Non-cancer Health Risk Research Articles

Cancer and non-cancer health risk assessment of occupational exposure to 1,3-butadiene in a petrochemical plant in Iran.

1,3-Butadiene is classified as carcinogenic to humans by inhalation. This study aimed to assess cancer and non-cancer risk following occupational exposure to 1,3-butadiene. This cross-sectional study was conducted in a petrochemical plant producing acrylonitrile butadiene styrene copolymer in Iran. Occupational exposure to 1,3-butadiene was measured according to the National Institute for Occupational Safety and Health 1024 method. Cancer and non-cancer risk assessment were performed according to the United States Environmental Protection Agency method. The average occupational exposure to 1,3-butadiene during work shifts among all participants was 560.82 ± 811.36 µg m-3. The average lifetime cancer risk (LCR) in the present study was 2.71 × 10-3; 82.2% of all exposed workers were within the definite carcinogenic risk level. Also, the mean non-cancer risk (hazard quotient (HQ)) among all participants was 10.82 ± 14.76. The highest LCR and HQ were observed in the safety and fire-fighting station workers with values of 7.75 × 10-3 and 36.57, respectively. The findings revealed that values of carcinogenic and noncarcinogenic risk in the majority of participants were within the definitive and unacceptable risk levels. Therefore, corrective measures are necessary to protect these workers from non-cancer and cancer risks from 1,3-butadiene exposure.

Petroleum hydrocarbon pollution in the Niger Delta: human health risk assessment of BTEX in biota

Based on the context of extensive petroleum hydrocarbon pollution in southern Nigeria, the concentrations of benzene, toluene, ethylbenzene and xylene (BTEX) in seafood were determined, and the health risks of these compounds were evaluated. Biota samples (Crayfish, Goby fish, Moonfish, Mudskipper, Mullet, Sardine and Tilapia) were collected from the Bonny Estuary from 2016 to 2018 and analyzed according to US EPA method 5030/8260C to determine the concentrations of BTEX. Risk assessment of BTEX to humans through the dietary route was conducted based on the lifetime cancer risk (LTCR) for benzene and the hazard quotient (HQ) for BTEX. The following BTEX concentration ranges were observed: benzene: < 0.01–0.36 mg/kg; toluene: 0.22–19.85 mg/kg; ethylbenzene: < 0.00–1.54 mg/kg; xylene: < 0.00–7.28 mg/kg. The median LTCR for benzene in children and adults was 0.65 and 0.30, respectively, which are higher than the limit recommended by the World Health Organization. The model showed that the LTCR is reducible by 99.9% and 66.6% if the concentration of benzene is 0.00001 mg/kg, and fresh seafood consumption is reduced to 10.4 g/day. The HQ for all BTEX compounds was greater than 1 (benzene: 1.0 × 104 (child), 4.9 × 103 (adult); toluene: 1.9 × 105 (child), 9.0 × 104 (adult); ethylbenzene: 9.4 × 103 (child), 4.4 × 103 (adult); xylene: 2.5 × 104 (child), 1.2 × 104 (adult)), which signifies a high non-cancer health risk to humans. These results are a reflection of the high level of petroleum hydrocarbon pollution in southern Nigeria and the debilitating human health consequences that could accompany it.

Ahtapotun (Octopus vulgaris) metal düzeylerinin değerlendirilmesi: sağlık riskleri tahmini

The levels of 13 different metals (Mg, P, K, Fe, Cu, Zn, Mn, Se, Al, Cr, As, Cd and Pb) in mantle and arm tissues of Octopus vulgaris species, which were caught from Mersin Bay in winter, spring and summer seasons, were determined. The results were compared between the tissues and seasons. Potential health risks of consumption of common octopus, which is an economically important species, were evaluated with the possibility that adult and child consumers will consume common octopus 1, 3 or 5 days a week. In this context, Estimated Weekly Intake Level (EWI), non-carcinogenic Target Hazard Quotient (THQ) and Lifetime Carcinogenic Risk (CR) were determined. Pb level was found to be above the limit level determined by FAO, EU and Turkish Food Codex. EWI values were found to be below the PTWI values determined by EFSA and FAO / WHO. THQ and ∑THQ values, which are indicative of non-cancer health risks for consumers, were determined as &lt;1. In terms of carcinogenic risk, it was determined that these values (&gt; 10-5) for As, Cr and Cd elements pose a carcinogenic risk to the consumer, but Pb values do not pose a risk.

