Average Concentrations Of Cr Research Articles

Reduction of Hexavalent Chromium from Soil of the Relocated Factory Area with Rice Straw Hydrothermal Carbon Modified by Nano Zero-Valent Iron (nZVI).

In order to reduce the content of Cr(VI) in the soil of the relocated chromium salt factory, the rice straw-derived hydrothermal carbon was prepared by hydrothermal method and loaded with nano zero-valent iron generated by liquid phase reduction, which effectively alleviated the self-aggregation problem of nano zero-valent iron (nZVI) in the treatment of Cr(VI) and improved the Cr(VI) reduction rate without changing the soil structure. The reduction effect of Cr(VI) in soil by key influencing factors such as carbon-iron ratio, initial pH value, and initial temperature was investigated. The results showed that nZVI modified hydro-thermal carbon composite (named RC-nZVI) had a good reduction effect on Cr(VI). Scanning electron microscope (SEM) and energy spectrum analysis showed that nZVI was evenly distributed on the surface of hydrothermal carbon, which effectively reduced the agglomeration of iron. Under the conditions of C/Fe = 1:2, 60 °C, with pH of 2, the average Cr(VI) content in soil decreased from 182.9 mg kg-1 to 21.6 mg kg-1. Adsorption kinetics of Cr(VI) by RC-nZVI fit well with the pseudo-second-order model, and the kinetic velocity constant revealed that Cr(VI) reduction rate decreased with increasing initial Cr(VI) concentration. Cr(VI) reduction by RC-nZVI was mainly dominated by chemical adsorption.

Characteristics and Source Analysis of Heavy Metals in Farmland Soil on the South of Dongting Lake

Based on the grid distribution method, 1589 topsoil samples were collected from farmland on the south side of Dongting Lake from April to August 2020. The content, potential ecological risk, spatial distribution characteristics, and source analysis of heavy metals in the soil were studied. The concentrations and pH of As, Cd, Pb, Cu, Zn, Ni, Cr, and Hg in the soil were determined using ICP-MS, ICP-OES, HG-AFS, and ISE methods. The results showed that the average concentrations of Zn, Cr, Pb, Cu, Ni, As, Cd, and Hg were 118.18, 82.21, 52.1, 33.76, 32.81, 18.25, 0.42, and 0.13 mg·kg-1, respectively. All heavy metals had medium or high variability. The soil was mainly weakly acidic with a pH between 3.96 and 7.90. Hg and Cd had high ecological risks. The spatial distribution of heavy metals showed a tendency of being high in the southwest and low in the northeast. The PMF and PCA methods were used to analyze the sources and calculate the contribution rates of the eight types of heavy metals. The PMF results showed that the contribution rates of soil heavy metals in the study area were as follows:agricultural activity sources (36.98%), natural sources (32.94%), water and soil exchange sources (17.05%), and atmospheric dry and wet deposition sources (13.03%). The PCA results showed that the soil heavy metals in the study area mainly came from agricultural activity sources (68.04%), natural sources (31.02%), and atmospheric deposition sources (0.94%). The conclusions of the two source analysis methods tended to be consistent, that is, agricultural activities were the main source of soil heavy metals in the study area. The vertical profile analysis showed that the contents of Cd, Hg, and Pb elements were high in the surface layer and low in the deep layer, and the phenomenon of anthropogenic input was obvious. These results can provide a scientific basis for the formulation of prevention and control countermeasures of farmland soil heavy metal pollution around Dongting Lake.

Bioaccumulation and health risks of multiple trace metals in fish species from the heavily sediment-laden Yellow River

The health risk caused by metal pollution is a global concern due to potential metal bioaccumulation, toxicity, and carcinogenicity with multiple sources and pathways. Here, the factors influencing metal bioaccumulation in more than a thousand fish individuals were investigated along a 5464 km continuum of the heavily sediment-laden Yellow River and the health risks to humans were evaluated. The average concentrations of Cr, Zn, As, Cu, Cd, and Pb were below the permissible limits established by domestic and foreign organizations. The fish showed biomagnification of Se and Sn through trophic transfer and a growth dilution effect for V, Mn, Co, Ni, Cu, Zn, As, Cd, and Ba. The concentrations and distributions of most metals in fish were mainly influenced by the trophic levels (δ15N) of fish and the content of the metals in the aquatic environment. The consumption of fish from the Yellow River does not pose a noncarcinogenic risk to the health of adults and juveniles. Cr and As could cause carcinogenic risks, and Cd and Pb also have carcinogenic risks, but these were within an acceptable range. The carcinogenic risks of fish consumption were relatively low in regions with low levels of metal pollution, such as the source region, while the risks were high in regions with heavy pollution and carnivorous fish at high trophic levels. In response to this threat, people can minimize these risks by adjusting their diet and appropriately reducing their consumption of aquatic products from the Yellow River.

