The present work has been oriented to the qualitative and quantitative assessments of the aftermath effects of 2014 flood tragedy on the organic, inorganic and microbial contaminants in the floodwater, with a particular emphasis on their relative health risks and microbial infectious hazards to the flood-affected population, using average daily dose, hazard quotient, hazard index (HI), cancer risk (CR) and quantitative microbial risk assessment. Statistical comparison of the organic and inorganic contents was performed using the paired t-tests, while the predominant socio-demographic profiles and health attributes of the respondents to flood-induced health risks (HI) were verified by the chi-square test and binary logistic regression analysis. Among all, Fe, Cu, Pb, Ni, Zn, Cr, Cd, chlorpyrifos, diazinon, polycyclic aromatic hydrocarbons, estriol, 17α-ethinylestradiol, estrone, β-estradiol and bisphenol A were detected at the study area after flooding. The microbiological quality of the floodwater samples has been tracked positive for Escherichia coli, Salmonella typhimurium and Shigella flexneri, with the mean concentrations of 6500, 50 and 180 CFU/100 mL, respectively. Exposure and health risk assessments revealed that the overall HI value for organic and inorganic contaminants in the water samples was 1.19, exceeding the USEPA maximum limit of 1, after the flood incidence. The largest CR contributors were Ni, Cr and Cd, while the infection risks (Pinf,single) associated with the exposure of E. coli, Salmonella spp. and Shigella spp. were identified to be 3.1 × 10-2, 1.2 × 10-4 and 3.2 × 10-5 for incidental scenario; and 8.3 × 10-1, 3.9 × 10-1 and 1.9 × 10-1 for intentional scenario, respectively. The findings of these integrated tools are critically important to provide a more reliable quantitative assessment of human health hazards and microbial risks for different environmental settings, to safeguard water resource, and preservation of public health and the overall river ecosystem.
Gastrointestinal diseases exert a profound impact on global health, leading to millions of healthcare interventions and a significant number of fatalities annually. This, coupled with escalating healthcare expenditures, underscores the need for identifying and addressing potential exacerbating factors. One emerging concern is the pervasive presence of microplastics and nano-plastics in the environment, largely attributed to the indiscriminate usage of disposable plastic items. These nano-plastics, having infiltrated our food chain, pose a potential threat to gastrointestinal health. To understand this better, we co-cultured human gastric fibroblasts (HGF) with polystyrene nano-plastics (PS-NPs) of diverse sizes (80, 500, 650 nm) and meticulously investigated their cellular responses over a 24-hour period. Our findings revealed PS particles were ingested by the cells, with a notable increase in ingestion as the particle size decreased. The cellular death induced by these PS particles, encompassing both apoptosis and necrosis, showcased a clear dependence on both the particle size and its concentration. Notably, the larger PS particles manifested more potent cytotoxic effects. Further analysis indicated a concerning reduction in cellular membrane potential, alongside a marked increase in ROS levels upon PS particles exposure. This suggests a significant disruption of mitochondrial function and heightened oxidative stress. The larger PS particles were especially detrimental in causing mitochondrial dysfunction. In-depth exploration into the PS particles impact on genes linked with the permeability transition pore (PTP) elucidated that these PS particles instigated an internal calcium rush. This surge led to a compromise in the mitochondrial membrane potential, which in tandem with raised ROS levels, further catalyzed DNA damage and initiated cell death pathways. In essence, this study unveils the intricate mechanisms underpinning cell death caused by PS particles in gastric epithelial cells and highlighting the implications of PS particles on gastrointestinal health. The revelations from this research bear significant potential to shape future healthcare strategies and inform pertinent environmental policies.
In an effort to seek a new technical platform for disposal of drinking water treatment sludge (DWTS: alum sludge), pyrolysis of DWTS was mainly investigated in this study. To establish a more sustainable thermolytic platform for DWTS, this study particularly employed CO2 as reactive gas medium. Thus, this study laid great emphasis on elucidating the mechanistic roles of CO2 during the thermolysis of DWTS. A series of the TGA tests of DWTS in CO2 in reference to N2 revealed no occurrence of the heterogeneous reaction between CO2 and the sample surface of DWTS. As such, at the temperature regime before initiating the Boudouard reaction (i.e., ≥700 °C), the mass decay patterns of DWTS in N2 and CO2 were nearly identical. However, the gaseous effluents from lab-scale pyrolysis of DWTS in CO2 in reference to N2 were different. In sum, the homogeneous reactions between CO2 and volatile matters (VMs) evolved from the thermolysis of DWTS led to the enhanced generation of CO. Also, CO2 suppressed dehydrogenation of VMs. Such the genuine mechanistic roles of CO2 in the thermolysis of DWTS subsequently led to the compositional modifications of the chemical species in pyrolytic oil. Furthermore, the biochar composite was obtained as byproduct of pyrolysis of DWTS. Considering that the high content of Al2O3 and Fe-species in the biochar composite imparts a strong affinity for As(V), the practical use of the biochar composite as a sorptive material for arsenic (V) was evaluated at the fundamental levels. This work reported that adsorption of As(V) onto the biochar composite followed the pseudo-second order model and the Freundlich isotherm model.
