Health cancer risk assessment for arsenic exposure in potentially contaminated areas by fertilizer plants: a possible regulatory approach applied to a case study in Moscow region-Russia

At present, fertilizer industry plants are considered as a potential source of soil contamination in Russia. Therefore health risk assessment should be pursued in Russian fertilizer plant areas, but unfortunately risk assessment methodology for contaminated sites does not have yet a regulatory value in Russia. In this paper a possible and intentionally simple regulatory approach for health cancer risk assessment at phosphogypsum waste-storing potentially contaminated sites is presented. The proposed approach is applied to a potential contaminated area located in the Moscow river (Moscow Region) protective zone. At this case-study area, arsenic has been chosen as a contaminant indicator, according to the proposed selection procedure. For estimating the human exposure to arsenic through various pathways the original McKone & Daniels '91 model has been adapted. As a specific result of the risk assessment for the case-study area, it has been shown that arsenic exposure pathways (in risk-ranking order) "ingestion of agricultural products," "groundwater uptake," "dermal contact," and "soil ingestion" pose a significant health risk. From a general point of view, the proposed and applied health risk assessment approach could give some contribution (for comparison and discussion) for policies on contaminated soils to other countries. In this perspective, the paper expressly considers the current Italian regulative situation concerning restricted use of risk analysis and concerning soil quality for agricultural land use.     

Identifying Soil Cleanup Criteria for Dioxins in Urban Residential Soils: How Have 20 Years of Research and Risk Assessment Experience Affected the Analysis?

This article reviews the scientific evidence and methodologies that have been used to assess the risks posed by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and presents a probabilistic analysis for identifying virtually safe concentrations of TCDD toxicity equivalents (TEQ) in residential soils. Updated data distributions that consider state-of-the-science cancer and noncancer toxicity criteria, child soil ingestion and dermal uptake, bioavailability in soil, and residential exposure duration are incorporated. The probabilistic analysis shows that the most sensitive determinants of dose and risk are childhood soil ingestion, exposure duration, and the selected TCDD cancer potency factor. It also shows that the cancer risk at 1 per 100,000 predicted more conservative (lower) soil criteria values than did the noncancer hazard (e.g., developmental and reproductive effects). In this analysis, acceptable or tolerable soil dioxin concentrations (TCDD TEQ) ranged from 0.4 to 5.5 ppb at the 95th percentile for cancer potency factors from 9600 to 156,000 (mg/kg/d)^?1 with site-specific adjustments not included. Various possible soil guidelines based on cancer and noncancer risks are presented and discussed. In the main, the current toxicology, epidemiology, and exposure assessment data indicate that the historical 1 ppb TEQ soil guidance value remains a reasonable screening value for most residential sites. This analysis provides risk managers with a thorough and transparent methodology, as well as a comprehensive information base, for making informed decisions about selecting soil cleanup values for PCDD/Fs in urban residential settings.     

Health risk assessment and source apportionment of PAHs in industrial and bitumen contaminated soils of Kermanshah province; NW Iran

A comprehensive study conducted for investigating the presence of polycyclic aromatic hydrocarbons (PAHs) in bitumen contaminated (BC) and industrial contaminated (IC) soils of Kermanshah province to evaluate their sources and health risk assessment. Forty-two surface soil (0-30 cm) samples were collected and analyzed for 16 PAHs. The total PAHs concentrations, show a mean value of 31.33 mg/kg and 56.31 mg/kg, ranging from 7.35 to 291.38 mg/kg and 6.59 to 662.83 mg/kg in BC and IC soil samples respectively. Positive matrix factorization model (PMF) was used to investigate the source apportionment of PAHs. PMF analysis identified four sources of PAHs as; fossil fuel combustion and unburned petroleum (28.76%), biomass/coal burning (23.55%), vehicular emissions (23.67%) and creosotes (24.01 %) in BC soils and biomass combustion (44.11%), unburned petroleum and coal combustion (17.54%), fossil fuel combustion (19.02%) and creosotes (19.32 %) in IC soils. Ecological risk assessment of PAHs showed that all of the PAHs levels are higher than the effects range low (ERL) values, except for benzo( a)anthracene. Three rings and fluoranthene of the PAHs in IC soils and Nap, Acy, Ace, Phe, Ant, Flt and DBA in BC soil samples reveal higher concentrations than the effects range median (ERM) values. Benzo( a)pyrene equation (BaP_eq) values indicate that the carcinogenic potency of PAHs should be given more awareness due to impending environmental risk in the study area. The total incremental life time cancer risk (ILCR) of exposure to PAHs is 9.21×10^-3 for adult and 9.54×10^-3 for children in BC soil samples and 1.13×10^-2 for adult and 1.17×10^-2 for children in IC soil samples. Estimated results of ILCR indicate that soil samples are potentially exposed to high cancer risk via both ingestion and dermal contact.     