Impact of Irrigation with Contaminated Water on Heavy Metal Bioaccumulation in Water Chestnut (Trapa natans L.)

This study investigated the monitoring of six heavy metals (Cd, Cr, Cu, Fe, Mn, and Zn) in pond water, sludge, and cultivated water chestnut (Trapa natans L.) crops in Saharanpur district of Uttar Pradesh, India. For this purpose, samples of pond water, sludge, and T. natans plant (nut, shoot, and root) were collected in November of 2021 and 2022 from three zones (Zone 1: agricultural area irrigated with borewell water, Zone 2: urban area irrigated with municipal wastewater, and Zone 3: rural area irrigated with mixed type of wastewater) and subsequently analyzed for heavy metal concentration using atomic absorption spectroscopy. The results showed that the physicochemical and heavy metal characteristics of pond water and sludge were significantly (p < 0.05) higher in Zone 2 and 3 than to those in Zone 1. The concentration of heavy metals in T. natans root was comparatively high followed by shoot and nut parts. The bioaccumulation factor (BAF) was maximum while using pond water as a reference medium compared to pond sludge. Overall, the increasing order of heavy metals in T. natans was observed as Cd < Cr < Cu < Zn < Mn < Fe. In the edible part (nut) of T. natans, the average contents of Cd (0.005 ± 0.002 mg/kg), Cr (0.134 ± 0.009 mg/kg), Cu (1.043 ± 0.104 mg/kg), Fe (9.589 ± 0.957 mg/kg), Mn (4.326 ± 0.753 mg/kg), and Zn (1.540 ± 0.537 mg/kg) were comparatively less than shoot and root parts. Overall, the results revealed that T. natans irrigated with contaminated irrigation supplies at Zone 2 and 3 showed the highest BAF of heavy metals than Zone 1. Because the heavy metal concentrations in edible parts of T. natans did not exceed the threshold limits, the contaminated water sources in the Saharanpur region of India should be used in a safe and controlled manner.

Outdoor Air Contaminants-Heavy Metals and Associated Health Risks in Duhok-Iraq

Toxic elements in the atmosphere can cause a variety of health and environmental problems. The current work aims to assess the concentrations of heavy metals associated with the air in the Duhok city-Kurdistan Region of Iraq. For the first time a low volume sampling pump with Glass Microfiber Filter paper was used. Forty samples of air filter aerosol particles were collected from several areas in the Duhok city, during the dry and rainy seasons. Samples of air filters were prepared by a microwave digestion system and assessed by inductively coupled plasma Optical-Emission Spectrometry (ICP-OES). The average concentrations of Cr, Zn, Ni, Cd, Fe, and Pb found in 20 sites in the study area for the dry season were 0.004 mg/m3, 0.007 mg/m3, 0.003 mg/m3, 0.002 mg/m3, 0.142 mg/m3, and 0.402 mg/m3 respectively. Also, the average levels of the mentioned elements were 0.003 mg/m3, 0.004 mg/m3, 0.012 mg/m3, 0.003 mg/m3, 0.138 mg/m3, and 0.645 mg/m3 respectively in wet season. Seasonal results confirmed no significant differences in the concentrations of elements measured at all study sites, with the exception of lead, which doubles during the rainy season. Results showed that the levels of metal concentrations in the present study exceeded the standard limits of WHO. The results of the health risk assessment showed that the population in Duhok city had a higher lifetime chance of developing cancer as a result of these air concentrations and their heavy metal content.

Heavy Metals in Soil around a Typical Antimony Mine Area of China: Pollution Characteristics, Land Cover Influence and Source Identification.

