Carcinogenic Risk Values Research Articles

The Accumulation of Toxic Elements (Pb, Hg, Cd, As, and Cu) in Red Swamp Crayfish (Procambarus clarkii) in Qianjiang and the Associated Risks to Human Health.

Due to rapidly expanding crayfish consumption worldwide, the food safety of red swamp crayfish (Procambarus clarkii) is of great concern. China is the largest consumer and producer of crayfish globally. As of yet, it is unknown whether the main crayfish production cities in China are within safe levels of toxic heavy metals and metalloids. For 16 consecutive years, Qianjiang city ranked first in China in processing export volumes of red swamp crayfish. This study presents a comprehensive analysis of the enrichment levels and associated health risks of the species in Qianjiang. In our research, samples of four crayfish tissues, including the head, hepatopancreas, gills, and muscles, were collected from 38 sampling sites distributed in Qianjiang to evaluate the concentration levels of five heavy metals (Pb, Hg, Cd, As, and Cu). The concentration levels of all five metals in muscle did not surpass the national standard. Furthermore, eight significant correlations have been found. For further in-depth assess risk of crayfish in Qianjiang, estimated daily intake (EDI), target hazard quotient (THQ), carcinogenic risk (CR), and estimated maximum allowable consumption rates (CRmm) were evaluated in the abdomen muscle and hepatopancreas. The THQ values for each metal were found to be less than 1, while the CR values were below 10-6. Additionally, the CRmm for adults was determined to be 17.2 meals per month. These findings, based on the analysis of five metallic elements included in this study, suggest that the consumption of crayfish abdomen muscle in Qianjiang does not pose any significant health risks. However, it is noteworthy that certain regions exhibit elevated levels of arsenic in the hepatopancreas, surpassing the national standard, thereby rendering them unsuitable for excessive consumption. In general, the findings can be used to provide guidance for safe dietary practices in China.

Risk Assessment of Selected Heavy Metals Contamination In Rice Grains in the Rajshahi City of Bangladesh

The concentrations of four heavy metals in rice grains and the health risk assessments of the metals were studied. Sixteen rice samples were gathered from Rajshahi, Bangladesh. Average lead, chromium, manganese, and cadmium concentrations measured in rice samples were 6.87, 0.43, 44.58, and 1.13 mg/kg, respectively. The concentration level found in most rice samples is greater than the acceptable limit as set by WHO. The risk assessment was done by using the intended hazard ratio and target carcinogenic risk where the values for the lead, manganese, and cadmium quotient were greater than 1. The target cancer-causing risk values for a maximum number of samples are lower than 10-4, which is considered safe. However, target carcinogenic risk values for cadmium are higher than 10-4, which is considered a carcinogenic risk. The results of the current investigations suggest that appropriate measures should be taken to determine the cause and origin of this heavy metal contamination. Journal of Engineering Science 14(1), 2023, 29-41

Accumulation Characteristics and Probabilistic Risk Assessment of Cd in Agricultural Soils Across China

To understand cadmium (Cd) pollution status and associated health risks in agricultural soils of China, a database including Cd concentrations of 160446 soil samples from 240 cities (counties) in 31 provinces was constructed based on domestic and foreign literature. The contamination factor and geochemical accumulation index were applied to explore the pollution level of Cd, and then health risks for different population groups were evaluated with the probabilistic risk assessment method based on Monte Carlo simulation. The results indicated that soil Cd concentrations in China ranged from 0.012 to 23.33 mg·kg-1, with the geometric mean of 0.473 mg·kg-1, which was 1.58 times the risk screening value of heavy metals in the soil of agricultural land (GB 15186-2018) (6.5<pH ≤ 7.5). From the perspective of different regions, the highest concentrations of soil Cd were found in central China, followed by southwest, south, northwest, northeast, east, and north China. From the perspective of time, there was no significant difference in soil Cd in different time periods (P>0.05). Cd pollution in agricultural soils was mainly distributed in Yunnan, Hunan, Guangxi, and Gansu provinces in China, which may have been related to the mining and smelting activities. The non-carcinogenic risks for all the population groups could be negligible, whereas there were potential carcinogenic risks for adults and seniors, with 5.81% and 4.49% of carcinogenic risk values exceeding the threshold of 1E-06 set by USEPA for adults and seniors, respectively. The results of this study provided valuable information for the pollution prevention and risk control of soil Cd pollution. To improve the accuracy of health risk assessment results, the exposure ingestion route of agricultural products and bioavailability of soil Cd should be considered in the probabilistic ecological risk assessment.