Assessment of the human health risks posed by exposure to chromium-contaminated soils

Millions of tons of chromite-ore processing residue have been used as fill in various locations in northern New Jersey and elsewhere in the United States. The primary toxicants in the residue are trivalent chromium [Cr(III)] and hexavalent chromium [Cr(VI)]. The hazard posed by Cr(III) is negligible due to its low acute and chronic toxicity. In contrast, Cr(VI) is a human carcinogen following inhalation of high concentrations. It can also cause allergic contact dermatitis. This evaluation addresses a residential site where the arithmetic mean (x) and geometric mean (gm) concentrations of Cr(III) in soil were 2879 and 1212 mg/kg (ppm). The mean and geometric mean concentrations of Cr(VI) were 180 and 4 mg/kg, respectively. The uptake (absorbed dose) of Cr(III) via soil ingestion, consumption of homegrown vegetables, and ingestion of inspired particles was determined. The uptake of Cr(VI) via dermal absorption from contact with surface soil and building wall surfaces, as well as inhalation, was also evaluated. The techniques used in this assessment are applicable for evaluating the human health risks posed by any residential site having contaminated soil. The potential for both sensitized and unsensitized persons to develop allergic contact dermatitis due to exposure to soil contaminated at these levels was found to be negligible. The estimated average daily dose (ADD) via ingestion and dermal absorption for the maximally exposed individual (MEI) was about 1500- and 40-fold below the EPA reference dose (RfD) for Cr(III) and Cr(VI), respectively. It was shown that for residential sites, the most important route of exposure to Cr(III) was incidental soil ingestion. Although not relevant to these sites specifically, if garden vegetables could be successfully grown in these soils, then they would probably be the predominant source of uptake of Cr(III). Since inhalation of Cr(VI)-contaminated dust (but not ingestion or dermal contact) poses a cancer hazard, the doses and associated risks were assessed. The estimated cancer risks for the MEI and most likely exposed individual (MLEI) were approximately 5 x 10(-9) and 2 x 10(-9), respectively. These levels of risk have always been considered well below those that warrant regulatory concern. For persons living on residential properties, the cancer risk due to inhaling suspended particles is likely to be less than 1 in 1,000,000 if Cr(VI) levels in soil are less than 180 mg/kg (ppm). Based on this analysis, the levels of Cr(III) and Cr(VI) at this and similar sites do not pose a health hazard following acute or chronic exposure.     

The human health risks assessment of mercury in soils and plantains from farms in selected artisanal and small-scale gold mining communities around Obuasi,Ghana

