Mean Hazard Index Research Articles

Exposure and Health Risk Assessment of Aflatoxin M1 in Raw Milk and Cottage Cheese in Adults in Ethiopia.

Aflatoxin M1 (milk toxin) found in milk is formed from the hepatic biotransformation of AFB1 (aflatoxin B1) and poses a risk to human health when consumed. The risk assessment of AFM1 exposure due to milk consumption is a valuable way to assess health risk. The objective of the present work was to determine an exposure and risk assessment of AFM1 in raw milk and cheese, and it is the first of its kind in Ethiopia. Determination of AFM1 was conducted using an enzyme-linked immunosorbent assay (ELISA). The results indicated that AFM1 was positive in all samples of milk products. The risk assessment was determined using margin of exposure (MOE), estimated daily intake (EDI), hazard index (HI), and cancer risk. The mean EDIs for raw milk and cheese consumers were 0.70 and 0.16 ng/kg bw/day, respectively. Our results showed that almost all mean MOE values were <10,000, which suggests a potential health issue. The mean HI values obtained were 3.50 and 0.79 for raw milk and cheese consumers, respectively, which indicates adverse health effects for large consumers of raw milk. For milk and cheese consumers, the mean cancer risk was 1.29 × 10-6 and 2.9 × 10-6 cases/100,000 person/year, respectively, which indicates a low risk for cancer. Therefore, a risk assessment of AFM1 in children should be investigated further as they consume more milk than adults.

Metals levels in Sarda orientalis collected from the commercial landings of Karachi Fish Harbor, Pakistan (northern Arabian Sea) and assessment of likely health risks to the consumers

Anthropogenic activities are the major source of chemical pollutants including heavy metals in the coastal ecosystem which may accumulate in the aquatic organisms through the food web. Metal contamination in the marine fish pose serious threat to human health. This study deals with the human health risks of metal accumulation from Sarda orientalis consumption. The quantities of heavy metals were investigated in muscle, gills, and liver of striped bonito from the commercial landings of Karachi Fish Harbor, Pakistan (northern Arabian Sea). Risk for human health was evaluated by iron, zinc, manganese, copper, lead, cadmium, estimated daily intake, hazard index, and risk index. The hazard index value is <1, indicating that the estimated exposure is below reference dose for the relevant metals for monsoon, winter, and pre-monsoon. The mean hazard index for iron, zinc, manganese, copper, lead, and cadmium was 1.20 × 10−2 for consumers. The mean risk index of lead for S. orientalis was 7.39 × 10−9. As a result, the metals did not exceed the World Health Organization’s and the United States Environmental Protection Agency’s toxicological reference.

Pollution characteristics and probabilistic health risk of potentially hazardous elements in soils near a typical coal mine in Panzhihua City, Southwest China

This study first assessed the pollution characteristics and probabilistic health risks of potentially hazardous elements (PHEs) in soils from the Dabaoding coal mining area in southwest China using Monte Carlo simulation. Experimental results showed that Cd was moderately enriched in soils, while Ni, Cr, and V were slightly enriched. However, the geoaccumulation index (Igeo) illustrated that the coal mining area had a low level of Cd pollution. PHEs produced a very high ecological risk to soils in the coal mining area, whereas Cd showed the highest contribution (82.56%). The mean hazard index of all soil PHEs was 7.45E - 02 and 4.18E - 01 for local adults and children, respectively, all of which were obviously lower than the maximum acceptable level of 1.0. However, Monte Carlo simulation analysis indicated that 1.08% of noncarcinogenic risk values for local children still exceeded the maximum acceptable level. Additionally, 10.84% and 18.40% of the total carcinogenic risk values for local adults and children, respectively, exceeded the threshold of 1E - 04. Indeed, Cr and Ni had the highest contributions to noncarcinogenic and carcinogenic risks, respectively. These findings suggest that Cd, Cr, and Ni should be identified as priority pollutants in coal mining areas. This study also provides valuable implications for policy-makers and environmental engineers, proposing efficient policies for better soil pollution control and remediation strategies in coal mining areas.

