Non-carcinogenic Hazard Quotient Research Articles

Occurrence and seasonal variations of organophosphate flame retardants in air and dust from college microenvironments at Qingdao, China: Implications for student's exposure and risk assessment

Organophosphate flame retardants (OPFRs) are widely used as alternatives to brominated flame retardants in a variety of consumer products and their consumption has continuously increased in recent years. However, their concentrations and human exposures in indoor microenvironments, particularly in a university environment, have received limited attention. In this study, the concentrations and seasonal variations of 15 OPFRs were assessed in typical microenvironments of two universities, including dormitories, offices, public microenvironments (PMEs: classroom, dining hall, gymnasium and library), and laboratories on the northern coast of China.Analysis of the OPFRs in both air and dust samples indicated widespread distribution in college campuses. The average concentration of ∑15OPFRs in the winter (12,774.4 ng/g and 5.3 ng/m3 for dust and air, respectively) was higher than in the summer (2460.4 ng/g and 4.6 ng/m3 for dust and air, respectively). The dust and air samples collected from PMEs and laboratories exhibited higher concentrations of OPFRs, followed by offices and dormitories. An equilibrium was reached between dust and air in all collected microenvironments. The daily intakes of OPFRs were significantly lower than the reference dose. Dust ingestion was the primary intake pathway in the winter, while inhalation and dust ingestion were the main intake pathways in the summer. The non-carcinogenic hazard quotients fell within the range of 10−7–10−3 in both the summer and winter, which are below the theoretical risk threshold. For the carcinogenic risk, the LCR values ranged from 10−10 to 10−8, indicating no elevated carcinogenic risk due to TnBP, TCEP, and TDCP in indoor dust and air.

Screening legacy and emerging organic pollutants in the contaminated soil of Dhaka, Bangladesh

The current understanding of the legacy and emerging organic pollutants in the soil of Bangladesh remains limited. Inadequate disposal practices, particularly in e-waste, landfills, and industrial operations, may lead to the pervasive presence of persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) in the country. This study aimed to systematically investigate the concentrations, sources, and risk assessment of halogenated flame retardants (HFRs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), organochlorine pesticides (OCPs), chlorinated paraffins (CPs), and PAHs in the contaminated soil of Dhaka's dumpsites, e-waste, and industrial areas collected in 2017. The total concentration of investigated pollutants averaged at 4790 ± 4040 ng g−1 dw, with the following order: ∑44CPs (4110 ± 4140 ng g−1 dw) > ∑16PAHs (422 ± 491 ng g−1 dw) > ∑16HFRs (190 ± 538 ng g−1 dw) > ∑209PCBs (43.5 ± 73.5 ng g−1 dw) > ∑50PCNs (17.7 ± 21.0 ng g−1 dw) > ∑27OCPs (9.41 ± 9.61 ng g−1 dw). The e-waste site exhibited the highest total concentration of the target pollutants, reaching 12,700 ng g−1 dw. CPs were the predominant contributors, accounting for averages of 81.8%, 70.5%, and 68.5% to waste landfills, e-waste, and industrial sites, respectively. A comprehensive analysis of 209 PCB congeners revealed their primary origin from Aroclor PCBs, with minor contributions from unintentionally produced PCBs. The highest incremental lifetime carcinogenic risk (ILCR) occurred in e-waste sites, contributed by dioxin-like PCBs, with a maximum value of 5.9 × 10−5 for adults, exceeding the limit 1.0 × 10−6 set by the U.S. EPA. The non-carcinogenic hazard quotients (HQs) were much lower, suggesting no significant risk from the investigated pollutants. Our findings highlight the importance of proper waste management and regulated e-waste recycling to mitigate potential hazardous risks to the Bangladeshi population.

