Multiple Exposure Pathways Research Articles

Multiple exposure pathways of first-year university students to heavy metals in China: Serum sampling and atmospheric modeling

In this study, we collected 308 serum samples from 17 to 20 year old first-year university students who were recruited from Lanzhou University in China a few days after their enrollment to measure the serum Pb, Cd, Hg, and As levels, and specific questionnaires for age, sex, settlement and dietary structure were designed. A 3-D atmospheric transport model was used to simulate the atmospheric concentration and dry deposition across China based on gridded Pb emission inventory to examine the association between the spatial distribution of serum concentrations and environmental fates of Pb. The mean serum Pb, Cd, Hg, and As concentrations averaged over all participating young students were 21.38, 1.46, 3.86, and 4.69 μg/L, respectively. The Pb, Cd, and Hg levels in 3%, 7%, and 20% serum samples exceeded the standards. The minimum serum As and Hg concentrations and the maximum serum Pb and Cd concentrations occurred in urban areas. Seafood diet habits (P < 0.05), sex (P < 0.05), and relocation (P < 0.01) caused significant differences in serum As, Pb, and Cd concentrations. A cluster analysis was carried out to classify the exposure pathways for target contaminants. The results indicated that 4 heavy metals in the serum of volunteers from northern China could be grouped into the same category, in which significant positive correlations were found between the serum heavy metal levels and background concentrations of surface soil. However, in other provinces and metropolises, the atmospheric pollution level played a critical role involving in the inhalation exposure pathway. We demonstrated that serum Pb levels in freshman students were related to the atmospheric transport and dry deposition of Pb.

Multi-pathway human exposure risk assessment using Bayesian modeling at the historically largest mercury mining district.

The largest mercury (Hg) mining district in the world is located in Almadén (Spain), with well-known environmental impacts in the surrounding ecosystem. However, the impact of mercury on the health of the inhabitants of this area has not been documented accordingly. This study aims to carry out a probabilistic human health risk assessment using Bayesian modeling to estimate the non-carcinogenic risk related to Hg through multiple exposure pathways. Samples of vegetables, wild mushrooms, fish, soil, water, and air were analyzed, and adult residents were randomly surveyed to adjust the risk models to the specific population data. On the one hand, the results for the non-carcinogenic risk based on Hazard Quotient (HQ) showed unacceptable risk levels through ingestion of Hg-contaminated vegetables and fish, with HQ values 20 and 3 times higher, respectively, than the safe exposure threshold of 1 for the 97.5th percentile. On the other hand, ingestion of mushrooms, dermal contact with soil, ingestion of water, dermal contact with water and inhalation of air, were below the safety limit for the 97.5th percentile, and did not represent a risk to the health of residents. In addition, the probabilistic approach was compared with the conservative deterministic approach, and similar results were obtained. This is the first study conducted in Almadén, which clearly reveals the high levels of human health risk to which the population is exposed due to the legacy of two millennia of Hg mining.

The SaniPath Exposure Assessment Tool: A quantitative approach for assessing exposure to fecal contamination through multiple pathways in low resource urban settlements.

Inadequate sanitation can lead to exposure to fecal contamination through multiple environmental pathways and can result in adverse health outcomes. By understanding the relative importance of multiple exposure pathways, sanitation interventions can be tailored to those pathways with greatest potential public health impact. The SaniPath Exposure Assessment Tool allows users to identify and quantify human exposure to fecal contamination in low-resource urban settings through a systematic yet customizable process. The Tool includes: a project management platform; mobile data collection and a data repository; protocols for primary data collection; and automated exposure assessment analysis. The data collection protocols detail the process of conducting behavioral surveys with households, school children, and community groups to quantify contact with fecal exposure pathways and of collecting and analyzing environmental samples for E. coli as an indicator of fecal contamination. Bayesian analyses are used to estimate the percentage of the population exposed and the mean dose of fecal exposure from microbiological and behavioral data. Fecal exposure from nine pathways (drinking water, bathing water, surface water, ocean water, open drains, floodwater, raw produce, street food, and public or shared toilets) can be compared through a common metric–estimated ingestion of E. coli units (MPN or CFU) per month. The Tool generates data visualizations and recommendations for interventions designed for both scientific and lay audiences. When piloted in Accra, Ghana, the results of the Tool were comparable with that of an in-depth study conducted in the same neighborhoods and highlighted consumption of raw produce as a dominant exposure pathway. The Tool has been deployed in nine cities to date, and the results are being used by local authorities to design and prioritize programming and policy. The SaniPath Tool is a novel approach to support public-health evidence-based decision-making for urban sanitation policies and investments.