Hazardous Air Pollutants in Fresh and Aged Western US Wildfire Smoke and Implications for Long-Term Exposure

Wildfires have a significant adverse impact on air quality in the United States (US). To understand the potential health impacts of wildfire smoke, many epidemiology studies rely on concentrations of fine particulate matter (PM) as a smoke tracer. However, there are many gas-phase hazardous air pollutants (HAPs) identified by the Environmental Protection Agency (EPA) that are also present in wildfire smoke plumes. Using observations from the Western Wildfire Experiment for Cloud Chemistry, Aerosol Absorption, and Nitrogen (WE-CAN), a 2018 aircraft-based field campaign that measured HAPs and PM in western US wildfire smoke plumes, we identify the relationships between HAPs and associated health risks, PM, and smoke age. We find the ratios between acute, chronic noncancer, and chronic cancer HAPs health risk and PM in smoke decrease as a function of smoke age by up to 72% from fresh (<1 day of aging) to old (>3 days of aging) smoke. We show that acrolein, formaldehyde, benzene, and hydrogen cyanide are the dominant contributors to gas-phase HAPs risk in smoke plumes. Finally, we use ratios of HAPs to PM along with annual average smoke-specific PM to estimate current and potential future smoke HAPs risks.

Persistent and Emerging Organic Pollutants in the Marine Coastal Environment of the Gulf of Milazzo (Southern Italy): Human Health Risk Assessment

The Gulf of Milazzo (north-eastern Sicily) has been recognized as Italian Site of National Interest (SNI; areas characterised by high level of contamination with potential effects on human health) in 2005 because of its high level of pollution. In this study we measured the concentration of Polycyclic Aromatic Hydrocarbons (PAHs), Organochlorine Pesticides (OCPs), and PolyBrominated Diphenyl Ether (PBDE) in seawater and sediments sampled from the Gulf of Milazzo in order to assess i) the environmental status of contamination, and ii) the cancer and non-cancer human health risk potentially due to dermal absorption from contaminated seawater and/or ingestion of contaminated fish. Particularly, POPs content in pelagic and demersal fish of different size classes (small, medium and large) were estimated, starting from the measured seawater and sediments concentrations, using the KABAM model. In particular, Monte Carlo simulation techniques were applied to address uncertainty in assessment of the risk and to provide quantitative estimates of probability of exposition. Ingestion of contaminated pelagic and demersal fish was the dominant pathway of exposition with high probability of significant cancer risk (Ingestion Cancer Risk >10-4) and significant non-cancer risk (Hazard Index >1). No human health risks emerged to be associated to dermal adsorption from contaminated seawater. Benzo(a)Pyrene shown the highest Ingestion Cancer Risk with respect to the other PAHs, while the highest Hazard Index for non-cancerogenic molecules was estimated for the PBDE47 congener.

Health risk assessment of inorganic arsenic exposure through fish consumption in Yellowknife, Northwest Territories, Canada

Yellowknife, Northwest Territories, Canada, is located near two closed gold mines. Elevated arsenic concentrations reported in fish are a public health concern. We collected 180 samples of three species of commonly consumed fish in 2013–2018 and analyzed arsenic species, including inorganic arsenic (As(III) and As(V)), monomethylarsonate (MMA), dimethylarsinic acid (DMA), and arsenobetaine. The average total arsenic concentration in fish muscle tissue was 2.30 ± 1.72 µg/g dry weight, and that in burbot liver tissue was 3.16 ± 2.49 µg/g dry weight. Nontoxic arsenobetaine was the main arsenic species in fish muscle (mean = 58.6 ± 34.5%), whereas DMA was the predominant species in burbot liver (mean = 76.6 ± 21.6%). On average, inorganic arsenic species accounted for less than 20% of the arsenic detected in fish. Data on the consumption of locally caught fish were collected from 1611 residents in Yellowknife in 2017 and 2018, including 1417 general residents and 194 members of the Yellowknives Dene First Nation. We evaluated the health risks from inorganic arsenic exposure using Monte Carlo simulations. Our results indicated that there were negligible non-cancer health risks, and the cancer risk was below the baseline cancer risk level of arsenic exposure among the Canadian general population.