Food consumption remains the commonest pathway through which humans ingest higher levels of mercury (Hg). Long-term exposure to Hg through Hg-contaminated food may result in acute or chronic Hg toxicity. Incessant discharge of Hg waste from ASGM facilities into nearby farms contaminates food crops. Ingestion of such food crops by residents may lead to detrimental human health effects. The human health risks upon exposure to total mercury (THg) and methylmercury (MeHg) in farmland soils and plantains from farms sited near ASGM facilities were studied in four communities around Obuasi, Ghana. The human health risk assessment was evaluated using hazard quotient (HQ), estimated average daily intake (_eAvDI), hazard index (HI) and Hg elimination and retention kinetics. Tweapease, Nyamebekyere and Ahansonyewodea had HQ, _eAvDI and HI for THg of plantains for both adults and children below the recommended USEPA limit of 1, 3 × 10⁻⁴ mg/kg/day and 1, respectively. Odumase had HQ, _eAvDI and HI for THg of plantains for both adults and children, higher than the guideline values. This meant that only Odumase may cause non-carcinogenic human health effects upon repeated exposure. The HQ, _eAvDI and HI values of MeHg for all the study areas were far below guideline values, hence may not pose any non-carcinogenic human health risks to residents even upon repeated exposure. Retention and elimination kinetics of Hg also showed that only plantains from Odumase may pose significant non-carcinogenic human health risks to residents because the final amount of inorganic mercury exceeded the extrapolated USEPA guideline value of 0.393 μg/kg/year.     

Development of a chronic noncancer oral reference dose and drinking water screening level for sulfolane using benchmark dose modeling

Sulfolane is a widely used industrial solvent that is often used for gas treatment (sour gas sweetening; hydrogen sulfide removal from shale and coal processes, etc.), and in the manufacture of polymers and electronics, and may be found in pharmaceuticals as a residual solvent used in the manufacturing processes. Sulfolane is considered a high production volume chemical with worldwide production around 18 000–36 000 tons per year. Given that sulfolane has been detected as a contaminant in groundwater, an important potential route of exposure is tap water ingestion. Because there are currently no federal drinking water standards for sulfolane in the USA, we developed a noncancer oral reference dose (RfD) based on benchmark dose modeling, as well as a tap water screening value that is protective of ingestion. Review of the available literature suggests that sulfolane is not likely to be mutagenic, clastogenic or carcinogenic, or pose reproductive or developmental health risks except perhaps at very high exposure concentrations. RfD values derived using benchmark dose modeling were 0.01–0.04 mg kg^?1 per day, although modeling of developmental endpoints resulted in higher values, approximately 0.4 mg kg^?1 per day. The lowest, most conservative, RfD of 0.01 mg kg^?1 per day was based on reduced white blood cell counts in female rats. This RfD was used to develop a tap water screening level that is protective of ingestion, viz. 365 µg l^?1. It is anticipated that these values, along with the hazard identification and dose–response modeling described herein, should be informative for risk assessors and regulators interested in setting health‐protective drinking water guideline values for sulfolane. Copyright © 2012 John Wiley & Sons, Ltd.     

Health risk assessment on residents exposed to chlorinated hydrocarbons contaminated in groundwater of a hazardous waste site

We conducted this study to estimate residents' chronic hazard and carcinogenic risk in a groundwater-contaminated community after on-site remediation in Taiwan during 1999-2000. We followed guidelines for assessing hazardous waste sites of the U.S. Environmental Protection Agency (EPA) and used empirically measured contaminant levels and exposure parameters to perform health risk assessment on seven chlorinated hydrocarbons. We measured groundwater concentrations of vinyl chloride, tetrachloroethylene, trichloroethylene, 1,1-dichloroethylene, 1,1,1-trichloroethane, cis-1,2-dichloroethylene, and 1,1-dichloroethane in 49 off-site residential wells by gas chromatography/mass spectrometry. Exposure parameters were mainly derived from our field survey of 382 residents, and partially from U.S. EPA default values. Total exposure dose estimation included routes of inhalation during showering and dermal absorption of showers and other activities involved with hand-water contacts. The ingestion route of water was not included because most residents drank boiled water with negligible contaminants. We calculated a hazard index (HI) for all seven chlorinated hydrocarbons and carcinogenic risks for known human carcinogen of vinyl chloride and probable human carcinogens of tetrachloroethylene and trichloroethylene, which had the same target organ, the liver. The HI values for reasonable maximal exposure (RME) and average exposure were 14.3 and 0.2, respectively. The cancer risks based on RME and average exposure (in parentheses) for vinyl chloride, tetrachloroethylene, and trichloroethylene were 8.4 x 10(-6) (7.3 x 10(-9)), 1.9 x 10(-4) (1.3 x 10(-7)), and 1.4 x 10(-4) (1.2 x 10(-6)), respectively. We applied Monte Carlo simulations to the sensitivity analysis, which showed that the contaminant levels, exposure duration, and time for showers were major determinants of health risks. We concluded that the contaminated groundwater was still unsafe for use even after the contaminated site underwent remediation by extraction and treatment in 1997.     