Multiple exposure pathways and urinary chromium in residents exposed to chromium

BackgroundEnvironmental hexavalent chromium contamination in northeast China has been ongoing for over 60 years and health outcomes related with chromium (Cr) pollution were observed in polluted arears, but exposure pathways remains unclear. This study aims to evaluate the association between Cr exposure dose through multiple exposure pathways and Cr concentration in urine, and identify the most contributed pathway. MethodsWe used risk assessment tools with individual exposure parameters to estimate eight individual Cr exposure doses (CD) for three exposure routes (inhalation, ingestion, and dermal contact) with four environmental media (underground water, soil, household dust, and PM10 in ambient air) in 134 residents living in three chromium polluted villages. We used the covariate-adjusted standardized urinary Cr concentration (casUCr) as the internal Cr exposure biomarker. Ridge Regression, Weighted Quantile Sum Regression (WQS) and Bayesian Kernel Machine Regression (BKMR) models were used to assess the effect of overall eight CDs on urine Cr concentration and compare the contribution of each CD. ResultsIn the ridge regression analysis, Cr exposure through ingestion of dust (βstd = 0.418, p-value = 0.009), inhalation of dust (βstd = 0.384, p = 0.031) and dermal contact with soil (βstd = 0.264, p = 0.192) had the highest impact on casUCr. In the WQS model, the overall CDs demonstrated a non-significant positive association with casUCr. CDs of dust ingestion, air inhalation and dust inhalation had the largest contribution on casUCr when fitted in the WQS model. In the BKMR model, the hierarchical variable selection showed that casUCr was mainly affected by CDs of household dust and dermal contact with soil. CD of dermal contact with soil exhibited a negative association with casUCr, while CDs of dust showed positive or non-linear trend. ConclusionsThis research proposed a new method to calculate individual Cr exposure dose of multi-pathway and applied different statistical methods to identify predominant pathway. For this study, Cr exposure through dust has the strongest effect on Cr concentration in urine. The results could help conduct target interventions to reduce Cr intake, such as blocking dust exposure to reduce Cr uptake for villagers living in these contaminated areas.

Characterization of triclosan and triclocarban in indoor dust from home micro-environments in Vietnam and relevance of non-dietary exposure

Contamination status, spatial variability, and exposure risk of triclosan (TCS) and triclocarban (TCC) in indoor dusts from different micro-environments were evaluated for the first time in Vietnam as well as in Southeast Asian region. TCS and TCC were measured in 89 dust samples collected from bedrooms, living rooms, and kitchens of private houses in four northern cities including Hanoi, Bac Ninh, Hung Yen, and Nam Dinh, by means of liquid chromatography–tandem mass spectrometry. Concentrations of TCS and TCC ranged from <5 to 1090 (median 33.2) and from <3 to 531 (median 19.3) ng g−1, respectively. Concentrations of TCS and TCC in the kitchen and bedroom dusts were markedly higher than levels found in the living room samples, probably due to their applications in kitchen utensils, household cleaning reagents, and personal care products. A strong positive correlation between TCS and TCC concentrations was detected in the whole dataset (R2 = 0.810, p < 0.001). For samples in which both TCS and TCC were quantified, TCS/TCC ratios ranged from 0.3 to 12 with a median value of 1.8, and did not show big differences between micro-environments. Human exposures to TCS and TCC through dust ingestion were estimated for various age groups with 95% CI daily intake doses ranging from (0.032–0.070) to (0.340–0.740) and from (0.017–0.033) to (0.175–0.345) ng kg-bw−1 d−1 for adults and infants respectively. Although our derived values were much lower than reference doses, more comprehensive risk assessment considering multiple exposure pathways of TCS and TCC is needed.

Pollution status and human health risk assessments of selected heavy metals in urban dust of 16 cities in Iran.