A comparative study on the metal loads and related human health risks of toxic metals between the vegetables from Southern and Northern regions of Nigeria consumed in Akwa Ibom State

Vegetables are consumed in both the developing and developed countries of the world due to their high nutritive values, however they also contain some high levels of toxic substances including metals. This research examined the variations in toxic metal loads between the vegetables from the southern and northern parts of Nigeria consumed in Akwa Ibom State. This study also assessed the sources of these toxic metals in the studied vegetables from both regions of the country. The cancer and non-cancer health risks related to the consumption of these vegetables by the adults and children populations were investigated. The results showed higher levels of As, Cd, and Ni in vegetables from the North than in the South; the levels of Cr were higher in vegetables from the South, whereas the levels of Pb varied between the vegetables from both regions. The difference in the variations in toxic metal levels was significant at p < 0.05 for As and Ni. The study identified two major separate factors responsible for the accumulation of toxic metals in the studied vegetables from both regions. The results also revealed that the consumers of these vegetables were not exposed to serious cancer and non-cancer health risks however, were exposed to more Cd via the consumption of Solanum lycopersicum. It was also observed that the consumers were more expose to the carcinogens through the consumption of vegetables from the north and the children were more susceptible.

ASSESSMENT OF HEAVY METALS LEVELS IN SOIL AND VEGETABLES IN THE VICINITY OF UNLINED WASTE DUMPSITE IN NNEWI, ANAMBRA STATE NIGERIA

Unlined waste dumpsites are known to generate pollutants in the environment where they are located. This study investigates the pollutant load of unlined dumpsite by assessing the heavy metals levels of soil and vegetables in and around the waste dumpsite. 16 samples (study samples and control) for each soil and vegetable samples (Telfairia occidentalis, Talinum triangulare and Amaranthus hydridus) were collected respectively during wet season. The levels of 10 heavy metals were analysed using Atomic Absorption Spectrophotometric method. The highest and lowest heavy metals concentrations in the study sample site for vegetables ranged from 11.5 mg/kg – 0.01 mg/kg, while 7.79 mg/kg - 0.00 mg/kg was analysed for control site. The soil heavy metals values ranged from 13.1 mg/kg – 0.28 mg/kg for study samples, while 7.45 mg/kg – 0.02 mg/kg for control site. The study samples heavy metal results for vegetables and soil were higher than the control samples, which was attributed to high mobility of metal ions as a result of its closeness to the dumpsite through leaching. The total transfer factors ranged from 3.89 – 3.01 for study samples and 3.46 – 2.75 for control samples. The study samples were higher than the control site due to high levels of soil contaminations. The vegetables samples showed high levels of heavy metals, which were above WHO/FAO limits. The risk index range of 16.015 – 14.551 for study samples, and 6.821 – 5.761 for control samples from the extrapolated vegetable results, revealed that the vegetables collected from both sites were above the critical value of 1. The vegetables are unfit for human consumption and can cause non-cancer health risks to the populace who consume them. A proper refuse disposal system in and around the residential areas should be adopted. Routine monitoring of heavy metals in such plants to prevent excessive accumulation of the metals in the food chain is also advocated.

Variations in the levels, source, cancer and non-cancer risks of trace metals in the local and exotic fruits

Local and exotic fruits are generally consumed for their high nutritive values however, they also contain high quantities of harmful substances including trace metals. This work investigated the variations in the levels of Cd, Cu, Fe, Ni, Pb, and Zn in the local Citurs sinensis, Persea americana, Citrus paradise, Malus domestica, and Citurs limon are their exotic counterparts. The cancer and non-cancer health risks related to the consumption of both the local and exotic fruits were also examined. The results obtained revealed higher levels of all the metals in the local fruits than in their exotic counterparts however; the mean values of the metals were within their recommended limits by FAO/WHO. Multivariate analysis indicated anthropogenic factor as the major source of trace metals in the studied fruits. The average daily intake rates of the metals were generally lower than their provisional tolerable daily intake limits by FAO/WHO. The study showed that the consumers of local fruits were more vulnerable to health hazard than those consuming the exotic ones. Results for the cancer risk and total cancer risk were generally within the acceptable range of 10-6 – 10-4 by USEPA. Though, the consumers of the locally sourced fruits were more exposed to carcinogens.