Health risk assessment of exposure to benzene, toluene, ethylbenzene and xylenes in a vehicle manufacturing industry in Iran

IntroductionConsidering the adverse carcinogenic and non-carcinogenic health effects of Volatile Organic Compounds (VOC) and specially Benzene, Toluene, Ethylbenzene and Xylenes (BTEX) which are widely used in vehicle manufacturing industry, it is clear that monitoring and control of occupational exposure to these substances is of utmost significance. More often than not the studies on occupational exposure to VOCs in vehicle manufacturing industry—specifically BTEX—have been carried out exclusively in paint shop units. The purpose of this study was to assess occupational BTEX exposure & health risk in different units of a vehicle manufacturing industry.Material and methodsFoam injection unit (FIU), gluing unit (GU), repair shop unit (RSU), molding unit (MU) as well as paint shop units (PSU) were selected for this study. Sampling and analysis were conducted based on National Institute for Occupational Safety and Health (NIOSH) 1501 guidelines by utilizing MSA personal sampling pumps set to 0.2 l/m and Gas Chromatography equipped with Flame Ionization Detector (GC-FID). Risk characterization and assessment was performed using Environmental Protection Agency Risk Assessment Information System (EPA RAIS).Results and conclusionThe results revealed that the concentration of benzene in gluing and paint shop units was above occupational exposure limits. Carcinogenic risk levels in 8 out of 10 units registered in the 1E-2 to 1E-4 range, and only two units registered a risk level below EPA’s acceptable risk level (10–6). The highest risk levels were measured in gluing, paint shop and repair shop units. Furthermore, the total non-carcinogenic hazard quotient was measured higher than 1 in 8 out of 10 studied units. Considering the abundance and wide use of VOCs -most notably BTEX- and the adverse carcinogenic and non-carcinogenic health effects of these compounds, it is advised to: change the type of paint used in paint shops, improve the existing ventilation systems, develop new and more efficient ventilation systems and conduct consistent training.

The effect of ascorbic acid and lemon juice on the extraction of metals from green tea, health risk assessment

The total heavy metal concentration (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn) in green tea leaves and metals leached into tea infusions of pure water with the addition of ascorbic acid and lemon juice at various temperatures (70, 80, and 100 °C) and steeping times (3, 5, and 7 min), were determined. Metal concentrations were analyzed by atomic absorption spectrometry and the flame technique (FAAS). Mean total concentrations of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn were < LOD, <LOD, 0.198, 4.527, 67.51, 333.7, 2.588, <LOD, 10.23 μg/g, respectively. The highest percentage of extraction in different solutions was in the case of Mn (up to 100%). The risk for adults through consumption of tea was mainly contributed by Mn, and non-carcinogenic hazard quotient (HQ) was slightly higher than 1 when infusions were heated to 100 °C. High percentages of Ni were extracted in pure water compared to water with addition, regardless of tea steeping time, followed by Cu in pure water and water with lemon juice. Fe was poorly extracted in all applied solutions; the highest percentage of extraction (17.21%) was determined in lemon juice solutions of at 100 °C during a steeping time of 7 min.

Comprehensive evaluation of the risk system for heavy metals in the rehabilitated saline-alkali land

A comprehensive assessment of the heavy metal system in the rehabilitated saline-alkali land holds significant importance, as the in-situ remediation process utilizing amendments substantially alters the initial physicochemical properties of the soil, which could lead to the migration or reactivation of previously stabilized heavy metals. In this context, the present study aims to evaluate the heavy metal content and health risk within the improved saline-alkali soil-plant system. Moreover, a comprehensive evaluation based on the TOPSIS-RSR method is carried out to accurately gauge the soil health status. The findings indicate that the modification process has an impact on the concentrations of heavy metals in the soil and crops, causing either an increase or decrease. However, the level of heavy metal pollution in the improved saline-alkali soil and rape remains within safe limits. The results of the migration of heavy metals after amendment application indicated that the migration of heavy metals in the soil was influenced by the properties of the heavy metals, the composition of the amendment, and leaching. Furthermore, the total non-carcinogenic hazard quotients in the soil and rape were within the safe threshold for all populations. The findings provided novel insights into the status and risk assessment of the pollution of improved saline-alkali soil.