Urban dust contamination is becoming progressively noticeable, and heavy metals are primary pollutants in urban environments. The contamination of heavy metals in urban dust has been affecting the urban citizens due to their adverse effects on human health, and understanding their effects is a crucial stage for its management. This study is a review of the reports of heavy metal pollution in urban dust of 16 cities in Iran, aimed at determining pollution status and health risk calculation on the nationwide scale, using geo-accumulation index (Igeo), potential ecological risk index (PER), and health risk assessment model. Six toxic elements, namely cadmium, copper, chromium, nickel, lead, and zinc were evaluated in this study. The results presented that the total heavy metal concentrations in the studied cities decreased in the sequences of Zn > Cu > Pb > Ni > Cr > Cd. The average concentrations of Cd, Cu, Ni, Pb, and Zn in the studied cities exceeded the Iran Standard Soil limits for residential areas. The mean levels of studied heavy metals for cities was in the order of Kermanshah > Tehran > Tabriz > Rafsanjan > Hamedan > Isfahan > Mashhad > Ahvaz > Abadan > Kerman > Bushehr > Kashan > Shiraz > Zahedan > Masjed-e-Soleiman > Arak. The Results of Igeo revealed that the pollution levels of Cd, Cu, Pb, Ni, Cr, and Zn in the studied cities ranged from unpolluted to moderate pollution categorizations. The mean potential ecological risk factor (Eir) values were below (Eri < 40), showing a low ecological risk level. Also, Eir values for all cities showed that Cd, Pb, and Cr had the highest ecological risks than other heavy metals. However, the total potential ecological risk index (RI) values for studied cities were 172.1, showing a moderate ecological risk level. Human health risk assessment evaluation showed that in contrast to adults, children have more possible health risks (non-carcinogenic). Among the multiple pathways of exposure, the ingestion pathway was the most important exposure for both groups of population, followed by skin exposure and then breathing exposure. Total hazard index (HI) values among three exposure routes, were less than harmless level (HI < 1), displaying that there was not a non-carcinogenic risk for both groups of population. Cancer risk (CR) study exhibited that the potential risk of cancer decreases in the order of chromium > nickel > cadmium. The CR ranks of chromium, nickel, and cadmium were less than the maximum permissible level, presented an insignificant carcinogenic risk.

Health Outcomes of an Integrated Behaviour-Centred Water, Sanitation, Hygiene and Food Safety Intervention-A Randomised before and after Trial.

Diarrhoeal disease in children under five in low income settings has been associated with multiple environmental exposure pathways, including complementary foods. Conducted from February to December 2018 in rural Malawi, this before and after trial with a control used diarrhoeal disease as a primary outcome, to measure the impact of a food hygiene intervention (food hygiene + handwashing) relative to a food hygiene and water, sanitation and hygiene (WASH) intervention (food hygiene + handwashing + faeces management + water management). The 31-week intervention was delivered by community-based coordinators through community events (n = 2), cluster group meetings (n = 17) and household visits (n = 14). Diarrhoeal disease was self-reported and measured through an end line survey, and daily diaries completed by caregivers. Difference-in-differences results show a 13-percentage point reduction in self-reported diarrhoea compared to the control group. There were also significant increases in the presence of proxy measures in each of the treatment groups (e.g., the presence of soap). We conclude that food hygiene interventions (including hand washing with soap) can significantly reduce diarrhoeal disease prevalence in children under five years in a low-income setting. Therefore, the promotion of food hygiene practices using a behaviour-centred approach should be embedded in nutrition and WASH policies and programming.

Health risk assessment of heavy metals in agricultural soils and identification of main influencing factors in a typical industrial park in northwest China

The accumulation of heavy metals (HMs) in the soil poses a threat to human health. In this study, 62 pairs of topsoil and wheat grain samples were collected from a typical industrial park in northwest China, and the human health risks associated with cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb) and zinc (Zn) were assessed through multiple exposure pathways. Meanwhile, the contribution of different environmental factors and their interactions were explored by using geo-detector. Results showed that Cd concentration in the soil ranged from 0.307 to 2.491 mg kg−1, with a median value of 0.588 mg kg−1, and almost half of the samples exceeded the pollution threshold. In comparison, other elements in the soil were below their mandatory thresholds. However, it is noteworthy that in addition to the median Cd concentration in wheat grains of 0.062 mg kg−1 (0.018–0.246 mg kg−1), the Pb concentration also reached 0.2 mg kg−1 (0.1–0.7 mg kg−1), with a sample over-standard rate of 48.39%. In addition, the health risk assessment results showed that the average total hazard index (HIt) for adults and children was 1.22 and 1.53, and the total carcinogenic risk (TCRt) was 7.0 × 10−4 and 2.32 × 10−4, respectively, both above acceptable criteria. Dietary intake was the main route of exposure. Among various factors, distance from industrial enterprises, altitude, and soil pH, distance from major roads were the most influential contributors. Their interactions were more prominent than the effects of single factors and this synergy deserves attention.