Summer and winter variations of BTEX concentrations in an oil refinery complex and health risk assessment based on Monte-Carlo simulations

The summer and winter concentrations of BTEX pollutants were investigated in various workplaces of an oil Refinery, Iran. In total 252 air samples from the breathing zones of the following employees were collected: supervisors, safetymen, repairmen, site men, and all workers. Carcinogenic and non-carcinogenic risk values were calculated based on the USEPA methodology using Monte Carlo simulations. BTEX concentrations were higher in the summer than in the winter season for all workstations, especially for toluene and ethylbenzene. The mean values of exposure to benzene for repairmen and site men were higher than threshold limit value of 1.60 mg/m3 for both seasons. Non-carcinogenic risk (HQ) values calculated for summer season for benzene, ethylbenzene, and xylene in all workstations, as well as for toluene for repairmen and site men exceeded acceptable level of 1. In winter season the mean HQ values for benzene and xylene in all workstations, for toluene for repairmen and site men, and for ethylbenzene for supervisors, repairmen, and site men were also > 1. For all workstations definite carcinogenic risk was indicated as calculated LCR values for benzene and ethylbenzene exposure were higher than 1 × 10–4 in both summer and winter seasons.

Health risk of heavy metal exposure in vegetable around owukpa coal mine field, north central Nigeria

The evaluation of trace metals in the environmental around Owukpa coal mine field, Ogbadibo Local Government Area, Benue State Nigeria was carried out to evaluate the degree of contamination due to mining activity in the area. The mean concentration of selected heavy metals (Ni, Fe, Cd, Cr, Pb and Mn) in Vegetables (Vernonia amygdalina) around coal mines were investigated. Results of the atomic absorption spectrophotometric (AAS) were as follows Ni (4.47), Fe (29.18), Cd (1.27), Cr (3.76), Pb (4.64), and Mn (12.84) with a variation pattern in the order: Fe&gt;Mn&gt;Pb&gt;Ni&gt;Cr&gt;Cd. It was observed that the trend of EDIs for heavy metals in the samples were in the order of Fe &gt; Mn &gt; Pb &gt; Ni &gt; Cr &gt; Cd. The HRIs of Ni, Cd, Cr and Pb were higher than 1 (HRI &gt; 1), with Carcinogenic Risk values of Cd (0.0668), Cr (0.0157), Fe (0.2432), Mn (0.1070), Ni (0.0340), and Pb (0.0003), respectively.

Intake of toxic metals through dietary eggs consumption and its potential health risk assessment on the peoples of the capital city Dhaka, Bangladesh

Around the world, hen meat and eggs are very widely consumed in dishes like curries, processed cuisine, and fast food. The ingestion of contaminated eggs poses a biochemical risk from the perspective of food safety due to the presence of heavy metal and trace element residues in hen eggs. The purpose of this study was to examine the concentrations of heavy metals in eggs from commercial chicken farms from capital city and hens from local area in order to identify the most significant heavy metal concentration in hen eggs. The concentrations of Cd, Cr, Cu, Pb, Mn, Ni, Fe, Zn, Co and As in samples of hen eggs collected from different locations were measured in the present study and concentrations of these selective metals were found to be between < 0.001, 0.01–0.89, 0.81–0.015, 0.81–58.8, 0.32–1.9, 0.05–1.03, 0.04–0.38, 10.6–104.02, 2.41–48.46, 0.04–0.5 mg/kg-fw and BDL respectively. The findings showed that Cu, Pb, Fe and Zn had levels over the dietary food's maximum permissible limit (MPL). Multivariate statistical studies showed that human activity was the main contributor to the presence of heavy metals in the sampled diets. Estimated daily intake (EDI), target hazard quotient (THQ) of individual heavy metals, and carcinogenic risk (CR) for lifetime exposure were used to evaluate the risks to human health associated with dietary intake of these metals through consumption of hen eggs. Provisional tolerable daily intake values (PTDI) for Pb, Cu, Zn, and Fe were higher, indicating that these metals might be harmful to human health if consumed in eggs by both children and adults. The evaluated foodstuffs can be consumed with low or less risk of exposure to heavy metals because the computed values of THQ and CR were below their respective allowed thresholds.