Here we investigate if lead may be a contributing factor to the observed population decline in a Baltic colony of incubating eiders (Somateria mollissima). Body mass and blood samples were obtained from 50 incubating female eiders at the Baltic breeding colony on Christiansø during spring 2017 (n = 27) and 2018 (n = 23). All the females were sampled twice during early (day 4) and late (day 24) incubation. The full blood was analysed for lead to investigate if the concentrations exceeded toxic thresholds or changed over the incubation period due to remobilisation from bones and liver tissue. Body mass, hatch date and number of chicks were also analysed with respect to lead concentrations. The body mass (mean ± SD g) increased significantly in the order: day 24 in 2018 (1561 ± 154 g)
Indoor microbial diversity and composition are suggested to affect the prevalence and severity of asthma by previous home microbiome studies, but no microbiome-health association study has been conducted in a school environment, especially in tropical countries. In this study, we collected floor dust and environmental characteristics from 21 classrooms, and health data related to asthma symptoms from 309 students, in junior high schools in Johor Bahru, Malaysia. The bacterial and fungal composition was characterized by sequencing 16s rRNA gene and internal transcribed spacer (ITS) region, and the absolute microbial concentration was quantified by qPCR. In total, 326 bacterial and 255 fungal genera were characterized. Five bacterial (Sphingobium, Rhodomicrobium, Shimwellia, Solirubrobacter, Pleurocapsa) and two fungal (Torulaspora and Leptosphaeriaceae) taxa were protective for asthma severity. Two bacterial taxa, Izhakiella and Robinsoniella, were positively associated with asthma severity. Several protective bacterial taxa including Rhodomicrobium, Shimwellia and Sphingobium have been reported as protective microbes in previous studies, whereas other taxa were first time reported. Environmental characteristics, such as age of building, size of textile curtain per room volume, occurrence of cockroaches, concentration of house dust mite allergens transferred from homes by the occupants, were involved in shaping the overall microbial community but not asthma-associated taxa; whereas visible dampness and mold, which did not change the overall microbial community for floor dust, was negatively associated with the concentration of protective bacteria Rhodomicrobium (β = -2.86, p = 0.021) of asthma. The result indicates complex interactions between microbes, environmental characteristics and asthma symptoms. Overall, this is the first indoor microbiome study to characterize the asthma-associated microbes and their environmental determinant in the tropical area, promoting the understanding of microbial exposure and respiratory health in this region.
Here we review contaminant exposure and related health effects in six selected Baltic key species. Sentinel species included are common eider, white-tailed eagle, harbour porpoise, harbour seal, ringed seal and grey seal. The review represents the first attempt of summarizing available information and baseline data for these biomonitoring key species exposed to industrial hazardous substances focusing on anthropogenic persistent organic pollutants (POPs). There was only limited information available for white-tailed eagles and common eider while extensive information exist on POP exposure and health effects in the four marine mammal species. Here we report organ-tissue endpoints (pathologies) and multiple biomarkers used to evaluate health and exposure of key species to POPs, respectively, over the past several decades during which episodes of significant population declines have been reported. Our review shows that POP exposure affects the reproductive system and survival through immune suppression and endocrine disruption, which have led to population-level effects on seals and white-tailed eagles in the Baltic. It is notable that many legacy contaminants, which have been banned for decades, still appear to affect Baltic wildlife. With respect to common eiders, changes in food composition, quality and contaminant exposure seem to have population effects which need to be investigated further, especially during the incubation period where the birds fast. Since new industrial contaminants continuously leak into the environment, we recommend continued monitoring of them in sentinel species in the Baltic, identifying possible effects linked to climate change, and modelling of population level effects of contaminants and climate change.
