Heavy Metal Element Concentrations Research Articles

Potential toxic elements (PTEs) in rhizosphere soils and crops under a black shale high geological background: Pollution characteristics, distribution and risk assessment

The LouShao Basin in Hunan Province is covered with two sets of black rock series containing various potential toxic heavy metal elements. The rock series are rich in various potential toxic heavy metal elements, and the weathered black shale is the main formation of local farmland soil, making it a typical area with high geological background in China. The purpose of this study is to assess the regional ecological and health risks by studying the correlation between the content of heavy metal elements enriched in rhizosphere soil, non-rhizosphere soil, and crops, and the concentration of heavy metal elements in the main source, black shale rocks. The results show that the elements in the black shale far exceed the world average of rock, severely affecting soil element concentrations. Se element is the most severely polluted in rhizosphere soil, exceeding the background value by 7 times. The concentration of heavy metals between rock-non-rhizosphere soil-rhizosphere soil-crops decreases linearly. The distribution of pollution has strong spatial autocorrelation, and the high geological background is the main reason. Pollution index results show significant pollution of Se, Cr, Hg, and Cd in crops, with the pollution of heavy metal element Cr in corn being extremely serious with Igeo = 6.71. The ecological risk order is Se > Cd > Cr > As > Pb > Hg. Humans mainly contact elements through skin contact and food chain intake. The HI value of heavy metal element Cd is greater than 1, indicating a high carcinogenic risk. Human exposure to Cd through skin contact and food chain intake may lead to related diseases such as kidney stones, and pose greater harm to children.

Chemometric assessment of electronic cigarettes based on the ICP-MS determination of multiple heavy metal concentrations

To elucidate the concentrations of heavy metal elements in commercially available electronic cigarettes and improve quality assessment. Inductively coupled plasma-mass spectrometry (ICP-MS) coupled to chemometrics was used to determine the concentrations of Cr, Ni, As, Cd, Sn, Sb, Hg, and Pb in the e-liquids and aerosols derived from 32 electronic cigarettes sold commercially under six brand names. The e-liquids contained: 4.858 to 274.658 (Cr), 17.292 to 3068.375 (Ni), 3.217 to 29.867 (As), 0.225 to 24.717 (Cd), 0.783 to 17.042 (Sn), 0.658 to 36.033 (Sb), 0.658 to 187.592 (Hg), and 2.458 to 17.417 (Pb) ng g−1. The aerosol samples contained: 276.075 to 3333.175 (Cr), 72.908 to 1150.183 (Ni), 4.567 to 86.958 (As), 0.400 to 12.842 (Cd), 1.092 to 32.142 (Sn), 0.976 to 10.633 (Sb), 3.483 to 234.708 (Hg), 27.833 to 849.100 (Pb) ng 100 puffs−1. The recovery of heavy metals ranged from 99.1% to 112.4% in the e-liquids and from 87.3% to 116.6% in the aerosols, with RSD values below 10%. Hierarchical cluster analysis grouped the e-liquids into eight clusters, and the aerosols into five, indicating differences between products within brands and between different brands. Orthogonal partial least squares discriminant analysis coupled with variable importance in projection (VIP > 1) identified As and Sb as the primary heavy metals causing differences between the e-liquids, while differences between the aerosols were caused by Hg, As, Pb, Cd, and Cr. The use of chemometric methods yields a greater depth of information that will support improvements to the quality control of e-cigarette products and the assessment of their potential risk to human health.

Estimating the Heavy Metal Contents in Entisols from a Mining Area Based on Improved Spectral Indices and Catboost.

