized (3.1 billion Chinese Yuan) and the use of fertilizers could be substantially reduced (the use of nitrogen fertilizers by 8.5% and the use of phosphate fertilizers by 18.1%). This review shows that China should formulate a unified policy and interdepartmental committee for sustainable application of sewage sludge to land and wastewater resource recycling management.

Characterization of soil trace metal pollution, source identification, and health risk assessment in the middle reaches of the Guihe River Basin

The natural environment, as well as human production and survival, is intrinsically dependent on soil. This study comprehensively assessed the pollution status, health risks, and sources of trace metals in the middle reaches of the River Gui Basin (MRGB) utilizing the geoaccumulation index, potential ecological risk index (PERI), and human health risk evaluation method. The findings of this study provide the following key insights: (1) only Cu and Pb levels in the MRGB soils did not exceed the background values established for soils in Weifang City (WFC). (2) The geoaccumulation status in most areas of the MRGB ranged from non-polluted to mildly polluted, with the overall ecological risk classification ranging from mild to moderate. (3) The cumulative non-carcinogenic risk for humans in the MRGB remained within acceptable limits, whereas the carcinogenic risk indices fell within tolerable levels. Oral ingestion emerged as the primary exposure pathway for both non-carcinogenic and carcinogenic health risks. (4) Cu, Zn, Ni, and Cr concentrations in MRGB soils primarily stemmed from natural sources associated with parent rocks, with Zn exhibiting additional influence from anthropogenic factors. In contrast, Pb, Cd, Hg, and As concentrations were predominantly driven by anthropogenic sources. Although the soils in the MRGB typically exhibited mild-to-moderate contamination levels, the contamination levels of Hg and Cd were notably more severe. As and Cr were significant health hazards. Most soil contamination sources are attributed to anthropogenic factors, warranting heightened attention from the relevant authorities.

Metals stress on soil enzyme activities and herbs defense in the vicinity of high traffic roadways

This study has investigated the impact of vehicle sourced heavy metals (HMs) on soil enzyme activities and plants in and around high traffic roadways near the metropolitan area. In detail, the defense response against HM pollution was studied by considering the commonly available herbs around the roadside area namely Alternanthera paronychioides, Ageratum conyzoides, Spilanthes acmella, and Parthenium hysterophorus. The study reported that the HM concentrations such as Cu, Ni, Zn, Mn, and Cr were observed in the range of 6.05 ± 0.1 to 309 ± 0.5 mg/kg in roadside soil and 5.2 ± 0.1to 451 ± 4.2 mg/kg in the herbs collected from roadside area. The soil enzyme (urease, dehydrogenase, amylase, catalase, peroxidase, and polyphenol oxidase) activities decreased by 22.56 to 77.84% in roadside soil and lower IC50 values were observed for DPPH (2.32-4.67) and H2O2 (1.59-2.15) free radical scavenging activities in plants collected from roadside area. The flavonoid and phenolic content in plants collected from the roadside area ranges from 12.65 ± 0.2 to 15.75 ± 0.3 mg quercitin/g and 0.61 ± 0.04 to 1.16 ± 0.1 mg gallic acid/g respectively while in plant collected from the control areas ranges from 7.96 ± 0.1 to 11.24 ± 0.05 and 0.47 ± 0.01 to 0.61 ± 0.1. In addition, the contamination factor (CF) (1.53-11.92) and geo-accumulation index (Igeo) (0.031-2.99) in soil and bioaccumulation factor (BAF) (0.72-2.73) of Cu, Ni, Zn, Mn, and Crin plants indicated that the soil and plants growing along the highway were heavily contaminated with HM. Finally, Pearson correlation matrix confirmed the inhibition effect of HM on soil enzymatic activities and enzymatic defense of plants in response to the HM stress.

