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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]

Metal/loid pollution from shipwrecking activities has drawn significant concern due to their persistent threat to the marine ecosystem and human health. We investigated the spatiotemporal distribution, pollution characteristics, risks, sources, and potential impact of metal/loids in the sediments and seafood in the Bay of Bengal at nearby open beaching shipwrecking yards in Bangladesh. We collected 78 sediments and 208 seafood samples from the exposed and control sites from 2018 to 2020 during the dry and wet seasons. The concentrations of 16 elements, including cadmium, arsenic, lead, chromium, manganese, copper, zinc, iron, tin, antimony, nickel, cobalt, molybdenum, vanadium, selenium, and thallium were measured using validated inductively coupled plasma-mass spectrometry (ICP-MS) methods. Based on the pollution indices (enrichment factor, geoaccumulation index, pollution index, and pollution load index), lead, arsenic, cadmium, selenium, copper, zinc, and tin from the dry season showed higher contaminations compared to the wet and their concentrations were increased from 2018 to 2020 with seasonal fluctuations. Sediment cadmium and arsenic posed relatively higher and moderate ecological risks. Health risk analysis indicated that lead, cadmium, and inorganic arsenic (estimated) in seafood species pose a possible health threat to the general population. Further, there were possible ecological and health risks for the metal/loids in combination based on the ecological risk index in sediment and the hazard index in seafood, respectively. Source apportionment suggested that anthropogenic activities through uncontrolled shipwrecking operations over the last four decades were the largest polluting dominator, contributing 55–77% of the metal/loid concentrations. Therefore, the data may inform mitigation strategies for emission control at the shipwrecking yards to protect marine ecosystems and their local population. [Display omitted] • A study of metal/loids in sediments and seafood related to shipwrecking impact. • Shipwrecking activities contributed 55–77% of the elemental concentrations. • Cd, Pb, and As were identified as the significant pollutants and risk contributors. • Contamination of metal/loids was increased with seasonal fluctuations. • Emission control is prudent to protect the marine ecosystem and human health. [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]

The fraction transformation from stable to mobile forms in sediments is continuous, slow, and spontaneous chain reactions causing static risks to the aquatic system. However, this process may change into abrupt, rapid, and dynamic paths when certain physicochemical conditions changed. Using the Delayed Geochemical Hazard (DGH) model, comprehensive methods combing both static and dynamic risk assessment were therefore conducted to evaluate the aforementioned processes. By applying these methods, arsenic (As) pollution in surface sediments of the Baiyangdian Lake (BYD Lake) was investigated thoroughly as a case study area. The results showed that the total As concentrations in those sediment samples ranged from 4.87 to 17.94 mg/kg, with an average of 8.75 mg/kg. In a fraction, Fe and Mn were observed to pose effects on the surface-adsorbed (As S) and residual fractions (As R) with the coefficient analysis. The static risk assessment showed that both the contamination and ecological risk are at a low level in the total content but a low to moderate risk in the fraction. The dynamic risk assessment posted the potential transformation paths of As in the sediments, indicating a trend of potential DGH burst in 45.24%–78.57% of the BYD Lake. In summary, this study provides a methodology for the risk assessment of arsenic that may extend to other heavy metal(loid)s combining static and dynamic processes in sediments. • As content and fraction in surface sediments were investigated in Baiyangdian Lake. • Comprehensive risks including static and dynamic risk were assessed synchronously. • Static risk of As was analyzed by employing four indices (I geo , ICF, E r i , and RAC). • DGH model provided potential transformation paths of As for revealing the dynamic risk. [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]