HUMAN HEALTH RISK ASSESSMENT OF HEAVY METALS IN WATER, FISH FEED AND THREE CULTURED CATFISH OF RAJSHAHI CITY, BANGLADESH

Heavy metals are very common contaminants to the environment through natural and anthropogenic sources and contamination depends on the type of contaminant, species, sampling location, trophic level, and rearing practices. The assessment of heavy metals (Co, Zn, Mn, Cu, Cd, Cr, Pb and Ni) in water, fish feed and three carnivorous catfish species (Heteropneustes fossilis, Mystus tengara, and Ompok pabda) from Rajshahi City, Bangladesh were analyzed using a flame atomic absorption spectrophotometer (AAS). The results were expressed as μg.g−1 wet weight. Results indicated that the metals in water and fish feed were found to be below the safe limit of the drinking water standard and fish feed. The concentration of heavy metals was detected as highest in fish organs (skin, gills and muscle) followed by pond water and lowest in fish feed. In the accumulation of heavy metals in different organs in three catfishes from four sampling ponds, no significant difference was found between the species and organs (p &gt; 0.05). The value of the bioaccumulation factor (BAF) from both water and fish feed was lower than 100, indicating potential heavy metal accumulation. The estimated daily intake (EDI) in three catfish species was below the tolerable daily intake (TDI). The mean target hazard quotient (THQ) and hazard index (HI) based on studied metals in three fish species were below 1 indicating that consumption of these fish can be safe for human health.

The ecological and health risks of heavy metal in vegetables irrigated with untreated wastewater under a semi-arid condition

The study evaluated the impact of wastewater irrigation (WW) on the severity of pollution and health risk potential of Zn, Cu, Cd, and Pb heavy metals in vegetables irrigated with WW versus those grown with fresh water (FW) across different vegetable kinds. This multifaceted assessment was conducted using the pollution index (PI), ecological risk (ER), bio-concentration factor (BCF), hazard quotient (HQ), overall hazard index (HI), carcinogenic risk (CR), and total carcinogenic risk (TCR). The findings revealed that WW irrigation increased metal concentrations across all soil samples and vegetable varieties in the order of Cd > Zn > Pb > Cu and Zn > Cu > Pb > Cd, respectively. When compared to the FW-irrigated soils, the values of PI and ER indicate a significant increase (an increase of 27%-3.3 times and 2.6-3.1 times, respectively) of the heavy metals in the WW-irrigated soils, falling their class from one to two (PI) and two (ER) grade. The order of heavy metals and BCF values exhibited the following pattern: Zn > Cu > Pb > Cd and Zn > Cu > Cd > Pb >, respectively, in all vegetables under WW irrigation and cabbage has the most potential to take up heavy metals compared with other crops. The mean HQ and HI were in the low category (0.1 ≤ HQ and HI < 1) and the CR and TCR were also within acceptable limits (1.00E-06 to 1.00E-04) by consuming veggies produced with WW, to children and adults implying that there are insignificant health risks to local inhabitants. However, the levels of HQ, HI, CR, and TCR were significantly higher in vegetables grown with WW than in those irrigated with FW, suggesting that wastewater irrigation has a major detrimental impact on human health.

Human dietary exposure to bisphenol-diglycidyl ethers in China: Comprehensive assessment through a total diet study

Despite the widespread use of bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE) in various consumer products as protective plasticizer, studies on human dietary exposure to these compounds are scare. In this study, nine bisphenol diglycidyl ethers (BDGEs) including BADGE, BFDGE, and seven of their derivatives were determined in the Chinese adult population based on composite dietary samples collected from the sixth (2016–2019) China total diet study (TDS). Contamination level of nine BDGEs was determined in 288 composite dietary samples from 24 provinces in China. BADGE·2H2O and BADGE are the most frequently detected and BADGE·2H2O presented the highest mean concentration (2.402 μg/kg). The most contaminated food composite is meats, with a mean ∑9BDGEs of 8.203 μg/kg, followed by aquatic products (4.255 μg/kg), eggs (4.045 μg/kg), and dairy products (3.256 μg/kg). The estimated daily intake (EDI) of ∑9BDGEs based on the mean and 95th percentile concentrations are 121.27 ng/kg bw/day and 249.71 ng/kg bw/day. Meats, eggs, and aquatic products are the main source of dietary exposure. Notably, beverages and water, alcohols were the main contributors of dietary exposure to BADGE and BADGE·2H2O, followed by animal-derived foods. Dietary exposure assessment demonstrated that human dietary BDGEs do not pose risks to general population based on the mean and 95th percentile hazard index with < 1. This is the first comprehensive national dietary exposure assessment of BDGEs in Chinese general population.