Heavy metal(loid)s contaminations in soils of Pakistan: a review for the evaluation of human and ecological risks assessment and spatial distribution

Heavy metal(loid)s (HM) contaminations in the soil poses threats to the human and ecological community due to their bioaccumulation, toxicity, and persistent nature in the ecosystem. This review was designed to know about the HM contamination in soils, ecological risk, distribution, and potential health risks. Soil HM concentrations published in the last 30 years were collected from Springer, Science Direct, Willey, Mendeley, ResearchGate, Google Scholar, etc. HM concentrations were used for the geo-accumulation index (Igeo), contamination factor, as well as integrated indices such as spatial distribution of ecological risk index. Similarly, the Igeo pattern was observed in Sindh > Baluchistan > Punjab > Khyber Pakhtunkhwa > Gilgit-Baltistan > Islamabad. Moreover, the high ecological risk mean values ranged (160 < ERI < 320) due to cadmium (Cd) was exhibited in the Punjab and Khyber Pakhtunkhwa provinces and Islamabad. Non-carcinogenic risk like hazard quotient was found higher for children (1.59) of Punjab due to arsenic (As) ingestion, whereas the lower risk was observed due to Zn (2.5E-08) for adults of Punjab province via inhalation pathway. Similarly, the health index (HI) from exposure to As (1.61) in soil was higher than the rest of the HM. Moreover, cancerous risk was determined and found in the tolerable range (10^-4-10^-6). This study recommended that HM contaminants in the soil need to be monitored on regular basis, especially in Baluchistan, Gilgit-Baltistan, and Sindh provinces.

Quantitative Source Apportionment of Potentially Toxic Elements in Baoshan Soils Employing Combined Receptor Models

Arable soils are crucial for national development and food security; therefore, contamination of agricultural soils from potentially toxic elements (PTEs) is a global concern. In this study, we collected 152 soil samples for evaluation. Considering the contamination factors and using the cumulative index and geostatistical methods, we investigated the contamination levels of PTEs in Baoshan City, China. Using principal component analysis, absolute principal component score-multivariate linear regression, positive matrix factorization, and UNMIX, we analyzed the sources and quantitatively estimated their contributions. The average Cd, As, Pb, Cu, and Zn concentrations were 0.28, 31.42, 47.59, 100.46, and 12.36 mg/kg, respectively. The Cd, Cu, and Zn concentrations exceeded the corresponding background values for Yunnan Province. The combined receptor models showed that natural and agricultural sources contributed primarily to Cd and Cu and As and Pb inputs, accounting for 35.23 and 7.67% pollution, respectively. Industrial and traffic sources contributed primarily to Pb and Zn inputs (47.12%). Anthropogenic activities and natural causes accounted for 64.76 and 35.23% of soil pollution, respectively. Industrial and traffic sources contributed 47.12% to pollution from anthropogenic activities. Accordingly, the control of industrial PTE pollution emissions should be strengthened, and awareness should be raised to protect arable land around roads.

Lead exposure in childhood and historical land use: a geostatistical analysis of soil lead concentrations in South Philadelphia parks

Elevated soil lead (Pb) concentrations in public parks and outdoor spaces continue to have a significant impact on the public health of urban communities. This study evaluated the geospatial and statistical relationships between soil Pb concentrations, the urban environment, and child blood lead levels (BLLs) in the neighborhood of South Philadelphia, PA. Soil samples (n = 240) were collected from forty (40) public parks and analyzed for Pb using a field portable X-ray fluorescence (XRF) analyzer. Geospatial mapping was used to investigate historical land use of each park, vehicular traffic on adjacent roadways, and density of residential/commercial development. Predicted child BLLs and BLL "high-risk areas" were identified using interpolation and biokinetic modeling. Childhood BLL data for South Philadelphia (n = 10,379) was provided by the Philadelphia Department of Public Health (2013-2015). Of the two hundred forty (240) soil samples collected, Pb levels for 10.8% of samples were ≥ 400 ppm. Two hundred sixty-nine of 10,379 children screened were identified with BLLs ≥ 5 µg/dL. Historical land use of each park was shown to be significantly correlated (p = 0.01) with soil Pb concentrations and child BLLs ≥ 5 µg/dL. Approximately 13.3% of the variance in child BLLs ≥ 5 µg/dL was attributed to historical site land use. Overall, undeveloped/greenspace historical land use exhibited the highest soil Pb concentrations in the study. Geospatial relationships were identified between census tracts with higher percentages of children with BLLs ≥ 5 µg/dL and interpolated BLL "high-risk" areas (≥ 3.5 µg/dL). The results of this study suggest soil accumulation time and historical land use may influence soil Pb concentrations and child BLLs in urban communities. Measured soil Pb concentrations were determined to effectively model community-wide contamination and childhood Pb exposure.