Distribution, Accumulation, and Risk Assessment of Pb and Cd in the Tea Plant Leaves, Black Tea, and Soil from Different Tea Plantations in Lahijan, Iran

Since heavy metals (HM) exist in the soil due to industrial activity and the usage of pesticides and fertilizers, monitoring the content of these pollutants is very significant. The current research aimed to determine the concentrations of cadmium (Cd) and lead (Pb) in the tea plant leaves, black tea, and soil and look for their correlations. Twenty-seven (27) samples were divided into three groups of tea plant leaves, black tea, and soil from the same tea plantations originating from Lahijan, Iran. The concentrations of Pb and Cd in samples were determined using a flame atomic absorption spectrophotometer. After that, some analyses were conducted to find the correlation between the content of Pb and Cd in tea plant leaves, black tea, and soil, and their health risks were evaluated. In leaves, black tea, and soil, the mean contents for Cd were 0.001, 0.044, and 0.044 ppm, whereas those for Pb were 0.501, 0.939, and 2.093 ppm, respectively. The results showed that Cd and Pb concentration means in tea plant leaves, black tea, and soil samples were lower than the guidelines recommended by EU, WHO, and national Iranian standards (P &lt; 0.05). The values of the non-carcinogenic hazard quotients (HQ) and the hazard index (HI) were below 1, indicating that these two HMs will not adversely affect consumers' health through the oral pathway of drinking tea. However, more attention should be paid to monitoring the content of HMs in soil. This research recommends that soil Pb contamination should be managed to ensure safe tea production in the study area. An effective management strategy appears necessary to ensure the quality and safety of tea plantations, as well as to reduce the risk of the accumulation of HMs in tea.

Comprehensive Investigation of Fluoroquinolone Residues in Apis mellifera and Apis cerana Honey and Potential Risks to Consumers: A Five-Year Study (2014-2018) in Zhejiang Province, China.

As a group of antibiotics largely used in China's animal husbandry, fluoroquinolone (FQ) residues in honey may pose potential threats to human health. This study performed a five-year investigation on the occurrence of FQ residues in honey in 521 Apis mellifera and 160 Apis cerana honey samples collected from Zhejiang Province, China and compared FQ residue profiles in honey with a subgroup of various factors. Deterministic and probabilistic risk assessments of exposure to FQ residues in honey were further conducted. Overall, four FQs were detected in 6.9% (47/681) of analyzed samples; banned norfloxacin with the highest level (7890 μg·kg-1) and detection frequency (4.9%) was the primary safety risk factor associated with honeybees raised in China. FQ detection frequency and concentration of rape honey was highest among four of the largest and most stable honeys (rape, acacia, chaste, and linden) in China. Processed honey from commercial sale channels had a significantly higher detection frequency of FQ residues than raw honey from apiaries. Deterministic assessment showed that the noncarcinogenic hazard quotient (HQ) value of the dietary intake of FQs by the local population was between 4.75 × 10-6 and 1.18 × 10-3, less than 1.0, indicating that FQ residues in honey posed a low risk for consumers. The order of the HQ value was ciprofloxacin > norfloxacin > enrofloxacin > ofloxacin. Probabilistic assessment showed that at P95, the HQ of FQs for the age groups of children, adolescents, adults, and older adults over 65 years ranged from 2.39 × 10-5 to 0.217, less than 1, and the exposure risk for adults was higher than for children and adolescents. Sensitivity analysis showed that FQ concentrations were the major contributors to health risks. Although a low risk was found, a strict hive management is needed for beekeepers regarding troubles of food safety, international trade, and human bacterial resistance.

