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Heavy metals pose significant threats to human health, particularly children. This study aimed to assess heavy metal pollution in children's playgrounds using surface dust as an indicator and to ascertain the associated exposure levels and health risks. A total of one hundred twenty dust samples were collected from the surface of playground toys in areas surrounding the cement factory in Bursa, Türkiye, on precipitation-free days. The heavy metal content of the samples was analyzed using ICP-MS. The average total concentration of heavy metals ranged from 2401 to 6832 mg/kg across the sampling sites, with the highest values observed at PG4, PG3, PG2, and PG1, respectively. The most commonly detected heavy metals in the samples included Cr, Mn, Fe, Co, Cu, Zn, Pb, Cd, As, and Ni. Statistical analysis revealed significant positive correlations (p < 0.01) among Cr, Mn, Fe, Co, Cu, Pb, As, and Ni, with Cu and Pb also showing correlation (p < 0.05). PCA analysis identified three principal components explaining 79.905% of the total variance. The Hazard Quotient (HQ) and Hazard Index values for heavy metals were found to be below the safe threshold (HQ < 1). Quantitative techniques such as the geoaccumulation index and enrichment factor are used to determine pollution levels at the sampling sites. Overall, the results indicate that cement factories significantly contribute to heavy metal pollution, with observed values varying based on proximity to the emission source., (© 2024. The Author(s).)

This research aimed to determine and evaluate the concentrations of As, Cu, Hg, Ni, and Pb, and the physicochemical properties of 48 agricultural soil samples, to identify potential ecological risks and their sources associated with heavy metals contamination in Usak, western Türkiye. Various methods were used to assess ecological risks, including geoaccumulation index (I geo ), enrichment factor (EF), degree of contamination (C deg ), potential ecological risk (RI), and pollution load index (PLI). The heavy metals concentrations ranged from 4 to 61 mg/kg for As, 8-48 mg/kg for Cu, 0.01-0.06 mg/kg for Hg, 30-813 mg/kg for Ni, and 4-30 mg/kg for Pb. The mean As and Ni concentrations were much greater than Earth's crustal average, the world's mean values, and mean values from many other emerging countries. Igeo and EF values for As, Ni, and Pb indicate various degrees of contamination. C deg values show that 96% of the study area is affected to some degree by contamination. For RI values, 38% indicate ecological risks ranging from moderate to considerable degrees. PLI values show that 75% of the agricultural soils are moderately polluted. Spatial distribution maps of C deg , RI, and PLI show that the northeastern and southwestern parts of the study area have been polluted to different levels by As, Ni, and Pb. Industrial activities and excessive use of fertilizers, pesticides, fungicides, and herbicides were identified as major sources of heavy metals contamination in the agricultural soils of Uşak., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

The works of literature evaluating the eco-environmental risks posed by metals in agricultural areas in developing countries remains limited. This study sought to evaluate the environmental and ecological risks posed by metals in the intensively cultivated areas of the Amik Plain as well as to determine the origins of the metals. For this purpose, 137 soil samples were taken from agricultural production areas of the Amik Plain, and 11 metals (Al, Fe, Ni, Pb, Co, Cr, Cu, Mn, Zn, Cd and As) were examined in the samples. As Ni had the highest average enrichment factor (EF) value (8.04) when compared with the other metals, the soils were found to be significantly enriched with Ni. The Pearson correlation analysis and principal component analysis showed that the Zn concentration was controlled by lithogenic sources, while the Ni, Pb, Cd, Cr and Cu concentrations were controlled by both anthropogenic and lithogenic sources.

Soil contamination by anthropogenic heavy metals has become a global issue. This study aimed to investigate cadmium (Cd) concentration, mobility, and contamination indices of Cd in soils in the Hamadan province, west of Iran. To investigate the concentration of Cd in soil, one hundred soil samples from wheat farms and five samples from control lands were collected. Pollution indexes, including Cd mobility, enrichment factor, geoaccumulation index, contamination index, and availability ratio, were investigated. The structural equation model was also used to evaluate effective parameters on cadmium durability in soil. Results showed that mean values of available phosphorus (P) were 83.65, 129, and 65 (mg kg -1 ) in three land-use types rainfed, irrigated, and controlled, respectively. The mean values of Cd in different land-use types of rainfed, irrigated, and controlled were 0.15, 0.18, and 0.08 (mg kg -1 ), respectively. The results indicated that the amount of Cd in both forms (available and total) in ones that received fertilizer, especially P fertilizers, was higher than in the controlled one. Other pollution indexes revealed that the study area had been slightly contaminated due to anthropogenic activities. Lime, clay, lead, and OM were identified as affective parameters on cadmium durability. Finally, the results demonstrated that the mobility rate was high. Cd had a higher potential mobility in soil samples in the rain-fed and irrigated land than in the controlled land, and Cd had a low retention time., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

This study examined the accumulation of potentially toxic elements (PTE) in oil palm (Elaeis guineensis) biomass, fruits, and soils. About 40 soil samples to a depth of 40 cm and 90 palm biomass samples from roots, leaves/stems, and fruits were collected from reclaimed tailings dam and control sites at two mining areas in southwestern Ghana. PTE concentrations and pollution indices were analyzed via various inferential statistics. The PTE (As, Fe, Zn, Mn, and Cu) concentrations in the palm roots were significantly higher (p < 0.001) than in the soil at Ghana Manganese Company (GMC) Ltd, Nsuta except for As which was significantly higher (p < 0.0001) in the fruits than the soil. Soil PTE concentration was however significantly higher (p < 0.0001) than that of the roots, leaves, and fruits at the Bogoso tailings dam. The contamination factors, enrichment factors, geoaccumulation indices, and pollution load index (PLI) of soils at the tailings dam and reclaimed sites were significantly higher than the control sites. The PLI of the reclaimed tailings and control sites at Bogoso were 17.98 ± 0.56 and 6.06 ± 0.58, respectively, implying the soils at Bogoso are severely polluted with As, Fe, Zn, and Mn while those of the GMC are unpolluted. Bioaccumulation factors were significantly higher in roots than in the leaves and fruits (p < 0.0001) and were greater than 2 at GMC. The translocation of Cu and As to the fruits was significantly high on both study locations with TF of As = 9 at GMC. PTE accumulation in the palm biomass reduced soil PTE concentrations, but the soils on these mined spoils were severely polluted. These high As contents, in the fruits, may contaminate the food chain and increase PTE-related health risks among human populations. Therefore, phytoremediation of mine spoils with oil palm should be done with caution. Experimental studies to examine soil amendment effects on PTE accumulation capacity or removal efficacy by the palm plants at various ages are recommended., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The concentrations of heavy metals in soft sediments of the Manavgat and Lara regions in Antalya, Türkiye were investigated to assess contamination levels and their potential sources, followed by multivariate statistical analysis and generation of spatial distribution maps. Results showed low contamination levels for As, Zn, and Cu, moderate contamination for Pb, Ni, and Mn, and very high accumulation for Co and Cr. Geoaccumulation index (Igeo) and contamination factor (CF) analyses revealed moderate enrichment for Mn and low enrichment for As, indicating no human-induced contamination in Cu, Pb, Zn, Mn, and As, while Ni, Co, and Cr originated mainly from agriculture. The maximum modified degree of contamination (mCd) value was at an extreme high level, with an average mCd of 4.12 indicating high contamination. Maximum pollution load index (PLI) value was 3.13, indicating high-grade pollution and an average value of 1.7 indicating moderate pollution., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Urban surface deposited sediments (USDS) are unique indicators of local pollution that pose a potential threat to the living environment and human health. Ekaterinburg is a highly populated metropolitan area in Russia with rapid urbanization and industrialization activities. In Ekaterinburg's residential areas, about 35, 12, and 16 samples are represented by green zones, roads, driveways, and sidewalks, respectively. The total concentrations of heavy metals was detected using a chemical analyzer inductively coupled plasma mass spectrometry (ICP-MS). Zn, Sn, Sb, and Pb have the highest concentrations in the green zone, while V, Fe, Co, and Cu represent the utmost values on roads. Moreover, Mn and Ni are the prevailing metals in the fine sand fraction of driveways along with sidewalks. Broadly, the high pollution in the studied zones is generated by anthropogenic activities and traffic emissions. The potential ecological risk (RI) was observed in high risk (IR > 600), even though the results of all heavy metals reveal no adverse health effects from the considered noncarcinogenic metal for adults and children by different exposure pathways except the children's exposure to Co in case of the dermal contact, where the HI values of Co for children in the studied zones are higher than the proposed level (> 1). In all urban zones, the total carcinogenic risk (TLCR) values are predicted as a high potential inhalation exposure., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