To understand contamination characteristics and identify sources of heavy metals in soil affected by complex mine activities, a detailed survey of soil heavy metals from different land cover types was investigated around the Xikuangshan (XKS) antimony mine in south-central China. Soil samples had average concentrations of Sb, As, Cd, Cr, Hg, Pb, Cu, Zn and Ni exceeding their background level in the Hunan province. Sb, As and Cd were the main pollutants. A total of 86.8% of samples were severely polluted, characterized by the Nemerow's comprehensive index, and 68.4% of samples were of very high potential ecological risk, primarily contributed by Sb, Cd and Hg. Among different land cover patterns, Hg, Pb and Cd concentrations showed a statistically significant difference. The application of Pearson correlation, principal component analysis (PCA) and hierarchical cluster analysis (HCA) combined with spatial interpolation GIS mapping revealed that Ni, Cr and Cu were mainly from natural parent materials, whereas other heavy metals were related to anthropogenic sources. Pb, As and Hg were mainly derived from smelting processes of sulfide minerals in the XKS area. The agricultural practice is the main factor for the accumulation of Cd and Zn, and sphalerite smelting also contributed to high Zn concentrations. Particularly, spatial variation of soil Sb concentrations was affected by multiple factors of complex antimony mine activities related to mining, beneficiation and smelting in the XKS area. These results are useful for the prevention and reduction of heavy metal contamination in soils by various effective measures in typical regions affected by antimony mine activities.

Pollution Levels for Airborne Hexavalent Chromium of PM2.5 in Typical Cities of China

As a carcinogenic pollutant, hexavalent chromium (Cr(VI)) in the ambient air has serious influences on public health. Due to its instability and difficulty in chemical analysis, few studies have been conducted on the regional concentration level of environmental Cr(VI), especially in China. The pollution levels of Cr(VI) in ambient PM2.5 were determined in two sampling sites of Beijing and Qingdao from September to December 2020. The concentrations of Cr(VI) were determined using Ion Chromatography-inductively coupled plasma mass spectrometry(IC-ICP-MS), and the Cr concentrations were simultaneously analyzed by Inductively Coupled Plasma-atomic emission spectrometry(ICP-AES). The main results are as follows: (1) Based on the analysis of samples collected at the sampling sites of Beijing and Qingdao, the concentrations of Cr(VI) in PM2.5 were (0.140 ± 0.065) ng/m3 and (0.091 ± 0.073) ng/m3, respectively; (2) During the sampling period, the mean ratio of Cr(VI) to Cr was (0.0623 ± 0.0969). The ratio of Cr(VI)/Cr in Beijing and Qingdao were 0.076 ± 0.104 and 0.041 ± 0.039, respectively. In conclusion, compared with other countries, the concentration of Cr(VI) at the sampling sites of Beijing and Qingdao showed lower values. The average concentration of Cr(VI) estimated by the ratio of this research in China is lower than that in South Korea and similar to those in Canada and Australia.

Analysis of Critical Source of Potentially Harmful Elements in Urban Road Dust During Winter in Taiyuan Based on Multiple Attribute Decision Making Method

In order to analyze the critical sources of potential harmful elements (PHEs) in road dust from Taiyuan during winter, 40 road dust samples were collected. The contents of PHEs, including As, Cd, Pb, Ni, Cr, Cu, and Zn, in the road dust samples were measured using inductively coupled plasma mass spectrometry and atomic fluorescence spectrometry. The ecological risks and human health risks posed by dust PHEs were assessed using NIRI and a health risk evaluation model recommended by USEPA, respectively. The sources of dust PHEs were identified by using the combination of principal component analysis and positive matrix factorization (PMF); the total PHE contents and the ecological risks and human health risks posed by PHEs in dust were apportioned to the PHE sources based on the PMF results; subsequently, the critical source of dust PHEs was determined using the multiple attribute decision making method (MADM). The results demonstrated that: 1 the average concentrations of As, Cd, Pb, Ni, Cr, Cu, and Zn were 17.92, 0.32, 69.10, 30.06, 107.74, 73.37, and 268.49 mg·kg-1, respectively, which were higher than the corresponding background values of soil in Taiyuan, indicating that the PHEs had accumulated in road dust; the mean value of NIRI was 63.86, demonstrating that PHEs in dust posed moderate risks, and the dust PHEs pollution was controllable. 2 Human health risk assessment indicated that exposure to PHEs in dust did not pose serious non-carcinogenic or carcinogenic risks. Ingestion was the most important pathway for exposure to PHEs in road dust that damages human health, and As and Cr have been found to pose the most risks among the seven PHEs. 3 The present study found three main sources of PHEs measured in the dust: natural, traffic, and industrial, which accounted for 35.95%, 40.25%, and 23.82% of the total concentrations of PHEs, respectively. 4 Industrial emissions contributed the least to the total PHEs contents in dust; however, the PHEs released from industrial sources caused relatively high risks, with the results of MADM indicating that industrial sources were the most critical source for dust PHEs. Our results indicated that the critical source identification of PHEs, which was determined to be the most pernicious source, could provide reference for subsequent pollution source control.