Multi-geostatistical analyses of the spatial distribution and source apportionment of potentially toxic elements in urban children's park soils in Pakistan: A risk assessment study

In the past few decades, contamination of urban children's parks (UCPs) with potentially toxic elements (PTEs) has been attracting more and more interest; however, assessment of eco-environmental and child exposure risks particularly in developing countries remains limited. The current study investigated PTE (Cr, Ni, Zn, As, Cd, and Pb) concentrations, potential sources, and their health risk assessment in UCP soils of 12 major cities in Pakistan. The results showed that the mean concentration of Ni exceeded the SEPA-permissible limit in all UCP sites, while other PTEs were found to be within acceptable limits. The soil properties such as pH, electrical conductivity, organic matter, and soil particles size were determined in UCPs soils. The contamination factor and pollution load index results indicated low to moderate pollution levels (CF < 3) and (PLI<1) for all PTEs except Ni in some of the selected cities. Quantile-quantile (Q-Q) plotting determined the normal distribution line for all PTEs in the UCPs. Principal component analysis showed the mixed sources of contamination from industrial emissions, fossil fuel combustion, vehicular emissions, wastewater irrigation, as well as solid waste disposal and natural sources of soil parent materials in all park sites. ANOVA results showed that all the PTEs except Cd had moderate to higher contamination values than the reference site. The risk assessment study revealed that children had high exposure to the selected PTEs via all exposure pathways. The hazard index (HI) mean value (1.82E+00) of Ni for all exposure pathways was greater than 1, while total risk value of Cr (1.00E-03) had exceeded USEPA limit, indicating cancer risk. Consequently, the study of UCPs soils revealed PTEs contamination that could pose a potential health risk to the local population in the studied UCPs regions of Pakistan. Thus, the present study recommends that the influx of PTEs originating from natural and anthropogenic sources should be mitigated and government should implement strict enforcement of environmental regulations and proper management, as well as air quality monitoring guidelines for public health should be strictly adopted to reduce traffic- and industrial emission-related to PTEs in metropolitan areas.

Technologies for the cobalt-contaminated soil remediation: A review

The cobalt-contaminated soil has exposed potential toxicity to humans, plants, and animals. Industrial activities like ore smelting, alloy manufacture, and electric and electronic devices production have induced the increased cobalt content in soil resulting in higher ecosystem risk in diverse environmental media. However, knowledge gaps in cobalt transfer in soil and the limited understanding of remediation techniques make it challenging to estimate their potential application scenarios. Thus, keeping in view the above facts, this paper summarizes the natural and anthropogenic sources arousing the increase of cobalt in soil and reviews the cobalt species in soil and factors that influence the mobilization of cobalt. Moreover, the status of the remediation technologies is critically evaluated, including phytoremediation, immobilization, and separation technologies (soil washing and electroremediation) with a focus on the application and mechanism of phytoremediation and immobilization. Based on the actual application, further improvements and prospects of all techniques are proposed. This comprehensive review might serve to guide technique selection and inspire more scientific exploration on the remediation of cobalt-contaminated soil.

Assessment of Contents and Health Impacts of Four Metals in Chongming Asparagus-Geographical and Seasonal Aspects

In this paper, the contents of four typical metals (Pb, Cd, Hg, and As) in asparagus, water, and soil from Chongming Island were quantitatively determined by inductively coupled plasma mass spectrometry (ICP-MS). The contents of these metals in asparagus showed a common rule of Pb > As > Cd > Hg in different harvest seasons and regions. Significant seasonal differences were found in the contents by difference analysis, but no obvious regional differences were observed. Furthermore, the asparagus did not accumulate these four metals from the soil in Chongming Island by the assessment of bio-concentration factor. The asparagus was proved safe by the analysis of single-factor pollution index and Nemerow pollution index. Through combining the analysis of the above indexes and the geological accumulation index, we found that 51.62% of soil samples were mildly polluted by cadmium. The results of health risk analysis showed that the risk value of children was higher than that of adults under oral exposure, but the four metals in asparagus possessed no obvious risk to health. The above assessments illustrate that the daily consumption of asparagus in Chongming Island will not cause potential health impacts. It is of benefit to ensure the quality and economic interests of asparagus planting in Chongming Island through the investigation of this study.