Polymetallic ore processing plants are serious sources of heavy metal pollution. The present study examined the degree of pollution of surface soils with the metals zinc, cadmium, lead, and copper in the single-industry town of Kentau, Kazakhstan, where an enterprise for the processing of lead-zinc ore has been operating for a long time. This enterprise ceased operations in 1994, and this study may be of interest in terms of assessing the current ecological state of urban soils after a 27-year period of possible soil self-cleaning processes. The study showed that the surface soils of Kentau retain fairly high concentrations of metals. The maximum detected concentrations of zinc, cadmium, lead, and copper were 592 mg/kg, 1.651 mg/kg, 462 mg/kg, and 82.5 mg/kg, respectively. According to the classification of the geoaccumulation index, the soils of the town belong to pollution classes II, III, and IV with moderate and strong pollution. The calculated potential ecological risk factor indicates that cadmium poses a considerable potential ecological risk, while lead showed a moderate ecological risk. In general, according to the obtained values of potential ecological risk factors, metals can be arranged in the following order: Cd > Pb > Zn > Cu. In this study, a five-step sequential extraction procedure by the method of A. Tessier was used, and the mobility factors of metals were calculated. Based on the data obtained, it was found that cadmium and lead have the highest mobility and, consequently, availability for biota in modern conditions, which may pose a potential risk to public health in the town., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Potentially toxic elements (PTEs) pollution in lake sediments is a serious threat to the ecological safety of lake water and human health, owing to anthropogenic activities. Studies on the distribution of pollution, the differences in lake types, and the influencing factors in China as a whole are lacking. This study collected data on PTEs (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in Chinese lake sediments published from 2005 to 2021, and aimed to evaluate pollution levels and spatial distribution characteristics of PTEs in lake sediments, differences in pollution in different types of lakes, and influencing factors. The results showed that (1) All metals in the lake sediments accumulated to different degrees, when compared to the background values. (2) The lake type pollution levels were ranked: urban lakes > reservoirs > plateau lakes > natural lakes. (3) The geoaccumulation and potential ecological risk indexes both indicated that Cd and Hg are the main pollutants, and that the overall ecological risk level of lake sediments in China is high. (4) The degree of economic and population growth is highly correlated with the concentrations of eight PTEs; the amount of fertilizer and pesticide used in agricultural activities are the main factors affecting As and Hg; industrial activities and traffic pollution emissions are the predominant factors affecting Cu and Ni. (5) In the interaction detection analysis, the Cr content was mainly influenced by natural factors; Cd, Pb, and Zn contents were affected more by human activities. This study provides a reference for understanding the current status and influencing factors of PTE pollution in Chinese lakes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Variability in the distribution of natural total Sb and Cd in freshwater sediments leads to difficulties in background value (BV) determination. This study aimed to establish a method to determine BV more accurately by investigating the vertical distribution of Sb and Cd in sediment cores collected from a typical river in alluvial plain in China and revealed the factors that control the variation of Sb and Cd BV, which has not been studied in alluvial freshwater sediment. The results suggested that uncontaminated samples for BV calculation should be determined by statistical analysis as human and natural disturbance led to high variation in contamination depth, from <5 cm to >55 cm. The sequential chemical extraction method showed a considerable amount of non-residual fractions of Sb and Cd, which accounted for 48% and 43% of the total, respectively. Acid extractable Cd (16%) was associated to the limestone geology in the area. Fine particles which governed by sedimentary environment contained more natural Sb and Cd, as strong positive correlation was found between clay content and Sb concentration (r = 0.89, p < 0.01), as well as Cd concentration (r = 0.54, p < 0.01). Based on these findings, a method combined with standard deviation and geochemical method was established to calculate the BV of Sb and Cd, and counter maps were made to cover the variation of BV in the Taipu river sediment. The pollution level has been evaluated by the geoaccumulation index more accurately.