Temporal trends in risk of bisphenol A, benzophenone-3 and triclosan exposure among U.S. children and adolescents aged 6–19 years: Findings from the National Health and Nutrition Examination Survey 2005–2016

BackgroundPhenolic compounds with potential adverse health effects are gradually being replaced. Little is known about the potential health risks of BPA, BP3, and TCS exposure in children and adolescents aged 6–19 years in the United States. ObjectivesTo determine trends and rates of change in hazard indices (HI) for three phenolics in U.S. children and adolescents for BPA, BP3, TCS, and to assess changes in gender, race/ethnicity, age, and potential health risks. MethodsMetabolic biomonitoring data from field-collected urine samples from the National Health and Nutrition Examination Survey (NHANES) were utilized. Daily intake of three phenols (bisphenol A, benzophenone-3, and triclosan) between 2005 and 2016 in children and adolescents were obtained. Cumulative risk indicators, including hazard quotient (HQ), hazard index (HI), and maximum cumulative ratio (MCR), were used for the health risk assessment of the three phenols. ResultsDuring this period, the change in LSGM HI was −2.9% per cycle [95% Cl: (−3.7%, −2.2%)], and the percentage of participants with HI > 0.1 decreased from 15.6% to 10.5%. Children (6–11 years) had higher mean HI values than adolescents (12–19 years), while female had higher LSGM HI values than male. MCR values were generally low and negatively correlated with HI. However, the average value of MCR increased from 1.722 to 2.107 during this period. ConclusionExposure to phenolics among U.S. children and adolescents has changed in recent decades. However, gaps in data limit the interpretation of trends but legislative activity and advocacy campaigns by nongovernmental organizations may play a role in changing trends. Moreover, there are growing concerns about the potential health risks associated with exposure to multiple phenols in children and adolescents.

Co-exposure of potentially toxic elements in wheat grains reveals a probabilistic health risk in Southwestern Guizhou, China.

Bijie is located at a typical karst landform of Southwestern Guizhou, which presented high geological background values of potentially toxic elements (PTEs). Recently, whether PTE of wheat in Bijie is harmful to human health has aroused people’s concern. To this end, the objectives of this study are to determine the concentrations of PTE [chromium (Cr), nickel (Ni), arsenic (As), lead (Pb), cadmium (Cd), and fluorine (F)] in wheat grains, identify contaminant sources, and evaluate the probabilistic risks to human beings. A total of 149 wheat grain samples collected from Bijie in Guizhou were determined using the inductively coupled plasma mass spectrometer (ICP-MS) and fluoride-ion electrode methods. The mean concentrations of Cr, Ni, As, Cd, Pb, and F were 3.250, 0.684, 0.055, 0.149, 0.039, and 4.539 mg/kg, respectively. All investigated PTEs met the standard limits established by the Food and Agriculture Organization except for Cr. For the source identification, Cr and Pb should be originated from industry activities, while Ni, As, and Cd might come from mixed sources, and F was possibly put down to the high geological background value. The non-carcinogenic and carcinogenic health risks were evaluated by the probabilistic approach (Monte Carlo simulation). The mean hazard quotient (HQ) values in the three populations were lower than the safety limit (1.0) with the exception of As (children: 1.03E+00). However, the mean hazard index (HI) values were all higher than 1.0 and followed the order: children (2.57E+00) > adult females (1.29E+00) > adult males (1.12E+00). In addition, the mean carcinogenic risk (CR) values for Cr, As, Pb, and Cd in three populations were all higher than 1E-06, which cannot be negligible. The mean threshold CR (TCR) values were decreased in the order of children (1.32E-02) > adult females (6.61E-03) > adult males (5.81E-03), respectively, all at unacceptable risk levels. Moreover, sensitivity analysis identified concentration factor (CW) as the most crucial parameter that affects human health. These findings highlight that co-exposure of PTE in wheat grains revealed a probabilistic human health risk. Corresponding measures should be undertaken for controlling pollution sources and reducing the risks for the local populace.