An in-depth human health risk assessment of potentially toxic elements in highly polluted riverine soils, Příbram (Czech Republic)

Environmental pollution by potentially toxic element (PTE) and the associated health risks in humans are increasingly becoming a global challenge. The current study is an in-depth assessment of PTEs including the often studied lead (Pb), manganese (Mn), zinc (Zn), arsenic (As) and the less-studied titanium (Ti), rubidium (Rb), strontium (Sr), zirconium (Zr), barium (Ba) and thorium (Th) in highly polluted floodplain topsoil samples from the Litavka River, Czech Republic. Soil chemical properties including carbon (C_ox) and reaction (pH_H₂O) together with iron (Fe) were assessed in the same soils. A portable X-ray fluorescence spectrometer (p-XRFS) (Delta Premium) was used to measure the PTEs and Fe contents of the soils. Soil organic carbon and reaction pH were determined following routine laboratory procedures. The concentration level of each PTE was compared against world average and crustal values, with the majority of elements exceeding the aforementioned geochemical background levels. Distributions of the PTEs were mapped. Two pollution assessment indices including enrichment factor (EF) and pollution index (PI) levels were calculated and their means for Zn (43.36, 55.54), As (33.23, 43.59) and Pb (81.08, 103.21) show that these elements were enriched. Zn, As and Pb accounted for the high pollution load index (PLI) levels observed in the study. The EF and PI distribution maps corresponded with the concentration distribution maps for each PTE. On health risk assessment, hazard quotients (HQ) in different human groups varied. Children had the highest HQs for all PTEs than adults (women and men). PTEs with high HQ levels in distinct human groups were As, Zr and Pb. Zirconium is a less likely element to pose a health risk in humans. Nonetheless, it should be kept in check despite its low pollution occurrence.

Heavy Metals in Soil and Sand from Playgrounds of Çanakkale City (Turkey), and Related Health Risks for Children

Children spend most of their time in playgrounds and, in parallel, constitute the social group most sensitive to contaminants. Here, we present the results of a comparative study of heavy-metal contents between soils and sand from sandboxes obtained from playgrounds of Çanakkale city. Average contents of soils followed the order of iron (Fe) (12,901 mg kg−1) > manganese (Mn) (475 mg kg−1) > zinc (Zn) (58 mg kg−1) > copper (Cu) (28 mg kg−1) > nickel (Ni), chromium (Cr) (21 mg kg−1) > lead (Pb) (18 mg kg−1). Sand had lower contents, however, due to the reduction of particles size through prolonged use, and accumulation of Fe/Mn (oxyhydr)oxides on sand grains tended to diminish the differences between soils and sand. Through chemometric analysis, Cr and Ni were found to have a lithogenic origin, while the rest of metals were related to anthropogenic activities. Spatially, heavy-metal contents followed the pattern of the city’s sprawl. Risk estimates on children’s health showed that ingestion was the most important exposure route, followed by dermal contact and inhalation. Exposure of children to sand was of similar importance to that of soils. These findings are significant, as the contamination of sand has not yet received much attention compared to the soil of playgrounds.

Adsorption of Cadmium by Brassica juncea (L.) Czern. and Brassica pekinensis (Lour.) Rupr in Pot Experiment

Heavy metal pollution in farmland threatens human life. It is not clear whether crops can adsorb heavy metals. In this study, the cadmium accumulation and tolerance in Chinese cabbage Brassica pekinensis (cv. Xiaoza-56) and the known Cd-accumulator Brassica juncea in hydroponics and pot experiment were investigated. Furthermore, we evaluated their potential on the phytoextraction of Cd-contaminated soil. The hydroponics with 1–50 μM Cd concentrations showed that both B. juncea and B. pekinensis had high Cd accumulation and tolerance with translocation factor closed to 1 at Cd levels < 25 μM. The pot study conducted with 5 to 100 mg Cd kg−1 soil indicated that B. juncea showed less tolerance and accumulation to Cd than B. pekinensis, especially at higher Cd levels. The bioconcentration factor was much higher than 1 in both B. juncea and B. pekinensis grown in <40 mg Cd kg−1 soil without showing biomass reduction. In the model evaluation, the ability of B. juncea and B. pekinensis to reduce the initial soil Cd concentration of 20 and 5 mg kg−1 to specific targets with a lower or higher biomass of 4 or 20 t ha−1, respectively. The above results indicate that B. juncea and B. pekinensis (cv. Xiaoza-56), which the latter is a better candidate for Cd phytoextraction in moderated Cd-contaminated soil. The results provide a reference for Cd pollution control.