Spatial distribution and assessment of the human health risks of heavy metals in a retired petrochemical industrial area, south China

Petrochemical industries are widely distributed in China. As a negative consequence, heavy metals in petrochemical area can result in soil contamination. However, the relevant research of heavy metals contamination in petrochemical area was few. In this study, a total of 103 topsoil samples (<20 cm) and 25 profile soil samples were collected and examined in a retired petrochemical industrial area, South China. The results showed the mean contents of Hg, Cd, As, Pb, Ni and Cu were 0.18, 0.69, 16.22, 47.24, 31.62 and 93.06 mg kg−1, respectively. The spatial distribution of six metals in topsoil was largely attributed to the industrial activities during the petroleum refining and transshipment process. Ni was the main pollutant in the petroleum refining process. While, the contamination of other metals mainly were caused by the leakage of the oil during transshipment. The migration of six metals to subsoil layers was also observable. In accordance, Hg, Cd, As, Pb, Cu, and Ni dropped by 95.02, 71.91, 89.45, 90.88, 99.22, and 65.07%, respectively, compared to their contents in topsoil. The contamination of the heavy metals was mainly caused during the process of petroleum refining and transshipment. The distribution of heavy metals in the factory was mainly affected by the industrial activities or the lateral infiltration of Lianhuashan River. Soil ingestion was the primary pathway for children and adults exposure to heavy metals. The total non-cancer human health risk induced by heavy metals was within the limit of USEPA (10−6 a−1). While the cancer risks alone induced by As through soil ingestion to children was 1.14 × 10−6 a−1, which exceeded the limit of USEPA. This study indicated that not only petroleum hydrocarbon but also heavy metals can cause soil contamination in a retired petrochemical industrial area, which provides a novel cognition. Altogether, measures should be taken in practice to substantially improve the soil quality in petrochemical industrial area.

Integration of cancer and non-cancer human health risk assessment for Aniline enriched groundwater: a fuzzy inference system-based approach.

This study outlines a methodological approach to evaluate the environmental risk from integrating data of Aniline in groundwater near to coal-based industries using fuzzy logic, and a comprehensive artificial intelligence approach and the results were validated using conventional risk assessment approach. The Aniline is well-known carcinogenic pollutant released from coal-based industries, so to understand the associated cancer and non-cancer risks (CR and NCR), 15 groundwater samples were analyzed for Aniline, whose concentration was found within the range 0.10-0.34mg/L, which is up to 68 times higher than the permissible limit. The alkaline pH of water samples resulted in reduced attractive forces between the soil particles with Aniline, and thereby increased percolation of Aniline into the groundwater. Women were at least risk in terms of Mamdani cancer risk (MCR) and Mamdani hazard index (MHI) which was observed up to 1.04E-04 and 3.04, respectively, while maximum MCR and MHI were observed in case of children, i.e., 1.21-E04 and 3.26, respectively. The newly proposed fuzzy inference rule-based Mamdani combined index (MCI) depicts the combined effect of both CR and NCR and was found to be highly correlated with each other. The detailed comparison analysis exhibited that the fuzzy inference rule-based MCI has better resolving ability to find out priority risk prediction over conventional methods under efficient parameter uncertainty control. Hence, it can be concluded that the fuzzy analyses can reflect human considerations and expertise in indices, empowering them to manage nonlinear, questionable, uncertain and subjective data. Therefore, this tool can predict the more meaningful risk estimation of any pollutants on human health.

Heavy Metals Bioaccumulation and Health Risks with Associated Histopathological Changes in Clarias gariepinus from the Kado Fish Market, Abuja, Nigeria