Concentrations and health risk appraisal of heavy metals and volatile organic compounds in soils of automobile mechanic villages in Ogun State, Nigeria.

This report presents the findings of the concentrations, distributions and health risks assessment of heavy metals (HMs) and volatile organic compounds (VOCs) in topsoils of two typical automobile mechanic villages (MVs) situated within Ogun State, Nigeria. One of the MVs is located in basement complex terrain (Abeokuta), while the second is in the sedimentary formation (Sagamu). Ten composite samples were collected at depth of 0-30cm with the aid of soil auger from spent oil-contaminated spots within the two MVs. The chemical parameters of interest were Pb, Cd, benzene, ethylbenzene, toluene, total petroleum hydrocarbon (TPH) as well as oil and grease (O&G). In addition, soil pH, cation exchange capacity (CEC), electrical conductivity (EC) and particle size distribution were also evaluated in order to find out their impacts on assessed soil pollutants. Results revealed that the soils in both MVs are of sandy loam texture, slight acidic to neutral pH, mean CEC < 15 cmol/kg and mean EC > 100 μS/cm. The mean concentration of each of analyzed HMs and VOCs in soils from the two MVs was < 5mg/kg, while the mean values of TPH and O&G content were > 50mg/kg. The mean Cd values in soils of both MVs were higher than the national soil screening level of 0.8mg/kg, but lower than the Canadian and Italian guidelines. There is no significant correlation between each of HMs/VOCs and any of assessed soil physicochemical variables. The non-cancer risk expressed in terms of hazard index (HI) was > 1 via oral ingestion route for adults and children at the two MVs, indicating adverse non-carcinogenic health risk. The HI > 1 value was obtained for adults only through the dermal absorption pathway in Abeokuta MV. However, HI values for the two age groups at the two MVs via inhalation route were < 1, indicating no likelihood of any non-carcinogenic effects via the breathing exposure. The potential of non-cancer risk via oral ingestion route in both MVs was derived from the contributive ratios of HMs and VOCs in the order: Cd > benzene > Pb > toluene. The carcinogenic risk (CR) values due to ingested Cd, benzene and Pb for both age groups at the two MVs exceed the safe limit range of 10-6 to 10-4. Cadmium, benzene and lead made considerable contributions to the estimation of CR through dermal exposure for adults only in Abeokuta MV. The CR values via inhalation pathway for adults and children in both MVs were within the threshold range. Artisans and children should circumvent accidental ingestion of contaminated soils in addition to wearing of protective clothes during routine vehicle maintenance activities.

Green remediation of Ni, Zn, and Cu in an electroplating contaminated site by wood vinegar with optimization and risk assessment

Wood vinegar (WV) is a renewable organic compound, possessing characteristics such as high oxygenated compound content and low negative impact on soil. Based on its weak acid properties and complexing ability to potentially toxic elements (PTEs), WV was used to leach Ni, Zn, and Cu contaminated soil in electroplating sites. In addition, the response surface methodology (RSM) based on the Box-Behnken design (BBD) was established to clarify the interaction between each single factor, and finally completed the risk assessment of the soil. The amounts of PTEs leached from the soil climbed with the increase of WV concentration, liquid-solid ratio, and leaching time, while they surged with the decrease of pH. Under optimal leaching circumstances (the concentration of WV= 100 %; washing time= 919 min; pH= 1.00), the removal rates of Ni, Zn, and Cu could reach 91.7 %, 57.8 %, and 65.0 %, respectively, and the WV-extracted PTEs were mainly from the Fe-Mn oxides fraction. After leaching, the Nemerow integrated pollution index (NIPI) decreased from an initial value of 7.08 (indicating severe pollution) to 0.450 (indicating no pollution). The potential ecological risk index (RI) dropped from 274 (medium level) to 39.1 (low level). Additionally, the potential carcinogenic risk (CR) values reduced by 93.9 % for both adults and children. The results revealed that the washing process significantly reduced the pollution level, potential ecological risk, and health risk. Coupled with FTIR and SEM-EDS analysis, the mechanism of WV removal of PTEs could be explained from three aspects: acid activation, H+ ion exchange, and functional group complexation. In summary, WV is an eco-friendly and high-efficiency leaching material for the remediation of PTEs polluted sites, which will maintain soil function and protect human health.