Identification of Metal Contamination Sources and Evaluation of the Anthropogenic Effects in Soils near Traffic-Related Facilities

Traffic-related facilities typically have much lower metal emissions than other sources; however, they can be numerous and widespread as well. Subdividing pollution sources is necessary to assess soil contamination characteristics and identify sources according to the contamination cause. Anthropogenic contamination by metals was quantitatively determined using contamination factor (Cf) and evaluated using multivariate analysis. More than half of the concentrations for Zn, Pb, and Cu in soils were higher than that in the natural background (NB). Cf of metals was, in decreasing order, Zn > Pb = Cu > Ni = As. Zn, Pb, and Cu were identified as anthropogenic contaminants in correlation analysis. Principal component analysis showed that the two main contamination causes were coarse particles from the maintenance or crushing activities of vehicles and nonexhaust/exhaust emissions. Clusters were classified according to those two anthropogenic and lithogenic causes and included Group I (Zn, Pb, and Cu in garages, auto repair shops, and auto salvage yards), Group II (Zn, Pb, and Cu in parking lots, driving schools, and roadsides), and Group III (As and Ni with high lithogenic properties). Anthropogenic input and sources of soil contamination by metals in traffic-related facilities were appropriately estimated through the combination of Cf and multivariate analysis.

Probabilistic-fuzzy risk assessment and source analysis of heavy metals in soil considering uncertainty: A case study of Jinling Reservoir in China

Considering the uncertainty caused by the random error of the sample measurement, the heterogeneity of spatial and temporal distribution of pollutants, and the traditional method of selecting a single parameter for evaluation, based on fuzzy theory, Hakanson potential ecological risk index (considering heavy metal enrichment, ecotoxicity and bioavailability) and United States Environmental Protection Agency health risk assessment system, the fuzzy ecological risk and health risk assessment methods for of heavy metals in soil were established. In the soil of the Jinling Reservoir area, Cd, which has high bioavailability, had the highest average contribution rate to RI, and thus was, regarded as a priority metal for ecological risk. Sites JL9 and JL11 were the priority areas. The heavy metals did not pose a clear hazard to human health, but children had a higher health risk. Pb and As were regarded as the priority metals for health risk. Fuzzy evaluation provided the risk interval and membership degree, contained more parameter information, quantified and reduced the uncertainty of parameters, provided more comprehensive results, and compensated for the deficiency of deterministic evaluation. As the main source of heavy metals, the intensity of agricultural activities in the study area must be controlled to avoid excessive input and accumulation of heavy metals, which may damage the ecological environment and endanger human health.

Geochemical fractionation and spectroscopic fingerprinting for evaluation of the environmental transformation of potentially toxic metal(oid)s in surface-subsurface soils

The contamination of soil by toxic metal(oid)s has emerged as a major concern worldwide, particularly in developing countries. A metals behavior in the soil environment is influenced by organic matter, mineral phases, and oxidation states in which a particular metal exists. However, the spectroscopic evidence of metal(oid)s interactions in soil with organic matter and mineral phases can induce an extensive understanding. The surface and sub-surface soils (0-50 cm) from four sites of upper Indus basin, Pakistan, were collected and analyzed by using FTIR (Fourier-transform infrared spectroscopy), XRD (X-ray diffraction) and XPS (X-ray photoelectron spectroscopy) in addition to ICP-MS (inductively coupled plasma mass spectrometry) and geochemical fractionation. Geochemical fractionation of metal(oid)s indicated that As, Cu, Ni, Pb, and Zn were mostly found in the potentially bioavailable fractions. However, an increase in the residual fraction was observed from top to bottom. The absorption bands of FTIR spectra were divided into three spectral regions 700-400, 1700-800, and 3700-2800 cm^-1. The soil was found rich in organic matter and capable of retaining metals as abundant peaks were observed in the mid-infrared region. The mineralogical analysis of soil samples testified silicon oxides and zeolite as major mineral phases. The XPS spectra showed broad peaks of As(III), As₂O₃, As₄S₄, PbO₂, and PbCo₃. The study concludes that the source identification of metal(oid)s in the upper Indus is crucial to find out the particular source of contamination in the soil.