This work is aimed to assess potential risk associated with the presence of metals and metalloids in soil at "Playa Las Petroleras" sector, located in Antofagasta (Chile). The zone under study has been affected by four oil spill events. This sector is located in an urban area by the sea. So, it has a great social and environmental relevance. The concentrations of 15 elements in soil samples were assessed, four of them presenting potential ecological risk: As, Co, Cu, and Pb. Nine pollution indices were applied to data: four single pollution indices and five integrated pollution indices to assess soil pollution. The single pollution indices show that the site bears potential ecological and environmental risk due to the presence of Cu, the site being classified as highly contaminated owing to a severe enrichment of this metal. For Co, all the indices allow classifying the site as little or uncontaminated, while the level of As and Pb pollution could be considered as ranging from uncontaminated to moderately contaminated. The integrated pollution indices show that average concentrations are highly contaminated mainly owing to the presence of Cu., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Information on spatial distribution and potential sources of heavy metals in agricultural lands is very important for human health and food safety. In this study, pollution degree of lead (Pb), cadmium (Cd), and nickel (Ni) in Yüksekova Plain, located on the border in the southeastern part of Turkey, was evaluated by geoaccumulation index (Igeo), modified contamination factor (mCdeg), and Nemerow pollution index (PI Nemerow ) combined with spatial autocorrelation using deep learning algorithms. A total of 304 soil samples were collected from two different depths (0-20 and 20-40 cm) in the study area, which covered 17.5 thousand ha land. Covariates were determined for spatial distribution models of Pb, Cd, and Ni by factor analysis (FA). Spatial distribution models for surface soils were developed using pedovariables (silt, sand, clay lime, organic matter, electrical conductivity, pH, Ca, and Na) determined by the FA and Igeo and mCdeg values by artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) models. The estimation success of models for different depths was assessed by root mean square error (RMSE), mean absolute percent error (MAPE), and Taylor diagrams. The RMSE and MAPE values showed a strong correlation between heavy metal contents and the covariates. The RMSE values of ANN-Ni 0-20 , ANN-Ni 20-40 , ANN-Pb 0-20 , ANN-Cd 0-20 , and ANN-Cd 20-40 models (0.01240, 0.07257, 0.0039, 0.00045, 0.00044, and 0.04607, respectively) confirmed the success of the models. Likewise, the MAPE values between 0.2 and 8.5% indicated that all models were very good predictors. In addition, the Taylor diagrams showed that the estimation performance of ANFIS and ANN models are compatible. The Igeo Ni and Igeo Pb values in both models at both depths indicated that strongly to extremely polluted (4-5) areas are quite high in the study area, while the Igeo Cd values revealed that unpolluted areas are widespread. The mC deg index value showed a moderate to high contamination at the first depth, while very high contamination at the second depth in most of the study area. Spatial distribution of PI Nemerow revealed that moderate pollution (2-3) is common in both soil depths of the study area. The PI Nemerow of subsurface layer was between 0.91 and 1 (warning limit class) in a small part of the study area. The results showed that vertical mobility of heavy metals is closely related to pedovariables. In addition, the ANN and ANFIS models are capable of exhibiting the heterogeneity in the spatial distribution pattern of high variation in the data. Thus, the locations with extreme contamination have been accurately determined. The pollution indices calculated considering the commonly used international reference values revealed that heavy metal pollution in some part of the study area reached the detrimental levels for human health and food safety. The results suggested that the pollution indices were more successful than simple heavy metal concentrations in interpreting the pollution risk levels. High-resolution spatial information reported in this study can help policy makers and authorities to reduce heavy metal emissions of pollutants or, if possible, to eliminate the pollution., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The Peruvian Amazon plain has abundant natural resources and is home to great biodiversity, which makes it an area with high economic potential. However, the use of its resources through various activities has contributed to the release of heavy metals (HMs) into its soils, generating severe pollution problems which have mainly affected the health of local populations and their ecosystems. Currently, there are no comprehensive studies that have identified the specific sources of contamination by HMs in the soils of this part of the Peruvian territory. In this sense, this research aims to identify the possible sources of contamination by HMs in the soils of the Peruvian Amazon plain to focus efforts on the establishment of adequate measures for the protection of the health of people and the ecosystem. In the present study, samples of topsoils (0-20 cm depth) and subsoils (100-150 cm depth) were collected for the analysis of 11 HMs (Co, Cr, Cu, Fe, Mn, Ni, Pb, V, Zn, Be, and Hg) in 48 sites located in four regions of the Peruvian Amazon plain (Loreto, Amazonas, San Martín, and Ucayali), over the year 2019. The enrichment factor and geoaccumulation index were applied to assess contamination levels of HMs. The results indicated that topsoils and subsoils presented a greater enrichment by the elements Be and Pb, and were classified as moderately contaminated. Likewise, the integral analysis of these indexes together with principal component analysis, hierarchical cluster analysis, correlation analysis, and coefficient of variation allowed the identification of potential sources of contamination by HMs. As a result, Fe, Co, Zn, Ni, V, and Cr were associated with natural or lithogenic sources (parent material, crude oil deposits, and organic matter decomposition). Hg was attributed to anthropogenic sources (illegal gold mining, atmospheric deposition, and vehicle emissions). Be, Pb, Cu, and Mn originated from natural sources (parent material, crude oil deposits, decomposition of organic matter, and forest fires) and anthropogenic (areas degraded by solid waste, illegal gold mining, agriculture, and hydrocarbons). These findings provide essential information to establish regulations and prevent and control HM contamination in soils of the Peruvian Amazon plain., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Fifty four sediment samples representing pre and post-monsoon seasons were collected along a transect from off Kochi, lying between the latitudes 9°57'59.5″-9°54'30.4″ and longitudes 76°11'7.04″-75°38'50.3″ of the South eastern Arabian Sea. The present study investigates the levels of trace metals (Zn, Cd, Pb, Cu, Fe, Ni, Mn, Co and Cr), total organic carbon (TOC), total inorganic carbon (TIC), elemental composition and grain size to assess the extent of environmental pollution and to discuss the distribution of these trace metals in the surficial sediments. Sediment pollution assessment was done using the Contamination factor (C.F), Geoaccumulation Index (Igeo), Enrichment Factor (EF), and Pollution Load Index (PLI). The majority of trace metals analysed in this study exhibited the highest concentrations at stations 1, 2 and 3 where the land-based anthropogenic input was found to be maximum., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Spatial distribution and ecological risk levels of toxic metals (Cu, Pb, Zn, Ni, Co, As, Sr, V, and La) in sediments from the southern Black Sea coastal (Türkiye) were evaluated. The sediment samples were taken in April and May 2019 from thirty-one stations, from depths ranged between 16 and 65 m. The average metal concentrations (in dry weight) varied from 59.4 ± 4.8 to 102.5 ± 12.3 for Cu, 39.3 ± 4,1 to 46.1 ± 2.9 for Pb, 104.5 ± 4.7 to 126 ± 6.9 for Zn, 21.2 ± 1.8 to 24.9 ± 1.4 for Ni, 9.8 ± 0.4 to 16.6 ± 1.5 for As, 16.7 ± 0.5 to 18.2 ± 0.9 for Co, 68.2 ± 11.4 to 123.3 ± 13.5 for Sr, 82.7 ± 13.1 to 97.3 ± 4.3 for V, and 16.2 ± 1.8 to 23.6 ± 1.8 μg g -1 for La. Geoaccumulation index (I GEO ), Sediment enrichment factor (SEF), and pollution load index (PLI) indicated that Cu and Pb are above the pollution limits. Thus, continuous pollution monitoring programs should be established. Moreover, measures should be implemented more effectively to prevent pollution., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Sediments from banks of the Sutlej River and roadside soils from vicinity of Ropar wetland (collected during pre- and post-monsoon seasons, 2013) were analysed to determine the spatiotemporal distribution of potentially toxic elements (PTEs, viz. arsenic, cadmium, cobalt, chromium, copper, iron, manganese, lead and zinc), which when present in high concentrations may pose health hazards and ecological risk. Contamination factor, degree of contamination, modified degree of contamination, metal pollution index, pollution load index, enrichment factor, geoaccumulation index and ecological risk index were also determined for these PTEs in the study area. Sediment and soil samples were found to be alkaline and non-saline (pH > 7.0; EC < 4500 μS cm -1 ) with sodium and potassium as major ions. Iron (mg kg -1 ) was found to be most abundant in sediments (1477.59-6512.45) and soils (922.64-12,455.00). Cadmium content in sediments exceeded the threshold value (0.99 mg kg -1 ) at 2 (pre-monsoon) and 3 (post-monsoon) sampling sites. In both seasons, cadmium (0.10-2.05) and cobalt (11.40-17.52) contents (mg kg -1 ) exceeded the threshold limits (0.06 and 8.00 respectively) in all roadside soils. Significant spatiotemporal variation (p ≤ 0.05) was observed for pH; EC; and calcium, magnesium, copper, iron and zinc contents. Low to moderate potential ecological risk was observed for both roadside soils (31.80-213.82) and sediments (41.47-236.73). Contamination factor, enrichment factor and geoaccumulation index for cadmium were highest in roadside soils (6.84, 46.91 and 2.19, respectively) and sediments (7.64, 167.46 and 2.35, respectively) due to settlement of coal fly ash released from the industrial setups, on sediments/soils of the study area., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Seventy-four surface sediment samples were collected from the Arctic Ocean and Bering Sea to determine the content of metal(loid)s (As, Cu, Cd, Ni, Pb, Zn and Cr). Metal(loid)s content in these sediments varied from 2.36-41.90 mg/kg for As, 8.63-82.28 mg/kg for Cu, 0.14-0.71 mg/kg for Cd, 11.86-100.60 mg/kg for Ni, 8.30-27.58 mg/kg for Pb, 39.93-391.43 mg/kg for Zn, and 40.96-106.49 mg/kg for Cr. The pH and water-soluble organic carbon content had considerable impacts on the content of metal(loid)s in sediment, but the texture of sediment has limited influence on metal(loid)s content in sediment. In addition, the hotspots of most of these metal(loid)s appeared in the Beaufort Sea region. The geoaccumulation index (I geo ) indicated that Cd was the metal with the highest contamination in these sediments, with 55.41% of the sample sites posing moderate pollution. The ecological risk for As, Cu, Ni, Pb, Zn and Cr indicates low ecological risk (100%), while Cd posed moderate risk (35.14%), considerable risk (54.05%) and high risk (10.81%) and attributed more than 76.45% of the total potential ecological risk of these metal(loid)s., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The Três Marias Reservoir is the ninth largest reservoir in Brazil, becoming crucial for national strategic development. However, many anthropic activities may affect the sediment quality, promoting the need for a proper environmental assessment. This research appraised the seasonal influences on the Três Marias Reservoir's sediment geochemistry, elucidating possible anthropogenic impacts. The concentrations of Mg, Al, Ca, Cr, Fe, Co, Cu, Cd, Ti, Mn, Ni, Zn, Ba, and Pb were measured in 78 samples of bottom sediments regarding the two seasons of the area, a dry winter and rainy summer. The median ± 2 median absolute deviation (MAD) settled the geochemical background and environmental thresholds for the two seasons. The sediment quality guidelines CONAMA 344/12 highlight the possible adverse ecological effects of pollutants. The hierarchical clustering analysis, the geoaccumulation index, and the pollution load index delineated the polluted zones. The pollution load index ranges from 0.25 to 2.28 in the dry season and 0.56 to 2.11 in the rainy season, defining three affected zones in the reservoir. Forestry and agriculture are the probable pollution sources, reaching warning levels that should be considered in further environmental strategies., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Stormwater ponds can provide flood protection and efficiently treat stormwater using sedimentation. As the ponds also host aquatic biota and attract wildlife, there is a growing concern that the sediment bound pollutants negatively affect aquatic organisms and the surrounding ecosystem. In this study, we used three methods to assess the accumulation and the potential ecological risk of 13 different heavy metals and metalloids (e.g. trace elements) including both elements that are frequently monitored and some which are rarely monitored in sediment from 5 stormwater ponds located within catchments with predominately industrial activities. Ecological risk for organisms in the older ponds was observed for both commonly (e.g. Cd, Cu, Zn) and seldom (e.g. Ag, Sb) monitored trace elements. The 3 methods ranked the degree of contamination similarly. We show that methods usually used for sediment quality assessment in aquatic ecosystems can also be used for screening the potential risk of other trace elements in stormwater ponds and may consequently be useful in stormwater monitoring and management. Our study also highlights the importance of establishing background conditions when conducting ecological risk assessment of sediment in stormwater ponds., (© 2021. The Author(s).)