Assessing Population Health Risks Posed by Air Pollution Related to Coal Mine Reclamation

Introduction: There is an urgent need for reclamation of abandoned coal mine lands in Kuzbass to reduce their adverse effects on the environment. Objective: To assess risks to public health posed by air pollution associated with coal mine liquidation and land reclamation. Materials and methods: We used data on the volume of maximum permissible emissions of the abandoned coal mine area for 2019 to assess the spread and exposure to pollutants at 40 points selected on the map of the city of Prokopyevsk, Kemerovo Region, and to estimate the maximum and mean concentrations of the contaminants. The values of carcinogenic risk and risks of non-carcinogenic effects were calculated in compliance with the Russian Guidelines R 2.1.10.1920–04, Human Health Risk Assessment from Environmental Chemicals, while risks of chronic toxicity were assessed using methods by Shcherbo et al. The calculated risk values were then compared with their acceptable levels. Risks were also assessed with account for the contribution of background concentrations of chemicals. Results: The list of priority pollutants included inorganic dust containing 20–70 % SiO2, nitrogen dioxide, nitrogen oxide, sulfur dioxide, carbon (soot), carbon monoxide, and inorganic dust containing &lt; 20 % SiO2. The estimated maximum and mean concentrations of airborne pollutants during mine reclamation activities were not exceeded at any exposure point. Hazard indices for acute exposures to pollutants exceeded the acceptable level at three points located closer to the sources. Carcinogenic risks did not exceed the level of acceptable risk at any point. Total risks of chronic toxicity were 1.2 and 1.75 times higher than acceptable at two points. Hazard indices estimated with account for the background levels of pollutants were 1.448–2.603 times higher than the acceptable level at all exposure points. The carcinogenic risk assessed taking into account the background levels was found to be acceptable. The most affected (target) critical organs and systems were respiratory organs and blood. Total risks of chronic poisoning assessed with account for background concentrations of ambient air pollutants exceeded the acceptable level by 3.15–5.40 times at all points. Conclusions: Reclamation activities have no significant effect on ambient air quality and health of the population of Prokopyevsk. Total risks of chronic toxicity and hazard indices exceed acceptable levels in residential areas located close to the reclamation site. High hazard indices and total risks of chronic toxicity established at all exposure points taking into account background concentrations of contaminants, are determined by generally poor environmental conditions in the city with the intensively developing coal industry.

Environmental Impact of Wasteyard Leachate Pollution, It’s Health Risks with Some Microbial and Ecological Implications

The study was carried out to assess the public health risks from the consumption of farm crops and vegetables cultivated around active municipal solid waste dumpsites in Delta State. Using the experimental research method soil and vegetation (cassava leaves) samples were collected from ten spatial locations around municipal solid waste dumpsites (SWD), scrap metals yards (SMY) and agricultural farms and subjected to laboratory analysis of relevant physic-chemical parameters. Heavy metals like cadmium “Cd”, iron “Fe”, nickel “Ni” and lead “Pb” concentrations including, total variable bacteria (TVB) and Salmonella spp load in collected samples were determined in accordance with standard procedures. The results revealed a substantial spatial dispersion of the heavy metals, TVB and Salmonella spp concentrations within the two study areas. Remarkably, the bacteria level was higher in the SWD than in the SMY while the heavy metals concentration was higher in the SMYs when compared to the SWD. Spatially, soil and vegetation around the SMD area had higher HMs’ Hazard quotient, Hazard index and Carcinogenic risk values, when compared to the soil around the SMY region, but all their status were within safe limits for the human health. Salmonella spp population in the SWD and SMY soil ranged from 1.33 to 39.33 cfu/g of dry soil and 1.04 to 8.67 cfu/g of dry soil respectively while the TVB count ranged from 6233 cfu/g to 46500 cfu/g of dry soil. Although the heavy metal contamination levels in the soil samples were within safe limits, the presence of the pathogenic bacterium in the soil pose health threat to the inhabitants of the regions.