In the study of the inversion of soil multi-species heavy metal element concentrations using hyperspectral techniques, the selection of feature bands is very important. However, interactions among soil elements can lead to redundancy and instability of spectral features. In this study, heavy metal elements (Pb, Zn, Mn, and As) in entisols around a mining area in Harbin, Heilongjiang Province, China, were studied. To optimise the combination of spectral indices and their weights, radar plots of characteristic-band Pearson coefficients (RCBP) were used to screen three-band spectral index combinations of Pb, Zn, Mn, and As elements, while the Catboost algorithm was used to invert the concentrations of each element. The correlations of Fe with the four heavy metals were analysed from both concentration and characteristic band perspectives, while the effect of spectral inversion was further evaluated via spatial analysis. It was found that the regression model for the inversion of the Zn elemental concentration based on the optimised spectral index combinations had the best fit, with R2 = 0.8786 for the test set, followed by Mn (R2 = 0.8576), As (R2 = 0.7916), and Pb (R2 = 0.6022). As far as the characteristic bands are concerned, the best correlations of Fe with the Pb, Zn, Mn and As elements were 0.837, 0.711, 0.542 and 0.303, respectively. The spatial distribution and correlation of the spectral inversion concentrations of the As and Mn elements with the measured concentrations were consistent, and there were some differences in the results for Zn and Pb. Therefore, hyperspectral techniques and analysis of Fe elements have potential applications in the inversion of entisols heavy metal concentrations and can improve the quality monitoring efficiency of these soils.

A deep spectral prediction network to quantitatively determine heavy metal elements in soil by X-ray fluorescence

A deep spectral prediction network is proposed for the determination of soil heavy metal element concentrations.

Mechanism of bonding, surface property, electrical behaviour, and environmental friendliness of carbon/ceramic composites produced via the pyrolysis of coal waste with polysiloxane polymer

A simple mixing-pressing followed by thermal curing and pyrolysis process was used to upcycle coal waste into high-value composites. Three coal wastes of different physicochemical properties were investigated. The hypothetical mechanisms of bonding between the coal particles and the preceramic polymer are presented. The textural properties of the coals indicated that the lowest volatile coal waste (PCD) had a dense structure. This limited the diffusion and reaction of the preceramic polymer with the coal waste during pyrolysis, thereby leading to low-quality composites. The water contact angles of the composites up to 104° imply hydrophobic surfaces, hence, no external coating might be required. Analysis of the carbon phase confirmed that the amorphous carbon structure is prevalent in the composites compared to the coal wastes. The dc volume resistivity of the composites in the range of 22 to 82 Ω-cm infers that the composites are unlikely to suffer electrostatic discharge, which makes them useful in creating self-heating building parts. The leached concentrations of heavy metal elements from the composites based on the end-of-life scenario were below the Toxicity Characteristic Leaching Procedure regulatory limits. Additionally, the release potential or mobility of the metals from the composites was not influenced by the pH of the eluants used. On the basis of the reported results, these carbon/ceramic composites show tremendous prospects as building materials due to these properties.Graphical

Spatial distribution and ecological risk assessment of heavy metal elements in rock‐soil in the mountainous areas of Southwest China: A case study of Xichang

This study employs the Muller geological accumulation index method and the Hakanson risk assessment method in combination with ArcGIS technology to assess the potential heavy metal pollution in soil. The study aims to investigate the geochemical characteristics, pollution degree, and potential ecological risks associated with soil heavy metal element content and distribution across various geological formations. The concentrations of eight heavy metals, namely Cu, Cd, Ni, Pb, Zn, Hg, As, and Cr, were analysed by collecting samples of the soil layer, parent material layer, and parent rock layer. The proportions of samples with different risk levels are accurately calculated to locate areas with high pollution risks. The findings are as follows: Firstly, the soil pH value in the study area is low, and the Cd and Cr concentrations are 1.38 and 1.20 times the background concentrations in soil in Sichuan Province, respectively. Moreover, Cu, Cd, Ni, Zn, and Cr concentrations are 1.23, 1.10, 1.20, 1.10, and 1.55 times the background concentrations in soil in China. Secondly, the distribution of heavy metal elements varies across different geological formation units, and the heavy metal contents of different samples from the same formation also varies significantly. The concentrations of heavy metal elements are influenced by different geological formations, with the pedogenic parent rock in the soil determining the initial concentrations of heavy metal elements. Thirdly, the spatial distribution of heavy metal elements indicates a good spatial distribution coupling relationship among the soil layer, parent material layer, and rock layer. The study suggests that the contents of the eight heavy metal elements in the soil inherited the characteristics of the parent material to a large extent and are influenced and controlled by the pedogenic parent rock (geological formation). Finally, the evaluation results reveal that all eight heavy metal elements exhibit moderate pollution, with a relatively large distribution area exhibiting moderate Cd, Hg, and As pollution and above. The overall study area exhibits a mild potential ecological risk level, with some areas at a moderate potential ecological risk level, distributed in patches across the study area. Cd and Hg exhibit relatively high potential ecological risks. The potential ecological risks of heavy metals are relatively high in the JKms and Tss units. While the overall quality of the soil in the study area is good, heavy metal pollution and potential ecological risks of some elements are still above ideal levels.

