Risk assessment and source identification of soil heavy metals: a case study of farmland soil along a river in the southeast of a mining area in Southwest China.

To investigate the heavy metals (HMs) contamination of surface farmland soil along the river in the southeast of a mining area in southwest China and identify the contamination sources, 54 topsoil samples were collected and the concentrations of seven elements (Zn, Ni, Pb, Cu, Hg, Cr, and Co) were determined by inductively coupled plasma optical emission spectrometry (ICP-OES) and atomic fluorescence spectrometry (AFS). The geo-accumulation index ([Formula: see text]) and comprehensive potential ecological risk index ([Formula: see text]) were used for analysis to determine the pollution degree of HMs and the risk level of the study area. Meanwhile, the Positive Matrix Factorization (PMF) model was combined with a variety of statistical methods to determine the sources of HMs. To explore the influence of the river flowing through the mining area on the concentrations of HMs in the farmland soil, 15 water samples were collected and the concentrations of the above seven elements were determined. The results showed that the concentrations of Pb, Cu, and Zn in soil all exceeded the risk screening value, and Pb in soil of some sampling sites exceeded control value of "Agricultural Land Soil Pollution Risk Control Standard".[Formula: see text] showed that Pb was heavily contaminated, while Cu and Zn were moderately contaminated. RI showed that the study area was at moderate risk. PMF and various statistical methods showed that the main source of HMs was the industrial source. In the short term, the river flowing through the mine has no significant influence on the concentration of HMs in the soil. The results provide a reference for the local government to control contamination and identify the sources of HMs.

Potentially toxic elements in cascade dams-influenced river originated from Tibetan Plateau.

Rivers originated from Tibetan Plateau are of great significance due to their environmental sensibility and fragility. However, the pollution of suspended particulate matter (SPM) in these rivers is rarely reported, in particular, the potentially toxic elements (PTEs) contamination. To clarify the status, sources, behavior, and risks of PTEs in SPM, a full investigation was conducted in dams-influenced Lancangjiang River basin. The findings revealed that the PTEs content (mg kg-1) ranked Mn (766) > V (151.7) > Zn (131.0) > Cr (94.6) > Ni (44.2) > Pb (36.7) > Cu (29.4) > Co (14.6) > Sb (2.6) > Mo (1.6) > Tl (0.78) > Cd (0.48). The multi-index assessment suggested that Sb and Cd were moderately severe to severe enriched PTEs with the enrichment factor values of 10.0 and 8.8 and the geo-accumulation index values of 2.2 and 2.0, respectively, while the rest of PTEs were minor/no enrichment. In contrast, Cr and Ni were major toxic elements in SPM which contributed 25 ± 10%, 24 ± 8% to the total toxic risk index. The high partition coefficients (e.g., 6.1 for Cr) were observed in most PTEs and resulted in the 96.3% of Cr, 85.2% of Zn, 83.6% of Pb, 77.8% of Ni, and 63.2% of Cu transportation in the SPM form. Natural inputs (e.g., soil erosion) are the main source (53.6%∼61.9%) of V, Cr, Mn, Co, Ni, and Tl, while fuel burning contributed 40.9% of Zn, 32.5% of Pb, and 37.3% of Cd. Moreover, 51.2% of Sb was attributed to industrial waste source, while porphyry copper/molybdenum deposits related milltailings were the co-source of Mo (54.4%) and Cu (34.8%). Overall, the PTEs geochemistry of SPM showed the potential in tracing regional environmental change.

Potentially toxic elements in weathered waste-rocks of Fushun western opencast mine: distribution, source identification, and contamination assessment.

To understand the current status of the contamination of potentially toxic elements (PTEs) after closing the Fushun Western Opencast Mine, this study has focused on the concentration, contamination assessment, and source identification of eight PTEs in weathered waste-rocks in four distinct areas of the mine. The mean concentrations of Ni, Cr, Zn, Cu, Pb, Hg, Cd, and As were 79.4, 86.3, 126, 64.8, 16.9, 1.04, 1.94, and 6.27 mg kg-1, respectively. The results demonstrated that Ni, Cr, Zn, Cu, Pb, Hg, Cd, and As were contaminated to different extents in different weathered waste-rocks and waste-rocks, among which there was considerable Cd contamination. Coal gangue area (CGA) exhibited the most polluted weathered waste-rocks, which can be attributed to severe pollution and moderate ecological hazards. Self-combustion gangue (SCG) contamination of waste-rocks was considerably serious and caused severe pollution and considerable ecological harm. Health risk assessments demonstrated that Hg had the highest non-carcinogenic risk. Ingestion of PTEs was found to be a primary route of exposure, while dermal and inhalation exposure was negligible. Principal component analysis (PCA) demonstrated that there were roughly three sources of PTEs in the weathered waste-rocks of the mine, natural sources related to the weathering of parent rocks, and human sources, including industrial emissions, mining activities, and atmospheric dust deposition and resuspension. This study advances our knowledge of PTEs in mines and provides policymakers with a reference for designing strategies to protect mine-based ecosystems.