Groundwater quality index and potential human health risk assessment of heavy metals in water: A case study of Calabar metropolis, Nigeria

The study aims to determine the spatial variability of physico-chemical characteristics and heavy metals constituent of groundwater within Calabar Metropolis, as well as the potential human health risk of adults and children to heavy metals through ingestion and dermal pathways. Fifty groundwater samples were collected from different locations and analyzed for pH, total dissolved solids, temperature, electrical conductivity, Zinc, Chromium, and iron following standard methods. The variables were subjected to principal axis factoring analysis, hierarchical cluster analysis, and geospatial analysis. The water quality index of the study area was determined using the weighted average water quality index (WAWQI) method while the potential health risk was assessed in accordance with the USEPA approach. The average concentrations of Cr, Fe, and Zn were 0.02 mg/l, 0.05 mg/l, and 0.22 mg/l, respectively. The results of the factor analysis revealed that the contamination from dissolved solids were probably from geogenic sources. The comparison of the results with the WHO standard revealed that the permissible limits for EC and Cr in drinking water were exceeded in 2 % and 4 % of the locations, respectively. The water quality of the study area ranges within four categories: “good” to “very poor”. The order of toxicity of heavy metals based on mean concentration and total hazard quotient s (HQs) for both adults and children was as follows Zn > Fe > Cr. The total mean HQs for adults and children, for Cr, Zn and Fe were obtained as 4.63E-01, 2.10E + 01, 2.06E + 00 and 1.62E + 00, 7.35E + 01, 7.21E + 00, respectively. The hazard index values obtained from the human health risk analysis for both adults and children revealed that the heavy metals (HMs) had a significant contribution to non-carcinogenic risk (HI > 1) due to exposure to groundwater from the study area. Children were more at risk compared to adults (mean HIchildren = 8.24E + 01 > mean HIadult = 2.35E + 01). The lifetime cancer risk due to Cr was significant for both adults and children (mean LTCRadult = 3.47*10-1 > 10-6, mean LTCRchildren = 1.22 > 10-6). The range of water quality rating calls for concern and immediate action.

Determination of Heavy Metals in Green Leafy Vegetables along Roadsides by Lagos-Badagry Expressway in Lagos, Nigeria

Heavy metals being natural components of the earth’s crust, cannot be degraded or destroyed. They are ubiquitous, so enter the human body through food, water and air, which in high concentrations in biological systems result in human diseases and disorders. Vegetable samples which included leaves of lettuce, spinach and pumpkin were collected from three wayside farms namely; Abule Ado, Abule Oshun and Oluti. A total of 36 samples were collected for the assessment of the heavy metal contents in the vegetables, which included lead (Pb), Zinc (Zn), Cadmium (Cd) and Chromium (Cr) using Flame Atomic Absorption Spectrophotometer (Buck Scientific 210 VGP model) in mg/kg. The average concentration of Pb, Zn, Cd and Cr in lettuce were 29.70, 25.85, 1.6 and 16.54 respectively. The mean concentration of Pb, Zn, Cd and Cr in spinach leaves were 28.84, 38. 43, 0.66 and 19.57 while the average concentration of Pb, Zn, Cd and Cr in pumpkin were 22.98, 38. 70, 0.70 and 29.70 mg/kg respectively. Lettuce had the highest concentration of Pb, while pumpkin had the least Pb concentration. Pumpkin had the highest concentration of Zn, followed by spinach, and the least concentration in lettuce. Lettuce had the highest concentration of Cd, followed by pumpkin and spinach with the least concentration of Cd. The highest concentration of Cr was observed in spinach, followed by lettuce, while pumpkin had the least Cr concentration. This study revealed that the concentrations of Pb, Zn, and Cd were within acceptable limits according to WHO, while Cr was found above that limit. If ingested, the heavy metals result in bioaccumulation and biomagnification, which as well lead to human disorders with children at higher risks than adults.