Concentrations and health risk assessment of Polycyclic aromatic hydrocarbons in Soils of an urban environment in the Niger Delta,Nigeria

The concentrations and compositional patterns of the United States Environmental Protection Agency (US EPA) 16 priority polycyclic aromatic hydrocarbons (PAHs) were determined in surface soils of an urban environment in the Niger Delta of Nigeria with a view to providing information on the sources, extent of contamination and human health risks of PAHs in these soils. The analyses were performed by means of gas chromatography-mass spectrometry (GC-MS) after extraction of the soils with hexane/dichloromethane and clean-up of the extracts. The concentration of Σ16 PAHs in the urban soils ranged from 188 to 684 µg kg^?1, while the ΣPAH_7c (carcinogenic PAHs) ranged from 28.5 and 571 µg kg^?1. The estimated carcinogenic and mutagenic potency factors for these sites ranged from 2.34 to 197 and 9.66 to 195 µg kg^?1 respectively. The composition of PAHs in these soils follows the order: 5-rings>4-rings>3-rings>6-rings>2-rings, and higher molecular weight PAHs accounted for a significant proportion of the Σ16 PAH concentration in this study. The results indicated that there is a high potential risk of cancer development as a result of exposure of PAHs via ingestion, dermal contact and inhalation. The diagnostic ratios indicate that the PAHs in these soils originated mainly from pyrogenic processes, such as combustion of petroleum, fossil fuels and biomass such as woods, charcoal straw and grasses. The results of this study provided information on the concentrations and compositional patterns of PAHs, which is useful in understanding the effects, sources, fate and transport of PAHs in soils, as well as environmental quality management and environmental forensic studies.     

Cadmium induced renal dysfunction among residents of rice farming area downstream from a zinc-mineralized belt in Thailand

High levels of cadmium (Cd) in paddy soil and rice, and a concurrent increase in urinary Cd of inhabitants in the Mae Sot District, Tak Province, Thailand first emerged in 2003. Risk factors such as occupation, sources of staple food and drinking water as well as biomarkers of adverse renal effects of the increased body burden of Cd were investigated in 795 residents, 30 years or older, whose urinary Cd levels were between 0.02 and 106 μg/g creatinine. Farmers who consumed their own rice and residents who sourced drinking water from wells and/or the river demonstrated increased urinary Cd. Age-adjusted mean urinary cadmium for male and female subjects who consumed well water was 5.7 μg/g vs. 6.1 μg/g creatinine while the corresponding value for male and female subjects who did not consume well water was 3.7 μg/g vs. 4.8 μg/g creatinine, respectively. Increased urinary levels of β₂-microglobulin and N-acetyl-β-d-glucosaminidase were observed with the increase in urinary Cd, indicating tubular dysfunction and renal damage associated with increase in Cd body burden. Consumption of well water and rice grown in the contaminated area increase the body burden of Cd. Cessation of exposure is essential to prevent and possibly recover from Cd toxicity, especially among the residents whose kidney damage and malfunction may be reversible.     