Occurrence of some rare earth elements in vineyard soils under semiarid Mediterranean environment.

A comprehensive investigation has been carried out into the concentrations of a range of REEs (neodymium Nd, cerium Ce, lanthanum La, yttrium Y, scandium Sc) in soils of vineyards belonging to the protected denomination of origin (PDO) Valdepeñas (Central Spain). The mean concentrations (expressed in mg kg-1) are Ce 70.6, Nd 32.9, La 36.2, Y 21.6, and Sc 13.7 in surface horizons (Ap), while in subsurface horizons (Bt or Bw and some Ck), the values are Ce 67.6, Nd 31.8, La 34.4, Y 19.6, and Sc 13.9. The relative abundance in these soils is Ce > La > Nd > Y > Sc in both the surface and subsurface horizons. These values are close to, or slightly higher than, the regional levels but similar to national and global averages, although relatively high values have been detected at certain sampling points. Another aim was to explain the spatial variations in these elements within the territory under study. It was found that the spatial variations are due to the nature of the parent materials and the pedogenetic processes, although the sparse spatial distribution patterns with prominent anomalies are interpreted arising from anthropogenic sources (fertilization). However, these anomalies did not present any environmental risk in the studied zone.

Pollution characteristics, risk assessment, and source apportionment of potentially toxic elements in road dust at two industrial parks in Trinidad and Tobago, West Indies.

Potentially toxic elements can enter the environment through natural and anthropogenic processes, with the latter considered the primary contributor. Road dust samples from two industrial parks on the island of Trinidad were investigated for heavy metal content, and the pollution status, potential health risks, and source apportionment were evaluated. Samples were acid-digested and analysed by flame atomic absorption spectroscopy. The average levels of cadmium, chromium, copper, manganese, nickel, lead, and zinc in road dust at the Frederick Settlement Industrial Park were 1.14 µg/g, 15.13 µg/g, 66.42 µg/g, 768.49 µg/g, 37.95 µg/g, 55.90 µg/g, and 573.04 µg/g, respectively, while average concentrations at the O'Meara Industrial Park were 1.20 µg/g, 16.97 µg/g, 42.72 µg/g, 482.65 µg/g, 21.12 µg/g, 136.77 µg/g, and 358.70 µg/g, respectively. Contamination assessments evaluated both Fredrick Settlement and O'Meara as typically uncontaminated to moderately polluted, with the overall ecological risk deemed low at all locations. Hazard index values at all sampling areas were lower than 1, indicating no potential non-carcinogenic risks to children or adults, while the carcinogenic exposure risks for cadmium, chromium, and nickel were considered low. Principal component analysis and cluster analysis revealed two main sources of contamination for Fredrick Settlement, and three main sources for O'Meara. Based on the groupings obtained, the presence of potentially toxic elements was attributed primarily to specific anthropogenic activities within the industrial parks, with lesser contributions from vehicular-related sources.

Seasonal Variation and Contamination Risk Assessment of Heavy Metals in Surface Sediment of an Estuary Alluvial Island in Eastern China.

The heavy metal pollution of estuary wetlands caused by industrial and agricultural production activities has aroused widespread concern. The Hakanson Pollution index, Geo-accumulation index (Igeo) and Redundancy analysis were used to explore the seasonal variation and contamination risk of heavy metals in surface sediments. Results showed that the heavy metal concentrations were ranked in descending order: Cd > Cu > Zn > Pb > Cr. The analysis result of HPI and Igeo showed that there was a low level of heavy metal contamination both in summer and winter. Redundancy analysis showed that the correlation between heavy metals and physicochemical properties of sediment was significantly different in winter and summer. Our findings provide scientific support for the prevention of heavy metal pollution in estuary wetlands.