Health risk assessment of heavy metals in drinking water: a case study in western cities of Mazandaran province, Iran

ABSTRACT Industrialisation and urbanisation in the world and Iran have led to high levels of heavy metal contamination in water resources. The health risk of exposure to heavy metals via drinking water in two western cities of Mazandaran province, Iran was assessed. The concentrations of arsenic (As), chromium (Cr), and lead (Pb) in 60 water samples collected from groundwater resources of the cities of Noshahr and Ramsar were determined using inductively coupled plasma mass spectrometry (ICP-MS). The carcinogenic and non-carcinogenic health risks assessment for adults, teenagers, and children were estimated in terms of hazard quotient (HQ) and lifetime cancer risk (LTCR), ‘respectively’. The average concentrations of As, Cr, and Pb in drinking water were ‘respectively’ 1.9, 21.6, and 1.8 µg/L in Noshahr and 1.2, 15.6, and 1 µg/L in Ramsar. These results showed that the concentration of metals in the studied areas were within standard ranges. The average HQs caused by exposure to Cr (0.229–0.383), As (0.200–0.333) and Pb (.016–.027) in Noshahr were lower than one. Also, the average HQ calculated due to exposure to Cr (0.151–0.253), As (0.132–0.219), and Pb (0.009–0.015) in Ramsar were within safe range. The non-carcinogenic risk of the heavy metals in Noshahr and Ramsar was in the following order: Cr > As > Pb. Based on the LTCR values, the carcinogenic risk of Cr in drinking water in the cities was higher than that of As. The LTCR values of As and Cr in drinking water for all the age groups in the cities were higher than the acceptable limit (10−5) recommended by the United States Environmental Protection Agency. The results can be helpful for health policy makers to prioritise interventions in the environmental health action plan and for people in taking protective measures such as using home water treatment devices.

Heavy Metals Pollution in Soil Around the Lead-zinc Smelting Plant in guanzhong Plain

[Objective] T To analyze and determine the content of eight heavy metals Cd, Cr, Cu, Pb, Hg, Zn, As, and Ni in 40 soil samples collected around a lead-zinc smelting plant in Guanzhong through experimental analysis, and to preliminarily grasp the content of heavy metals in the soil around the smelting plant, and to conduct pollution research and evaluation.. [Method] In mid to late April 2020, 40 soil samples (with a sampling depth of 0-30 cm) were collected from the vicinity of a lead zinc smelter in Guanzhong. The heavy metal content was determined through transcoding, natural air drying, and grinding processes.. [Results] The average contents of Cd, Cr, Cu, Pb, Hg, Zn, As, and Ni in the soil around a lead zinc smelter in Guanzhong were 0.40, 85, 26.0, 48, 0.078, 108, 12.5, and 26 mg. kg-1, respectively. Except for Ni, the average contents of Cd, Cr, Cu, Pb, Hg, Zn, and As were higher than the background values of soil elements in China and Shaanxi Province, especially Cd, Hg, and Pb, The content is 4.26, 2.60, and 2.28 times the background values of soil elements in Shaanxi Province, and 4.12, 1.2, and 1.85 times the background values of soil elements in China. By calculating the standard deviation and coefficient of variation, it was found that the standard deviation and coefficient of variation of Cd, Pb, and Zn in the soil around the smelter were relatively large, indicating that these three heavy metal elements accumulated significantly in the soil.. [Conclusion] The soil around a lead-zinc smelter in Guanzhong is mainly contaminated by multiple heavy metal complexes, mainly Cd pollution. The atmospheric sedimentation around the smelter and dust from mining sites may be the main sources of pollution..