Human exposure to legacy and emerging flame retardants in indoor dust: A multiple-exposure assessment of PBDEs

Human exposure to flame retardants (FRs) in indoor environments is a growing concern. In this study, the concentrations of polybrominated diphenyl ethers (PBDEs) and their alternatives, such as novel brominated flame retardants (NBFRs), dechlorane plus (DP), and organophosphate flame retardants (OPFRs), were measured in dust from indoor environments in Korea to investigate their occurrence, contamination profiles, and health risks. Legacy and emerging FRs were detected in dust samples, indicating widespread contamination of indoor environments. The concentrations of alternative FRs were higher in dust from offices compared with house dust, suggesting that office environments are major consumers of alternative FRs. Similar compositional profiles for indoor dust were found for PBDEs in different microenvironments and regions, while OPFR composition varied widely due to disparate applications. The estimated daily intakes of PBDEs, NBFRs, and OPFRs via dust ingestion were lower than the reference doses proposed by previous studies. A multiple-exposure assessment showed that dust ingestion was a major contributor to total PBDEs for toddlers and adults. However, major exposure pathways of BDEs 47 and 209 differed between toddlers and adults. Our study suggests that multiple exposure pathways should be considered in a comprehensive exposure assessment of PBDEs.

Risk assessment concepts and approaches for indoor air chemicals in Japan.

Individuals living in general indoor environments are exposed to a greater variety of chemical pollutants, albeit at lower concentrations, compared with industrial workers in occupational environments. These pollutants can result in a variety of adverse health effects, including those affecting the respiratory, neurological, reproductive, dermatologic, and cardiovascular systems. In Japan, indoor air quality guidelines have been established for 13 chemicals since 1997, and these developments have continued on the basis of scientific discussions in the Committee on Indoor Air Pollution (CIAP) that was set up by the Ministry of Health, Labour and Welfare. However, the types and concentrations of these pollutants have been observed to be inconsistent over time due to lifestyle changes and the development of novel household products and building materials. Therefore, continuing the monitoring of indoor chemicals and the development of indoor air quality guidelines for substances that pose potential high health risks are essential for the protection of public health. In indoor environments, there are multiple media by which humans come in contact with indoor chemicals and multiple exposure pathways that can affect human health, particularly for semi-volatile organic compounds (SVOCs). This is defined as aggregate exposure. Furthermore, combined exposure to multiple low-level pollutants occurs in indoor environments. In this article, a comprehensive overview of the indoor air quality guidelines in Japan and assessment approaches for developing indoor air quality guidelines is provided. In addition, future issues facing approaches for indoor chemicals, including aggregate exposure to SVOCs and combined exposure to multiple pollutants with common toxicological effects in indoor environments, are discussed.

Assessment of the impact of selected changes in the deep geological repository model on its long-term safety

The deep geological repository system provides long-term protection against the undesirable effects of ionizing radiation on the population and the environment. An important part of the long-term safety strategy is development of a monitoring program that collects information about the behaviour of the deep geological repository throughout its whole lifetime. A simplified model of the disposal system, geosphere, and biosphere was developed using the GoldSim simulation tool to demonstrate the behaviour of the hypothetical deep geological repository located in crystalline rocks. Also an initial model of the reference biosphere was created based on the scenario of an agricultural habitation (normal evolution scenario) and it was developed based on the recommendations provided in the BIOMASS methodology. After a significant period of time, disposal containers will be degraded and evolution changes in the repository system will occur. Several important parameters appear in the annual effective dose calculation for an individual from critical exposure group within the reference biosphere model. One of them are, for example, distribution coefficients and so-called translocation factors that define the transported rate of released radionuclides into the environment. This paper provides a view into the selected part of the deep geological repository through the data obtained by monitoring during the selected period of time. Simulations describing changes in the repository system. The aim of this contribution is to evaluate the impact of selected changes on the annual effective dose for an adult individual from a critical exposure group while it is assumed, that the respondent consumes contaminated crops and animal products. This model includes various biosphere components and multiple exposure pathways such as inhalation, ingestion and external exposure.

In Vivo Evaluation of Histopathological Alterations and Trace Metals Estimation of the Small Intestine in Bisphenol A-Intoxicated Rats.