Altitudinal-modulated sediment inputs rather than the land-uses determine the distribution of lead in the riparian soils of the Three Gorges Reservoir.

Lead (Pb) as a toxic metal has potential ecological hazards for aquatic quality. However, the variation in the distribution patterns of Pb and its fractions in flooding soils with frequent and anti-seasonal water-level fluctuation and various human disturbances remains unclear. In this study, the distribution of Pb and its fractions in the riparian soils of the Three Gorges Reservoir (TGR) were delineated based on the differences in altitude and land-uses including farmland, orchard, forest and residential area. Then, we assessed the contamination and eco-risk of Pb in the soils and deciphered the key factors determining the distribution of Pb and its fractions. The results showed that the concentrations of Pb and its fractions in the soils decreased significantly with altitude, while the significant difference was not observed among the land-uses. The contamination of Pb in the soils reached a moderate level, and its eco-risk was very low by the potential eco-risk index and mobile Pb fraction. The source of soil Pb at the upper zone (> 160 m) was mainly from natural inputs, while the source at the lower zone (≤ 160 m) was attributed to anthropogenic contributions including ores mining, fossil fuel combustion, vehicle emissions and atmospheric deposition indicated by Pb isotopic ratios. With the limited effect of land-uses, the sediment inputs regulated by frequent water-level fluctuation determined the altitudinal distribution of Pb and its fractions in the flooding soils. The soil particle size dominated the migration and transformation of Pb over other soil properties such as pH and organic matters. The results of this study indicate that the anthropogenic Pb mainly exists in the soils of lower riparian zone in the TGR, and the frequent and anti-seasonal dry and rewetting alternation aggravates the potential for the Pb migration downstream due to the determinant of soil particles.

Fractions, Contamination and Health Risk of Cadmium in Alpine Soils on the Gongga Mountain, Eastern Tibetan Plateau.

Anthropogenic cadmium (Cd) in alpine soils is mainly from long-range atmospheric transport. Because of the high toxicity and mobility, whether the accumulation of Cd in the soils threats to ecosystem safety remains unclear. The fractions of soil Cd along three altitudinal transects on Gongga Mountain were analyzed to decipher the drivers on its mobility, and its contamination and health risk were assessed. The concentrations of Cd in the organic (O) and mineral (A) horizons were significantly higher on the eastern and southern transects than the western transect. The Cd fractions in the two horizons dominated by acid-soluble and reducible Cd. Soil organic matter and pH modulated the mobilization of soil Cd. Cadmium reached a moderate contamination level on the eastern and southern transects, but no or slight contamination on the western transect. The soil Cd had a low non-carcinogenic risk and no carcinogenic risk despite of adults or children.

Effects of Artificial Islands Construction on the Spatial Distribution and Risk Assessment of Heavy Metals in the Surface Sediments from a Semi-closed Bay (Longkou Bay), China.

Artificial islands construction can significantly influence the spatial distribution of heavy metals in inshore sediments. In this study, the distribution and contamination of heavy metals (Cd, Co, Cr, Cu, Ni, Pb, Zn, As and Hg) in inshore sediments of the Longkou Bay and artificial island adjacent areas were investigated in 2013 and 2014, respectively. Results showed that the contents of heavy metals increased in the Longkou Bay and decreased in the west of the artificial island in 2014 compared with 2013. The contamination and potential eco-risk of heavy metals in the sediments were higher in 2014 than those in 2013. Cd and Hg showed a high potential eco-risk in LK02, and other metals were in the lower level. The results indicated that after the construction of artificial islands in the Longkou Bay, the contamination and eco-risk of heavy metals in the sediments markedly increased in the Longkou Bay.

Contamination and health risk assessment of heavy metals in PM10 in mining and smelting basin Bor in Serbia.

The objective of this study was to investigate concentration and spatial distribution of four heavy metal elements (As, Cd, Pb, and Ni) in PM10 in town near mining and smelting basin, Bor (Serbia). Human health risks for each heavy metal were assessed using a human exposure model. Results showed that air does not contain significant heavy metal elements concentrations at all three measurement points in Bor. The spatial distribution pattern of all tested metals coincided with the locations of mining area and the most populated part of town (domestic sources and traffic), as well as wind direction. The contamination evaluation indicated that As, Cd, Ni and Pb in air originated from anthropogenic sources-industry, heating and traffic. The non-cancer health risk assessment showed that ingestion was the primary exposure route for all metals and that Pb, and As were the main contributors to non-cancer risks in both children and adults. HI values were calculated for children (HI = 2.34-4.15E-06), indicating that children will likely experience higher health risks compared with adults (HI = 2.67-4.73E-07). The non-cancer risks posed by all studied heavy metal elements and the cancer risks posed by As, Cd, and Ni to both children and adults in Serbia fell within the acceptable range.