Geochemical characterization of altered rocks and element dispersion around an abandoned mining site in an arid zone: A case study of Fatira gold mine area, Eastern Desert, Egypt

Environmental impacts related to mining are widespread due to poor waste management. Fatira abandoned gold mine area in Egypt was studied for the geochemical/mineralogical properties of alterations haloes, mine tailings, stream sediments under dry conditions and impacts to nearby environment. Results of this study indicated that stream sediments and soil-tailings mixture were derived from felsic sources, while tailings, weathered and old tailings were obtained from intermediate-felsic sources. The Pb load was much higher in weathered rocks, soil-tailings mixture and old tailings, while metals like As, Co, Cr, Cu, Ni, V, and Zn show elevated values in weathered rocks nearby Fatira mine area and in downstream sediments. The tailings have high average concentrations of heavy elements, Sr (439), Zn (389), Cu (310), and Cr (50) (in mg/kg), higher than the toxicological standard values for contaminants indicating adverse effects to the neighbouring environment, whereas, soil-tailings mixture have higher As (263), Pb (56) and Al2O3 (17 wt%) reflecting the metavolcanics and granite composition of country rocks. At lower depths of tailings, escalated concentrations of Al2O3, K2O, Na2O, and Fe2O3, and little CaO, MgO, As, Pb, Zn, Cu, and Ni are indicate variable input from intermediate rocks, grey granites, felsite dykes and pink granites. Chemically altered granites showed replacement of hornblende into actinolite, calcite, pitted ilmenite and in-situ formation of Fe-oxides/hydroxides. Low hydraulic conductivity of the rocks increased the intensity of weathering. Gypsum and goethite are recorded due to repetitive sulfides decomposition. The element enrichment that exceeds the standard toxicological values in tailings, soil-tailings mixture, weathered rocks and stream sediments have severe effects on health. Integrating the chemistry, mineralogy and microtextural analyses in the study area is required for accurate geoenvironmental forecasting that facilitate mine rehabilitation with an effective management plan.

Health risk assessment of heavy metal exposure through vegetable consumption around a phosphorus chemical plant in the Kaiyang karst area, southwestern China.

The phosphorus chemical industry is an important source of heavy metals in farmland. Vegetables grown on contaminated soil potentially impose adverse effects on human health. In this study, the pollution status and health risks of heavy metals in vegetables around a phosphorus chemical plant in Kaiyang County, Guizhou Province, southwestern China, were assessed, and the low-accumulation vegetables were screened by bioaccumulation factor (BAF) and cluster analysis. Results showed the average concentrations of Hg, As, Cd, Pb, Cr, Mn, Co, and Zn in vegetables were 0.015, 0.728 0.382, 0.227, 0.850, 27.227, 0.525, and 6.438mg/kg, respectively. The single-factor pollution index showed that Cd was moderately polluted, and Cr, Hg, As, and Pb were slightly polluted. The Nemerow pollution index showed that the overall heavy metal pollution was classified as moderately polluted. The accumulation of heavy metals in different vegetables varied greatly, and chard, crown daisy, chayote, pumpkin, eggplant, white radish, sweet potato, carrot, and potato were selected as the low-accumulator vegetables. The consumption of all vegetables except chayote poses both carcinogenic and noncarcinogenic risks; among them, the consumption of sweet potato leaves has the highest health risks. The local population needs to adjust plantation structure and change dietary habits, and government should strengthen the management of phosphorus chemical plant pollution.

Heavy metal levels in the soil near typical coal-fired power plants: partition source apportionment and associated health risks based on PMF and HHRA.

In this study, five priority metals recommended by the Ministry of Ecology and Environment of China (MEEC) were investigated. In the Bijie region of Guizhou Province, three typical coal-fired power plants were chosen as the research locations. A combination of 24 soil samples was obtained at various distances and depths from the point source of contamination. The authors found that the average contents of As, Cd, Cr, Ni, and Pb were 14.15, 1.52, 16.80, 40.71, and 53.00mgkg-1, respectively, with Cd and Pb pollution prominent. In another, soil heavy metal (SHM) content tends to increase or decrease dependently with the increase of sampling distance and depth, with total concentrations ranging from 77.14 to 157.33mgkg-1. Combining PCA and PMF models, the number of source factors was determined more clearly and accurately using PCA, and the Q-value of PMF was used for validation. The PCA-PMF indicated that the primary anthropogenic sources were transportation-related activities and emissions from coal combustion. The health risks of SHMs under three different exposure routes were then assessed using the HHRA. The findings showed the five HMs in order of non-carcinogenic risk were As > Pb > Cr > Ni > Cd. The comprehensive non-carcinogenic risk for children under the oral intake route around plant B and C was greater than 1, pointing to a potential health risk to children from the soils. The carcinogenic risk of HM was less than 1.00E-04 for both single-factor and multifactor under all three exposure routes, which is below the tolerable limit.

