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The potential impacts of coal mining on health have been addressed by the application of impact assessment methodologies that use the results of qualitative and quantitative analyses to support their conclusions and recommendations. Although human epidemiological analyses can provide the most relevant measures of risk of health outcomes in populations exposed to coal mining by-products, this kind of studies are seldom implemented as part of the impact assessment methods. To review the use of human epidemiological analyses in the methods used to assess the impacts of coal mining, a systematic search in the peer review literature was implemented following the PRISMA protocol. A synthesis analysis identified the methods and the measures used in the selected publications to develop a thematic review and discussion. The major methodological approaches to assess the impacts of coal mining are environmental impact assessment (EIA), health impact assessment (HIA), social impact assessment (SIA) and environmental health impact assessment (EHIA). The measures used to assess the impacts of coal mining on health were classified as the estimates from non-human-based studies such as health risk assessment (HRA) and the measures of risk from human epidemiological analyses. The inclusion of human epidemiological estimates of the populations exposed, especially the general populations in the vicinity of the mining activities, is seldom found in impact assessment applications for coal mining. These methods rather incorporate HRA measures or other sources of evidence such as qualitative analyses and surveys. The implementation of impact assessment methods without estimates of the risk of health outcomes relevant to the potentially exposed populations affects their reliability to address the environmental and health impacts of coal mining. This is particularly important for EIA applications because these are incorporated in regulatory frameworks globally. The effective characterization of the impacts of coal mining on health requires quantitative estimates of the risk, including the risk measures from epidemiological analyses of relevant human health data. [ABSTRACT FROM AUTHOR]

Aqueous film-forming foam (AFFF) has historically contained high concentrations of long-chain per-and polyfluoroalkyl substances (PFAS), which have been linked with adverse health outcomes. However, the toxicity of historical AFFFs remains largely unknown, presenting uncertainties in their risk assessment. This study assessed the toxicity of historical AFFFs by exposing human liver cells (HepG2) to various dilutions of 3M Light Water AFFF or Ansulite AFFF (0.001%, 0.002%, 0.005%, 0.009%, 0.019%, 0.038%, 0.075%, 0.15%, and 0.3%) for 24 h. The effects of the two AFFF formulations on the cell viability, intracellular reactive oxygen species (ROS) production, Nrf2-ARE activity, and DNA damage were assessed by CellTiter 96® Aq ueous One Solution Cell Proliferation Assay (MTS kit), dichlorofluorescein diacetate assay, luciferase assay, and alkaline Comet assay, respectively. The results revealed that the two brands of AFFFs tested were toxic to HepG2 cells at dilutions lower than the recommended 3% application formulation. Specifically, exposure to 3M Light Water AFFF or Ansulite AFFF induced a dilution-dependent decrease in cell viability, increased intracellular ROS production, and increased Nrf2-ARE activity. However, except for the highest concentration (lowest dilution) of 3M Light Water AFFF tested (0.038%.), both 3M Light Water AFFF and Ansulite AFFF did not significantly induce cellular DNA damage. Overall, 3M Light Water AFFF was more toxic than Ansulite AFFF. The findings from this study provided valuable in vitro toxicity data that may better inform the health risk assessment of these historical AFFFs. [Display omitted] • The toxicity of 3M Light Water AFFF and Ansulite AFFF was assessed in HepG2 cells. • Both formulations induced a dilution-dependent decrease in cell viability. • Both formulations induced a dilution-dependent increase in oxidative stress response. • Both formulations did not significantly induce cellular DNA damage. • 3M Light Water AFFF was comparatively more toxic than Ansulite AFFF. [ABSTRACT FROM AUTHOR]