Studies regarding how environmental risk evolves in abandoned mining areas in the medium term have been seldom carried out. The answer to this question is not obvious despite it is essential in order to evaluate the need to take urgent control measures in these areas. Fifty-two samples corresponding to soils (from natural pasture and arable lands) and mine tailings were collected in the surroundings of an old Spanish Pb/Zn mine (San Quintín, Central Spain). Current concentrations of pseudo-total and available metal (loid)s (Pb, Zn, Cd, Cu, As and Ag) were determined and the environmental risk assessment (ERA) was conducted with these data and those corresponding to a sampling previously carried out in 2006. ERA was carried out by calculating the geoaccumulation index (Igeo), the pollution load index (PLI) and the potential ecological risk index (PER). Results demonstrated that Pb and Zn concentrations have increased in the soils of the plots surrounding the mining areas causing a moderate rise in most of the determined pollution indices between 2006 and 2020. It was especially significant in the pastureland areas, with increases up to 17% in the number of soil samples that reached the highest risk classification in 2020 as compared to those taken in 2006. The results obtained here demonstrate that the environmental risk can actually increase in a continuous way in abandoned mining areas despite the closure of the mining operation and the effect of the possible natural attenuation., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Street dust samples were collected from industrial and commercial cities (Jamshedpur and Ranchi during monsoon and post-monsoon seasons) for detecting the levels of Cr, Cd, Cu, Ni, Pb, Zn, As, Co, Al, and Mn. The industrial city recorded higher metal concentrations compared to commercial. Similar trend of pseudo-total metal concentrations was observed in both the seasons at industrial city (Al > Mn > Zn > Cr > Pb > Cu > Ni > Cd) and only monsoon season at commercial city (Al > Mn > Zn > Cu > Cr > Pb > Ni > Cd). Zn > Cd was the most bioaccessible metal throughout the cities (monsoon and post-monsoon). The geochemical parameters (Igeo, EF, CF) were highest for Cd and lowest for Ni (both cities for the two seasons). Pollution Load Indices (PLI zone) were highest during the post-monsoon season in the industrial city. The highest carcinogenic risk was posed by Cr ranging from 1.87E-05 to 4.80E-05, in both the cities through ingestion and inhalation pathways. Children were found at higher risks, while the bioaccessible fractions posed neither carcinogenic nor non-carcinogenic threats to the population. Principal component analysis and correlation analysis indicated the influence of vehicular and industrial emissions, especially steel industry and coal-based thermal power plants as the major source of metals in street-dust. The outcomes of this work will be useful in providing baseline information of pollution along with their consequent environmental and human health risks of Jharkhand state., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Eleven heavy metals (V, Cr, Mn, Co, Fe, Ni, Cu, Zn, As, Cd, and Pb) in surface sediment in the intertidal zones of the Yellow River Estuary, China were analyzed by inductively coupled plasma-mass spectrometry in summer and autumn 2019. Results indicated that the 11 heavy metals had the same sources. Sediment particle size and total organic matter were the main factors influencing the distribution of heavy metals. Most sites in the intertidal zones of the study area were not contaminated with V, Cr, Fe, Co, Zn, Pb, Cu, As, Mn and Ni, while Cd was the priority pollutant. Heavy metal pollution risk in autumn was higher than that in summer, which may be due to hydrodynamic effects. The present study showed that the heavy metal concentrations in the study area had a temporal decreasing trend compared to previous studies, which may be due to the reduction in human activities., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

In this paper, the distribution, degree of pollution and sources of Cu, Pb, Zn, Cd, Cr, As, Co, Ni and Hg in the surface sediment of Sanmen Bay were studied. The average concentrations of the identified potentially toxic elements (PTEs) were in the following order: Zn > Ni > Cr > Cu > Pb > Co > As>Cd > Hg. Almost all PTEs had a significant positive correlation with TOC, clay and Al; Cr had no significant correlations. Apart from Hg, the contamination levels of 8 PTEs were at those considered to be low-to-no pollution. Comparatively, the contamination level of Hg was much higher than the background value, which indicated moderate pollution. The source of this pollution may have included industrialization, urbanization and/or transport of industrial waste materials. Both geoaccumulation index (I geo ) and potential ecological risk (RI) values suggested that Hg was the major contributor to the ecological risk posed by the selected PTEs., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The presence of potentially toxic elements (PTEs) in soil and plants is a risk factor to human well-being and the environment. Soil and leaves from a traditional medicinal plant, Vachellia karroo, known as the sweet thorn plant, were assessed to determine the extent of pollution by PTEs from gold mine tailings in a case study area of Matjhabeng Local Municipality, South Africa. A risk classification tool was developed using the different indicators of pollution quantified to describe the pollution risk at each sampling site. High concentrations of copper, cadmium, lead, nickel, and zinc were measured in the soil, which exceeded the maximum permissible soil quality limits. The enrichment factor and geoaccumulation index results also confirmed heavy soil pollution by copper, nickel, and zinc, with exceptionally heavy pollution by cadmium and selenium. The PTEs in the soil were in an exchangeable form, with the sweet thorn plant accumulating lead and selenium at toxic levels, which poses a risk to the health of the local people as the plant is used for medicinal purposes. The overall pollution risk classification tool of the sampling sites showed that 17% were high-risk areas, 53% were moderate-risk areas, and 20% of the sites were low-risk areas.