Assessing the ecological and health implications of soil heavy metals in vegetable irrigated with wastewater in calcareous environments

The introduction of heavy metals from wastewater irrigation to the soil-crop-human biological domain has become a vital environmental and human health challenge. We evaluated the impact of wastewater irrigation (WW) on the severity of heavy metal pollution and health risk potential in different vegetables under WW versus fresh water (FW) irrigation. A multifaceted assessment was conducted using the pollution index (PI), ecological risk (ER), bio-concentration factor (BCF), hazard quotient (HQ), overall hazard index (HI), carcinogenic risk (CR), the bio-concentration factor (BCF), and total carcinogenic risk (TCR). The findings revealed that WW irrigation increased metal concentrations across all soil samples and vegetables in the order of Cd > Zn > Pb > Cu and Zn > Cu > Pb > Cd, respectively., The PI and ER indices indicated a significant increase of 27–330% and 260–310%, respectively in the WW-irrigated soils compared to the FW-irrigated soils. The heavy metals concentrations in the edible tissues of vegetables and their associated BCF values under WW irrigation exhibited the orders, Zn > Cu > Pb > Cd and Zn > Cu > Cd > Pb >, respectively Cabbage had the greatest potential to take up heavy metals compared with other crops. The mean HQ and HI were in the low risk category (0.1 ≤ HQ and HI < 1). Likewise, CR and TCR values were within acceptable limits (1.00E-06–1.00E-04) by consuming veggies produced with WW to children and adults, implying that there are no significant health risks to local inhabitants. However, the levels of HQ, HI, CR, and TCR were significantly higher in vegetables grown with WW than in those irrigated with FW, suggesting that wastewater irrigation may have a detrimental impact on human health.

Accumulation and risk assessment of heavy metals in rice: a case study for five areas of Guizhou Province, China.

In the present study, the concentration and accumulation abilities of five heavy metals (Cd, Hg, As, Pb, Cr) in rice were assessed and their human health risk to local citizens had been evaluated. Soil and rice samples (125 samples) were collected from Guiyang (GY), Qiannan (QN), Bijie (BJ), Tongren (TR), and Zunyi (ZY) in Guizhou Province. Heavy metals were measured by inductively coupled plasma-mass spectrometry (ICP-MS) after microwave digestion. The mean concentrations of Cd, Hg, As, Pb, and Cr were 0.58, 0.65, 12.31, 38.70, and 87.30mg/kg in soil and were 0.05, 0.005, 0.11, 0.07, and 0.34mg/kg in rice, respectively. The bioconcentration factors (BCF) decreased with the order Cd > Hg > As > Cr > Pb. Non-carcinogenic risk in this study was evaluated using the method of the hazard quotient (HQ) and hazard index (HI). The mean HQ values for Cd, Hg, Pb, and Cr were all lower than the standard limit (1.0) for children and adults, except As with the mean HQ for children of 2.79. The mean HI values for children and adults were 4.22 and 1.42, which exceeded 1.0. The mean carcinogenic risk (CR) values of As and Pb for children and adults were higher than the upper limit of the acceptable range (1 × 10-4) established by the United States Environmental Protection Agency (USEPA). In a conclusion, the non-carcinogenic and carcinogenic risks induced by heavy metals for children were higher than thatfor adults. This study revealed that consumption of rice in study areas may pose potential non-carcinogenic and carcinogenic risks to humans, and As was the largest contributor.

Polycyclic aromatic hydrocarbons (PAHs) in soils around oil refineries; Case study: Erbil and Kirkuk refineries, Iraq- A modelling approach.