Bioavailability (BA) determines the potential harm of a contaminant that exerts on the receptor. However, environmental guidelines for site contamination assessment are often set assuming the contaminant is 100 % bioavailable. This conservative approach to assessing site risk may result in the unnecessary and expensive remediation of a contaminated site. The National Environmental Protection Measures in Australia has undergone a statutory 5-year review that recommended that contaminant bioavailability and bioaccessibility (BAC) measures be adopted as part of the contaminated site risk assessment process by the National Environment Protection Council. We undertook a critical review of the current bioavailability and bioaccessibility approaches, methods and their respective limitations. The 'gold' standard to estimate the portion of a contaminant that reaches the system circulatory system (BA) of its receptor is to determine BA in an in vivo system. Various animal models have been utilised for this purpose. Because of animal ethics issues, and the expenses associated with performing in vivo studies, several in vitro methods have been developed to determine BAC as a surrogate model for the estimation of BA. However, few in vitro BAC studies have been calibrated against a reliable animal model, such as immature swine. In this review, we have identified suitable methods for assessing arsenic and lead BAC and proposed a decision tree for the determination of contaminant bioavailability and bioaccessibility for health risk assessment. [ABSTRACT FROM AUTHOR]

Worldwide chronic arsenic (As) toxicity has become a human health threat. Arsenic exposure to humans mainly occurs from the ingestion of As contaminated water and food. This communication presents a review of current research conducted on the adverse health effects on humans exposed to As-contaminated water. Chronic exposure of As via drinking water causes various types of skin lesions such as melanosis, leucomelanosis, and keratosis. Other manifestations include neurological effects, obstetric problems, high blood pressure, diabetes mellitus, diseases of the respiratory system and of blood vessels including cardiovascular, and cancers typically involving the skin, lung, and bladder. The skin seems to be quite susceptible to the effects of As. Arsenic-induced skin lesions seem to be the most common and initial symptoms of arsenicosis. More systematic studies are needed to determine the link between As exposure and its related cancer and noncancer end points. [ABSTRACT FROM AUTHOR]

In vivo models show that the bioavailability of soil contaminants varies between site and type of matrix. Studies demonstrated that assuming 100% bioavailability of arsenic (As) and lead (Pb) from soils and mine waste materials overestimates the risk associated with human exposure. In in vitro systems, the simulated bioavailability of a contaminant is referred to as the "bioaccessibility" and is used as an alternative quantitative indicator for in vivo derived bioavailability estimates. The general concept of the in vitro extraction test is to predict the bioavailability of inorganic substances from solid matrices by simulating the gastrointestinal tract (GIT) environment. The aims of this study were to: (1) investigate the bioaccessibility of As and Pb from various mine wastes, including tailings, heap leach, and waste rock, using a physiologically based extraction test (PBET); (2) validate the bioaccessibility values from PBET with in vivo bioavailability values measured using animal models; and (3) correlate PBET results with the bioavailability values measured from alternative in vivo models (rats and cattle, from Bruce, 2004). Significant correlation was observed between bioaccessibility values from PBET, and bioavailability values generated for both rats and cattle, demonstrating the potential to utilize PBET as a relatively inexpensive alternative to in vivo models for bioavailability assessment. [ABSTRACT FROM AUTHOR]

Beijing parks always have a large flow of local residents and tourists, and the soil Pb could threaten human health by incidental ingestion. Soil samples from eleven parks in Beijing were collected to assess the human health risk associated with Pb. Lead bioaccessibility in these parks ranged from 3.2 ± 0.4% to 12.1 ± 0.5% in the physiologically based extraction test (PBET) gastric phase and increased when approaching the city center. The chemical forms and soil properties (Fe, organic matter, and grain size) were important factors affecting the soil Pb bioaccessibility. The geo-accumulation index of Beihai Park (BH, near the city center) reached 1.3 ± 0.1 indicating moderate contamination. Lead health risk to children in BH should be of concern though its hazard quotient was below one. Results obtained from the Diffusive Gradients in Thin-films (DGT)-induced fluxes in the soils (DIFS) model showed that Pb-release in some parks farther from the city center was a "partially sustained case" (R diff < R < 0.95) indicating that soil particles could partially replenish effective Pb to the soil solution. A relatively higher desorption rate constant (k 1) and shorter characteristic response time (T c) were also found in these parks, indicating non-negligible release risk. Soil Pb based on the PBET method and DIFS model could provide a reliable reference to park managers for the health risk management of Pb pollution. Image 1 • Lead pollution and risk in urban park soils were systematically investigated. • In vitro methods were used to assess Pb accumulation and health risk. • DIFS model was used to study Pb resupply capacity in urban park soils. [ABSTRACT FROM AUTHOR]