Spatial distribution of heavy metals and their potential sources in the soil of Yellow River Delta: a traditional oil field in China.

In this study, soil samples were collected from different layers throughout the whole Yellow River Delta (YERD), in north China. The total concentration of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), lead (Pb) and zinc (Zn) was determined to demonstrate their spatial distribution and pollution status in different layers of soils throughout the whole YERD. The obtained results suggested a relatively low contamination of heavy metals as observed through the evaluation of CF and RI. The potential ecological risk of Hg is not so severe. Also, the maximum potential threat could be noted only from Cd instead of Hg based on the widespread degree of pollution, which breaks traditional concept that oil production escalates mercury in the soil. The obtained value of EF proves a higher enrichment of heavy metals in the surface soil than in the layer of deep soil induced by human activities. Human activities only slightly elevate As, Cd and Pb. As has the strongest ability downward to lower layer, followed by Cd and Pb in YERD. The source of heavy metals predominantly stems from natural deposits, and their concentrations are controlled by the nature of their association with the mineral. Overall, it shows that the petroleum industry instead of agriculture could be treated as an important source to bring anthropogenic heavy metals in the soils. The human influence only elevated the concentration of heavy metals in the soil of the areas corresponding to the intensive production of oil. In this study some of the measures have also been proposed to avoid and control soil pollution as well as the health risk caused by heavy metals.

Quantitative assessment on soil concentration of heavy metal-contaminated soil with various sample pretreatment techniques and detection methods.

Detection and quantification of heavy metals in soil samples are significant in terms of environmental monitoring and risk assessment for metals. In order to improve the accuracy and precision to detect heavy metal, in this study, four standard samples (NASS-4, NASS-5, NASS-9, and NASS-16) were analyzed by evolving heating (electric heating plate, water bath, and microwave) and acidic systems (includes HCl, HNO3, HF, and HClO4). The result shows that different pretreatment methods have different effects on the extraction of heavy metal elements and five heavy metal elements (Cu, Zn, Pb, Ni, and Cr) were selected for optimization through pretreatment methods. Although the contents of heavy metals were same but we found diversity in the results. Under optimal conditions, the selected standard samples were analyzed by inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and atomic absorption spectroscopy (AAS), and the results were compared. The results show that different elements have their own most suitable detection methods, such as for Pb, the most suitable method is ICP-MS; and for Zn, the most suitable method is AAS. Pretreatment methods and detection techniques are combined to find and improve accuracy of results for certain elements. This study provides a reliable detection method for the accurate detection of heavy metals in the environment.

Reducible Fraction Dominates the Mobility of Vanadium in Soil Around an Iron Smelter.

Soil samples were collected to determine the pollution status, spatial distribution and mobility of Vanadium (V) in soil around an iron smelter in Panzhihua. The results showed that the topsoils and deep soils were unpolluted to moderately polluted and the subsurface soils was unpolluted with V. V concentrations in the topsoils decreased with the increase of the altitudes and the distances to the smelter. There was a great potential mobility of V in soil and the reductive dissolution of reducible V in the topsoils was responsible for the high concentration of V in the deep soils. Therefore, more attention should be paid to the reducible V when evaluating the mobility of V in soil.

Distribution, fractionation and risk assessment of mercury in surficial sediments of Nansi Lake, China.