Earthworm biomarker responses on exposure to commercial cypermethrin

Cypermethrin is a synthetic pyrethroid insecticide used worldwide in agriculture, home pest control, disease vector control, and food safety. It accumulates in soil. Therefore, traces of cypermethrin may frequently appear in vegetables grown in contaminated soil. There is a push now to develop biomarkers as early warning indicators of environmental pollution. In this study, DNA damage (tail DNA%, tail length, and olive tail moment), the micronucleus, neutral red retention (NRR) time, and pinocytic adherence ability of coelomocytes were investigated in Pheretima peguana earthworms exposed to cypermethrin in filter paper tests. The NRR time of earthworm coelomocytes decreased significantly at a concentration of 3.5 × 10^?3 µg · cm^?2 (1/100 LC₅₀) after 48 h exposure, with a highly negative correlation with cypermethrin concentration. Pinocytic adherence ability of coelomocytes also declined significantly at a cypermethrin concentration of 3.5 × 10^?2 µg · cm^?2 (1/10 LC₅₀). The DNA damage to earthworm coelomocytes (tail DNA%, tail length, and olive tail moment) increased considerably at the highest concentration (3.5 × 10^?1 µg · cm^?2) although the correlation between tail DNA% and cypermethrin concentration was low. Thus, physiological biomarkers were more sensitive than the genotoxic effects in earthworms exposed to commercial cypermethrin. Although a suite of earthworm biomarkers could be used to evaluate cypermethrin terrestrial pollution, the NRR test is easier to conduct and a more sensitive indicator. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 597–606, 2015.     

Development of toxicity values and exposure estimates for tetrabromobisphenol A: application in a margin of exposure assessment

Tetrabromobisphenol A (TBBPA) is used in a diverse array of products to improve fire safety. The National Toxicology Program (NTP) recently completed a 2‐year bioassay for TBBPA. The objective of the present study was to develop a cancer‐based and a non‐cancer based toxicity value and to compare such to appropriate estimates of human exposure. Data from the NTP 2‐year and 13‐week studies were selected to develop candidate toxicity values. Benchmark dose modeling and subsequent evaluation of candidate values resulted in selection of an oral reference dose (RfD) of 0.6 mg kg^?1 day^?1 based on uterine hyperplasia in rats and an oral cancer slope factor (OSF) of 0.00315 per mg kg^?1 day^?1 based on an increased incidence of uterine tumors in rats. Lifetime average daily dose (LADD) estimates ranged from 2.2 E^?7 to 3.9 E^?6 mg kg^?1 day^?1 based on age‐adjusted exposures to TBBPA via breast milk consumption, dietary intake, soil/dust ingestion and drinking water ingestion in infants, young children, older children and adults. Average daily dose (ADD) estimates ranged from 3.2 E ^?7 to 8.4 E^?5 mg kg^?1 day^?1. Resulting margin of exposure (MOE) values were > 800 000 for non‐cancer endpoints and > 32 000 000 for cancer‐based endpoints. These data collectively indicate a low level of health concern associated with exposures to TBBPA based on current data. It is anticipated that the exposure estimates, along with the toxicity values described within, should be informative for understanding human health hazards associated with TBBPA. Copyright © 2015. The Authors. Journal of Applied Toxicology Published by John Wiley & Sons Ltd.     

Study of polycyclic aromatic hydrocarbons (PAHs) in soil samples from Al-Ahdab oil field in Waset Region,Iraq

Levels of thirteen polycyclic aromatic hydrocarbons (PAHs) were studied in 24 soil samples collected from the Ahdab oil field in Waset region, Iraq. The whole analysis was carried out using the gas chromatography with mass spectrometry (GC/MS) in the single ion monitoring (SIM)-mode. The total PAHs concentrations were ranged between 19?μg/kg (Site 15) and 855?μg/kg (Site of 16). The results of these samples were compared among each other according to their toxicity equivalence in μg TEQ/g concentrations and with the results of other studies. The total estimated cancer risks of exposure to PAHs in soil samples were ranged from 1.02?×?10^?7 to 4.59?×?10^?6. By multiplying the estimated cancer risk values by 10⁶, then the estimated theoretical cancer cases per million is between 0.0 and 5. The total estimated cancer risks in this study were within the acceptable range of excess cancer risk speci?ed by the Environmental Protection Agency in the United States.     