The combined effects and toxicological interactions of perfluoroalkyl and polyfluoroalkyl substances (PFAS) mixtures remain largely unknown even though they occur as complex mixtures in the environment. This study investigated the toxicity of individual and combined PFAS to human liver cell line (HepG2). The Combination Index (CI)-isobologram equation method was used to determine the toxicological interactions of PFAS in binary, ternary and multi-component mixtures. The results indicated that the cytotoxicity of individual PFAS to HepG2 cells increased with increasing carbon chain lengths when separated into non-sulfonated and sulfonated groups. The respective cytotoxicity of PFAS is in the order of PFDA > PFNA > PFOA > PFHpA for perfluoroalkyl carboxylic acids and in the order of PFOS > PFHxS for perfluoroalkane sulfonic acids. The toxicological interaction of PFOS and PFOA with other PFAS clearly showed a different pattern of combined toxicity in HepG2 Cells. The binary, ternary, and multi-component combinations of PFOS with PFOA, PFNA, PFDA, PFHxS, and PFHpA displayed synergistic interactions for almost all inhibitory effect levels tested, whereas, either synergistic or antagonistic effect was observed in mixtures with PFOA. Overall, the pattern of interactions of PFAS mixtures is predominated by synergism, especially at low to medium effect levels; the exceptions to this were the antagonistic interactions found in mixture with PFOA, PFHxS, and PFHpA. These cytotoxicity results may have an implication on the health risk assessment of PFAS mixtures. Image 1 • Combined toxicity of up to 6 PFAS was evaluated in HepG2 cells for the first time. • Cytotoxicity of individual PFAS increased with increasing carbon chain lengths. • PFOS and PFOA interact differently with PFHxS and PFHpA in HepG2 cells. • Toxicity interaction of PFAS mixtures is mostly predominated by synergism. • Understanding PFAS mixture toxicity can better inform their risk assessment. Cytotoxic effects of individual PFAS to HepG2 cells increased with increasing carbon chain lengths, and the pattern of interaction of PFAS mixtures is mainly predominated by synergism. [ABSTRACT FROM AUTHOR]

Some polyaromatic hydrocarbons (PAHs) and metals are known human carcinogens and the combined toxicity data of these co-contaminants are important for assessing their health risk. In this study, we have evaluated the combined genotoxicity, AhR activity and cell cycle parameters of four PAHs (benzo[a]pyrene (Ba]P), naphthalene (Nap), phenanthrene (Phe) and pyrene (Pyr)) and three metals (arsenic (As), cadmium (Cd), and lead (Pb)) in HepG2 cells using a flow cytometry based micronucleus (MN) test CAFLUX assay and nuclear fluorescence assay, respectively. The mixtures of B[a]P and metals induced a maximum of four fold increase in the MN formation compared to B[a]P alone. The higher combination of PAHs and metals did not significantly increase the MN formation. The mixtures of metals or non-carcinogenic PAHs were found to increase or decrease the aryl hydrocarbon receptor (AhR) activation of B[a]P in HepG2 cell based CAFLUX assay. Overall, the results showed that combined genotoxicity of PAHs and metals in HepG2 cells vary depending on the concentrations and number of the chemicals that are present in the mixtures and the effects of higher order combinations appear to be largely unpredictable from binary combinations. In this study, we have demonstrated the use of flow cytometry based MN test to screen the genotoxicity of environmental chemicals and its mixtures. [ABSTRACT FROM AUTHOR]