Application of the PDMS Passive Sampling Method to Assess Bioavailability and Health Risks Associated with PAH-Contaminated Soil

Integrating bioavailability into risk assessments is an effective way to objectively assess human health risks. In this study, the bioavailability of 16 polycyclic aromatic hydrocarbons (PAHs) in contaminated soil from a coking plant was evaluated using the polydimethylsiloxane (PDMS) passive sampling method. The results showed that the bioavailability factor (BAF) of each PAH, predicted using PDMS fibers, ranged from 0.46% to 9.74%. The PDMS passive sampling method was more stable in testing the bioavailability of PAHs with more than 4 benzene rings; a preliminary relationship was established between the BAF and the log value of the octanol–water partition coefficient (logKow). After considering their bioavailability, the carcinogenic risks (CRs) and non-carcinogenic hazard quotients (HQs) associated with the 16 PAHs were reduced by 1 to 2 orders of magnitude. Only the health risks associated with benzo(a)pyrene and dibenzo(a,h)anthracene exceeded the acceptable level. The PDMS passive sampling method provides a useful tool for estimating oral bioavailability, and incorporating its results into human exposure testing can help to refine the health risk assessment of contaminants through oral ingestion.

Status, sources, and human health risk assessment of DDT pesticide residues in river sediments in a highly developed agricultural region in the upper Yangtze River in China.

The concentrations of DDT and its metabolites in 19 sediment samples from a highly developed agricultural region in the upper reaches of the Yangtze River were measured. Non-carcinogenic hazard quotient for different age groups was evaluated using reference doses provided by the USEPA, and the excess lifetime cancer risk due to eating fish was assessed based on the local eating habits. The results showed that this region had a high level of residual DDT (12.84 ± 8.97 ng/g), which mainly came from the historically used technical DDT in agriculture. The non-carcinogenic risk was just acceptable in the region, but 11 of the 19 sites showed an unacceptable carcinogenic risk. Although DDT has been banned for decades, there were still notable health risks, especially for children. Special attention should be given to the potential health risks in historically developed agricultural regions.

Distribution, enrichment mechanisms, and health risk assessment of high-fluorine groundwater in the Yudong Plain, Henan Province, China.

The Yudong Plain is in the eastern part of Henan Province, China, where there is little rain and high evaporation. Compared to other areas in Henan Province, the groundwater fluorine content is generally high, which affects the health of residents. Based on the systematic analysis of water chemistry data of shallow and mid-depth groundwater samples in the Yudong Plain, the causes of shallow and mid-depth high-fluorine groundwater in the Yudong Plain were explored using mathematical statistics, spatial interpolation, and ion ratios. The results show that the fluorine contents of both shallow and mid-depth groundwater in the study area are high. The shallow samples had fluorine contents ranging from 0.1 to 4.89mg/L, with an exceedance rate of 48% and an average content of 1.15mg/L. The fluorine content of mid-depth samples ranged from 0.14 to 3.32mg/L, with an exceedance rate of 68% and an average content of 1.33mg/L. The shallow high-fluorine groundwater is mainly distributed in the central low-lying area, and its main hydrochemical type is HCO3-Na·Mg; the mid-depth high-fluorine groundwater is mainly distributed in strips in the north and east of the study area, and its main water chemistry type is HCO3-Na. Fluorine enrichment in shallow groundwater in the study area is controlled by rock weathering, evaporation concentration, and competitive adsorption, while leaching and dissolution of fluorine-containing minerals in sedimentary strata are the main factors influencing fluorine enrichment in mid-depth groundwater. The results of the human health risk assessment (HRA) showed that the mean non-carcinogenic hazard quotients (HQs) in shallow groundwater were 0.95, 0.64, 0.57, and 0.55 for infants, children, teenagers, and adults, respectively, while the mean non-carcinogenic HQs in mid-depth groundwater were 1.11, 0.74, 0.66, and 0.63, respectively. The study provides a scientific basis for the rational development and use of groundwater in the area and offers theoretical support for the prevention and control of groundwater pollution.