Political tensions in Iraq have made attention to environmental issues not a priority for the authorities. Therefore, the influence of Kirkuk and Erbil refineries on contamination of the surrounding soil by polycyclic aromatic hydrocarbons (PAHs), were studied. 25 soil samples were collected and analyzed using high-performance liquid chromatography (HPLC), and their fate and health risk were investigated using Exposure Model for Soil-Organic Fate and Transport (EMSOFT) and the Monte Carlo Simulation (MCS) model. High ∑PAHs contamination (raged from 212.8 to 12,790.4ppb), the dominance of pyrogenic sources, and high ecological risk were observed. The mean hazard index values for children (0.043) are higher than those for adults (0.02), while the incremental lifetime carcinogenic risk values for adults (8.50E-4) are greater than those for children (5.27E-4). Pyrene is the significant soil PAH from the depth of 3cm downwards, while phenanthrene and fluorene are the major constituents of PAHs between the depth of 3 and 10cm. Also, low molecular weight PAHs significantly decrease in soil layers over the time frame, and maximum PAHs concentrations belong to high molecular weight PAHs over 20years. Using an appropriate monitoring system, as well as sound management decisions to reduce the emission of environmental pollution are needed. Also, it seems that the use of constant values for soil physicochemical parameters such as moisture and porosity, despite seasonal variations, may result in uncertainty for fate and transport modelling. Therefore, seasonal sampling and analysis of soil parameters, would be helpful. The online version contains supplementary material available at 10.1007/s40201-022-00809-y.

Ecological-health risks assessment and source apportionment of heavy metals in agricultural soils around a super-sized lead-zinc smelter with a long production history, in China

Smelting activities are considered as the primary cause of heavy metal (HM) accumulation in soils, and the human health around the smelter has been a great concern worldwide. In this study, a total of 242 agricultural soil samples were collected around a large scale Pb/Zn smelter in China, and eight HMs (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) were analyzed to assess HMs status, ecological -health risks, and identify source. Monte Carlo simulation was utilized to evaluate the probabilistic health risks, and positive matrix factorization (PMF) was employed to identify sources. The results revealed the average contents of five heavy metals (Cd 5.28 mg/kg, Pb 203.36 mg/kg, Hg 0.39 mg/kg, Zn 293.45 mg/kg, Cu 37.14 mg/kg) are higher than their background values in Hunan province. Cd had the highest mean pollution index (PI) of 41.8 and the greatest average ecological risk index (Er) of 1256.34, indicating that Cd was the primary enriched pollutant and had a higher ecological risk than other HMs. The mean hazard index (HI) through exposure to eight HMs was 2.95E-01 and 9.74E-01 for adults and children, respectively, with 35.94% of HI values for children exceeding the risk threshold of 1. Moreover, the mean total cancer risks (TCR) were 2.75E-05 and 2.37E-04 for adults and children, respectively, with 75.48% of TCR values for children exceeding the guideline value of 1E-04. In addition, the positive matrix factorization results showed smelting activities, natural sources, agricultural activities and atmospheric deposition were the three sources in soils, with the contribution rate of 48.62%, 22.35%, and 29.03%, respectively. The uncertainty analysis of the PMF indicated that the three-factor solution is reliable. This work will provide scientific reference for the comprehensive prevention of soil HM pollution adjacent to the large smelter.

Long-term orchard practice affects the ecological and human health risk of soil heavy metals in a calcareous environment.

The contamination of agroecosystems with heavy metals, caused by the long-term agricultural practices (e.g., the application of extensive agrochemical), has become a high-priority issue for soil-food-human health. Our study aimed to estimate the effect of the agricultural activities on contamination severity and health risk potential of heavy metals in the soil-urban apple orchards versus control soils across various soil types and apple cultivars. This research assessed pollution index (PI), pollution load index (PLI), ecological risk (ER), bio-concentration factor (BCF), hazard quotient (HQ), and overall hazard index (HI). The results revealed a significant increase in the concentration of all metals of the orchard soils, ranging 30-51%, 19-24%, 70-137%, 25-33%, and 16-23% for Zn, Cu, Cd, Pb, and Ni, respectively, versus those in the control soils. Compared to the control soils, PI, PLI, and ER reflected a significant increase in the orchard soils ranging 13-67%, 18-45%, and 18-33%, respectively, which has downgraded their scoring class by one grade. Cd and Pb were not detected in the samples collected from the apple cultivars 'Golden Delicious' (GD) and 'Red Delicious' (RD), indicating no toxic levels of Cd and Pb. Compared to the GD, the concentration of Zn, Cu, and Ni was comparatively higher in RD, implying varying heavy metal accumulation potentials in two different apple cultivars. The mean HQ and HI were in the low category (0.1 ≤ HQ and HI < 1) in both GD and RD cultivars, meaning that GD and RD are safe for local residents to be consumed and do not pose a significant potential risk to the health of consumers. However, HQ and HI were significantly higher in the RD cultivar than in the GD cultivar in most apple samples.