The human health risk associated with arsenic in food in Southeast Brazil was quantified. Based on the most commonly consumed food types in the Brazilian diet, the maximum inorganic As (iAs) daily intake from food (0.255 μg kg −1 body weight per day) is approximately 9% of the Benchmark Dose Lower Limit (BMDL 0.5 ) of 3 μg kg −1 body weight per day set by the World Health Organization (WHO) and Food and Agriculture Organization (FAO) Joint Expert Committee in Food Additives (JECFA). When water is included, the contribution of food to the total intake varies from 96.9% to 39.7%. Rice and beans, the main Brazilian staple food, contribute between 67 and 90% of the total As intake from food (46–79% from rice and 11–23% from beans). The substantial contribution of beans to total As food intake is reported for the first time. The broad range of As concentrations in rice and beans highlights the variable and potentially large contribution of both to As food intake in places where diet consists largely of these two food categories. [ABSTRACT FROM AUTHOR]

Traditional Chinese medicines (TCM) are increasingly being used as alternative medicines in many countries, and this has caused concern because of adverse health effects from toxic metal bioavailability such as mercury (Hg) and arsenic (As). The aim of this study was to investigate the bioavailability of As and Hg from TCM after a single exposure dose using an animal model of female Sprague–Dawley rats. The rats were divided into 6 groups which included four groups treated with sodium arsenite (NaAsO2), arsenic sulfide (As 2 S 3 ), mercuric chloride (HgCl 2 ), mercuric sulfide (HgS), and two groups treated with TCM containing high Hg or As (Liu Shen Wan: As 7.7–9.1% and Hg 1.4–5.0%; Niuhang Jie du Pian: As 6.2–7.9% and Hg <0.001%). The samples of urine, faeces, kidney and liver were collected for analysis and histological assay. The results indicated that relatively low levels of As and Hg from these TCM were retained in liver and kidney tissues. The levels of As in these tissues after TCM treatment were consistent with the levels from the As sulphide treated group. With the exception of the mercuric chloride treated group, the levels of Hg in urine from other groups were very low, and high levels of As and Hg from TCM were excreted in faeces. The study showed poor bioavailability of As and Hg from TCM as indicated by low relative bioavailability of As (0.60–1.10%) and Hg (<0.001%). Histopathological examination of rat kidney and liver tissues did not show toxic effects from TCM. [ABSTRACT FROM AUTHOR]

Although the Nrf2-ARE pathway plays a critical role in cellular protection against toxicity and oxidative stress from environmental chemical stressors, the association between exposure to per - and polyfluoroalkyl substances (PFAS) mixtures and the changes of Nrf2-ARE pathway remains largely unexplored. This study evaluated the potential of PFAS to induce the Nrf2-ARE pathway as individual compounds and as binary, ternary, and multicomponent mixtures in the ARE reporter-HepG2 cells and compared the mixture toxicity data to the predictions by concentration addition (CA) model. The toxicological interactions between PFAS mixture components were also determined by the model deviation ratio (MDR) between the CA predicted and mixture toxicity values. The induction of the Nrf2-ARE pathway was quantified using the luciferase system, and the endpoint assessed was the concentration that induced an induction ratio (IR) of 1.5 (EC IR1.5). The results showed that exposures to both individual and mixed PFAS induced the Nrf2-ARE pathway in ARE reporter-HepG2 cells. Based on the MDRs, the combinations with PFOS showed synergistic interactive effects, while the combinations with PFOA showed additive effects. These results indicate that the CA model underestimated the mixture toxicity of PFAS with PFOS co-exposures and may have health risk assessment implications. [Display omitted] • Potential inducing effects of mixed PFAS on the Nrf2-ARE pathway were determined. • Inducing effects of individual PFAS increased as the carbon length increases. • The combinations with PFOS showed higher inducing effects than those with PFOA. • CA model may underestimate the mixture toxicity of PFAS with PFOS co-exposures. • Nrf2-ARE modulation may serve as a rapid screening tool for toxicity testing of PFAS. [ABSTRACT FROM AUTHOR]