BPA, a ubiquitously used plasticizer, has become one of the contaminants of emerging concern and causes many serious health implications in humans due to multiple exposure pathways. The current study was aimed at investigating the deformities of structures that arise by exposure of the small intestine to BPA through trace elements estimation of tissues as well as the study of serum profile. Two major groups of Wistar rats were established: one control group and the other experimental group, which was further divided into four groups based on dose (10 mg/kg/bodyweight and 25 mg/kg/bodyweight, respectively) and duration of exposure (6 and 12 weeks, respectively). Histological study of the small intestine showed the distorted structures in the experimental groups. The special staining performed illustrated the accumulation of calcium deposits in the small intestinal tissue in treated groups. Trace metals estimation showed a significant increase in the metallic content of sodium and iron and a decrease in the calcium content in the experimental groups (p=0.05). Serum profiling illustrated an increase in total iron-binding capacity and glucose levels and a decrease in the serum total iron level (p=0.05). An increased expression of a proinflammatory cytokine (IFN-α) was observed in the liver. From all these findings, it was inferred that BPA caused many structural alterations in the small intestinal tissue, which further affected its functioning. The calcium deposits seen through special staining affected the motility of the small intestine and caused its dysfunction. It was also induced from serum profiling that BPA affected the homeostasis of iron and glucose and caused its imbalance. Also, as BPA got absorbed from the small intestine and reached the liver via the blood stream, it caused hepatoxicity in the liver and led to increased inflammatory response by IFN-α against the toxicant.

Clarifying Temporal Trend Variability in Human Biomonitoring of Polybrominated Diphenyl Ethers through Mechanistic Modeling.

Human biomonitoring data collected from individuals of the same age sampled in different years provide within-age temporal trends, which are often employed to evaluate the effectiveness of chemical regulatory policies. For polybrominated diphenyl ethers (PBDEs), this within-age temporal trend has been observed to vary between congeners and age groups. We systematically explore the mechanisms responsible for such variability through simulating human exposure via multiple exposure pathways to PBDEs released from multiple lifecycle stages. Our simulation indicates that, after new use of PBDEs is banned, emissions to the outdoor environment from use and waste disposal outlast those to the indoor environment from the indoor use phase, leading to slower decline rates in the contamination of food items sourced from the outdoor environment than that from indoors. Compared with indoor exposure pathways, the consumption of contaminated food contributes more to the exposure (i) to more hydrophobic, recalcitrant congeners, and (ii) of adults than children, which results in slower rates of decline in the within-age temporal trend of those congeners and in adults. The within-age temporal trend is influenced to a lesser extent by the elimination of PBDEs from the human body, e.g., differences in biotransformation potential of congeners, growth dilution, and pre- and postnatal exposures by children.

Multiple pathways of human exposure to poly- and perfluoroalkyl substances (PFASs): From external exposure to human blood

Exposure to PFASs may result in adverse health effects. This study aimed to characterise the exposure to PFASs from diet, house dust, indoor air, and dermal contact and the relative contribution from different external exposure pathways to human serum concentrations. Daily intakes of 18 perfluoroalkyl acids (PFAAs) and 12 PFAA precursors from diet, dust ingestion, inhalation of indoor air and dermal absorption were estimated using a comprehensive dataset comprising 61 adults from the Oslo area, Norway. Concentrations of PFAAs and PFAA precursors in house dust, indoor air, hand wipes, foods and drinks were utilised to estimate the daily intakes. Perfluorooctanesulfonate (PFOS) was the predominant PFAS in serum for this study group. On a median level, perfluorooctanoate (PFOA) contributed most to the total estimated daily intake of PFAAs, with a median intake of 280 (range: 72–1810) pg·kg bw−1·day−1, covering both direct and indirect (precursors) exposure. Out of this, only 3% (range: <1–48%) of the total PFOA intake came from indirect exposure. Dietary exposure from ingestion of food and drinks was in general the predominant exposure pathway, followed by exposure from ingestion of house dust, inhalation of indoor air, and dermal absorption, but considerable variations were observed among individuals. House dust ingestion and indoor air inhalation contributed most to the total intakes for some participants, for which most of them were among the 20% participants with the highest total estimated intakes. Some statistical significant associations between concentrations of PFASs measured in serum and estimated intakes were observed. Measured serum concentrations and modelled serum concentrations based on external exposure estimates were in the same order of magnitude for PFOS, PFHxS, PFOA, and PFNA, but only PFOA concentrations were comparable, 1.9 and 2.0 ng mL−1 for observed and modelled serum concentrations, respectively. The estimated daily intakes of PFASs in this study were lower than the health-based guidance values, e.g. the tolerable weekly intakes derived by EFSA. This study underlines the importance of performing studies considering multiple exposure pathways on an individual basis.