Dietary exposure to potentially harmful elements in edible plants in Poland and the health risk dynamics related to their geochemical differentiation

Differences in the health risk values calculated for consumers of potentially harmful elements (PHEs) present in edible plants were investigated. Based on a comprehensive literature search, the highest PHE contents in plants were identified in the southern and western regions of Poland, that also revealed the highest geochemical enrichment with Zn, Pb, Cu, As, Cd, and Tl. The highest unacceptable non-carcinogenic risk (HQ) values for mean PHE contents in Poland were found for Pb: toddlers (2.80), pre-schoolers (1.80), and school-aged children (1.45) and for Cd for toddlers (1.42). The highest unacceptable carcinogenic risk (CR) values for mean As content was observed for adults (5.9 × 10–5). The highest non-carcinogenic risk values for consumers were reported in Silesia, Lower Silesia, Lublin, Lesser Poland, and Opole Provinces, indicating the impact of geochemical variability on risk values.

Occurrence and probabilistic risk assessment of polycyclic aromatic hydrocarbons in blood and urine of auto-mechanics in Akure Metro, Nigeria

This study provides baseline data on the concentration of polycyclic aromatic hydrocarbons (PAHs) in blood and urine samples of auto-mechanics, using Nigeria as a case study. Eighteen auto-mechanics participated in the study excluding two controls. The concentrations for the ΣPAHs across all participants (excluding control) ranged from 1.67 to 3.30 (2.17 ± 0.58) in blood with a significantly higher (P < 0.05) range of 7.61 to 10.76 (8.69 ± 1.00) in urine. The high molecular weight PAHs (4-6 rings) dominated the PAH profile in both blood (≥ 92%) and urine (≥ 87%) across all locations. Dibenz(a)anthracene was the most distributed PAH, while acenaphthene and indeno(1,2,3-cd)pyrene were the least distributed. The dermal route constituted approximately 99% of the total chronic exposure, followed by ingestion, and the least via inhalation. The hazard index (HI) was below the safe thresholds (HI = 1), suggesting non-carcinogenic PAH effects. However, all the participants including control samples had carcinogenic risk (CR) values above the acceptable level of 10-6 in both blood and urine samples. The carcinogenic and mutagenic potencies were higher in urine than in blood. The results suggest less acute toxicity and more potential chronic effects. The computed elimination ratio (> 1) suggests low excretion in urine and a potentially harmful trend. Molecular diagnostic ratios and principal component analysis suggest mixed PAH sources. The study revealed biomonitoring solely dependent on blood analysis may greatly underestimate health risks due to PAH exposure. To the best of our knowledge, this study is the first to provide levels of PAHs in the blood and urine of Nigerian mechanics. Findings herein will support policymakers at all levels in re-focusing attention to the less prioritized professions that pre-disposes people to PAHs and other emerging pollutants in society.

Characterization of drinking groundwater quality and assessment of human health risk in Xin’an spring basin, a typical mining and karst area of the northern China