The accumulation of element and heavy metal concentrations in different parts of some carrot and radish types.

Vegetables, which are an important part of human nutrition, are very rich in minerals necessary for human health, and heavy metals can be found in vegetables at high rates because they can be easily taken by plant roots and leaves. In this study, the macro, micro element and heavy metal element concentrations accumulated in different parts of some carrot and radish types were investigated. The element concentrations in the samples were analyzed by Inductively coupled plasma optical emission spectrometry (ICP-OES; Varian-Vista Model) equipment. P, K, Ca, Mg and S contents of the head of orange and black carrot samples were determined as 602.30 and 727.23mg/kg, 19,790.91 and 22,230.21mg/kg, 1765.66 and 1609.41mg/kg, 580.34 and 660.79mg/kg and 376.21 and 4444.46mg /kg respectively. Also, exterior parts of orange and black carrots contained 281.65 and 336.43mg/kg P, 7768.37 and 10,109.44mg/kg K, 169.88 and 272.18mg/kg Ca, 112.08 and 189.28mg/kg Mg and 135.43 and 217.60mg/kg S, respectively. P and K contents of the head parts of radish samples (white, red and black radish) were determined between 302.14 (red radish) and 1111.53mg/kg (black radish) to 13,717.2 (red radish) and 22,202.4mg/kg (white radish), respectively. Fe amounts of the roots of radish samples changed between20.47 (red radish) and 45.93mg/kg (white radish). As and Ba were the most abundant heavy metals in both carrot and radish parts. The Ni contents of the parts of the carrots contain more than 50% lower than the head part. Also, while Pb contents of the parts of orange carrot change between 0.189µg/g (interior of body) and 0.976µg/g (shell), Pb amounts of the black carrot parts were recorded between 0.136 (head) and 0.536µg/g (interior of body). The results obtained differed according to the vegetable type and parts. The head part of the radishes was the richest in zinc, followed by root, shell, exterior of body and interior of body in descending order. In general, the parts where heavy metals were most localized were the head and shell parts. The most localized parts of heavy metals in radishes were the head, shell and root parts. As a result, the most of the edible inner parts of carrots and radishes are thought to have a positive effect on human health, since their heavy metal content is low.

Heavy metal levels and sources in suspended particulate matters of the glacier watersheds in Northeast Tibetan Plateau

This study collected summer meltwater runoff samples from several glacier watersheds of the northeast Tibetan Plateau during June-July 2017, and measured the concentrations of 17 trace elements (Li, Be, Sc, V, Cr, Co, Ni, Cu, Zn, Ga, Rb, Mo, Cd, In, Sb, Cs, Ba) in meltwater suspended particulate matter (SPM), in order to reveal the elemental concentration, spatial distribution, and water quality in remote glacier watershed under regional anthropogenic activities. Results showed that, the concentration of heavy metal elements was relatively high in Yuzhufeng Glacier basin, ranging from 0.57 μg/L (In) to 1,551.6 μg/L (Ba), whereas in Qiyi Glacier basin it was the lowest, ranging from 0.02 to 85.05 μg/L; and relatively medium in other glacier watersheds, with total elemental concentration varying from 1,503.9 to 1726.2 μg/L. Moreover, enrichment factors (EFs) of SPM heavy metals showed significantly higher value in the downstream than that of upper glacier region of the watershed. Most heavy metals with low EFs mainly originated from crust dust, while others with higher EFs (e.g., Cd, Sb) probably originated from anthropogenic sources. Spatially, the EFs of heavy metals were higher in Yuzhufeng and Laohugou Glacier basins; while in other regions the EFs were relatively low, which may be caused by regional land-surface and atmospheric environmental differences surrounding the various glacier watersheds. Compared with other remote locations in global range, heavy metals level (e.g., Cu, Ni, and Zn) in this region is relatively higher. Meanwhile, we find that, though the water quality of the glacier basin in northeast Tibetan Plateau was relatively clean and pollution-free, it is still obviously affected by regional anthropogenic activities. Mining activities, transportation and natural weathering and erosion processes in the study areas have important effects on the content of heavy metal pollutants of river-water SPM in the glacier watershed. Moreover, backward air-mass trajectories demonstrated the potential atmospheric pollutants transport from the surrounding cities and suburbs, to deposit in the snowpack and glaciers, and then melted out and released into meltwater runoff. This study provides a new perspective on more complete view of heavy metals distribution in glacier watershed, and new understanding for the cryosphere water environment evaluation in the Tibetan Plateau region.