Humans are exposed to complex mixtures of per- and polyfluoroalkyl substances (PFAS). However, human health risk assessment of PFAS currently relies on animal toxicity data derived from individual substance exposure, which may not adequately predict the risk from combined exposure due to possible interactions that can influence the overall risk. Long-chain perfluoroalkyl acids (PFAAs), particularly perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are recognised as global emerging contaminants of concern due to their ubiquitous distribution in all environmental media, wildlife, and humans, persistency, bioaccumulative-, toxic-, and human health-risk potentials. This article reviews the current understanding of the human health risks associated with PFAS exposure focusing on more recent toxicological and epidemiological studies from 2010 to 2020. The existing information on PFAA mixtures was also reviewed in an attempt to highlight the need for greater focus on their potential interactions as mixtures within the class of these chemicals. A growing number of toxicological studies have indicated several adverse health outcomes of PFAA exposure, including developmental and reproductive toxicity, neurotoxicity, hepatotoxicity, genotoxicity, immunotoxicity, thyroid disruption, and carcinogenicity. Epidemiological findings further support some of these adverse human health outcomes. However, the mechanisms underlying these adverse effects are not well defined. A few in vitro studies focusing on PFAA mixtures revealed that these compounds may act additively or interact synergistically/antagonistically depending on the species, dose level, dose ratio, and mixture components. Hence, the combined effects or potential interactions of PFAS mixtures should be considered and integrated into toxicity assessment to obtain a realistic and more refined human health risk assessment. ga1 • Human health risks associated with PFAS exposure are critically reviewed. • PFAS exposures have been associated with several adverse human health outcomes. • The mechanisms underlying the adverse health effects remain unclear. • Mixed PFAS interactions must be considered for a refined health risk assessment. [ABSTRACT FROM AUTHOR]

Bioaccessibility (BAC) of fine surface dust (FSD, particle size ≤10 μm) and surface dust samples (particle size ≤250 μm) collected from a gold mining district was used as a tool to determine the portion of arsenic that would be available via simulated lung and gastrointestinal (G.I) fluids. BAC was considered low for both tests (lung 2.7 ± 1%, n = 5 and G.I 3.4 ± 2%, n = 14 for residential surface dust samples). An analytical procedure was developed to further identify arsenic-bearing phases found in FSD samples and analyze the main components that regulate arsenic solubility. Up to five different arsenic-bearing phases were identified among a total of 35 minerals surveyed by scanning electron microscopy-based automated image analysis (Mineral Liberation Analyzer - MLA). Arsenic-bearing Fe oxy-hydroxides and mixed phases comprised the main arsenic phases encountered in FSD samples, thus likely being responsible for regulating arsenic bioaccessibility. Transmission electron microscopy showed that the mixed phases comprised a mix of oriented nanostructure aggregates formed by hematite and goethite entangled with phyllosilicates. The main As-bearing phases identified in FSD samples are similar to those reported in soil samples in the same region. The predominant arsenic-bearing phase encountered in the ore was arsenopyrite, mostly in large particles (>10 μm in size), and therefore unlikely to be found in residential dust. Arsenic intake from both inhalation and ingestion were minimal when compared to total arsenic intake (considering food and water ingestion), which itself was <7% of the value established by the Food and Agriculture Organization of the United Nations Benchmark Dose Lower Confidence Limit (BMDL 0.5) of 3.0 μg per kg−1 body weight per day. These results indicated that the relative risks associated with arsenic exposure by inhalation and oral ingestion in this region are low. Unlabelled Image • Single particle As-bearing phase identification in <10 μm particles ca. gold mine. • Arsenic was mainly associated with nanostructured iron oxy-hydroxides in dust. • Arsenic was mainly found as arsenopyrite in the ore. • PBET (3.4%) and lung (2.7%) As bioaccessibility were low in residential areas. • Risk to human health by ingestion/inhalation was low despite high As concentrations. [ABSTRACT FROM AUTHOR]