Extensive mineral exploitation activities in history have aggravated potential toxic elements (PTEs) contamination in agricultural soils in China. Comprehensive ecological risk assessment is of great significance to orientate the restoration of contaminated soils, especially for those with high background values and multiple sources. The study area is located in the major rice producing area of China. Historically, there was a silver mine and a lead-zinc mine in the area, which were successively closed during the investigation. The intensive mining activities caused serious PTEs pollution in the agricultural soils around the mining area. In this study, five PTEs (As, Cd, Cr, Hg and Pb) selected to assessed the potential of geoaccumulation index in assessing agricultural soil potential risk assessment by identifying ecological risk sources. 315 of soil samples collected in 2009, 2014, 2018 were comprehensively analyzed by single pollution index evaluation (single factor index, geoaccumulation index), comprehensive evaluation (Nemerow index, potential ecological risk index) and trend analysis. Single factor index analysis showed that geoaccumulation index considered the impact of natural diagenesis of background values and human activities on the environment, ensuring high evaluation accuracy comparing to other methods used in typical complex agricultural soils. The modified potential ecological risk index revealed that the high background area did not represent high risk area, which was consistent with the implementation effect of governance measures. This study can provide important insights for policymakers and environmental engineers to quantitatively recognize the soil pollution and the effectiveness of governance based on applicable and reasonable evaluation methods., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The distribution and enrichment of trace metals in sediments of the South China Sea along the entire coast of Vietnam were described. The concentrations of Cr, Ni, Zn, and Pb in the sediments showed a significant positive correlation with fine-sized fractions and TOC. In contrast, the concentration of As was not positively correlated with particle size and other metals. The relatively positive correlations of Cd with Fe, Al, Ti, Sc, TOC, P, Cr, Ni, Zn, and Pb indicated that it comes from different sources. Ecotoxicological indexes of all elements showed low values, except for Cd in the southwestern part of the South China Sea area, which is likely related to the influx of suspended matter from the Mekong River., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The South African National Road (N3) in the KwaZulu-Natal province is one of the major transportation routes from the Durban harbor. In this study, metal concentrations in Bidens pilosa L., which grows alongside the N3, and soil were determined using inductively coupled plasma - optical emission spectrometry to evaluate the impact of soil quality on the uptake. Furthermore, the distribution of Pb and Cd was mapped using the geographic information system (GIS) approach to identify the potential benefits of spatial data applications in soil studies. Plant concentrations of toxic metals, especially Pb, were high and were linked to high soil concentrations. The target hazard quotients indicated a low risk of adverse effects due to Cd exposure and increased risk due to As and Pb exposure. The carcinogenic risk was high for As and Cd exposure at all sites and Pb at 40% of the sites. Soil quality indicators (geoaccumulation indices and enrichment factors) showed soils to be moderate to heavily contaminated. Principal component analysis indicated different anthropogenic sources of contamination, including vehicular emissions and a combination of industrial, agricultural, and social impacts. Kriging interpolation depicted the spatial diffusion of Cd and Pb concentrations throughout the study area with different hot-spot areas of metal contamination for these two metals. The study demonstrated that the plants growing along national roads are not suitable for human consumption., (© 2021. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The Fuyang River system (FRS) in north China, for a long time, is seriously polluted with organic compounds and heavy metals due to industrialization. However, the information on heavy metal pollution in this area is still limited, and health risks raised by trace elements are neglected up to now. To characterize the heavy metal pollutants and assess their potential ecological risks scientifically in FRS, surface sediments were collected from 66 sampling sites selected according to the hydrological and anthropogenic conditions along the river. A total of twelve metal pollutants (e.g., Cr, As, and Hg) in the sediments were detected among the distributaries. A combining application of geoaccumulation index (I geo ), ratio of secondary phase and primary phase (RSP), and the ecological risk factor (Er i ) in this study gave systematic assessment results of single or combined pollution status raised by heavy metals in this area. The results show that Cr, Ni, Cu, As, Cd, Co, and Sn are mainly dispersed in the river reaches of Xingtai City and pose potential health risks in midstream, as per the geoaccumulation index and Pearson's correlation analyses. In particular, Cd accumulates strongly in sediments of Ming River and Aixinzhuang dam from Xingtai City. In upstream and downstream of FRS, the potential ecological risk is low, except in Yongnian County where high ecological risk was caused by Cd and Hg. These findings provide new insights into the pollution characteristics and assessment of the potential ecological risks induced by heavy metals along FRS, which suggest new directions should strategically tend to typical pollutants control by policy formulation and taking effective measures to prevent and manage heavy metal pollution in North China., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The accumulation of tailings from gold mining and smelting may result in PTE pollution. We investigated PTE contamination from a large amalgamated gold mine tailings pond in Pinggu County, Beijing. In November 2017, 30 soil samples were collected around the tailings pond. The concentrations and pollution degree of PTEs in the samples and the sources of Sb, As, Cd, Cu, Pb, Zn and Hg were analyzed. The average concentration of these elements in soil samples near the tailings pond (16.24, 28.29, 0.99, 171.04, 263.25, 99.73, 0.72 mg/kg, respectively) were higher than their corresponding standard values and background values of the study area. The geoaccumulation index showed that the pollution degree of As, Pb and Hg was moderate, while Sb and Cu present non-pollution to moderate pollution. The average EF values of the elements were Sb (38.31), As (4.23), Cd (0.71), Cu (3.68), Pb (21.24), Zn (0.82) and Hg (5.29), respectively. The environmental risk assessment developed throughout the PERI method indicated that Sb, As, Hg and Pb were the main pollutants in the study area. The three quantitative risk indicators (RI, Igeo and EF) were positively correlated, and all of them indicated that PTEs had significant pollution to the local area. Thus, Sb, As, Pb, Cu, and Hg pollution should be highly concerning. Multivariate statistical analysis shows that the pollution of PTEs was mainly caused by the accumulation of tailings ponds after gold mining and smelting. The research result is of great significance for the prevention and control of soil pollution of PTEs near the tailings pond.

The need to generate internal revenue by most individuals and government in Nigeria has led to the establishment of quarries in different parts of Ebonyi state of Nigeria. This study was aimed at determining the risk associated with the heavy metal burden in the state. Soil samples from the quarrying environments designated as MS1, MS2, and MS3 were analyzed for the metal profile using inductively coupled plasma optical emission spectrometry (ICP-OES). The result showed that the mean concentration of metals which is a representation of the whole sites showed a higher concentration of Ca (40.065 ± 1.011 ppm), Mg (12.450 ± 8.815 ppm), K (16.631 ± 14.670 ppm), and Mn (19.539 ± 3.225 ppm) while Na (1.326 ± 0.117 ppm) was low. The heavy metal profile showed Pb (0.120 ± 0.027 ppm), Fe (27.718 ± 1.523 ppm), Zn (2.227 ± 0.570 ppm), Cu (6.267 ± 1.402 ppm), Ni (1.856 ± 0.472 ppm), Mo (1.758 ± 0.258 ppm), Cd (0.023 ± 0.006 ppm), Cr (0.037 ± 0.011 ppm), etc. Hg was found to be below detectable limit while the Cs was not radioactive. The mean values were found to be lower than the permissible limit of each metal. The pollution index (PI) was calculated for the different sites, and the result reveals that MS3 (0.0426) had a higher PI when compared to MS1 (0.0341) and MS2 (0.0317). Therefore, the PI of the sites showed MS3 > MS1 > MS2. These results showed that the environment is still as safe as PI < 1. The geoaccumulation index also showed a safe environment since its values were less than 0 which means that the environment is practically uncontaminated. Other risk determining parameters showed that the three locations were still within a safe level. Although the results of the study have shown a safe environment, it is still necessary to keep close monitoring of the heavy metal profile of the environment, since these metals can bioaccumulate in living tissues with time.

The concentration of trace metals Mn, Pb, Ni, Zn, and Cu in the core sediment from Kabar Tal wetland was analyzed to understand the level of contamination in the vertical profile. Additionally, total organic carbon (TOC) and available phosphorus (AP) were also analyzed to infer the biogeochemistry of trace metals and the correlation that exists among them. Five core sediments were collected at the end of the monsoon season from different locations in the study area, representing diverse anthropogenic and agricultural activities. The average concentration of trace metals in sediments followed the order Mn > Pb > Ni > Zn > Cu. The trace metal concentration in the surface sediments was higher and decreased with depth in the vertical profile. Contamination factor (CF), geoaccumulation index (Igeo), enrichment factor (EF), and pollution load index (PLI) were used to evaluate sediment quality and the pollution status of the lake sediments. Cu, Zn, and Ni showed minor to moderate enrichment, and Pb showed a severe level of enrichment in all the core sediment samples. However, the sediment quality guidelines' index indicates that the sediments are moderately polluted with copper, zinc, and nickel and severely polluted with lead. There exists a strong positive correlation among Pb-Ni, Ni-AP, and AP-Pb, and a strong negative correlation among TOC-Ni, TOC-Pb, and TOC-AP for all the sediment samples. Additionally, the principal component analysis (PCA) and cluster analysis (CA) suggest that a good similarity exists among Pb, Ni, and Zn. The study indicates that trace metals in wetland sediments have originated from multiple anthropogenic sources like agricultural runoff (fertilizers), direct addition of solid wastes, discharge of untreated wastewater, and long-range transport from the oil refinery in the wetland.