Speciation, bioaccessibility and human health risk assessment of chromium in solid wastes from an ultra-low emission coal-fired power plant, China

Chromium (Cr) in solid wastes from ultra-low emission (ULE) coal-fired power plants (CFPPs) could engender adverse effects on environment and human health. Hence, solid waste samples containing bottom ash, fly ash, gypsum and sludge were collected from a typical ULE CFPP in China to study the distribution, speciation, bioaccessibility and human health risk of Cr. The results showed that Cr was depleted in gypsum, whereas significantly enriched in bottom ash, fly ash and sludge comparing with feed coal. The ratios of Cr(VI) to total Cr in solid wastes were relatively low, but the increase of flow fractions in Cr chemical binding forms implied the deterioration of environmental stability. Based on the in vitro simulated digestion methods of solubility bioavailability research consortium (SBRC) and physiologically based extraction test (PBET), the bioaccessibility of Cr in the gastric and intestinal phases reached the highest values in either gypsum or sludge. After incorporating bioaccessibility in human health risk assessment, the carcinogenic risk (CR) within acceptable limits of Cr in solid wastes to adults and children was concluded, with the non-carcinogenic hazard quotient (HQ) was all within the safety threshold. The Monte Carlo model was applied to evaluate the uncertainty analysis of human health risk assessment at 5% and 95% confidence interval, and the fitting results were consistent with the calculation results of the carcinogenic and non-carcinogenic risk for adults and children. This study is expected to provide insights for the integration of bioaccessibility into the health risk assessment of Cr in solid wastes from ULE CFPPs, thus is conducive to the disposal of solid wastes and human health protection.

Human-Health and Environmental Risks of Heavy Metal Contamination in Soil and Groundwater at a Riverside Site, China

The contaminated site is considered a high-risk pollution source due to the accumulation of industrial waste and wastewater, which affects the soil and groundwater environment. In this study, through soil and groundwater investigation, we outlined the characteristics of heavy metal contamination in the soil and groundwater of the contaminated site, assessed the health risk of the contaminated site to humans, and established a numerical model to predict the ecological and environmental risks of the site. The results of the study showed that the maximum contamination concentration of pollutants (lead, arsenic, cadmium) in the soil all exceeded the Chinese environmental standard (GB36600-2018, Grade II), that the maximum contamination concentration (cadmium, Cd) of the groundwater exceeded the Chinese environmental standard (GB14848–2017, Grade IV), and that the heavy metal pollution was mainly concentrated in the production area of the site and the waste-residue stockpiles. The total carcinogenic risk and non-carcinogenic hazard quotient of the site’s soil heavy metal contaminants exceed the human acceptable limit, and there is a human health risk. However, the groundwater in the area where the site is located is prohibited from exploitation, and there is no volatility of the contaminants and no exposure pathway to the groundwater, so there is no risk to human health. The simulation prediction results show that, with the passage of time, the site groundwater pollutants as a whole migrate from south to north, affecting the northern surface water bodies after about 12 years, and there is a high ecological and environmental risk. The above findings provide a scientific basis for the study of the soil and groundwater at the riverside contaminated site.

Origin and Implications of Pollution in Coastal Groundwater of the Guangdong Province

The groundwater resource is crucial to the urbanization and industrialization in the Guangdong coastal area; the rapid development of Daya Bay has presented a challenge for the management of the groundwater quantity and quality. Therefore, a novel approach to hydrochemical analysis, which, combined with the health risk model and the water quality index (WQI), was used to explain the hydrochemistry characteristics and risks to human health of groundwater in the Guangdong coastal areas in addition to investigating the factors controlling groundwater quality. The results showed that the average concentration of total dissolved solids (TDS) in groundwater was 1935.26 mg/L and the quality of water was weakly alkaline. The dominant hydrochemical types of groundwater were identified to be Mg-HCO3 and Na-Cl·HCO3. The main factor influencing the hydrochemical composition was rock weathering, while the result of principal component analysis (PCA) shows seawater intrusion and anthropogenic inputs also have an effect on the water quality. The conclusions of the water quality assessment indicated that most of the groundwater samples were acceptable for drinking. However, both WQI and the non-carcinogenic hazard quotient (HQ) values indicated unacceptable risks in any area of Maoming, Zhanjiang and Shantou, and, according to the hazard index (HI) value, children in the study area are at more danger to health risks than adults. It is suggested that both groundwater salinization and nitrate pollution should be paid attention to when improving groundwater quality and exploring the sustainable utilization of groundwater resources.