Groundwater is an important natural resources of drinking water in mining area in Xin’an spring basin, northern China. To foster the sustainable development and utilization of groundwater, a total of 332 groundwater samples, including 147 pore groundwater, 95 fissure groundwater and 90 karst groundwater, were collected and hydrochemical parameters were applied to assess the groundwater quality and human health risks caused by oral ingestion. The results showed that the major chemical components of groundwater in Xin’an spring basin were HCO3−, SO42−, NO3−, Cl−, Ca2+, Mg2+, Na+, total hardness (TH), and total dissolved solids (TDS). The contents of TDS, TH, SO42−, NO3−, F−, Fe, Mn, Pb, and As in groundwater were exceed the standard of groundwater quality (SGQ) limits. The main hydrochemical types of groundwater were HCO3-Ca·Mg and SO4·Cl–Ca·Mg. The factors controlling the groundwater chemistry mainly were mineral weathering, evaporation, cation exchange, and anthropogenic input. The results of water quality assessment showed that the karst and fissure groundwater in study area was mainly excellent-good quality water, while pore groundwater was mainly good-medium quality water. The poor and extremely poor quality water was mainly distributed in Changzhi basin, and the greater contribution made by Pb, Mn, NO3−, Fe, SO42−, TH and TDS. The range of hazard index (HI) values of groundwater was 0.28 to 27.79, and the HI values mainly contributed by NO3−, F−, As, ingestion rate (IR) and exposure duration (ED). The cumulative carcinogenic risk (CCR) values ranged from 1.5 × 10–7 to 2.78 × 10–3, and the greater contribution made by Cr, As, Cd, IR and ED. The results of health risk assessment suggested that some parts of the study region may pose a significant non-carcinogenic risk and a high probability in developing cancer to local residents, and infants were at greatest risk to health, followed by children and adults, while teenagers were at least at risk. This study will provide a deeper insight into the water quality situation and geochemical evolution of groundwater in Xin’an spring area, and will assist decision-makers to formulate management strategies of drinking water safety for the study area.

Spatial distribution, sources, and risk assessment of potentially toxic elements in cultivated soils using isotopic tracing techniques and Monte Carlo simulation

Potentially toxic elements (PTEs) in cultivated lands pose serious threats to the environment and human health. Therefore, improving the understanding of their distinct sources and environmental risks by integrating various methods is necessary. This study investigated the distribution, sources, and environmental risks of eight PTEs in cultivated soils in Lishui City, eastern China, using digital soil mapping, positive matrix factorisation (PMF), isotopic tracing, and Monte Carlo simulation. The results showed that Pb and Cd are the main pollutants, which posed higher ecological risks in the study area than the other PTEs. Natural, mining, traffic, and agricultural sources were identified as the four determinants of PTE accumulation via a PMF model combined with Pearson correlation analysis, showing that their contribution rates were 22.6 %, 45.7 %, 15.2 %, and 16.5 %, respectively. Stable isotope analysis further confirmed that local mining activities affected the HM accumulation. Additionally, non-carcinogenic and carcinogenic risk values for children were 3.18 % and 3.75 %, respectively, exceeding their acceptable levels. We also identified that mining activities were the most important sources of human health risks (55.7 % for adults and 58.6 % for children) via Monte Carlo simulations coupled with the PMF model. Overall, this study provides insights into the PTE pollution management and health risk control in cultivated soils.

Indoor Volatile Organic Compounds: Concentration Characteristics and Health Risk Analysis on a University Campus.

Volatile organic compounds (VOCs) are major indoor air pollutants that contain several toxic substances. However, there are few studies on health risk assessments of indoor VOCs in China. This study aimed to determine the concentration characteristics of VOCs on college campuses by collecting VOC samples from different locations on campus during different seasons combined with the exposure times of college students in each location obtained from a questionnaire survey to assess the possible health risks. The highest total VOC concentration (254 ± 101 µg/m3) was in the dormitory. The seasonal variation of TVOC concentrations was related to the variation of emission sources in addition to temperature. Health risk assessments of VOCs were evaluated using non-carcinogenic and carcinogenic risk values, represented by hazard quotient (HQ) and lifetime cancer risk (LCR), respectively. The non-carcinogenic risks at all sampling sites were within the safe range (HQ < 1). Dormitories had the highest carcinogenic risk, whereas the carcinogenic risk in the other three places was low (with LCR < 1.0 × 10-6). Moreover, 1,2-dichloroethane was identified as a possible carcinogenic risk substance in the dormitory due to its high LCR (1.95 × 10-6). This study provides basic data on health risks in different locations on campus and a basis for formulating measures to improve people's living environments.