CONCENTRATION OF CR, MN, NI, PB, AND ZN IN A POPULATION LIVING NEAR AN INDUSTRIAL AREA IN THE BRAZILIAN EASTERN AMAZON

In Barcarena, several industries are in operation, some of these industries generate highly toxic by-products, which end up influencing the social, economic, and health conditions of the residents. This study aimed to evaluate the exposure of an amazonian population to the elements Cr, Mn, Ni, Pb, and Zn using hair as a bioindicator. The results showed the average hair contents of Cr (2.5±1.5 μg g-1), Mn (15.5±12.3 μg g-1), Ni (5.4±9.0 μg g-1), Pb (18.7±15.4 μg g-1), and Zn (274±227 μg g-1) in the studied residents were higher than the averages of the elements in other countries population. The highest concentrations of Ni, Pb, and Zn were detected in children under 11 years old. Cr stood out for presenting the highest levels in the 21 to 30 years old group and Mn presented a higher concentration range for the 11 to 20 years old group. Cr showed a significant correlation with age (0.901; p=0.014) in the group of children (age <11 years).

Assessment of chromium contamination in the soil and khat leaves (Catha edulis Forsk) and its health risks located in the vicinity of tannery industries; A case study in Bahir Dar City, Ethiopia

Industrial effluents containing trace metals can contaminate water, soil and plants, as well as can cause serious human health impacts. The aim of this study was to assess the concentration of chromium in the soil and khat leaves using spectroscopic methods and to evaluate its potential human health risk on the consumers. The average concentrations of total chromium in the soil samples ranged from 71.01 ± 12.05 to 317.55 ± 23.14 mg kg−1. These values were greater than the control (7.6 ± 0.47 mg kg−1). The average concentrations of total Cr in the khat leaves ranged of 6.5 ± 1.76 to 30.01 ± 2.91 (mg kg−1). These values were higher than the maximum permissible Limits in vegetables 2.3 mg kg−1. The estimated daily intake (EDI) of an adult man weighing 70 kg and consuming on average 100 g of khat leaves per day was found in the range of 0.200–0.454 mg kg−1 body weight day−1. The target hazard quotient (THQ) of Cr from khat leaves consumption was found in the range of 0.001–0.076, which were <1, indicating no potential non-carcinogenic harmful health risk to the consumers in the society. Despite this, the regional EPA must pay close attention to controlling the use of irrigation water contaminated with tannery effluents in order to safeguard khat consumers. Furthermore, consumers must be aware of the health risks and refrain from consuming khat leaves cultivated in the study areas.

Distribution pattern and ecological risk assessment of heavy metals and PAHs in sediments of the entrance of Musa estuary, Persian Gulf to establish desalination plant

Musa estuary is a critical channel in northwest of Persian Gulf. The aim of present study was to assess the distribution pattern and ecological risk of heavy metals and PAHs in sediments of this estuary to evaluate the possibility of the establishment of desalination plant in this area. To this end, polycyclic aromatic hydrocarbon (PAH) and heavy metal pollution in surface sediments of Musa estuary from 12 stations was evaluated, and the potential sources of pollution and their ecological risks were investigated. The conductivity, temperature, and depth data from the sampling area were also reported. Twenty-two metals including aluminum (Al), Magnesium (Mg), Iron (Fe), Titanium (Ti), Manganese (Mn), Barium (Ba), Chromium (Cr), Vanadium (V), Nickel (Ni), Zirconium (Zr), Zinc (Zn), Copper (Cu), Lead (Pb), Arsenic (As), Cobalt (Co), Uranium (U), Caesium (Cs), Molybdenum (Mo), Beryllium (Be), Tin (Sn), Cadmium (Cd), and Thallium (Tl) were analyzed using Inductively Coupled Plasma Mass Spectrophotometer (ICP-MS), and PAHs were determined by GC/MS instrument. Results indicated that most of the stations were moderately polluted regarding Cr and Ni. Average concentrations of As, Cr, and Ni in most of sediments were higher than their threshold effect levels throughout sampling area. Enrichment factor based on average element levels demonstrated that elements in studied area originated from natural sources. In addition, results indicated low to moderate PAH pollution levels in sediment samples; the source of pollution was estimated to be pyrolitic. In general, results demonstrated that PAHs and heavy metals pose no threat regarding adverse biological effects, and the studied area has enough potential for accepting development projects related to desalination plants.