Impact of Storage on Levels of Phthalates in Sachet and Bottled Water Brands in Enugu State, Nigeria

ABSTRACT The determination of phthalate ester concentrations in stored packaged water brands produced in Enugu State was carried out and the health risks evaluated. Packaged water samples were obtained in four batches from six sachet water and six bottled water factories, and stored outdoor for 1 month before analysis, while control samples were obtained and analysed immediately after purchase. Solvent extraction was carried out using dichloromethane, and phthalates concentrations were determined using Gas Chromatography-Mass Spectrometry. The range of limit of detection, recovery analysis and limit of quantitation were 0.001-0.002 mg/L, 81.26–91.47% and 0.003-0.006 mg/L respectively. The concentrations (µg/L) of DMP, BBP, MEHP, DBP and PADHE were<0.002–0.13, 0.41–1.84, <0.002–19.66, 0.76–4.22 and <0.002–0.81 in the bottled water and 0.11–0.36, <0.002–0.43, 0.21–5.75, 0.87–3.28 and <0.002–0.57 in the sachet water. Dimethyl phthalate (DMP) concentrations in the exposed and stored sachet water were significantly higher (P˂0.05) than that obtained from bottled water. There were also significantly higher (P<0.05) concentrations of Diethyl phthalate (DEP), Butyl benzyl phthalate (BBP), Di-butyl phthalate (DBP) and phthalic acid decyl hept-2-yl ester (PADHE), and pH in exposed sachet water than the control. Non-carcinogenic hazard quotient for phthalate esters in the packaged water samples was ˂1, which indicates no carcinogenic health risk. The contribution of individual phthalates to drinking water for Mono-2-ethylhexyl phthalate in both adults and toddlers exceeded the 0.5% TDI in some of the packaged water brands. Results suggest that increased concentrations of phthalate esters in the exposed packaged water samples were as a result of storage temperature, while the presence of phthalate esters in few of the control samples was probably from the packaging process. Although the levels of phthalates were low, regular consumption of packaged water could be detrimental to health of the general populace.

Fluoride contamination, spatial variation, and health risk assessment of groundwater using GIS: a high-density survey sampling in Weifang City, North China.

The present study, with the aid of GIS, utilizes high-density groundwater (GW) sampling data (1398 samples) to analyze the spatial variation characteristics of GW fluoride in Weifang City (WFC), and evaluate the health risks associated with drinking water routes. The concentration of fluoride in the GW of WFC is observed to be between 0.08 and 9.16mg/L, with a mean value of 0.62mg/L. The fluoride concentration of a total of 192 GW samples exceeded the limit of China's GW quality standards (1mg/L), accounting for 14.74%. The GW fluoride concentration in most areas of WFC is less than 1mg/L. However, the relatively high-value zones are mostly concentrated in the upper reaches of Wen River, the east of Shouguang, the southeast of Anqiu, the east of Qingzhou, the east of Fangzi, and the southeast and northwest of Gaomi. The hydrochemical types of GW in WFC are mostly HCO3-Ca·Mg and SO4·Cl-Ca·Mg, while GW samples with hydrochemical types HCO3-Na and SO4·Cl-Na are characterized by high fluoride content. The hydrochemical characteristics of GW in WFC are mostly dominated by rock weathering. In addition, the northern coastal plain is evidently influenced by seawater intrusion. The concentration of fluoride in GW is affected by the dissolution of fluorine-containing minerals, cation exchange, and alkaline environmental factors. The effect of GW by seawater intrusion and very high content of Na+ will decrease the fluoride content of the GW through cation exchange. Health risk assessment demonstrated that the mean values of non-carcinogenic hazard quotient (HQ) for infants, children, teenagers, and adults were 0.52, 0.35, 0.31, and 0.30, respectively. In addition, the distribution characteristics of GW fluoride in high health risk areas (HQ > 1) in WFC are further consistent with the spatial variation of GW fluoride content. Overall, the health risk distribution area of GW fluoride in WFC is decreasing in the following order: infants > children > teenagers > adults.