Indospicine is a hepatotoxic non-proteinogenic amino acid that has only been found in Indigofera plants including a number of species abundant in central Australia. These legumes are palatable to feral camels and indospicine residues derived from these plants accumulates in camel meat tissue. Indospicine-contaminated camel meat has caused liver disease and mortalities in dogs after a short period of dietary exposure. Since camel meat is also exported for human consumption, this raises concern about the human health risks of consuming indospicine-contaminated camel meat harvested from central Australia. The objective of this study was to assess the indospicine levels in camel meat and its associated potential health risk to the Australian population and the vulnerable sub-population of indigenous Australians from the consumption of such feral camel meat. Two main quantitative probabilistic exposure assessments were conducted through the use of Monte Carlo simulations. The first exposure assessment considered the indospicine concentrations in real-field camel meat samples. The second assessment was based on a simulated probabilistic distribution of indospicine residues in camel meat, involving eight (8) predictive factors that were derived from our published research data and other secondary sources. The first assessment predicted that the estimated risk of developing indospicine₋induced hepatotoxicosis from contaminated camel meat consumption was 800 per 10 000 of the average Australian population (8.0%), and higher for the indigenous Australians (10.0%). The second exposure assessment demonstrated there was a higher risk (>31%) for the whole Australian population and for the indigenous Australian population. In conclusion, this risk assessment study shows that, while there is a low risk amongst Australians of hepatotoxicosis being associated with the consumption of indospicine-contaminated camel meat, such consumption is still a cause for concern, since the assessment based on the simulated probabilistic distribution of indospicine concentrations in camel meat demonstrated a substantially higher risk. It is therefore advisable that an indospicine residue monitoring program should be implemented to ensure food safety of Australian camel meat. Additionally, the risk of dietary indospicine exposure from other livestock grazing Indigofera in all global regions should also be considered. Image 1 • Heptatotoxic indospicine forms residues in meat tissue of camels grazing Indigofera. • Dogs have died from eating contaminated meat and human health risk is of concern. • Quantitative probabilistic exposure assessments characterised potential health risk. • Assessments based on real-field camel meat samples suggest low health risk. • Residue monitoring program warranted to ensure food safety of Australian camel meat. [ABSTRACT FROM AUTHOR]

Mixed contamination of benzo[ a ]pyrene (B[ a ]P), arsenic (As), cadmium (Cd), and lead (Pb) is a major environmental and human health concern. The mixture toxicity data on these co-contaminants are important for their risk assessment. In this study, we have determined the mixture toxicity of As, Cd and Pb, and B[ a ]P with As, Cd or Pb in HepG2 cells. The binary mixtures of Cd + As, Cd + Pb and As + Pb and B[ a ]P + metals (B[ a ]P + As, B[ a ]P + Cd and B[ a ]P + Pb) were evaluated for their interaction on the cytotoxicity using the MTS assay. A full factorial design (4 × 5) was used to determine the interaction toxicity and all the six mixtures showed significant interaction on the cytotoxicity. We further investigated the role of oxidative stress (reactive oxygen species (ROS) generation) and antioxidant defense mechanism (total glutathione (GSH) level) with the observed cytotoxicity. The mixtures of metals reduced the total GSH level and increased the ROS generation, respectively. In the case of mixtures of B[ a ]P and metals, both total GSH level and ROS generation were increased. Overall, the binary mixtures of metals and B[ a ]P with metals caused a dose dependent toxicity to HepG2 cells. The results also showed a significant contribution of oxidative stress to the observed toxicity and the potential protective role of the total GSH level against this mixture toxicity. The findings of interaction between B[ a ]P and metals might have an impact on the potential human health risk of this mixtures at contaminated sites. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous, toxic, and persistent environmental chemicals of concern that have been widely detected in all environmental matrices including human biological fluids. Although humans are exposed to complex mixtures of PFAS, it remains uncertain whether the co-exposure to PFAS mixtures could induce genotoxic damage in humans. Hence, this study evaluated the combined genotoxicity of PFAS mixtures in a human cell line system. To assess the possible genotoxic damage caused by human exposure to PFAS and their mixtures, we investigated their potential to induce cytotoxicity (cell viability) and genotoxicity (DNA damage) in a human liver cell line (HepG2). The selected PFAS include perfluorononanoic acid (PFNA), perfluorooctane sulfonic acid (PFOS), perfluorodecanoic acid (PFDA), perfluorooctanoic acid (PFOA), and perfluorohexane sulfonic acid (PFHxS). The interaction toxicities of these PFAS in binary mixtures were also determined using the additive index approach. The results revealed that exposure to PFNA, PFOS, PFDA, PFOA, and PFHxS singly and in binary mixtures induced a concentration-dependent decrease in cell viability. The additive index values indicated that the binary mixtures of PFOS + PFNA, PFOS + PFDA, and PFOS + PFOA displayed synergistic interaction, whereas the binary mixtures of PFOS + PFHxS, PFOA + PFNA, PFOA + PFDA, and PFOA + PFHxS behaved additively. Using the alkaline Comet assay, the potential of PFAS and their mixtures to induce DNA damage was evaluated based on a 1:1 ratio of the concentration of respective compounds required to produce a 1/10th of effective concentrations causing 50 % inhibition in cell viability (EC 50). The results revealed that exposure to PFNA, PFOS, PFDA, PFOA, and PFHxS singly and in binary mixtures (PFOS + PFNA, PFOS + PFDA, PFOS + PFOA, PFOS + PFHxS, PFOA + PFNA, PFOA + PFDA, and PFOA + PFHxS) caused a moderate increase in cellular DNA damage, but no dose-response relationship was observed. Overall, this study indicates that the tested PFAS causes a concentration-dependent decrease in cell viability and only a modest increase in cellular DNA damage under these conditions. [Display omitted] • The first study on the combined genotoxicity of PFAS binary mixtures to HepG2 cells. • Potential to induce cytotoxicity and genotoxicity was assessed after 24 h exposure. • Exposure to PFAS mixtures caused a dose-dependent decrease in cell viability. • Exposure to mixed PFAS moderately increases DNA damage with no dose-response relationship. [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]