Heavy metals and their sources, potential pollution situations and health risks for residents in Adıyaman province agricultural lands, Türkiye.

In this study, the contents of heavy metals (HMs) such as Al, Cd, Co, Cr, Cu Fe, Mn, Ni, Pb and Zn in soil samples collected from 403 sampling locations of the agricultural lands of Adıyaman Province (Türkiye) were determined by Inductively Coupled Plasma‒Optical Emission Spectrometry (ICP‒OES). The mean concentrations of Al, Cd, Co Cr, Cu Fe, Mn, Ni, Pb and Zn HMs were detected 28,986, 3.60, 15, 127, 52.67, 45,830, 817, 62.40, 10.75 and 66.25mgkg-1, respectively. These results showed that the average concentrations of Cd, Cr, Cu, Fe, Mn and Ni exceeded the Upper continental crust average. To determine and to evaluate the contamination status and distribution of HMs in agricultural soils, metal pollution parameters such as enrichment factor (EF), geoaccumulation index (Igeo), contamination factor (Cf), pollution load index, potential ecological risk factor (Er), and potential ecological risk index (RI) were used. Factor analyses (FA) and principal component analyses (PCA) indicated that Cd, Cr and Ni levels were influenced by anthropogenic sources, Fe by both lithological and anthropogenic sources, and other HMs by lithogenic origins. For both children and adults, the hazard index (HI) and total hazard index (THI) values of HMs were < 1, suggesting that non-carcinogenic health risks to residents through ingestion, inhalation pathways, and dermal contact were currently absent. In addition, the cumulative carcinogenic risk (CCR) results were within the acceptable risk range (10-4 to 10-6). The results showed that children were more sensitive to the non-carcinogenic and carcinogenic effects of HMs.

Heavy Metal Emissions from Coal-fired Power Plants and Heavy Metal Pollution Characteristics and Health Risks in Surrounding Soils

The aim of this study was to reveal the influence of heavy metal emissions from the flue gas of coal-fired power plants on the surrounding soil environment. Seven heavy metals, including As, Cd, Cr, Cu, Pb, Hg, and Ni, were detected in the flue gas of six coal-fired power plants in Shijiazhuang, and the heavy metals in the soil surrounding the power plants were analyzed. The source analysis and health risk assessment of the heavy metals were carried out. The results showed that after a series of flue gas pollutant control measures, the emission concentrations of different heavy metals in the flue gas of the coal-fired power plants ranged from 0.11 to 6.32 mg·(MW·h)-1, and Cu, Cr, and Ni were the main pollutants. The total amount of the seven heavy metal elements discharged into the atmosphere by each power plant was 33.56-275.71 kg·a-1. The average contents of Cr, Cu, Pb, Hg, and Ni in the surface soil surrounding the coal-fired power plant were higher than the background values of Hebei soil, and the contents were 1.16-2.32 times higher than the background values. The heavy metal content in the soil around the power plants was proportional to the heavy metal emissions in the flue gas. The heavy metal content in the soil under different wind directions first increased and then decreased gradually with the increase in distance from the power plants. Source analysis showed that coal combustion emissions contributed the most to heavy metals in soil around the power plants (41.4%), followed by industrial emissions (23.6%) and transportation emissions (19.6%). Altogether, human activities played a leading role in soil heavy metal enrichment, accounting for 84.6%. The health risk assessment showed that the overall health risk of metal elements in the soil surrounding the power plant was within acceptable limits.