Evaluation of the impact factors on the leaching risk of steel slag and its asphalt mixture

In recent years, there has been an increasing interest in steel slag asphalt mixtures. Steel slag has good mechanical properties, but there is a risk of leaching of heavy metal elements during the steel slag stockpiling process and after paving asphalt pavement. Therefore, this work firstly investigated the effect of different influencing factors on the leaching concentration of heavy metal elements during the steel slag stockpiling process and analyzed the leaching mechanism by microstructure. Then, the gray relational analysis method was adopted to compare the magnitude of the effects of asphalt type, grade type, binder content and temperature on the leaching concentration of heavy metal elements in steel slag asphalt mixes. The results showed that the leaching concentration of heavy metal elements from steel slag increased rapidly due to the acid rain effect. With the formation of CaSO4 crystals to fill the micro-pores on the steel slag surface, the leaching concentration of heavy metals slowed down. Cu is the element with the largest leaching risk coefficient. The increase of specific surface area and the decrease of pH value will increase the leaching risk of heavy metals in steel slag. The leaching risk of steel slag was significantly reduced after it was prepared into asphalt mixes. The main influencing factor for the leaching risk of heavy metal elements from steel slag asphalt mixes is the type of grading, the secondary factors are temperature and asphalt content. Considering the high temperature environment common in asphalt pavements during use, it is recommended to use dense-graded asphalt mixtures in areas of high temperatures.

Wet Scavenging in Removing Chemical Compositions and Aerosols: A Case Study Over the Lake Urmia

AbstractLake Urmia, NW Iran, and S Caucasus region, has lost approximately three‐fourth of its water volume resulting in increased exposure of lacustrine deposits. Therefore, the role of Lake Urmia desiccated saline lands on local aerosols and rainwater compositions is still vague. This study investigates the temporal and seasonal patterns of rainwater chemistry from January 2018 to June 2018 (six months) in 13 stations throughout the Lake Urmia basin. The samples collected were analyzed using triple quadrupole inductively coupled plasma mass spectrometry (ICP‐QQQ) and ion chromatography (IC) to measure elemental and ionic concentrations. Then, the Hybrid Single‐Particle Lagrangian Integrated Trajectory model (HYSPLIT) was applied to identify the pathway and contribution of emissions. The results depict that the concentration of elemental and ionic components over different parts of the Lake Urmia basin are significantly different. West and north directions have the highest concentrations of marine ions associated with fewer toxic elements. In contrast, the east and south directions show a high concentration of heavy metal elements and ions. The high level of heavy and toxic elements at the east and south directions indicates that local anthropogenic sources are more influential. The seasonal and monthly variabilities of chemical compositions depict that the highest concentration of Na+, Mg2+, Ca2+, K+, Cl−, Br−, NO3−, Al, Cr, Mn, Fe, and Co were in the spring season and SO42−, NH4+ and NO2− were highest in winter. Seasonal variation for MSA, organic acids (i.e., Pyruvate, Adipate, and Oxalate), Ni, Cu, Zn, V, and Ti were not apparent. Cluster‐mean HYSPLIT backward trajectories results show the most dominant air mass sectors are from W (a: Iraq, Syria, and Arabian deserts; b: Mediterranean Sea; and c: KSA) and NE (the Caspian Sea and its vicinity), contributed to almost 65% and 22%, respectively. These air masses bring a significant quantity of crustal and marine aerosols, respectively. It is inferred that the Lake Urmia dried‐up lakebeds have less impact on the contribution of emissions across the region.