Background.Aquatic pollution by heavy metals has become a global problem and is of great concern due to the detrimental effects on aquatic ecosystems and possible human uptake.Objectives.The present study aimed to evaluate tissue bioaccumulations of heavy metals and possible human health risks in addition to associated cellular damages in fish for sale in a fish market in Abuja, Nigeria.Methods.Clarias gariepinus sold at the Kado Fish Market in Abuja, Nigeria, in March–April 2017 and March–April 2018 were randomly purchased and sampled. The heavy metal contents of the sampled fish were assayed and used to assess the extent of potential health risks to human consumers. The extent of histopathological changes associated with the bioaccumulations in the sampled fish were also evaluated according to standard procedures.Results.Levels of most heavy metals were above permissible limits, except for lower levels of zinc (Zn) in liver and muscle and higher levels of lead (Pb) in muscle in the sampled fish. Similarly, significant (p<0.05) liver bioaccumulation occurred for Zinc (Zn), chromium (Cr), iron (Fe), and copper (Cu) compared to their levels in muscle. The total hazard index (non-cancer risk across all metals) was 0.0415, which is very low and acceptable. The cancer risks ranged between the acceptable values of 1.98 × 10−5 – 3.71 × 10−6. Associated histopathological changes, which occurred in the sampled fish, differed between the various assayed tissues.Conclusions.Most of the heavy metals were significantly bioaccumulated (p<0.05) and were above the permissible levels, particularly in liver samples. The levels of muscle heavy metal bioaccumulation in the sampled fish posed no apparent cancer or non-cancer health risks to human consumers. However, further efforts are needed to minimize heavy metal aquatic environmental pollution to safeguard the health of aquatic flora and fauna and human consumers because of the tendency of these pollutants to persist and bioaccumulate to toxic levels over time.Competing Interests.The authors declare no competing financial interests.

Trace elements contamination in groundwater and associated human health risk in the industrial region of southern Sonbhadra, Uttar Pradesh, India.

The present study assesses the pollution load of the groundwater with reference to the trace elements (i.e. As, Hg, Cd, Cr, Cu, Fe, Mn, Zn, Ni, Co and Pb) and the potential health risk by its consumption for the residents of Obra, Renukoot and Anpara industrial clusters of Southern Sonbhadra, Uttar Pradesh, India. For this, 220 groundwater samples were collected during post- and premonsoon seasons in 2015. pH varied from slightly acidic to alkaline in both the seasons. Geochemical analysis of the area showed that all the three clusters are severely contaminated with Fe, Pb, Cd, Cr, As and Hg during both the seasons. High concentration of heavy metals indicates that groundwater was contaminated with natural as well as anthropogenic sources. For all the three clusters, the mean values of heavy metal pollution index were found above the critical index in both the seasons with Anpara in lead. For the majority of groundwater samples across the clusters during both the seasons, substantial non-cancer health risk was observed due to target hazard quotient values of Cr, Cd, As, Pb and Hg higher than unity. The hazard index value for children was very high compared to adults which means that children are more susceptible to health impairment in terms of non-carcinogenic health risk. Carcinogenic risk was higher for adults than children in the entire study area.

Polybrominated diphenyl ethers (PBDEs) in surface water and fish tissues from Sundays and Swartkops Estuaries, Eastern Cape Province, South Africa: Levels, spatial distribution, seasonal variation and health implications

This study investigates the levels, composition profile and potential sources of polybrominated diphenyl ethers (PBDEs), in surface water and fish tissues from Sundays (SDE) and Swartkops Estuaries (SWE). The concentration of Ʃ ∑6PBDEs ranged from 2.5 to 39.1 ng/L for SDE and 2.5 to 168.8 ng/L for SWE. BDE-17, BDE-47, and BDE-100 were the predominant congeners in the sample matrices from both estuaries. In all the ten sampling sites studied, samples from the Motherwell Canal recorded the highest mean concentration as indicated by the hierarchical cluster analysis. Seasonal variations of the contaminants showed a high level of PBDEs in autumn for SDE, while for SWE samples collected in the summer recorded the highest concentration. The Ʃ ∑6PBDEs in muscles of twenty-two specimens of Mugil cephalus collected from SDE ranged from 1.3 to 9.1​ ng/g ww, while the concentration in twenty specimens of Pomadasys commersonnii from SWE ranged from 0.41 to 76.3 ng/g ww. The polybrominated diphenyl ethers (PBDEs) levels were higher in the gills of both fish species compared to their muscles. Hence, this study ascertains that the consumption of these fish species does not pose a non-cancer health risk. This paper suggests that long-term exposure and bioaccumulation of PBDEs as well as other organic contaminants should be investigated in various environmental matrices in other estuaries in South Africa.