Organophosphate ester concentrations in infant food and dietary risk assessment for the infant population in China

Organophosphate esters (OPEs) are extensively used as plasticizers and flame retardants, whereas information on OPEs in infant foods is limited. In this study, twelve OPEs were investigated in 207 infant food samples collected from ten provinces in China. Mean concentrations of ∑OPEs found in cereal-based complementary foods (5.59 ± 5.54 ng/g) were higher than in infant formulas (2.68 ± 1.86 ng/g) under the upper bound (UB) hypothesis (unpaired t-test, p < 0.05). TEP, EHDPP, TCEP, and TDCPP were found to be the dominant OPEs in infant foods. The mean estimated dietary intakes (EDIs) of the OPEs were 50.2 ng/kg bw/day for infants aged under three years. The mean and 95th percentile hazard index (HI) of OPEs under the UB hypothesis were 6.6 × 10−3 and 1.9 × 10−2, respectively. The dietary risk assessment results showed that the exposure of Chinese infants to OPEs does not indicate a health concern.

Evaluation of plastic packaged water quality using health risk indices: A case study of sachet and bottled water in Accra, Ghana

Plastic packaged water is the drinking water of choice for urban populations across Africa but its quality remains questionable in most developing countries. Six hundred (600) packages, consisting of sachet and bottled water, were sampled from two high-end companies in Accra (Ghana) and stored through their shelf lives under an average room temperature of 30 °C. The samples were tested for physicochemical quality and the presence of bacteria and phthalate esters at 2n × 3 periods, where n is the sampled batch number. The data were described and modelled with embedded Bayesian and Machine Learning algorithms in JASP0.16.0.0 and Argo-4.1.3. The results reported lower than regulated levels of electrical conductivity (163.66 μS/cm), alkalinity (39.67 mg/L), and residual chlorine (<0.01 mg/L) while the pH was generally within specification (6.5–7.7). All samples showed progressive biological contamination following the third week (sachet samples) and the sixth week (bottled water) of incubation. Initial samples, including raw water, processed bulk water and packaged water did not present detectable microbial growth. The total microbial load in sachet samples grew at 0.936 cfu/week and 1.006 cfu/week for the bottled samples although the results did not exceed 1000 cfu/L (0-976 cfu/100 mL). Modelled mean probability of infection was 1.196 × 10−4 in 67% of the samples. Raw and processed water samples did not show detectable levels of phthalate contaminants. The mean hazard index calculated on the individual hazard quotients of phthalates was 7.41 × 10−3 ± 8.20 × 10−4, suggesting lower acute risk potential. Mean integrated lifetime cancer risk (ILCR) was determined to be 1.53 × 10−3 ± 1.71 × 10−4 within a range of 2.86 × 10−4 and 7.18 × 10−3. Mean child ILCR was about 70% of adult ILCR and increased from 4.16 × 10−4 to 2.41 × 10−3 for sachet and 4.93 × 10−4 to 7.18 × 10−3 for bottled water. For adult ILCR, sachet water presented 2.86 × 10−4 to 1.65 × 10−3, and 3.38 × 10−4 to 4.93 × 10−3 for bottled water. This study confirmed the presence of phthalates and pathogenic bacteria in the samples, at-risk levels that require mitigation.