Assessing the ecotoxicological effects of long-term contaminated mine soils on plants and earthworms: relevance of soil (total and available) and body concentrations

The interactions and relevance of the soil (total and available) concentrations, accumulation, and acute toxicity of several essential and non-essential trace elements were investigated to determine their importance in environmental soil assessment. Three plant species (T. aestivum, R. sativum, and V. sativa) and E. fetida were simultaneously exposed for 21 days to long-term contaminated soils collected from the surroundings of an abandoned pyrite mine. The soils presented different levels of As and metals, mainly Zn and Cu, and were tested at different soil concentrations [12.5, 25, 50, and 100 % of contaminated soil/soil (w/w)] to increase the range of total and available soil concentrations necessary for the study. The total concentrations in the soils (of both As and metals) were better predictors of earthworm uptake than were the available concentrations. In plants, the accumulation of metals was related to the available concentrations of Zn and Cu, which could indicate that plants and earthworms accumulate elements from different pools of soil contaminants. Moreover, Zn and Cu, which are essential elements, showed controlled uptake at low concentrations. The external metal concentrations predicted earthworm mortality, whereas in plants, the effects on growth were correlated to the As and metal contents in the plants. In general, the bioaccumulation factors were lower at higher exposure levels, which implies the existence of auto-regulation in the uptake of both essential and non-essential elements by plants and earthworms.     

Evaluation of arsenic levels in grain crops samples, irrigated by tube well and canal water

The aim of this study was to evaluate the uptake of arsenic (As) by grain crops (wheat, maize and sorghum) grown on agricultural soil irrigated with tube well water (SIT) as test samples and for comparative purposes, same grain crop samples grown on agricultural soil irrigated with fresh canal water (SIC) were marked as control samples, collected simultaneously from three sub-districts of Khairpur, Pakistan. Moreover, this paper demonstrated the total and EDTA (0.05 M) extractable As in both understudied soils that correlate with the respective total As in the edible parts of the studied grain crops. A significantly high accumulation of As was found in grains grown on SIT as compared to those grown on SIC. This study highlights the increased danger of growing food crops in the agricultural land continuously irrigated by As contaminated ground water.     

Eco-toxicological and epidemiological assessment of human exposure to polycyclic aromatic hydrocarbons in the Niger Delta, Nigeria

Epidemiological examinations of polycyclic aromatic hydrocarbons (PAHs) exposure in biological bodies have shown the potential risk of cancer induction. Environmental media containing PAHs were analyzed in the Niger Delta region. Gas chromatographicmass spectrometric analyses were carried out on samples and 98% of the samples contained carcinogenic PAHs. The concentration of the 7 potential carcinogenic PAHs (?? _carc ^soil 7PAHs) in the soils varied from 297?C4080.6±546.3 mg/kg (min-max +/- standard deviation) with a median of 419 mg/kg, the concentrations for non-carcinogenic PAHs ranged from 315?C1999±300 mg/kg with a median of 497.5 mg/kg. The total concentrations of PAHs (?total H2O17PAHs) in water samples varied from 119.8?C450.0±117.9 mg/L with a median of 141.9 mg/L, while the sediment concentrations ranged from 6.0?C132.0±28.7 mg/L with a median of 62.73 mg/L. Concentrations of benzo(a) pyrene (BaP), which most likely originated from crude oil spillage in the area was determined as 66.95±73.47 mg/kg in soil samples. To evaluate human exposure to carcinogenic PAHs sources, the toxic equivalence factors (TEFs), mutagenic potency equivalent factors (MEFs) and the incremental lifetime cancer risk (ILCR) methodologies were used to calculate the exposure risk. Carcinogenic equivalents (BaP-TEQ) and mutagenic equivalents (BaP-MEQ) were calculated from the potency relative to BaP (TEF) and BAP (MEF) respectively. BaP-TEQ (mg/kg) for ?? _carc ^soil 7PAHs were determined as 98.80±125.81 and varied from 68.20?C953.84 mg/kg, while the BaPMEQ (mg/kg) for ?? _carc ^soil 7PAHs were determined as 124.01±163.37 and varied from 87.24?C1237.82 mg/ kg. The BaP-TEQ (mg/kg) for ?? _carc ^H2O 7PAHs were determined as 16.79±14.44 and varied from 5.55?C52.69 mg/L, similarly the BaP-MEQ (mg/kg) for ?? _carc ^H2O 7PAHs were determined as 9.29±8.15 and varied from 1.55?C29.80 mg/kg. The cumulative ILCR from the water and soil contaminations were determined as 1.13×10^?4 and 6.42×10^?4 respectively for children, while values of 1.09×10^?4 and 6.19×10^?4 were determined respectively for adult. The ecotoxicological assessments in this study indicate contamination of environmental media in the region with high potential of acute toxicity sufficient enough to induce carcinogenic effects and chronically affect the human health of residents with prolonged exposures.     