Nansi Lake is composed of four sub-lakes from north to south: Nanyang Lake, Dushan Lake, Zhaoyang Lake and Weishan Lake. An environmental pollution investigation was carried out to determine the fractionation, and pollution assessments of mercury (Hg) in surficial sediments from Nansi Lake. Results showed that the mean concentration of Hg was 3.1 times higher than its background value (0.015 mg kg-1), and the high concentration of Hg which even reached up to five times than the background value in the part of Dushan Lake and Weishan Lake, which indicated that there are obvious spatial differences. The content of Hg was positively correlated with that of total organic carbon, and negatively correlated with that of pH and SiO2 in surface sediments. An improved Tessier sequential extraction procedure was used to study the fractions of Hg in sediments. The results indicated that Hg existed primarily in the fraction of residual, which accounts for 58.4% of total mercury (THg), and the percentage of extractable Hg was only 1.93% of total mercury. High concentrations of mercury of non-residual phase were found in part lake area from the Nanyang Lake and the Weishan Lake, which indicating a higher potential ecological risk relative to the other lake areas. Based on the values of enrichment factor and geo-accumulation index, most part of Dushan Lake and Nanyang Lake and Weishan Lake were in a moderate pollution. And based on the fractionation of mercury, risk assessment code of Hg exhibited low risks to the environment in Nansi Lake.

Vertical profile, contamination assessment of mercury and arsenic in sediment cores from typical intertidal zones of China.

The vertical profiles, contamination levels, and potential ecological risks of mercury and arsenic were studied from the sediment cores of seven typical intertidal zones, including the Liaohe River Estuary, the Jianhe River Estuary, the Dagu River Estuary, Yancheng Shoal, the Dongtan Yangtze River Estuary, Hangzhou Bay, and the Pearl River Estuary. Marine sediment quality standards, the threshold effect level (TEL), and the probable effect level (PEL) were used as guidelines to evaluate sediment quality. In addition, the geo-accumulation index (Igeo) and potential ecological risk index ([Formula: see text]) were used to assess contamination and potential ecological risks from mercury and arsenic. The results showed that the Pearl River Estuary was moderately polluted by mercury and represented a high potential ecological risk, while other areas were uncontaminated or mildly contaminated with low or moderate potential ecological risks. The Pearl River Estuary was mildly polluted by arsenic and represented a mild potential ecological risk, while other areas were unpolluted and also posed a mild potential ecological risk.

Assessment of heavy metal contamination of road dusts from industrial areas of Hyderabad, India.

Road dust in industrial areas carries high levels of toxic heavy metals. Exposure to such polluted dust significantly affects the health of people residing in these areas, which is of major concern. The present study was taken up with an aim to highlight the magnitude and potential sources of accumulation of heavy metals in 32 road dust samples collected from six industrial areas of Hyderabad. Acid-digested sample solutions were analyzed by ICP-MS for Cu, Zn, Cr, Co, Pb, Ni, V, Zr, Ce, Y, and Hf. The road dusts exhibit significantly high mean metal levels which are much above their crustal abundances. The relative ordering of mean metal contents is Zr > Zn > Pb > Cr > Ce > Cu > V > Ni > Y > Co > Hf. Elevated pollution indices (I geo, EF, C (i) f, and C deg) reveal that the road dusts are pollution impacted showing varying degree of heavy metal contamination. Strong positive correlations exhibited by metal pairs Cu-Zn, Cr-Ni, Ce-V, Y-Ce, and Hf-Zr imply their origin from common anthropogenic sources. Principal component analysis grouped the metals according to the sources which contributed to their accumulation. The present study confirms to an intensive anthropogenic impact on the accumulation of heavy metals in the studied road dusts attributable mainly to strong influences of vehicular and industrial activity and partly to domestic and natural processes. The results obtained imply the need for further investigations to assess their ecological implications and human health risks.

Particle size distribution and characteristics of heavy metals in road-deposited sediments from Beijing Olympic Park.

Due to rapid urbanization and industrialization, heavy metals in road-deposited sediments (RDSs) of parks are emitted into the terrestrial, atmospheric, and water environment, and have a severe impact on residents' and tourists' health. To identify the distribution and characteristic of heavy metals in RDS and to assess the road environmental quality in Chinese parks, samples were collected from Beijing Olympic Park in the present study. The results indicated that particles with small grain size (<150 µm) were the dominant fraction. The length of dry period was one of the main factors affecting the particle size distribution, as indicated by the variation of size fraction with the increase of dry days. The amount of heavy metal (i.e., Cu, Zn, Pb and Cd) content was the largest in particles with small size (<150 µm) among all samples. Specifically, the percentage of Cu, Zn, Pb and Cd in these particles was 74.7%, 55.5%, 56.6% and 71.3%, respectively. Heavy metals adsorbed in sediments may mainly be contributed by road traffic emissions. The contamination levels of Pb and Cd were higher than Cu and Zn on the basis of the mean heavy metal contents. Specifically, the geoaccumulation index (Igeo) decreased in the order: Cd>Pb>Cu>Zn. This study analyzed the mobility of heavy metals in sediments using partial sequential extraction with the Tessier procedure. The results revealed that the apparent mobility and potential metal bioavailability of heavy metals in the sediments, based on the exchangeable and carbonate fractions, decreased in the order: Cd>Zn≈Pb>Cu.