Security Risk and Influencing Factors of Agro-Products in Farmland Soil Around a Typical Mining Smelter

The security risks of heavy metal pollution in agro-products are becoming increasingly serious. This paper investigated the heavy metal contamination of farmland soils and agro-products around a typical mining smelter in Hunan province, and explored the influencing factors based on principal component and correlation analyses. The results showed that the soils were significantly contaminated by heavy metals, with a mean concentrations of Cd, Cu, Pb, and Zn of 9.12, 358, 303, and 185 mg·kg-1, respectively, pH range from 4.67 to 7.22. All the sites included were under strict control. With regards to the agro-products, the concentration of heavy metal elements were different, and the order of heavy metal concentrations was Zn>Cu>Pb>Cd, with an order of biological enrichment factor(BCF) of Cd>Zn>Cu>Pb. Over-the-standard elements in agro-products included Pb and Cd at 78% and 41%, respectively, which indicated a higher security risk from these products. The accumulation of the same heavy metals in leaf vegetables were generally higher than sweet potatoes and solanaceous vegetables. The heavy metal concentrations in soils corresponded to the first principal component(P<0.01), with the variance reaching 88.0%, which dominated the sources of Cd, Cu, Pb, and Zn in agro-products. The enrichment characteristics were mainly affected by the type of crops, and was also regulated by the soil pH, cation exchange capacity, and soil organic matter(the correlation coefficients of r were -0.407- -0.641, P<0.05). In conclusion, there was a combined heavy metal pollution and high risk in soils and agro-products. Therefore, the planting of crops in the study area should be avoided, and soil remediation measures should be implemented to reduce security risks.

Analysis of the spatial distribution of heavy metals in an area of farmland in Sichuan province, China

To accurately visualize the spatial distribution of heavy metal pollution and provide information that assists in remediating farmland soil, this study employed GIS technology and collected 0–20 cm-depth surface soil and shallow groundwater samples from farmland in Jianxin Village, Xiba Town, Wutongqiao City, Sichuan Province, China. The soil samples were decomposed using a high-temperature closed digestion method, and the contents of Cr, Cd, Pb, As, Cu and Zn were determined using ICP-MS. A geographic semi-variogram analysis was then conducted to delineate spatial variations in the heavy metal concentrations within the soil, and a spatial distribution map of heavy metals in the soil was drawn using ArcGIS10.2 software based on a GIS Kriging interpolation spatial structure analysis. The results showed that all heavy metal element concentrations exceeded the soil background values of Sichuan Province; the exceeded rates of Cr, Cd, and Zn were 100%. All Cd samples exceeded the soil baseline value, and the pollution accumulation of Cr, Cd, and Zn was determined as being serious. Through a comparison of cross-validation methods, a theoretical optimal semi-variogram model of six heavy metal elements was obtained. Indexes C0/(C0 + C) of Cd, Pb, As, Cu, and Zn were in the range of 48–75%, which showed that their contents related to structural factors, such as the soil parent material and topography, and also to non-structural factors such as human activities. The index C0/(C0 + C) of Cr was more than 75%, which indicates that its content is mainly related to non-structural factors and human activities. The spatial correlation followed the order of Cu > Cd > Pb > Zn > As > Cr. The vertical distribution of heavy metals was greatly affected by the soil physical properties: the Cu and Pb contents of sandy soil decreased at first and then increased with depth; the Cr, Zn, and As contents first increased and then decreased with depth; and the Cd contents decreased with depth. In clay soil, there was little change in the Cu content with depth; the Cd, Zn, Pb, and As contents first decreased and then increased with depth, and the Cr content increased first and then decreased with depth. These results show that visualizing the spatial distribution of heavy metal contamination using GIS technology is significant for providing information that can be used to remediate farmland soil.