Widespread risks of dental fluorosis in cotton rats (Sigmodon hispidus) residing on petrochemical waste sites

Fluoride has been identified as a ubiquitous contaminant of soils where petrochemical wastes have been disposed. The purpose of this study was to assess how widespread toxicity risks are to resident vertebrates from chronic exposure to fluoride in the soil of petrochemical-contaminated waste sites. In total, 573 wild cotton rats (Sigmodon hispidus) were examined. The rats that were seasonally collected from 12 contaminated and 12 ecologically matched reference sites across Oklahoma over a 3-yr period. The risks of cotton rats exposed to fluoride were analyzed by means of gross examination, histopathology, and scanning electron microscopy of rat incisors. Cotton rats from reference sites showed no pathologic changes in incisors (98%). In comparison, 46% of cotton rats from contaminated sites had various degrees of dental lesions. The prevalence and severity of dental lesions in cotton rats from contaminated sites were significantly influenced by season. There was a 45% increase in prevalence and a 65% increase in severity of dental lesions from summer to winter. This study demonstrated that cotton rats are very sensitive biomonitors for assessing toxicity risks from soils contaminated with fluoride and that such assessments should consider seasonal influences.     

Predicting health risk from exposure to trihalomethanes in an Olympic-size indoor swimming pool among elite swimmers and coaches

ABSTRACT

Disinfection by-products (DBP) such as trihalomethanes (THM) are formed when chlorine and bromine interact with natural organic materials in chlorine-treated swimming pools. Epidemiological evidence demonstrated an association between exposure to swimming pool environment and adverse health effects. Therefore, this study aimed to assess carcinogenic and non-carcinogenic risk of long-term exposure of elite swimmers and their coaches. In an Olympic-size indoor chlorinated swimming pool, THM levels were determined in water (21–69 µg/L), in the boundary layer above the water surface (59–397 µg/m³), and in the air surrounding the pool (28–390 µg/m³). These values were used to predict multi-pathway chronic daily intake (CDI), cancer risk (CR) and hazard index (HI). Oral and dermal CDI for swimmers were 2.4 × 10^?6 and 2.0 × 10^?8, respectively. The swimmers’ inhalation CDI (1.9 × 10^?3 mg/kg/day) was estimated to be sixfold higher than levels obtained for coaches (3.3 × 10^?4 mg/kg/day). According to guidelines, the HI was acceptable, but CR exceeded the recommended limit for both, coaches (CR: 5.5 × 10^?7–8.5 × 10^?5; HI: 6.5 × 10^?4–1 × 10^?1) and swimmers (CR: 1.4 × 10^?5–3.6 × 10^?4 HI: 1.6 × 10^?2–4.3 × 10^?1). Our findings provide further support to the need to develop comprehensive guidelines to safeguard the health of individuals involved in elite swimming.     