In an effort to assess the potential contamination and determine the environmental risks associated with heavy metals, 51 surface sediment samples (0-4 cm) were collected in the Zhoushan Islands coastal sea of the East China Sea (ECS). The heavy metal concentrations, grain size and total organic carbon (TOC) contents of these surface sediments were comprehensively analyzed. The results showed that the order of the average concentrations of heavy metals is Zn > Cr > Cu > Pb > As > Cd > Hg. Zn, Cr, Cd and Hg exhibit similar distribution and which derived from a common source, however, Cu, Pb and As present different distribution. The metal enrichment factor (EF) and geoaccumulation index (I geo ) values both suggest that Cu and Cd likely pose environmental risks. The results of this study could provide scientific data to authorities in charge of sustainable marine management., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

As a historic gold mining area, the City of Benoni has numerous water bodies close to major tailings dams and mine dumps. Here we assess spatial patterns in the sediment geochemistry of five dams and four natural pans within a 5-km radius of the core mining area to determine the degree of contamination7 by mining-associated pollutants. XRF analysis was used with a geoaccumulation index to assess the degree of contamination above background levels. Prevailing winds blow from the north and north-west with less dominant winds from the east. Sediment concentrations of As, Cu, Pb, Ni and Zn are highly correlated across the region, suggestive of a common source. Except for one pan showing evidence of local industrial pollution, the most contaminated sites are the dams to the west of the mine dumps where concentrations of As, Cu, Pb and Zn increase towards the central mining area, with highest trace metal concentrations in Kleinfontein Dam, adjacent to a reworked mine dump. Sites upwind of the central mining area showed little evidence of mining-related contamination. Trace contaminant concentrations in sediments of these dams are much greater than those found in the nearby Springs-Blesbokspruit wetlands adjacent to more recently active mines. The potential risks to aquatic ecosystems and recreational users of these urban and suburban water bodies from these wind-blown, legacy mining contaminants merit further investigation.

The Republic of Azerbaijan suffers from low agricultural productivity caused by soil salinization and erosion, and limited and insufficient soil data are available for economic and political reasons. In this study, soil salinity and heavy metal levels were assessed. Environmental risk assessment was conducted to evaluate the potential risk posed by soils to human health. Soil guideline values were proposed to monitor soil pollution in the Republic of Azerbaijan. Water extraction and spatial variability analysis were conducted to understand soil salinization and heavy metal pollution. Among the 20 studied elements, the elements Ca, Cl, and S and the heavy metals Cr, Ni, and Pb were classified as problematic on the basis of the geoaccumulation index, and As was also identified as posing a possible risk on the basis of the potential ecological risk index. Based on the developed soil guideline values for agricultural soil, the As, Cr, and Ni in the soil samples exceeded their respective guidelines by 31.3, 41.8, and 61.6%, respectively. Water extraction results confirmed that 99% of the leached ions were cationic salts, and the most problematic ion was Na, followed by Ca, Cl, and S. The extractability values of Cr and Ni were significantly lower than those of other heavy metals, which implies that their actual leaching potential may be overestimated. The linear regression and spatial variability analysis confirmed that leachable salts have accumulated in lowland areas due to the capillary rise of water and evaporation, but the distribution of heavy metals confirmed that As, Cr, and Ni were abundant in agricultural soils. Our results clearly showed that heavy metal soil contamination and high salinity levels are major problems that should be considered when assessing food safety and health hazards in the Mugan Plain of Azerbaijan. Therefore, future studies should be performed for additional environmental risk assessment, detailed hazard identification, and health risk assessment.

Abandoned mining areas have left a legacy of environmental damage with potential public health implications. The present study aimed at (1) assessing the level of contamination of the sites surrounding the Agrokipia abandoned copper mine in Cyprus through the mobilization of potentially toxic elements (PTEs), (2) correlating results with the mineralogy of the area, (3) discussing potential ecological and human health risks, and (4) proposing regeneration strategies. To this effect, the levels of 22 PTEs and other major elements were assessed in the acidic water of pit lakes, the tailings, the waters, and sediments of several streams originating from the mining site and flowing through the village of Agrokipia, and from agricultural soil from an impacted adjacent olive orchard. The pH values of water (pH < 2.7) in the pit lakes uncovered the acidic and oxidizing conditions that prevailed in the area. The acidity and the examined PTE concentrations in stream waters followed a decreasing trend with increasing distance from the tailing, reaching background values in a distance of 1500 m. The tailing spoil-heap was significantly enriched with Cu, Zn, Pb, Cd, Cr, and Ag (e.g., enrichment factor values up to 29 for Cu and 120 for Ag). Stream sediments and agricultural soil were contaminated with PTEs (mainly Cu, Zn, Pb, Cd, Cr, Ag, and Li), as evident by several contamination indices (i.e., enrichment and contamination factor). The level of contamination was correlated with the reported mineralogy of the site. The values of the degree of contamination (Cdeg = 62) and pollution load index (PLI = 2.4) indicated contamination of the sediments of the Voulgarides stream flowing through the village, suggesting potential public health implications to the local community. In addition, the values of the ecological risk factor suggested that the studied streams pose moderate ecological risks, mainly mediated by Cd and Cu. Overall, the results highlighted the need for undertaking regeneration measures for safeguarding environmental sustainability and public health.

Paddy rice, one of the most important food crops in Southeast Asia, is considered a main source of human exposure to heavy metal contamination because it efficiently accumulates heavy metals. In the present study, of Japonica rice grains, straw, roots, leaves, and husks and rhizosphere paddy soils (0-20 cm and 20-40 cm depth) were collected from Zunyi in northern Guizhou Province, China. The forms of heavy metals, including Cr, Cd, Pb, Cu, and Zn, in the two soil profiles were investigated using Tessier's five-stage sequential extraction procedure. There was no heavy metal pollution in the study area based on the evaluation of the geo-accumulation index and the potential ecological risk index. Accumulation varied from one area to another, and the highest metal accumulation was found in the order of root > stems > leaves. The bioaccumulation factor (BCF) results revealed that during the grain-filling stage, the rice had high BCF values (> 1) for Cd and Zn. The target hazard quotient (THQ) of ingestion peaked for Cd and reached its minimum level for Zn in not only in adults but also in children. The THQ was ranked as Cd > Cu > Pb > Cr > Zn for both adults and children. The hazard index values for adults and children for the five heavy metals were 1.81 × 10 -3 and 1.55 × 10 -3 , respectively, indicating that these metals have little effect on the human body. The lifetime carcinogenic risk values for local adults and children were 4.28 × 10 -5 and 5.92 × 10 -5 , respectively, both of which were within the tolerable to acceptable risk range. In summary, obvious hazards for local adults and children were not observed in this study. Considering the total amount and chemical forms of Cd, it is necessary to notify the appropriate departments about the possible rice contamination caused by Cd in the soil.