Cancer and Non-Cancer Risk Concerns from Metals in Electronic Cigarette Liquids and Aerosols

We evaluated metal concentrations in e-liquids and e-aerosols from eight studies and estimated the range of corresponding cancer and non-cancer risks. Chromium and nickel were the leading contributors to cancer risk, with minor contributions from cadmium, lead, and arsenic. The increased cancer risks, assuming exposure to 2 mL/day, ranged from 5.7 to 30,000 additional cancers in a million e-cigarette users. The average cancer risk was 3 in 1000. Cancer risks in the mid to upper end of these ranges exceed acceptable levels. The hazard quotient (HQ) approach was used to evaluate non-cancer risks. Hazard quotients exceeding 1.0 indicate the possibility for non-cancer adverse health effects. Estimated exposures at the maximum reported concentrations of nickel, chromium, and manganese resulted in HQ values of 161, 1.1, and 1.0, respectively, with additional contributions from lead. The average concentration of nickel resulted in an HQ value of 14. We conclude from these studies that exposure to metals in e-cigarette liquids and aerosols may pose a significant cancer and non-cancer health risk at the mid and upper end of the reported ranges. The device design and heating elements appear to be the main source of metals in e-aerosols. The large range of metals within and across e-cigarette brands indicate the need for improvements in product design, enforced product safety regulations and manufacturing quality control. Implementation of such measures could reduce metal exposure in e-cigarette users.

Seasonal distribution, risks, and sources of endocrine disrupting chemicals in coastal waters: Will these emerging contaminants pose potential risks in marine environment at continental-scale?

Coastal waters are the critical ecologically fragile regions under the influence of the fastest economic developing pace and the extensive anthropogenic activities in coastal zone. Little information on the seasonal distribution, risks, and sources of endocrine disrupting chemicals (EDCs) which are emerging contaminants to pose potential risks at very low concentrations in coastal waters at continental-scale is available. This study investigated the coastline-based distribution, risks, and sources of target EDCs in coastal water of China. EDCs in coastal waters of China showed significant spatio-temporal variation with phenolic compounds serving as predominant EDCs. Bisphenol A (BPA) was detected in all water samples with average concentration of 449.2/186.3 ng/L in winter/summer while estrone was the main steroidal estrogen with the average concentration of 87.2/2.7 ng/L in winter/summer. EDCs in coastal waters of South China Sea Area showed higher concentrations. EDCs in coastal waters exerted high ecological risks and estrone/BPA averagely accounted for over 61%/71% of total risk quotient in winter/summer. Average estradiol equivalent concentration of all target EDCs reached 68.87/1.76 ng/L in winter/summer. EDCs in coastal waters did not pose potential non-cancer health risks for humans. The positive matrix factorization (PMF) model was firstly used to identify and quantify possible sources of EDCs. The PMF analysis showed that wastewater and sewage might be the main source for EDCs in coastal waters. EDCs in coastal waters showed high estradiol equivalent concentration and ecological risks at continental-scale, highlighting that EDCs contamination has become a crucial stress affecting the sustainable development of coastal regions.

Geochemical relationship and translocation mechanism of arsenic in rice plants: A case study from health prone south west Punjab, India

Rice is a recognised hyperaccumulator of arsenic (As) and is a serious concern for rice varieties grown in As contaminated soil-water systems. In this regard, groundwater, soil and rice-plant samples (two varieties: PR122 and PUSA1121) collected from 10 sites of district Bathinda were studied for their physicochemical characteristics and As concentration. In vitro studies were carried out to study the role of antioxidant enzymes in As uptake and translocation mechanism. The results showed that the As concentration in water and soil samples ranged from 54 to 132 μg/L and 6.62–19.56 mg/kg, respectively. The As in rice roots, straw, husk and grains of PR122 ranged from 1.89 to 8.56, 0.20–5.3, 0.12–1.42, 0–0.12 mg/kg, respectively and 1.24–8.16, 0.54–5.11, 0.11–1.06 mg/kg and below detection limit (BDL), respectively for PUSA1121. Although a moderate correlation (r = 0.37) was observed between As in groundwater and soil, the higher As concentration found in both media in Behman and Teona areas indicates that we cannot ignore the role of groundwater in As contamination. Spearman correlation analysis indicates the positive impact of As from groundwater and soil in aerial parts of both rice varieties except grains. In vitro studies showed an increase in antioxidant enzyme activities with the increase in As toxicity (15–60 μM), which indicates As tolerant behaviour in both rice varieties. The hazard quotient (HQ) for both rice varieties is < 1, which suggest no potential non-cancer health risk, however the cancer risk (CR) for PR122 variety exceeded (2.06 × 10−4) the acceptable limit of 1 × 10−4 (USEPA). Based on the present study, it can be concluded that both the rice varieties are tolerant to As and their grains are safe for human consumption.