Multiple exposure pathways and health risk assessment of heavy metal(loid)s for children living in fourth-tier cities in Hubei Province

In the past, most research focused on the children living near a typical contaminated area but ignored the health risks of children living in the fourth or fifth tier cities without typical contaminated sources. These cities are now facing a series of problems, such as serious environmental pollution, undeveloped health system and so on. Furthermore, the development of modern logistics for food delivery has altered lifestyles that directly impact diets and eating patterns. In this study, multiple exposure pathways and health risks of children to heavy metal(loid)s were studied based on questionnaire-based surveys and field sampling of soil, dust, fine particulates, drinking water and food. We found that Pb, Cd and Mn levels in environmental samples were very high indicating a serious pollution problem. Inhalation exposure via aerosol particles was the most important pathway and was greater than exposure by food ingestion. The hazard index for Mn via aerosol particles was >1 even at the 5th percentile and Mn levels in urine was 10 times higher than those of people living in typical contaminated areas. The total incremental lifetime cancer risk (ILCR) for all metal(loid)s was also higher than the threshold at the 95th percentile. This study highlights health risks to children living in fourth tier cities and the importance of air pollution control to protect heavy metal exposure for children.

Human Health Risk Associated with Multiple Pathway Exposure to Arsenic in Contaminated Wetlands Cultivating Invasive Fish

Human Health Risk Associated with Multiple Pathway Exposure to Arsenic in Contaminated Wetlands Cultivating Invasive Fish

Health risk assessment of heavy metals in soil samples from an abandoned industrial waste dumpsite in Ibadan, Nigeria.

This study was carried out to determine the concentrations of heavy metals in the soil samples collected from an abandoned lead acid battery (LAB) industrial waste dumpsite in Ibadan, southwestern Nigeria. This was to assess the potential risks of the heavy metals on human due to exposure among local residents (children and adults) of the area. Forty (40) soil samples were collected over the entire dumpsite at 0-20cm depth. The elemental concentrations of Pb, Cr, Cd, Zn, Cu, and Ni were measured using an atomic absorption spectrophotometer (AAS) technique. The contamination load was estimated by employing index of geoaccumulation (Igeo) and potential human health risks due to multiple exposure pathways (inhalation, dermal absorption, and ingestion) were estimated using the risk-based equations and exposure parameters developed by the United States Environmental Protection Agency (USEPA). The average concentrations (± standard deviation) of Pb, Cr, Cu, Mn, Cd, Ni, and Zn were 3.79 ± 2.16, 8.36 ± 3.90, 7.77 ± 2.70, 7.75 ± 3.10, 4.31 ± 0.82, 3.09 ± 2.29, and 3.07 ± 1.74μg/g, respectively. The mean values of Igeo follow the order of Mn < Cr < Pb = Ni < Zn < Cu < Cd. The dermal contact with the heavy metals appeared to be the major route of exposure to children followed by inhalation and ingestion. Inhalation is the main route of exposure for the adults. The hazard quotients (HQ) of all the heavy metals are lower than 1, implying that the adverse health impact on the children and adult exposed to heavy metals from the dumpsite was relatively moderate. The hazard index (HI) values of Cd were 2.0 and 1.2 for exposed adults and children, respectively. The carcinogen risks for inhalation exposure ranged from 2.3 × 10-6 to 6.4 × 10-6, which falls within the acceptable limit of 10-4 to 10-6. There is concern over the potential health risk of the local residents, most especially the children living in the vicinity of the dumpsite due to the possibility of dispersal of heavy metals to the entire community, leading to long-life exposure and residents' detrimental health.