Surficial marine sediments were sampled along the south-east coast and in Discover Bay Jamaica. Total elemental composition was determined for the sediments using three techniques. Total mass fractions of Al, As, Br, Ce, Co, Cr, Cs, Eu, Fe, La, Mn, Sb, Sc, Th, U, V, and Zn were determined using instrumental neutron activation analysis; Cu, Ni, Pb, Sr and Zr using energy dispersive X-ray fluorescence; and Hg using a direct mercury analyser. Potential anthropogenic hotspots were assessed using indices including enrichment factor (EF), geoaccumulation index (I geo ), ecological risk (E r ) and potential ecological risk index (R i ). The quality of the sediments was also assessed using the sediment quality guidelines (SQGs). Temperature, pH, salinity, dissolved oxygen and organic carbon content (OC) were determined to assess variation across sample sites. Results indicated moderate to severe ecological risk at sites in Port Royal and Discovery Bay with ecological risk values as high as 381.9., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In order to investigate the degree of contamination of heavy metals (As, Cd, Cr, Cu, Fe, Pb, and Ni) in the Aqyazi River in Iran, sediment samples were collected from the river receiving wastewater from an iron-manufacturing plant. For this study, contamination indices, geoaccumulation index (I geo ), contamination factor (CF), and pollution load index (PLI), were used to assess contamination by the heavy metals. The results of the I geo indicated that the sediments were moderately contaminated by Cu and strongly to extremely contaminated by Cd. Based on spatial distribution of concentrations and the I geo , mining activity was the source of Cu and Cd in the Aqyazi River. Furthermore, the elevated I geo of Cd at upmost northern station was not influenced by the mining activity, suggesting that there may be another upstream anthropogenic source of Cd. The CF values indicated the same trend as the Igeo. The PLI was calculated using all the metals analyzed in this study, and displayed that the sediments were not polluted. However, the PLI was re-calculated using only Cu and Cd and indicated that the sediments were polluted. Our results suggest further studies to trace another source of Cd upstream of the Aqyazi River and to investigate influence of the river waters on accumulation of heavy metals in soils and vegetables downstream.

This study aims to determinate the background geochemistry values for 23 chemical elements on the Amapá coastline. To do so, 8 cores were sampled (≤70 cm) along the Cuñaní Estuary. The metal concentrations were measured by means of inductively coupled plasma mass spectrometry. In mg.kg-1, the background values for Ba, Sr, Y, Sc, V, Cr 2 O 3 , Co, Ni, Cu, Zn, Ga, As, Rb, Nb, Sn, Cs, Ta, W, Hg, Pb, Bi, Th, and U were, respectively, 392.41, 133.29, 29.22, 12.80, 109.13, 0.008, 13.82, 22.69, 19.73, 75.09, 19.50, 14.77, 94.81, 15.62, 3.38, 6.59, 1.05, 1.82, 0.04, 19.02, 0.27, 13.25, and 3.57. The background geochemistry values for the region are an important tool for monitoring the metal concentrations and serve as a baseline for comparison with possible incidents of contamination with these elements on the Amapá coast., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The quality of soils polluted by trace elements around the facilities with the Cu and Zn smelting activities and the post-flotation tailings pond from copper industry were assessed. The level of the contamination of soils was determined on the basis of the contamination factor and the geoaccumulation index. The geoaccumulation index allows to distinguish more degrees of soil contamination and simplifies the assessment of the useable value of soil. The degrees of soil contamination and the pollution load index were shown. It has been shown that the pollution indices are a useful tool in describing the soil quality and planning corrective actions in the areas contaminated as a result of industrial activity. Histograms of pollution indices were used in order to detect the distribution of trace elements in soils. The content of metals in biomass was assessed using bioaccumulation indices. Triticum L. and Brassica napus L. show low bioaccumulation of studied metals in cereal plants. The correlations were used in order to detect the relationship among trace elements in soil as well as the relationship of metal (soil)-metal (plant) and metal bioaccumulation (plant)-metal (soil). The highest values of indices were recorded for the Oława smelter, presumably due to the long operation period before technological changes limiting the emission of pollutants were introduced. This research area was classified as very highly contaminated with all trace elements. Soils around other facilities are at least moderately contaminated.

Coal production and utilization are recognized as two principal sources of potentially toxic elements in the environment. Here the published literature (2008-2018) was searched to collect data on As, Ni, Cd, Cu, Cr, Hg, Pb and Zn concentrations in soils near different types of coal industrial areas such as coal mines, thermal power plants, coal chemical plants, coal mining cities and coal waster piles. The contamination levels of soils and associated health risks were assessed using global reference materials and multiple contamination indices. The results revealed that average concentrations of potentially toxic elements varied widely, yet most of them exceeded global averages in background soils and upper continental crust concentrations. Spatial distribution analysis suggested the concentrations of potentially toxic elements varied according to coalification and combustion conditions. Higher concentrations were found in Southeast Asia, South Europe, and North Africa compared with other regions. Assessment of the geoaccumulation index revealed that contamination levels of Cd and Hg were higher than those of other elements. In particular, Ni, Cd, Zn, and Hg were most likely to accumulate in soils near coal mining areas, while Cd and Hg tended to accumulate near coal chemical plants. Regarding non-carcinogenic risks, oral ingestion was the major pathway of exposure to potentially toxic elements in coal industry-associated soils, followed by dermal contact and inhalation. Tolerable non-carcinogenic risk of potentially toxic elements and relatively high carcinogenic risks of As were observed. Children were most vulnerable to non-carcinogenic risks, while the carcinogenic risks estimated for adult and children populations were similar. Accordingly, As should be designated as top candidates for priority control to protect human health in the vicinity of coal industry-associated areas. This study provides timely information for developing control and management strategies to reduce soil contamination by potentially toxic elements in different types of coal industrial areas., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019. Published by Elsevier B.V.)

Exploring the enrichment and controlling factors of heavy metals in soils is essential because heavy metals can cause severe soil contamination and threaten human health when they are excessively enriched in soils. Soil samples (total 103) from six soil profiles (T1 to T6) in the Mun River Basin, Northeast Thailand, were collected for the analyses of the content of heavy metals, including Sc, V, Co, Ni, Mo, Ba. The average contents of soil heavy metals decrease in the following order: Ba, V, Ni, Sc, Co, and Mo (T1, T3, T4 and T5); Ni, V, Ba, Co, Sc, Mo, and Ba (T2); Ba, V, Sc, Ni, Mo, and Co (T6). An enrichment factor (EF) and geoaccumulation index were calculated to assess the degree of heavy metal contamination in the soils. The EFs of these heavy metals in most samples range from 0 to 1.5, which reveals that most heavy metals are slightly enriched. Geoaccumulation indexes show that only the topsoil of T1 and T2 is slightly contaminated by Ba, Sc, Ni, and V. Soil organic carbon (SOC), soil pH and soil texture are significantly positively correlated with most heavy metals, except for a negative correlation between soil pH and Mo content. In conclusion, the influence of heavy metals on soils in the study area is slight and SOC, soil pH, soil texture dominate the behavior of heavy metals.

Heavy metals including copper (Cu), zinc (Zn), cadmium (Cd), chromium (Cr), lead (Pb), and arsenic (As) were investigated in 89 pairs of rice plant and paddy soils around Dongting Lake area, China. Rice plants and soils were collected with GPS device, and heavy metal contents in different rice plant tissues and soils were measured. The aim of the present study was to assess the heavy metal pollution and translocation in the whole soil-rice system, including the consequent human health risk for residents. According to the indices of average geoaccumulation (I geo ) of the studied elements, paddy soils in study area were moderately polluted by Cd, lowly polluted by Pb, and not polluted by Cu, Zn, Cr, and As. Considering the much higher concentrations of studied elements in roots than in other tissues of rice plants, a great mass of these elements was assumed to be confined in the roots. The low translocation factors from root to shoot (Tf root-shoot ) of all the studied heavy metals (0.04-0.74) underpinned this. The high translocation factors from soil to root (Tf soil-root ) of Cd (9.12), As (4.38), and Zn (2.05) indicated the high bioavailability of these heavy metals for rice plant. The health risk assessment using target hazard quotients (THQs) model indicated that Cd (5.17 for adults and 4.49 for children respectively) and As (3.61 for adults and 3.14 for children respectively) could cause human health risk both for adults and children. Further, given the rate of individual THQ values exceeding one, Cu might also be considered as a potential human health dangerous element in the study area. It was worth noting that as one of the main pollutants, Pb did not show human health risk through rice grain consumption due to its low Tf values in soil-rice system. However, the risk identification of As using comparisons of measured concentrations with risk screening value in Chinese paddy soil standard (GB15618-2018) was not consistent with the human health risk assessment result. This might indicate that site-specific risk screening values of As in China is in demand.