Application of the maximum cumulative ratio (MCR) as a screening tool for the evaluation of multiple metal mixtures in shellfish in Chinese population

The objective of this study was to investigate the potential effects from exposure to multiple metals, including cadmium (Cd), chromium (Cr), arsenic (As), mercury (Hg), nickel (Ni) and lead (Pb) that exist in shellfish in Chinese populations, and evaluate the impacts of cumulative exposures among individuals. A total 15,469 individual shellfish samples were analyzed following a protocol for elemental analysis. A total of 25,669 respondents were selected through stratified multi-stage cluster sampling from 31 survey sites in China. Individual shellfish consumption data and body weight were collected and analyzed with a 24-hour dietary recall method on three non-consecutive days. The consumers were divided into two groups: aged 2–12 years group and aged ≥13 years. Exposure levels were estimated based using a semi-probabilistic risk assessment method and cumulative exposures among individual persons using the maximum cumulative ratio (MCR) method. The mean, median and 95th percentile of all metals exposure for age 2–12 years group were higher than age ≥13 years group, but none exceeded the respective reference doses of the metals. The mean hazard indices (HI) of each metal in shellfish for both age groups were less than 1. The MCR values calculated among 1283 consumers ranged from 1.28 to 3.25 with the average MCR value was 2.22. There were 51 (3.98%) consumers in group I, 1186 (92.44%) consumers in group II, 26(2.03%) consumers in group III A, and 20 (1.56%) consumers in group III B. And cadmium (Cd) and lead (Pb) produced the HQMax that trigged cumulative exposures. It was concluded that heavy metals did not present a potential health risk to people solely through shellfish. The cumulative risks indicated that 7.56% of the surveyed consumers were of concern because of high HI of metals exposure, and Cd, Pb, and Ni made significant contributions to the potential risk.

Health risk assessment of airborne bacteria and fungi in different-type buildings in Kunming, a typical temperate Chinese city

The risk assessment of airborne bacteria and fungi between different-type buildings located in temperate climate zone is still unclear. We applied the culturable method to characterize the airborne bacteria and fungi in 10 residences, 1 school, 2 office buildings, 1 hospital, and 1 library during winter in Kunming, China. In a total of 79 rooms, 152 culturable microbial samples were investigated. Results showed that there were significant disparities in bacterial concentrations among various types of buildings. The highest culturable bacterial concentration was found in residences, while the lowest was in the library. In contrast, the fungal concentrations showed little difference. The risk assessment indicated that occupants in different types of buildings in Kunming had an acceptable exposure risk (hazard index &lt; 1) for bioaerosols. The exposure risk for bacteria in residence was significantly higher than in the others, while the mean hazard index of fungi in residence was significantly higher than in schools, hospitals, and libraries. Ventilation could reduce the HI of bioaerosols in rooms. This study is helpful to give practical implications for assessing microbial characteristics in different types of buildings and highlight the significance of evaluating the microbial concentrations in residence in temperate climate zone in China.

Appraisal of groundwater vulnerability in south-central part of Bangladesh using DRASTIC model: An approach towards groundwater protection and health safety

Groundwater intrinsic vulnerability maps are considered a promising means for forestalling groundwater resources from contamination during recent years. In the present study, the DRASTIC model was used to predict groundwater vulnerability using hydro-geochemical data and Geographic Information System (GIS). The DRASTIC vulnerability index showed that the aquifer system of the study area (57%) was at moderate risk in terms of pollution. The groundwater quality index (GWQI) indicated that 89% of the study area exhibited poor water quality and was unsuitable for drinking. The mean hazard index (HI) for three age groups was higher than the threshold limit (1), suggesting potential non-carcinogenic public health threats. Carcinogenic risk (CR) showed wide variations with ranges between 1.2 × 10−4 and 4.6 ×10−2, and all of the sampling sites exceeded the threshold limit (CR> 10−4), which suggests people might have experienced a lifetime cancer risk. Among three categorized age groups, Group 2 (6–15 years) was the most vulnerable. However, it has been expected that this work will helps the decision maker for better manage groundwater resources in the study area.