Health risk assessment of heavy metals in the water environment of Zhalong Wetland,China

Concentrations of the Cu, Cd, Cr, As, Zn and Ni in water samples from 272 sampling stations in the water environment of Zhalong Wetland, China were studied. Health risk assessment associated with six heavy metals and metalloid was conducted using health risk assessment model from United States Environmental Protection Agency. It can be concluded that the mean concentrations of Cu, Ni, Zn, As, Cd and Cu were 0.19, 0.45, 0.52, 4.9, 0.12 and 0.24 μg L^?1, respectively. The carcinogenic risk of Cr, As and Cd in the discharged area, experimental area, buffer area and core area were lower than the maximum allowance risk level recommended by International Commission on Radiological Protection (ICRP 5.0 × 10^?5 a^?1). The non-carcinogenic risks (Cu, Zn, Ni) was also lower than the maximum allowance levels recommended by ICRP. Though it was lower than the level, it was very approaching to maximum acceptable risk level, need to draw attention to the relevant departments.     

Nitrosamine formation from the reaction of methamphetamine with gaseous nitrous acid

Methamphetamine is the most commonly seized amphetamine-type stimulant (ATS) worldwide. Chemical residues associated with the use or manufacture of methamphetamine can persist in the air and surfaces in a property for over 5 years and potentially pose risks to the health and safety of the public. When a house is tested for contamination, the test focuses on the presence of surface methamphetamine residue; however, other hazardous chemicals may also be present, including methamphetamine precursors and reaction products. As little has been reported about the ageing of the methamphetamine inside dwellings, there is currently large uncertainty regarding its fate and/or degradation products in such environments. If the indoor reactivity of methamphetamine is similar to that of nicotine-derived third-hand smoke, the production of a carcinogenic nitrosamine is an expected result. Thus, this proof-of-concept study investigated the reaction of methamphetamine with the common gaseous indoor oxidant nitrous acid (HONO) and monitored the fate of the resulting reaction products in simulated laboratory experiments to further understand the potential health risks associated with contaminated properties. Surface methamphetamine residue was observed to decrease with an exponential decay with an upper limit of 2.38 ± 0.5 × 10⁻³ min⁻¹ upon exposure to HONO gas (5.7 ppmv, 0.25 L min⁻¹). N-nitrosomethamphetamine (NMA), a suspected human mutagen and carcinogen, was detected to have a steady-state formation over the sampling time frame, with a surface area concentration of 0.87 μg/100 cm², suggesting that the risks to public health for properties contaminated with methamphetamine may be currently underestimated.     

Study of heavy metal levels in indoor dust and their health risk assessment in children of Ahvaz city,Iran

The concentration of heavy metals in household dust and their health risks on children living in different areas of Ahvaz city was investigated during November 2013 to October 2014 in Iran. Totally, 108 dust samples were taken from their houses in three different areas including S₁ (industrial), S₂ (heavy traffic) and S₃ (residential zone far away from industrial and traffic emission sources). The samples were analyzed for eight selected heavy metals (Cr, Ni, Cu, Mn, Pb, Zn, Co and Cd) using an inductively coupled plasma optical emission spectroscopy (ICP-OES, Spectro Arcos Model, Germany). Exposure and risk assessment of these metals were estimated using USEPA’s exposure parameters. Results showed that the mean values of all heavy metals in tempered months were significantly higher than the other months (p?<?0.05). Cancer risk and non-carcinogenic risk (hazard index) of Ni, Cr, Cd and Pb from indoor dust exposure were estimated for children via three exposure pathways (ingestion, inhalation and dermal contact). The non-cancer risks to children in all samples were lower than acceptable level of 1, while the potential cancer risks from Ni intake in S₁ and S₂ were 1.57E???06 and 1.19E???06, respectively, and for Cr in S₁ and S₂, it was 1.43E???06 and 1.15E???06, respectively, which these values were slightly higher than the acceptable level (1?×?10^?6). In conclusion, household dust of Ahvaz city would probably have a significant potential to cause cancer in most exposed children.