The bioaccessibility of lead (Pb) in contaminated soils has been extensively studied, including the influence of soil properties on Pb bioaccessibility. However, little is known about the effects of other metals/metalloid, such as arsenic (As), cadmium (Cd) on the bioaccessibility of Pb, i.e. whether As or Cd could increase or decrease the solubility of Pb in human gastrointestinal tract when Pb-contaminated soil and As-contaminated (or Cd-contaminated) soil are ingested simultaneously. Furthermore, it is far from clear that if soil property could make a difference to these effects. In this study, seven types of soils were collected in Australia and spiked with As, Cd or Pb. Gastric bioaccessibility of Pb ranged from 44 ± 0.9% to 100 ± 6.7% whilst intestinal bioaccessibility dropped to 1 ± 0.2% to 36 ± 1.7%. Statistical analysis shows total Pb in soil was the most significant controller for bioaccessible Pb. Effects of As and Cd on the bioaccessibility of Pb in simulated human digestive system were studied by mixing As-spiked soil (or Cd-spiked soil) with Pb-spiked soil of the same type during bioaccessibility test. Results reveal that neither As nor Cd had impact on Pb bioaccessibility, which indicates when As, Cd and Pb aged in soils separately, they may behave independently in the bioaccessibility measuring system. This finding can be part of evidence to assume additive effect when it comes to estimate the bioaccessibility of mixtures of independently-aged As and Pb (or Cd and Pb) in 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]

This paper presents a summary of some relevant documents published during the last decades regarding arsenic contamination in Brazil until December 2018, including scientific papers, reports and regulatory documents. Natural and anthropogenic arsenic sources were covered, excluding those related to agriculture. International "key" documents related to arsenic contamination were used to support the discussion and comparative analysis. This paper aims: (a) to summarize and discuss some available data (including Portuguese written documents) concerning arsenic contamination in Brazil, mainly geographical, geological, geochemical, environmental and health studies; (b) to critically review the published studies comparing their main findings; (c) to describe and compare ancient and recent contamination events; and (d) to highlight key knowledge gaps, and identify promising areas for future researches. The arsenic contamination scenario in Brazil results not only from mining. Natural or anthropogenic emissions caused by great magnitude phenomena as flooding, erosion, landslide and, water scarcity equally impact arsenic mobilization/immobilization equilibria. Our literature review demonstrates that arsenic contamination of soils, sediments and water sources is observed at least at three of the five geographically defined Brazilian regions (Northern, Southern and, Southeastern regions). Arsenic enriched soils, and waters naturally occur all around the country and anthropogenic activities have been the main contributory factor to the environmental contamination since the 18th Century. Geogenic materials (topsoil and mining tailings), and water samples could contain extremely high arsenic concentrations, i.e. 21,000 mg kg−1 or 1,700,000 μg L−1, respectively, have been found mainly at the "Iron Quadrangle". Moreover, if we consider both the Brazilian and international parameters, the health risks associated with the human exposition to arsenic are of significant concern. For those reasons, constant monitoring of As contaminated areas in Brazil is mandatory. Furthermore, it is necessary to learn from the mistakes made in the past in order to prevent or minimize future problems. Unlabelled Image • A scenario of arsenic contamination in Brazil was depicted. • Arsenic contamination from mining activities in Brazil is an ongoing concern. • Collapse of Fundão Dam led to extensive As contamination in the Rio Doce Basin. • Mobility of As in and out of different environmental compartments is complex. • Arsenic equilibrium is influenced by anthropogenic factors. [ABSTRACT FROM AUTHOR]