Incorporating bioaccessibility and source apportionment into human health risk assessment of heavy metals in urban dust of Xiamen, China

Heavy metals in urban dust could pose noticeable human health risks, but there are few studies focusing on comprehensive human health risk assessment with the incorporation of both bioaccessibility and source apportionment in urban dust. Thus, fifty-eight urban dust samples were collected from kindergartens in Xiamen to analyze the bioaccessibility-based, source-specific health risk of heavy metals (V, Co, Ni, As, Mo, Cr, Mn, Cu, Zn, and Pb). Most heavy metals, except for V and Mn, were significantly enriched in urban dust based on their values of geoaccumulation index (Igeo) and may be influenced by human activities. The oral bioaccessibility values of heavy metals, which were estimated by the Solubility/Bioaccessibility Research Consortium (SBRC) in vitro model, ranged from 1.563% to 76.51%. The source apportionment determined by applying the absolute principal component analysis-multiple linear regression (APCS-MLR) model indicated five main potential sources, coal combustion, traffic and industrial, natural, construction and furniture sources, and unidentified sources, with contributions of 34.09%, 20.72%, 18.72%, 7.597% and 18.87%, respectively, to the accumulation of heavy metals in urban dust. After incorporating bioaccessibility adjustments, lower non-carcinogenic and carcinogenic risks of heavy metals were observed than those based on total metal content, with the mean hazard index (HI) values being less than the threshold value (1) and the mean total carcinogenic risk (TCR) values exceeding the precautionary criterion (10-6) for both adults and children. By combining bioaccessibility-based health risk assessment and source apportionment, traffic and industrial emissions and coal combustion dominated the noncarcinogenic and carcinogenic risks induced by heavy metals in urban dust, respectively. This study is expected to promote the systematic integration of source apportionment and bioaccessibility into health risk estimation for heavy metal contamination in urban dust, thus providing useful implications for better human health protection.

Comparison of the Potential Ecological and Human Health Risks of Heavy Metals from Sewage Sludge and Livestock Manure for Agricultural Use.

Sewage sludge and livestock (chicken, swine and cattle) manure samples were collected from the Yanmenguan Cattle Herbivorous Livestock Area to compare the potential ecological and human health risks caused by heavy metals contained in them. In this study, the Class II level of Quality Control of Imported Organic Fertilizers is selected as the limit standard value of heavy metals. Based on the mean content values, no heavy metal in cattle manure was higher than the limit standard value; the content of Cu in swine manure was higher than the limit of Cu; the content of Zn in sewage sludge, chicken manure and swine manure were all higher than the limit of Zn; and the content of Cr in sewage sludge and chicken manure were all higher than the limit of Cr. Results indicated that sewage sludge and livestock manure all had high contents of Zn, Cu and Cr. The mean pollution index (PI) suggested that Cu, Zn, As and Cr in sewage sludge and livestock manures all induced potential ecological risks. According to the mean Nemerow’s synthetic pollution index (PN) values, swine manure had the highest potential ecological risk for agricultural use. Daily exposure to Cu, Zn and Cr was higher than other heavy metals from sewage sludge and livestock manures, and heavy metal exposure was always higher for children than adults, with ingestion as the main pathway. Non-carcinogenic risk was caused mainly by Cu and Cr, based on the higher hazard quotient (HQ) values for adults and children. There was no non-carcinogenic risk for all people, except exposure of Cu from swine manure for children, which was 1.76 times higher than the threshold value of 1. According to the mean hazard index (HI) values, only swine manure had a non-carcinogenic risk for children. As the carcinogenic risk index (Risk) values were continuously greater for As than Cd, As had a higher carcinogenic risk than Cd. There was no carcinogenic risk for any single heavy metal, although As exposure from sewage sludge was found to have an inapparent carcinogenic risk for both adults and children. Regarding the RISK value, sewage sludge had an unacceptable carcinogenic risk for adults and children, and swine manure had an unacceptable risk for children only. In general, for both non-carcinogenic and carcinogenic risks, ingestion was the main pathway, and children were more sensitive than adults. Comparing the four kinds of organic waste, cattle manure was the safest for agricultural use in terms of ecological and human health risks. In multiple comparisons, swine manure was significantly different regarding potential ecological risk and non-carcinogenic risk, and sewage sludge was significantly different regarding carcinogenic risk.