Contamination, risk and quantitative identification of nutrients and potentially toxic elements in the surface sediments of Baiyangdian Lake, North China.

Potentially toxic elements (PTEs) in lake sediments are concerning because of their toxic effects on lacustrine ecosystems and human health. Baiyangdian Lake (BYDL), the "pearl of North China", plays a vital role in maintaining the ecological health of North China. Here, risk assessment and source identification of nutrients and PTEs in sediments were performed. The results showed that the sediments were highly contaminated with total organic carbon (TOC) and total nitrogen (TN), but contamination by total phosphorus (TP) was minor, and the ecological risk associated with Cd was considerable, especially in the northern region. The average noncarcinogenic hazard quotient of PTEs increased in the order of Zn < Hg < Cd < Cu < Ni < Pb < Cr < As. Statistical analyses indicated that Al, Ti, Fe, Co, Cr, Hg, Ni, and rare earth elements were primarily from natural origins; Pb was derived from local tourism development and pollution by fishermen; and TOC, TN, TP, As, Cd, Cu, Zn, and Mn were mainly derived from industrial and agricultural activities. Additionally, the mean contribution rates of industrial wastewater and domestic sewage sources, agricultural sources, and natural sources to BYDL sediment pollution were 59.9%, 17.9%, and 22.2%, respectively. Spatially, industrial and domestic sewage sources contributed more in the northwestern region (average 79.8%) than in the southern region (average 35.5%), while agricultural sources contributed the most in the southwestern region (average 41.3%). These findings will advance our knowledge of the spatial differences, contamination risks and sources of nutrients and PTEs in BYDL and provide a scientific basis to help policy-makers establish a healthy ecological community in BYDL of the Xiong'an New Area.

Potentially toxic elements dynamics in the soil rhizospheric-plant system in the active volcano of Fogo (Cape Verde) and interactions with human health

Volcanic eruptions disturb directly and indirectly the ecosystems. Direct impact occurs on the soil–plant system with an input of new elements and indirect hazard occurs by consumption of these plants. Fogo island (Cape Verde Republic) has an active volcano and the last eruption occurred in 2014–15, expelling large amounts of materials that spread all over the island. Soils and edible plants were collected all over the island. Pollution indexes reveal contamination in all samples, mostly due to Hg and Ni and with moderate contribution of Co, Cr, Cu and Pb. Mercury is the PTE with higher contribution to the non-carcinogenic hazard quotient, both by soil ingestion and inhalation. Carcinogenic risk exceeds the target risk in all samples with the higher contribution of Ni. Transfer factor from soils to plants decreasing order is Mn > As > Zn > Cr > Cu > Cd > Pb > Ni > Co > Hg, being < 1 except for As and Mn (TF > 1 point to a significant accumulation of elements in edible plants). The hazard risk index and targeted hazard quotient shows that potential negative health outcomes can be induced by As, Cr, Cu, and Zn by consumption of edible plants.

Heavy metals in sediment and fish from two coastal lagoons of the Mexican Central Pacific

The present work analyzed the concentration of As, Cd, Pb, and Hg in sediment and the Hg concentration in fish muscle from two coastal lagoons in the states of Jalisco (Barra de Navidad Lagoon) and Colima (Cuyutlan Lagoon), Mexico. Both lagoons showed relatively low levels of metal contamination and potential health risk compared to other Mexican areas. A non-carcinogenic hazard quotient (HQ) was determined. As (10.7 ± 1.3 - 25.4 ± 3.1 μg g -1 ) and Pb (42.7 ± 4.2 - 123.9 ± 14.7 μg g -1 ) concentrations exceeded the permissible levels, otherwise for Hg and Cd were below the limits. The highest total mercury concentration was found in Haemulopsis sp. and Lutjanus sp. with 0.23 and 0.1 μg g -1 (wet weight) respectively, out of 14 species of fish analyzed that are frequently consumed locally. HQ based on the national daily per capita consumption of fish in Mexico and the consumption of fish associated with fishing communities in Mexico showed an HQs >2, which manifests the vulnerability of these communities to persistent toxic and bioaccumulative contaminants.