Drinking Water Treatments for Arsenic and Manganese Removal and Health Risk Assessment in White Rock, Canada

The City of White Rock, Canada has been facing challenges of elevated concentrations of arsenic and manganese in its drinking water supply. A pilot water treatment study was conducted to explore effective contaminant removal solutions for human health risk mitigation. The arsenic and manganese removal performance of four treatment processes, including ozonation-manganese greensand filtration (OSF), OSF-iron-based granular media adsorption (OSFIA), the Burgess Iron Removal Method (BIRM), and BIRM-iron-based granular media adsorption (BIA) were evaluated. The non-cancer health risks and the incremental lifetime cancer risks (ILCR) posed by arsenic in different water sources were also assessed. The results show that OSFIA treatment achieved the highest arsenic and manganese removal. An average arsenic removal rate of 68.5% (initial concentration = 9.3 μg/L) was observed using OSFIA during two months of treatment, while manganese (initial concentration = 133.9 μg/L) can be completely removed. The arsenic removal was mainly be attributed to the adsorption of iron-based granular media. The mean values of non-cancer health risks of arsenic exposure due to oral intake of treated water were identified to be lower than the critical threshold for different age groups. In addition, the probability of critical ILCR occurrence can be greatly reduced. Based on the results from the pilot study, OSFIA was selected to construct a full-scale water treatment plant. Arsenic and manganese concentrations in the effluent from the plant can be reduced to a low-to-undetectable level, achieving negligible health risks to the residents of the city.

Cancer and non-cancer health risks from carcinogenic heavy metal exposures in underground water from Kilimambogo, Kenya

Water is very crucial for man, animals and plants because of its health implications in case it is polluted. Water has many uses like drinking for man and animals, domestic use and for agricultural use. The concentration levels of Cd, Ni and Pb in borehole water of Kilimambogo region were measured using the atomic absorption spectrometer (AAS). pH was measured on site using a digital pH standard meter. The use of fertilizers and chemicals from the neighboring small scale farms and the large pineapple farms could easily contaminate the water table. The mean heavy metal concentration for Cd, Ni and Pb were found to be 6.4, 6.9 and 42.0 ppm respectively. The mean hazard quotients (HQ) were 26.2, 1.4 and 57.0.for adults and 12.9, 0.69 and 27.9 for children for the corresponding elements. The mean carcinogenic risks for Cd, Ni and Pb were 4.9 × 10−2, 1.2 × 10−2 and 7.3 × 10−3 for adults and 1.1 × 10−2, 2.8 × 10−2 and 1.6 × 10−3 for children respectively. The mean metal pollution index (MPI) and heavy metal evaluation index (HEI) were 10 and 934, higher than the set critical threshold value of 100. Therefore, the borehole sources are enriched with heavy metals and should be periodically monitored.

Effects of location, climate, soil conditions and plant species on levels of potentially toxic elements in Chinese Prickly Ash pericarps from the main cultivation regions in China

The presence of potentially toxic mineral elements is often reported in soil, fruits and vegetables. The concentrations of these are influenced by location, climate and soil conditions, and plant species. This study reports levels of aluminium (Al), arsenic (As), cadmium (Cd), lead (Pb), manganese (Mn) and nickel (Ni) in the soils where Chinese Prickly Ash - Zanthoxylum bungeanum (ZB) and Z.armatum (ZA) are grown. Soil and pericarp samples were taken from 72ZB and ZA plantations in 12 provinces. The soil pollution index (PI) was generally low for As (0.04-0.35), Pb (0.01-0.74) and Ni (0.15-1.06). The PI was higher for Cd (0.06-6.99) and was assessed at three categorical levels: 'low' (in 26% of soils), 'moderate' (in 67% of soils) and high (in 7% of soils). The majority (94%) of soils were slightly polluted with Cd with the integrated pollution index in the range 0.17-2.02. More than 60% of pericarp samples posed a high non-cancer health risk based on the hazard index, while 43% of pericarp samples posed a considerable cancer risk based on the incremental lifetime cancer risk. The mean temperature and the mean relative humidity contributed most significantly (28% and 10%, respectively) to variation in the concentrations of potentially toxic elements in the pericarps. This study provides a comprehensive report on the concentrations of potentially toxic elements in the soils and associated pericarps, and the effects of location, climate, and soil on the levels of potentially toxic elements in the soil and pericarps, including the effects of tree species.