Assessment of potential ecological risk index based on heavy metal elements for organic farming in micro catchments under humid ecological condition

Soil pollution, influenced by both the natural and anthropogenic factors, significantly reduces environmental quality. This research was carried out in some micro catchments located on Ordu province of Black Sea Region-Turkey in order to determine potential ecological risk index based on heavy metal elements (HMs) for organic farming. For this purpose, 166 soil samples (0-20 cm) were taken from the study area and some physical and chemical and HM concentrations (Cd, Cu, Cr, Ni, Pb and Zn) analysis were done. In this study, it was determined; i-) some physical and chemical properties of catchments’ soils, ii-) HM contents and the correlation relation between physico-chemical properties of soil and HM concentrations and iii-) potential ecological risk index (PERI). PERI was calculated using the data obtained to evaluate the environmental risks of HMs in the region. The results showed that Cu concentration in 3%, Cr in 0.6% and Ni in 4.8% of the soil samples exceeded the threshold levels whereas, the concentrations of other HMs were lower than the critical values. Statistically, it was also found significantly positive relationships between sand content and Cu of soils whereas, it was determined significantly negative relationships between EC and Cu. In addition, according to the obtained PERI results, while 54% of total soil samples were low while, 42% of them were moderate class. Only 4% of them were classified as significant ecological risk level. Moreover, according to mean potential ecological risk index of these HMs, it can be ordered as Cd>Pb>Cu>Ni> Zn>Cr.

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.

Derivation of the Thresholds of Available Concentrations of Heavy Metals in Soil Based on Agricultural Product Safety

Based on the total and available concentrations of heavy metal elements in agricultural soil, and the concentrations of heavy metals in rice collected from Daye city, Hubei province, and the thresholds of available concentrations of heavy metals were derived by species sensitivity distribution (SSD). The over-standard rates of Cd and Cu in the soil were 90.7% and 42.6%, respectively, which indicates that agricultural soil in Daye city exhibits signs of Cd and Cu pollution. The rates of Cd and Pb were 50.9% and 89.8% in brown rice samples, respectively, which exceeds the safety standards of agricultural products. The SSD curves for Cd and Pb were fitted with BurrⅢ distribution based on the ratio of the concentration in brown rice and the available concentration in the soil. The hazardous concentrations (HC5) were derived inversely from the agriculture product safety standards. The thresholds of available Cd and Pb were 0.02 mg·kg-1 and 0.005 mg·kg-1, respectively. Compared with those of available Cd in other countries and studies, the threshold of available Cd is scientifically shown to be reasonable. Soil is not necessarily the main source of Pb in rice; thus, the rice species does not represent the derivation of the threshold of available Pb. Moreover, a lack of the accumulation data of Pb at low accumulation levels and multiple soil pollution levels leads to unreliable derivation. The results indicate that the threshold of available Pb does not have practical significance in soil pollution control.

STUDY OF THE PHYSICO-CHEMICAL PARAMETERS CHARACTERIZING THE QUALITY OF EL’MENIA LAKE. ALGERIA

The objective of this work is to evaluate the physico-chemical quality of El-Menia Lake, experiencing the effect of the discharges of waste water in this lake. The results of physico-chemical study show that El-Menia Lake is characterized by a high conductivity and very hard quality with remarkable pollution in most points. Concerning the concentrations of heavy metal elements we found a high concentration in some metals like the lead, cadmium, cobalt and some metals less than standard value of surface water.

Second-Hand Infant Care Plastic Products Sold in Markets of Kalar City, Kurdistan Region, Iraq: Heavy Metals Contamination and Risk Assessment

In this study, health risk assessment and contamination have been performed of fourteen toxic heavy metals in six second-hand plastic infant care products collected from markets of Kalar city, Kurdistan region of Iraq. Second-hand infant care plastic products might impose serious health concerns if they contain high levels of heavy metals. The toxic heavy metal elements concentrations have been identified and analyzed using inductively coupled plasma optical emission spectroscopy (ICPOES, Spectro Arcos). Many of the investigated products contain considerable or high levels of the examined heavy metals according to the European Union EU safety limits for brittle, pliable, liquid and sticky toy materials. The highest level of heavy metals has been noticed was of zinc 10643.4 mg/kg in sample ST1 (183% higher than the allowable limit). High concentrations of lead Pb, mercury Hg, and chrome Cr have also detected. Statistical analysis of Pearson correlation matrix CM, and hierarchical cluster analysis HCA found significant correlations between many heavy metals and infant care samples respectively. Health risk assessment for sample ST6 identified a moderate significant hazard index regarding heavy metals of arsenic, mercury, and cobalt with HI values of 0.5652, 0.2967 and 0.1211 respectively. This work leads thus safety measure is respected in the investigated infant care samples. Furthermore, stringent procedures are needed to limit the handling and importing of such products into the markets in the future.