Cancer incidence and mortality associated with non-occupational and low dose exposure to Libby vermiculite in Minnesota

BackgroundA vermiculite processing plant in a Minneapolis, Minnesota neighborhood utilized asbestos-containing ore from Libby, Montana from the late 1930's until 1989. Multiple pathways of exposure to Libby asbestos were characterized in a cohort of over 6000 plant workers and residents living near the plant. ObjectiveWe conducted a cohort linkage study to assess the impact of cumulative low dose exposure and the role of occupational history on asbestos-related mortality and cancer morbidity among cohort members residing near a vermiculite plant. MethodsCohort members alive in 1988 (n = 5848) were linked to the Minnesota Cancer Surveillance System to identify incident cases of mesothelioma, lung cancer, and all-cancer diagnosed from 1988 to 2010. Proportional incidence ratios (PIRs) were calculated for mesothelioma and lung cancer. Vital status and cause of death were ascertained from Minnesota vital records and the National Death Index (1988–2011). Mortality rates of the cohort (2001–2011) for asbestos-related outcomes were compared to the Minnesota population to estimate standardized mortality ratios (SMRs) and stratified by gender, exposure, and occupational history categories. ResultsWe identified seven cases of mesothelioma, with elevated incidence only in females (PIR = 11.76, 95% CI: 3.17, 30.12). Lung cancer was elevated in both genders: PIR = 1.54 (95% CI: 1.19, 2.0) in males and 1.62 (95% CI: 1.21, 2.12) in females. We found elevated mortality from COPD, lung cancer, and mesothelioma among females (SMR for mesothelioma in females = 18.97, CI: 3.91, 55.45), among the 546 deaths identified. All four deaths from mesothelioma occurred in the >75th percentile of exposure (>0.0156 fiber/cc x months). The SMR for lung cancer and all respiratory cancer was elevated even after controlling for occupation. ConclusionsCommunity exposure to Libby amphibole asbestos from a vermiculite processing plant is associated with increased risk of COPD, lung cancer and mesothelioma incidence and mortality, most notably among females, and is likely to remain a public health issue for years to come.

Health risk apportionment of arsenic from multiple exposure pathways in Paracatu, a gold mining town in Brazil

This study assessed various exposure pathways of arsenic and their health risk apportionment to the residents of Paracatu, a gold mining town in Brazil. We measured arsenic concentrations in 50 groundwater and surface town water samples from nearby residences, 38 surface soil dust from residential/commercial dwellings and roadside of Paracatu, and 600 airborne dust samples including PM10 and total suspended particulates (TSP), in additional to a previous reported food survey containing 90 samples from 15 major food categories. For the surface soil dust, bioaccessibility of arsenic as a surrogate of bioavailability was determined using an in vitro physiologically based extraction test (PBET). Rice and bean were found to contain the highest levels of arsenic in which the arsenic speciation was measured whereas the percentages of inorganic arsenic of other food items were taken from the literature for the risk apportionment calculation. The results show that the contribution of inhaled arsenic is ≤3% of the total daily intake, even assuming 100% BAC. The average bioaccessibility of arsenic in the surface soil dust was 3.4 ± 2.0% (n = 17) with a bioaccessible concentration of 4.1 ± 3.7 mg/kg. Food was the main contributor of the daily total intake of arsenic with rice and beans being the most significant ones. The total arsenic intake (ingestion + inhalation) is about 10% of the JECFA BMDL0.5 of 3 μg/kg b.w. per day, and the combined risk based on the cancer slope calculation is similar to the arsenic intake from the consumption of 2 L of water containing 10 μg/L of arsenic, a maximum concentration recommended by WHO. The holistic approach by addressing multiple pathways of exposure is considered a useful tool for health risk assessment throughout the life of mine including mine closure, and can be applied at legacy sites.

The State of Public Health Lead Policies: Implications for Urban Health Inequities and Recommendations for Health Equity.

Although lead has been removed from paint and gasoline sold in the U.S., lead exposures persist, with communities of color and residents in urban and low-income areas at greatest risk for exposure. The persistence of and inequities in lead exposures raise questions about the scope and implementation of policies that address lead as a public health concern. To understand the multi-level nature of lead policies, this paper and case study reviews lead policies at the national level, for the state of California, and for Santa Ana, CA, a dense urban city in Southern California. Through a community-academic partnership process, this analysis examines lead exposure pathways represented, the level of intervention (e.g., prevention, remediation), and whether policies address health inequities. Results indicate that most national and state policies focus on establishing hazardous lead exposure levels in settings and consumer products, disclosing lead hazards, and remediating lead paint. Several policies focus on mitigating exposures rather than primary prevention. The persistence of lead exposures indicates the need to identify sustainable solutions to prevent lead exposures in the first place. We close with recommendations to reduce lead exposures across the life course, consider multiple lead exposure pathways, and reduce and eliminate health inequities related to lead.