Arsenic fractionation and contamination assessment in sediments of thirteen lakes from the East Plain and Yungui Plateau Ecoregions, China.

Arsenic (As) fractions in the sediments of seven lakes from East Plain Ecoregion and six lakes from Yungui Plateau Ecoregion, China, were investigated. Results indicated that the total As concentrations in sediment samples of lakes of the East Plain Lake Ecoregion are higher than those of Yungui Plateau Lake Ecoregion. Residual As is the main fraction in sediment samples of lakes from both ecoregions, followed by reducible As and soluble or oxidizable As. The total As is correlated to oxidizable As and residual As in sediment samples from both lake ecoregions. As distribution in sediment samples of lakes of the East Plain Ecoregion appears to be affected by human activity, while the As origin mainly comes from natural sources in sediment samples of lakes in the Yungui Plateau Ecoregion. The potential ecological risk index and geoaccumulation index values suggest "low to moderate" risk degree and "unpolluted to moderately polluted" for As in the studied lake sediments.

Filling the Knowledge Gap Regarding Microbial Occupational Exposure Assessment in Waste Water Treatment Plants: A Scoping Review.

BACKGROUND: Wastewater treatment plants (WWTPs) are crucial in the scope of European Commission circular economy implementation. However, bioaerosol production may be a hazard for occupational and public health. A scoping review regarding microbial contamination exposure assessment in WWTPs was performed. METHODS: This study was performed through PRISMA methodology in PubMed, Scopus and Web of Science. RESULTS: 28 papers were selected for data extraction. The WWTPs' most common sampled sites are the aeration tank (42.86%), sludge dewatering basin (21.43%) and grit chamber. Air sampling is the preferred sampling technique and culture-based methods were the most frequently employed assays. Staphylococcus sp. (21.43%), Bacillus sp. (7.14%), Clostridium sp. (3.57%), Escherichia sp. (7.14%) and Legionella sp. (3.57%) were the most isolated bacteria and Aspergillus sp. (17.86%), Cladosporium sp. (10.71%) and Alternaria sp. (10.71%) dominated the fungal presence. CONCLUSIONS: This study allowed the identification of the following needs: (a) common protocol from the field (sampling campaign) to the lab (assays to employ); (b) standardized contextual information to be retrieved allowing a proper risk control and management; (c) the selection of the most suitable microbial targets to serve as indicators of harmful microbial exposure. Filling these gaps with further studies will help to provide robust science to policy makers and stakeholders.

Vertical distributions and potential contamination assessment of seldom monitored trace elements in three different land use types of Yellow River Delta.

The Yellow River Delta (YRD) is the second largest petrochemical base in China and the impact of human activities has been continuously increasing in recent decades, however, the contamination status of seldom monitored trace elements (SMTEs) in YRD has rarely been reported. This study evaluated the levels, vertical distributions, contamination status and sources of SMTEs in soil samples of three different land use types in YRD. The results indicated that the vertical distributions of SMTEs contents showed a gradually upward increasing trend for the soil profiles of black locust forest, while the SMTEs contents displayed a gradually upward decreasing trend for the soil profiles of cotton field. However, the SMTEs contents in the oil field area showed no significant difference among different depths. The vertical distributions of SMTEs were very likely related to the anthropogenic disturbance in the later stage. The environmental pollution status assessment of SMTEs showed obvious enrichment of Cs, Sn, and U in the soils of YRD. Moreover, the potential source analysis based on multivariate statistical methods indicated that Ga, Rb, Cs, Sc, Sn, Tl, Be, Bi, Ca and Mo were clustered together and positively correlated with Al, Fe, Mg and K, and may be mainly associated with geochemical weathering process, while the Ce, La, Th, U, Nb, Ta, and Hf may be impacted by both natural process and human activities. Though the SMTEs pollution status was not very serious, our results highlighted the non-negligible influence of anthropogenic activities on vertical distributions of SMTEs in three different land use types from YRD. Our results provide valuable information for understanding the vertical distribution and pollution status of SMTEs in YRD.