Spatiotemporal variability of heavy metals and identification of potential source tracers in the surface water of the Lhasa River basin.

The Lhasa River basin is the economic and population center of Tibet and has abundant resources. Due to its harsh weather condition, high elevation, and inconvenient accessibility, few studies have focused on heavy metal distributions in this region. In the present study, to investigate the dissolved trace metal pollution and its controlling factors, 57 water samples from the Lhasa River and its tributaries were collected during three water flow regimes in 2016. The data on the dissolved fraction revealed that the Lhasa River basin appeared to have no to low pollution levels. However, the Lhasa River water showed alkaline characteristics which may affect the presence of heavy metal elements in a dissolved fraction. The concentration of heavy metal elements in colloidal or particulate matter therefore needs attention. Multivariate analyses were performed to determine the significant relationship between the data and to identify controlling factors for dissolved heavy metals in the study area. The results suggested that Mn, Cd, Cu, and Zn originated from a natural geological background, whereas Pb originated from mining drainage and As was influenced by geothermal flows. The concentration of dissolved heavy metals in the Meldromarchu tributary was greatly affected by the mining drainage water, while that in the Tölungchu tributary was greatly influenced by the geothermal water sources. This paper provides the first comprehensive analysis of dissolved heavy metal pollution characteristics and the controlling factors of pollution during the three different water flow regimes of the Lhasa River basin.

Geochemical characteristics and source analysis of soil heavy metals in Luling coal mine, northern Anhui Province

In order to understand the characteristics of soil heavy metal pollution in Luling Coalmine Area, we collected 26 soil samples, and using X-ray fluorescence to determine the concentrations of heavy metal elements. The method of factor analysis and cluster analysis are applied to identify the sources of heavy metal pollution. Results show that: (1) the average contents of heavy metal elements in soil is: Co<Pb<Cu<Ti<Zn<Cr<V<Mn, coefficient of variation shows the coal mining activities have a certain degree of pollution of Zn, Cu, Co. (2) Co and (Mn, Cu), Ti and (Cr, V) are significantly correlation, V and (Mn, Cr), Cu and Mn have a certain correlation, low correlation between Pb, Zn and other elements; (3) the results of factor analysis showed that heavy metal elements can be extracted into three factors, FC1 is controlled by Mn-Pb-Cu-Co, FC2 controlled by Ti-Cr-V, while the FC3 is controlled by Zn, combined with the practical, consider three factors representing coal mining factors, natural factors, traffic factors; cluster analysis also has consistent conclusion with the factor analysis.

Evaluating Metal Effects on the Reflectance Spectra of Plant Leaves during Different Seasons in Post-Mining Areas, China

This study examined the relationship between the leaf reflectance of different seasons and the concentration of heavy metal elements in leaves, such as Co, Cu, Mo, and Ni in a post-mining area. The reflectance spectra and leaf samples of three typical plants were measured and collected in a whole growth cycle (June, July, August, and September). The Red Edge Position (REP), Readjustment Normalized Difference Vegetation Index (RE-NDVI), and Photochemical Reflectance Index (PRI) were extracted and used to explore its relation with the heavy metals concentrations in leaves between different seasons. The results show that all three Vegetation Indices (VIs) were insensitive indicators for monitoring the metal effects of vegetation in different seasons, which showed similar trends. Based on this, the Continuum Removal Indices (CRIs) were proposed from the continuum removed approach and extended for detecting the effects of heavy metal pollution over a full growth cycle. The relationship between the metal concentrations and CRIs of different plants was respectively analyzed by Stepwise Multiple Linear Regression (SMLR) and Partial Least Squares Regression (PLSR). It is found that a significant correlation exists between the band depth and the concentration of Cu and Ni based on the White birch data sets using the PLSR, resulting in a small deviation from the established relationships. Compared with VIs, the approach of coupling CRIs and multiple regressions was effective for improving the estimation accuracy. The presented study provides a detection model of leaf heavy metals that can be adapted to different growing cycles, even an arbitrary growing cycle.