Chemical Fractionation, Environmental, and Human Health Risk Assessment of Potentially Toxic Elements in Soil of Industrialised Urban Areas in Serbia

The primary focus of this research was the chemical fractionation of potentially toxic elements (PTEs) and their presence in several industrialised cities in Serbia. Furthermore, their origin, contamination levels, and environmental and human health risks were assessed. The results indicated that the examined soils were characterised by slightly higher Cu, Ni, Pb, and Zn levels than those set by European and national regulations. These elevated Cu, Pb, and Zn concentrations were caused by intensive traffic and proximity to industry, whereas the higher Ni levels were a result of the specific geological substrate of the soil in the study area. The environmental risk was found to be low and there was no enrichment/contamination of the soil with these elements, except in the case of Pb, for which moderate to significant enrichment was found. Lead also poses a potential non-carcinogenic risk to children through ingestion and requires special attention due to the fact that a significant proportion of this element was present in the tested soil samples in a potentially available form. Analysis of the health risks showed that children are more at risk than adults from contaminants and that ingestion is the riskiest exposure route. The carcinogenic risk was within the acceptable limits.

Lead Pollution, Demographics, and Environmental Health Risks: The Case of Philadelphia, USA

Lead (Pb) soil contamination in urban environments represents a considerable health risk for exposed populations, which often include environmental justice communities. In Philadelphia, Pennsylvania (PA), Pb pollution is a major concern primarily due to extensive historical Pb-smelting/processing activity and legacy use of Pb-based paints and leaded gasoline. The U.S. Environmental Protection Agency (USEPA) organized and/or compiled community-driven soil sampling campaigns to investigate Pb content in surface soils across Philadelphia. Using these data (n = 1277), combined with our own dataset (n = 1388), we explored the spatial distribution of Pb content in soils across the city using ArcGIS. While assessing Zone Improvement Plan (ZIP)-code level data, we found strong correlations between factors, such as the percentage of children with elevated blood lead levels (% EBLL) and % minority population as well as between % EBLL and % children in poverty. We developed a “Lead Index” that took demographics, median measured Pb-in-soil content, and % EBLLs into account to identify ZIP codes in need of further assessment. Our results will be used to help lower the Pb-exposure risk for vulnerable children living in disproportionately burdened communities.

The Optimization Strategy of the Existing Urban Green Space Soil Monitoring System in Shanghai, China

High concentrations of potentially toxic elements (PTE) create global environmental stress due to the crucial threat of their impacts on the environment and human health. Therefore, determining the concentration levels of PTE and improving their prediction accuracy by sampling optimization strategy is necessary for making sustainable environmental decisions. The concentrations of five PTEs (Pb, Cd, Cr, Cu, and Zn) were compared with reference values for Shanghai and China. The prediction of PTE in soil was undertaken using a geostatistical and spatial simulated annealing algorithm. Compared to Shanghai’s background values, the five PTE mean concentrations are much higher, except for Cd and Cr. However, all measured values exceeded the reference values for China. Pb, Cu, and Zn levels were 1.45, 1.20, and 1.56 times the background value of Shanghai, respectively, and 1.57, 1.66, 1.91 times the background values in China, respectively. The optimization approach resulted in an increased prediction accuracy (22.4% higher) for non-sampled locations compared to the initial sampling design. The higher concentration of PTE compared to background values indicates a soil pollution issue in the study area. The optimization approach allows a soil pollution map to be generated without deleting or adding additional monitoring points. This approach is also crucial for filling the sampling strategy gap.

Potentially toxic elements' occurrence and risk assessment through water and soil of Chitral urban environment, Pakistan: a case study

This study investigated the concentrations of potentially toxic elements (PTE) including copper (Cu), chromium (Cr), cobalt (Co), cadmium (Cd), nickel (Ni), iron (Fe), zinc (Zn), lead (Pb), molybdenum (Mo) and manganese (Mn) in water and soil of the Chitral city, Pakistan. For this purpose, water (n = 66) and soil (n = 48) samples were collected from various locations of the Chitral city and analyzed for the PTE concentrations. Determined PTE concentrations were evaluated for the human and ecological potential risk. Results revealed that hazard quotient through water consumption was less than the threshold limit (1). However, for soil, the Fe mean hazard index (HI > 1) value for children only surpassed the threshold limits. The mean cancer risk index values via soil exposure were higher (RI > 1 × 10^-4) through consumption of Co, Ni and Cd for children and only Co for adults. Contamination factor (CF) values for Mo, Cd and Fe were found very high, considerable and moderate for 79%, 8% and 77% of sampling sites, respectively. Geoaccumulation index (I_geo) showed that soils were moderately-heavily polluted due to Mo. Potential ecological risk index (PERI) values exhibited considerable risk with an average risk index value in the range 190 < RI < 380. Higher values of CF, I_geo and PERI revealed the presence of pollution and pose risk to ecological environment.