The bioavailability and bioaccessibility of heavy metals mainly depend on their speciation in soils; however, the relationship between bioaccessibility and its speciation as determined as fractionation remains to be better characterized. Therefore, Cd fractionations in three types of long-term Cd-spiked soils were determined using a modified BCR method, and compared with Cd bioaccessibility data obtained from four in vitro gastrointestinal simulation assays including the IVG, PBET, SBRC, and UBM. The results shows that the majority of Cd were found in the exchangeable/acid soluble (B1) and reducible (B2) fractions (total percentage > 97%) after being spiked and aged for three years, indicating high Cd bioavailability; the bioaccessibility of Cd ranged from 57.7 ± 1.8% to 99.3 ± 2.8% in the gastric phase, and from 5.8 ± 2.0% to 35.9 ± 1.8% in the intestinal phase, respectively. Among the four assays, the strongest positive correlation was observed between Cd bioaccessibility based on the PBET assay and its B1 fraction in the spiked soils (r 2 gastric: 0.62 and intestinal: 0.52), suggesting that the PBET assay maybe more suitable for determining Cd bioaccessibility in aged contaminated soils. [ABSTRACT FROM AUTHOR]

Recent decades have seen a growing popularity of in vitro bioaccessibility being utilised as a screening tool in human health risk assessment. However the existing bioaccessibility studies only focus on single contaminant. Considering human are likely to ingest multi-contaminants, these contaminants could interact within human gastrointestinal tract which may lead to an increase or decrease in bioaccessibility. In this study, seven different types of soil were spiked with arsenic (As) or cadmium (Cd) and aged for one year. The effects of soil properties on the bioaccessibility were examined. Moreover, the interaction between As and Cd in simulated human digestive system was studied by mixing As-spiked soil with Cd-spiked soil of the same type during bioaccessibility test. Results shows the bioaccessibility of As ranged from 40 ± 2.8 to 95 ± 1.3% in the gastric phase and 16 ± 2.0 to 96 ± 0.8% in the intestinal phase whilst a significant difference was observed between Cd gastric bioaccessibility (72 ± 4.3 to 99 ± 0.8%) and intestinal bioaccessibility (6.2 ± 0.3 to 45 ± 2.7%). Organic carbon, iron oxide and aluminium oxide were key parameters influencing the bioaccessibility of As (gastric and intestinal phases) and Cd (intestinal phase). No interactions between As and Cd during bioaccessibility test were observed in any soils, which indicates As and Cd may age independently and did not interact while being solubilised during bioaccessibility test. Thus additive effect may be proposed when estimating the bioaccessibility of mixtures of independently-aged As and Cd in soils. [ABSTRACT FROM AUTHOR]

[Display omitted] • Many brown rice samples contained hazardous concentrations of arsenic and cadmium. • Concentration of toxic elements in brown rice is grain-size dependent. • Sum of non-carcinogenic risk associated with As and other elements exceeds unity. • Carcinogenic risk from As or Cr in brown rice may be as high as one in every 10,000. • Results can inform the national monitoring program for rice quality and type. Twenty-two brown rice varieties available in the Qatari market were analyzed for essential and toxic elements by ICP-MS. Found concentrations (µg/kg) were: As: 171 ± 78 (62–343), Cd: 42 ± 60 (4–253), Cr: 515 ± 69 (401–639), Pb: 6 ± 7 ( 1 in million, may possibly be > 1 in 10,000 based on conservatively high brown rice consumption rates of 200 g/d or 400 g/d in Qatar. These elevated risks may be applicable to specific population subgroups with diabetic conditions who consume only brown rice. Non-cancer risks are mainly derived from Mn, V, Se, and Cd with a hazard index > 1 from some brown rice samples. [ABSTRACT FROM AUTHOR]