A Machine Learning Approach for Spatial Mapping of the Health Risk Associated with Arsenic-Contaminated Groundwater in Taiwan's Lanyang Plain.

Groundwater resources are abundant and widely used in Taiwan’s Lanyang Plain. However, in some places the groundwater arsenic (As) concentrations far exceed the World Health Organization’s standards for drinking water quality. Measurements of the As concentrations in groundwater show considerable spatial variability, which means that the associated risk to human health would also vary from region to region. This study aims to adapt a back-propagation neural network (BPNN) method to carry out more reliable spatial mapping of the As concentrations in the groundwater for comparison with the geostatistical ordinary kriging (OK) method results. Cross validation is performed to evaluate the prediction performance by dividing the As monitoring data into three sets. The cross-validation results show that the average determination coefficients (R2) for the As concentrations obtained with BPNN and OK are 0.55 and 0.49, whereas the average root mean square errors (RMSE) are 0.49 and 0.54, respectively. Given the better prediction performance of the BPNN, it is recommended as a more reliable tool for the spatial mapping of the groundwater As concentration. Subsequently, the As concentrations estimated obtained using the BPNN are applied to develop a spatial map illustrating the risk to human health associated with the ingestion of As-containing groundwater based on the noncarcinogenic hazard quotient (HQ) and carcinogenic target risk (TR) standards established by the U.S. Environmental Protection Agency. Such maps can be used to demarcate the areas where residents are at higher risk due to the ingestion of As-containing groundwater, and prioritize the areas where more intensive monitoring of groundwater quality is required. The spatial mapping of As concentrations from the BPNN was also used to demarcate the regions where the groundwater is suitable for farmland and fishponds based on the water quality standards for As for irrigation and aquaculture.

A Simplistic Unsaturated Zone Leaching Model-based Probabilistic Human Health Risk Assessment of Groundwater around the Ariyamangalam Dumping Site

BACKGROUND AND AIM: The human health risk assessment (HHRA) of groundwater around the Ariyamangalam open dumping site was conducted, assuming oral ingestion and dermal contact exposure scenarios. METHODS: Observed data of metal concentration in the leachate was used to compute non-carcinogenic hazard quotient (HQ) and cancer risk (CR) by integrating the leaching model with probabilistic HHRA framework. RESULTS:Results from 10,000 Monte Carlo simulations showed that the average value of cadmium (Cd) and lead (Pb) concentration from ground surface up to water table depth exceeded the safe permissible limit. The 95th percentile value of Cd concentration at the water table for sand and silty clay soil was estimated as 0.188 mg/L and 0.104 mg/L, respectively, much higher than safe limit of 0.005 mg/L. The 95th percentile value of HQ for all the subpopulations was found to be 2 - 4 orders higher than safe limit (1) via oral ingestion exposure to cadmium- and lead-contaminated groundwater. The child I (1-5 year) category was most affected by groundwater, as CR value of 1.86E-03 was observed for oral ingestion scenario, highest among all the considered cases. The 95th percentile and maximum value of cancer risk (CR) due to lead were found to be 10 to 1000 times higher than safe level (1E-06) for both the soil types. However, for the skin dermal contact scenario, only maximum value of CR for the child (6-10 year) and teen (11-18 year) exceeded the safe level. Variance attribution analysis showed that the metal concentration (80% variance contribution), as a primary contributor towards uncertainty in the risk estimates, while exposure duration (ED), ingestion rate (IR), and event duration (tevent) were observed as secondary contributors. CONCLUSIONS:The findings of this study highlighted the significance of model-driven HHRA approach and indicated that people residing in the vicinity of dumpsite should consume only treated groundwater. KEYWORDS: Unsaturated zone, Leaching Model, Contaminant Transport, Human Health Risk, Cancer Risk, Monte Carlo Simulations