Spatiotemporal distribution characteristics of potentially toxic elements in agricultural soils across China and associated health risks and driving mechanism

Comprehensive analysis of spatiotemporal distribution characteristics of potentially toxic elements (PTEs) in soils of China, and associated driving mechanism and health risks is crucial for soil pollution prevention and risk control. In this study, a total of 8 PTEs in agricultural soils of 236 city case data from 31 provinces of China were collected from literatures published between 2000 and 2022. The pollution level, dominant drivers and probabilistic health risks of PTEs were analyzed using geo-accumulation index (Igeo), geo-detector model, and Monte Carlo simulation, respectively. The results indicated a notably accumulation of Cd and Hg, with Igeo of 1.13 and 0.63, respectively. Cd, Hg and Pb showed strong spatial heterogeneity, whereas As, Cr, Cu, Ni, and Zn has no significant differentiation. PM10 was the dominant driver for accumulation of Cd (0.248), Cu (0.141), Pb (0.108), and Zn (0.232), and PM2.5 has a significant effect on accumulation of Hg (0.245); however, soil parent material was primary driver for accumulation of As (0.066), Cr (0.113), and Ni (0.149). PM10 ∩ wind speed accounted for 72.6 % of Cd accumulation, and mining industry ∩ soil parent materials for 54.7 % of As accumulation. Approximately 38.53 %, 23.90 %, and 12.08 % of the hazard index values exceeded 1 for the minors aged 3- < 6, 6- < 12, and 12- < 18 years, respectively; whereas approximately 0.22 %, 0.21 %, 0.20 %, 0.54 % and 0.42 % of the carcinogenic risk values were greater than 1E-04 for individuals aged 3- < 6, 6- < 12, 12- < 18, 18- < 44, and 44- < 70 years, respectively. As and Cd were considered as priority elements for soil pollution prevention and risk control in China. Moreover, the hotspots of PTE pollution and associated health risks were mainly observed in southern, southwestern and central China. The results of this study provided a scientific basis for developing strategies for pollution prevention and risk control of soil PTEs in China.

Bioaccessibility and reliable human health risk assessment of heavy metals in typical abandoned industrial sites of southeastern China

Heavy metal pollution caused by a large number of abandoned industrial sites cannot be underestimated, but its human health risks have not been accurately assessed. This study investigated the pollution of heavy metals in soils of the typical abandoned industrial sites in southeastern China. Based on the bioaccessibility of different heavy metals (Pb, Ni, Cu, Zn, Cd, Cr) in the industrial soils, the human health risks were accurately evaluated, and the controlling factors were quantitatively assessed. The results showed that the heavy metals in each typical abandoned industrial sites had a high degree of spatial heterogeneity. Among them, Cd was the most susceptible to relevant discrete input from external factors such as human activities, followed by Zn, Pb, Cr, Ni and Cu. The bioaccessible concentration of heavy metals by the physiological-based extraction test (PBET) had a good correlation (R2 = 0.58 ∼ 0.86) with its bioavailable concentration by diethylenetriaminepentaacetic acid (DTPA) extraction. The regression model based on soil parameters had great potential to predict the bioaccessibility of heavy metals in abandoned industrial sites (R2 = 0.49 ∼ 0.95). The total concentration of heavy metals, Fe, soil texture and pH were the controlling factors of the metal bioaccessibility. Compared with the total concentration, the hazard index (HI) and carcinogenic risk (CR) values calculated based on gastrointestinal bioaccessibility were decreased by 39.0∼77.9% and 68.2∼79.9% in adults, and 45.3∼88.0% and 73.9∼83.5% in children, respectively. This work provides a feasible theoretical basis for reliable assessment of the human health risks of heavy metals in the abandoned industrial sites in the future.

HEAVY CADMIUM METAL DETERMINATION CONCENTRATION IN CHEESE

Objective: The purpose of this study was to look into the concentration of the heavy element Cadmium and its health risks in cheese samples available in Iraqi markets. Methods: 72 random samples of six country groups (15 Iran, 9 Iraq, 9 Egypt, 15 Turkey, 15 Hungary, and 9 Saudi Arabia) available in Iraqi markets were collected and analyzed using an atomic absorption spectrophotometer, Shimadzu model AA7000, USA. Results: The highest average Cd metal level in the samples was found in Iranian cheese, while the lowest was in Iraqi ones. The descending Cd order of the countries was Turkey&gt;Hungary&gt;Egypt&gt;Iran&gt;Saudi Arabia&gt;Iraq, according to the T-test confirmation. The daily Cd metal intake ( ), Cd target hazard quotient ( ), and Cd carcinogenic risk ( ) values were less than the permissible and risk values. Conclusion: Eventually, the health risk parameters revealed that there are no pose risks from those cheeses to Iraqi consumers.