Shandong is one of the main areas for protected vegetable cultivation in China. A total of 88.5% of the facility soil samples had a pH between 7.0 and 8.4, indicating the majority of the soils were alkaline. Key properties, including total nitrogen (TN), organic matter (OM), electrical conductivity (EC), available phosphorus (AP), and available potassium (AK), showed an increasing trend with the number of years. The geoaccumulation index (I geo ) indicated that the Cd and Hg contents ranged from uncontaminated to moderate contaminated, while the risk of Hg and Cd reached the class of considerable risk as indicated by the potential ecological risk factor ([Formula: see text]). The mean of Hakanson potential ecological risk index (RI) was 234.00, with the highest contribution from Hg (55.26%), followed by Cd (38.81%). It indicated that the survey area was at the moderate-risk level and Hg had the highest potential ecological risk factor, followed by Cd.

Street dust and soil are important materials for evaluating the contaminants level in industrial areas. Detailed size-resolved distribution of metal(loid)s in street dusts and soils influenced by industrial activities has rarely been investigated. This study was carried out to understand how industrialization might affect the size distribution of metal(loid)s concentration and contamination level in the street dust and soil from Murcia, southern Spain. An industrial and a natural areas were selected and surface soil and street dust samples were taken. They were fractionated into eleven size classes and total concentrations of Pb, Zn, Cu, Cd, Cr, Ni, As and Fe were determined in both the bulk samples and their fractions. Enrichment factor, geoaccumulation index, and mass loading of different heavy metal(loids) were calculated. The results indicated that the street dust from natural and industrial areas had almost the same particle size distribution, both containing higher percentage of coarse-sized particles than the soil. Industrialization seems to have only slightly affected the concentration of most elements studied in the soil. In contrast, the concentrations of the heavy elements in bulk industrial dust samples and all their size fractions were extremely higher than those from the natural area. This means that the industrial activities only affected the size dependency of the concentration (contamination level) of certain elements (Pb, Zn, Cu, Cd, and Cr) in the street dust, but not in the soil., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Sediment can accumulate trace elements in the environment. This study profiled the magnitude of As, Ba, Cd, Co, Cu, Cr, Ni, Pb, Se, and Zn pollution in surface sediments of the west coast of Peninsular Malaysia. Trace elements were digested using aqua regia and were analyzed using the inductively coupled plasma-mass spectrometry. The extent of elemental pollution was evaluated using with the enrichment factor (EF) and geoaccumulation index (I geo ). This study found that the elemental distribution in the sediment in descending order was Zn > Ba > Cr > Pb > Cu > As > Ni > Co > Se > Cd. Zn concentrations in all samples were below the interim sediment quality guideline (ISQG) (124 mg/kg). In contrast, Cd concentrations (2.34 ± 0.01 mg/kg) at Station 31 (Merlimau) exceeded the ISQG (0.70 mg/kg), and the concentrations of As in the samples from Station 9 (Tanjung Dawai) exceeded the probable effect level (41.60 mg/kg). The I geo and EF revealed that Station 9 and Station 31 were extremely enriched with Se and Cd, respectively. All stations posed low ecological risk, except Station 31, which had moderate ecological risk. The outputs from this study are expected to provide the background levels of pollutants and help develop regional sediment quality guideline values. This study is also important in aiding relevant authorities to set priorities for resources management and policy implementation.

Variability of background concentration of toxic trace metal(loid)s in sediments can often lead to under/over-report of contamination level, even in detailed scale. In this study, both surface (5-10 cm) and subsurface (> 10 cm) sediments were collected at many sites in a small lake (0.528 km 2 ) with multi-function (irrigation, aquaculture, and watercourse) in an industrial area. Total concentration of trace metal(loid)s (Cd, Cr, Co, Cu, Ni, Sb, Pb, and Zn) and potential reference elements (Ti, Zr, Rb, and Li) were analyzed. The results showed that although the trace metal(loid)s were mainly lithogenic in subsurface sediments, the variability of baseline concentration was significant. For Sb, this variability was a result of alteration in hydrological parameters as well as sediment properties including Fe/Mn oxide contents, particle size distribution, and organic matter contents. Comparison of the normalized Sb concentration in samples from two sediment cores indicated that Ti is the best reference element for normalizing Sb to reduce the impact from particle size and natural source. Enrichment assessment using modified EFs (Ti as reference element) and I geo index (measured baseline concentration) suggested that about 70% of the surface sediments were at least moderately polluted by Sb in the lake, as a result of recent anthropogenic input, mainly from nearby industries, e.g., concrete factory and textile factory. Modified EFs should be used, instead of I geo index, when Sb enrichment was relatively low in sediment. The anomalies of Sb background concentration may need regulator attention when assessing the level of sediment contamination.

Among the threats to air, soil, and water posed by urbanization, heavy metals appear particularly hazardous. Playgrounds and sport facilities are unique urban places, widely used by children and youth. The aim of this research was to evaluate heavy metal pollution in urban soils, identify relationships among topsoil metal distributions, and assess related health risks in two Polish cities - Warsaw and Bydgoszcz. According to the Regulation of the Polish Minister of the Environment guidelines for total content of Pb, Cu, Zn, Ni, Cd and Co our study sites were classified as uncontaminated. Applied Geoaccumulation Index (I geo ; Müller, 1969) largely confirmed this classification, with only two of the investigated Warsaw areas "moderately polluted" with Pb. Generally, only Pb and Zn concentrations exceeded reference background levels for Polish soils. The highest concentrations of Pb and Zn were found in the city centers, the oldest areas where pollution risk is potentially the highest. Metal mobility and solubility were mainly correlated with total content, indicating potential risk from lead and zinc. At some sites in Warsaw, where mean Pb concentration was 87.25 mg kg -1 and Zn 207.25 mg kg -1 , health risks from ingestion and inhalation seemed significant, particularly for children. In Bydgoszcz use of the studied playgrounds and sport facility areas did not pose a risk to human health. Finally, the study (especially in Warsaw) indicates the need for continued monitoring and suggests lowering permissible limits of these metals in soils, especially in recreational areas, may decrease childrens' exposure risk to these pollutants., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Several tools have been developed and applied to evaluate the metal pollution status of sediments and predict their potential ecological risk assessment. To date, a comprehensive relationship between the information given by these sediment tools for predicting metal bioavailability and the effective toxicity observed is lacking. In this work, the possible inter-correlations between the data outcoming from using several qualitative evaluation tools of the sediment contamination (contamination factor, CF, the enrichment factor, EF, or the geoaccumulation index, Igeo), metal speciation on sediments (evaluated by the modified BCR sequential extraction procedure) and free metal concentrations in pore waters were studied. It was also our aim to evaluate if these assessment tools could be used for predicting the pore waters toxicity data as toxicity proxy. Principal component analysis and cluster analysis revealed that two quality indices used (CF and EF) were highly correlatable with the more labile fractions from BCR sediment speciation. However, neither of these parameters did correlate with the toxicity of pore waters measured by the chronic toxicity (72 h) in Pseudokirchneriella subcapitata. In contrast, the toxic effects of the given total metal load in sediments were better evaluated by using an additive metal approach using pore water free metal concentrations., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Heavy metals have become a subject of special concern worldwide, mainly due to high persistence in the environment, toxicity, biogeochemical recycling and ecological risk. Therefore, the objective of this investigation was to analyze the spatial-temporal distribution of heavy metals in water and sediments to determine the environmental status of El Guájaro Reservoir, where such studies have not been developed. Two measurement campaigns (dry and wet period) were carried out and eight sampling stations were selected. A comparison of water and sediment quality parameters with existing national and international regulations was done. Also, heavy metal distribution maps were generated, and the geoaccumulation index was calculated to identify sources and sediments contamination level. Based on the obtained results, agriculture and mining activities are the main causes of the reservoir contamination. This metals levels could be a potential risk for the aquatic life and the populations that are supplied from this water body.