Occupational health risks of VOCs emitted from the working face of municipal solid waste landfill: Temporal variation and influencing factors.

Volatile organic compounds (VOCs) emission on the working face of a large sanitary landfill in northern China was characterized in a one-year long sampling campaign. A total of 67 VOCs with average annual concentration of 2903.01μg/m3 were detected. Ethanol was the dominant species of detected VOCs, accounting for 76.4-82.3% of the total volatile organic compounds (TVOCs) concentration. VOCs emission showed seasonal variation as the highest concentration was detected in summer and lowest appeared in winter. Furthermore, 50 VOCs identified were non-carcinogenic chemicals and 21 of them were carcinogenic chemicals. Risk assessment showed that the average total non-carcinogenic risk value (HIT) was 4.95, which far exceeded the threshold value of 1; and the average total carcinogenic risk value (RiskT) was 8.45×10-5, close to the limit of 1×10-4. That means both the non-carcinogenic and carcinogenic risks of long-term exposure to these VOCs could not be ignored. Some of the oxygenated compounds (Acrolein, Ethyl acetate, etc.), halocarbons (1,1,2-Trichloroethane, 1,2-Dichloropropane, etc.) and aromatic compounds (Naphthalene, m+p-Xylene, etc.) consisted the main contributors to non-carcinogenic risks. Meanwhile, carcinogenic risks were mainly caused by halocarbons (cis-1,2-Dichloroethylene, FREON11, etc.) and aromatic compounds (Benzene, Ethylbenzene, etc.). In addition, statistical analysis revealed that the HIT values were related to the concentrations of risk aromatic compounds, halocarbons and hydrocarbons; RiskT values were only related to the concentrations of risk aromatic compounds and halocarbons. The research results provide an important theoretical basis for occupational risk management and VOCs emission prevention in landfills.

Enrichment, sources, and distributions of toxic elements in the farming land's topsoil near a heavily industrialized area of central Bangladesh, and associated risks assessment

Toxic element accumulation in the surrounding soils of the advanced industry- and agriculture-oriented areas may lead to severe environmental degradation and harmful impact on inhabitants. This work examined the concentration of some concerned toxic elements (Cr, Pb, Cd, Cu, As, and Ni) in the representative topsoil from 10 industrially contaminated sites in central Bangladesh (Narayanganj district) using an Inductively Coupled Plasma Mass Spectrometer concerning the probable ecological and human health risks. The mean concentrations (mg/kg) of the elements were found in the order of Ni (58.1 ± 11.8) > Pb (34.1 ± 14.3) > Cr (32.1 ± 6.77) > Cu (14.5 ± 3.30) > Cd (2.74 ± 1.08) > As (1.49 ± 0.43). The findings pointed out that diversified manmade events enhanced the intensities of elemental contamination through the studied sites. Source analysis showed that Cr, Pb, As, and Cd may originate from industrial wastewater and agricultural activities, whereas Cu and Ni came from natural sources. The geo-accumulation index level for Cd (1.70–3.39) was determined as grade 3 (moderately to strongly polluted), the enrichment factor score for Cd (13.9) fell in the very severe enhanced category (cluster 5), and the highest contamination factor value was found for Cd (15.7). The contamination degree values for all the tested elements signify a moderate to severe contamination grade; conversely, pollution load index levels depicted the nonexistence of elemental pollution. The assessment revealed serious Cd pollution in agricultural soils and moderate to significant potential ecological risk for the rest of the examined toxic elements. Furthermore, hazard index values exceeded the safe exposure levels, indicating that there was potential non-carcinogenic risk in the soils for children and adults. Ingestion exposure had much higher carcinogenic risk values than inhalation and cutaneous exposure, and children are exposed to considerable carcinogenic hazards. Therefore, it is suggested that the harmful practices that expose this farming soil to contaminants should be stopped immediately and effective environment-friendly techniques of waste management and effluent treatment should be employed in the study area.