Blood plasma was collected during 2016-2018 from healthy incubating eiders (Somateria molissima, n = 183) in three Danish colonies, and healthy migrating pink-footed geese (Anser brachyrhynchus, n = 427) at their spring roost in Central Norway (Svalbard breeding population) and their novel flyway through the Finnish Baltic Sea (Russian breeding population). These species and flyways altogether represent terrestrial, brackish and marine ecosystems spanning from the Western to the Eastern and Northern part of the Baltic Sea. Plasma of these species was analysed for seroprevalence of specific avian influenza A (AI) antibodies to obtain information on circulating AI serotypes and exposure. Overall, antibody prevalence was 55% for the eiders and 47% for the pink-footed geese. Of AI-antibody seropositive birds, 12% (22/183) of the eiders and 3% (12/427) of the pink-footed geese had been exposed to AI of the potentially zoonotic serotypes H5 and/or H7 virus. AI seropositive samples selected at random (n = 33) showed a low frequency of serotypes H1, H6 and H9. Future projects should aim at sampling and isolating AI virus to characterize dominant serotypes and virus strains (PCR). This will increase our understanding of how AI exposure may affect health, breeding and population viability of Baltic common eiders and pink-footed geese as well as the potential spill-over to humans (zoonotic potential).
The Baltic/Wadden Sea Flyway of common eiders has declined over the past three decades. Multiple factors such as contaminant exposure, global warming, hunting, white-tailed eagle predation, decreased agricultural eutrophication and infectious diseases have been suggested to explain the decline. We collected information on body mass, mercury (Hg) concentration, biochemistry and untargeted metabolomics of incubating birds in two colonies in the Danish Straits (Hov Røn, n = 100; Agersø, n = 29) and in one colony in the Baltic proper (Christiansø, n = 23) to look into their metabolisms and energy balance. Body mass was available from early and late incubation for Hov Røn and Christiansø, showing a significant decline (25-30%) in both colonies with late body mass at Christiansø being the lowest. Whole blood concentrations of total mercury Hg were significantly higher in birds at Christiansø in the east compared to Hov Røn in the west. All birds in the three colonies had Hg concentrations in the range of ≤1.0 μg/g ww, which indicates that the risk of effects on reproduction is in the no to low risk category for wild birds. Among the biochemical measures, glucose, fructosamine, amylase, albumin and protein decreased significantly from early to late incubation at Hov Røn and Christiansø, reflecting long-term fastening as supported by the decline in body mass. Untargeted metabolomics performed on Christiansø eiders revealed presence of 8,433 plasma metabolites. Of these, 3,179 metabolites changed significantly (log2-fold change ≥1, p ≤ 0.05) from the early to late incubation. For example, smaller peptides and vitamin B2 (riboflavin) were significantly down-regulated while 11-deoxycorticosterone and palmitoylcarnitine were significantly upregulated. These results show that cumulative stress including fasting during incubation affect the eiders' biochemical profile and energy metabolism and that this may be most pronounced for the Christiansø colony in the Baltic proper. This amplify the events of temperature increases and food web changes caused by global warming that eventually accelerate the loss in body weight. Future studies should examine the relationship between body condition, temperature and reproductive outcomes and include mapping of food web contaminant, energy and nutrient content to better understand, manage and conserve the populations.
BACKGROUND: The intense interactions between people, animals and environmental systems in urban informal settlements compromise human and environmental health. Inadequate water and sanitation services, compounded by exposure to flooding and climate change risks, expose inhabitants to environmental contamination causing poor health and wellbeing and degrading ecosystems. However, the exact nature and full scope of risks and exposure pathways between human health and the environment in informal settlements are uncertain. Existing models are limited to microbiological linkages related to faecal-oral exposures at the individual level, and do not account for a broader range of human-environmental variables and interactions that affect population health and wellbeing.
METHODS: We undertook a 12-month health and environmental assessment in 12 flood-prone informal settlements in Makassar, Indonesia. We obtained caregiver-reported health data, anthropometric measurements, stool and blood samples from children
In recent years, ozone pollution in China has been shown to increase in frequency and persistence despite the concentrations of fine particulate matter (PM2.5) decreasing steadily. Open crop straw burning (OCSB) activities are extensive in China and emit large amounts of trace gases during a short period that could lead to elevated ozone concentrations. This study addresses the impacts of OCSB emissions on ground-level ozone concentration and the associated health impact in China. Total VOCs and NOx emissions from OCSB in 2018 were 798.8 Gg and 80.6 Gg, respectively, with high emissions in Northeast China (31.7%) and North China (23.7%). Based on simulations conducted for 2018, OCSB emissions are estimated to contribute up to 0.95 µg/m3 increase in annual averaged maximum daily 8-hour (MDA8) ozone and up to 1.35 µg/m3 for the ozone season average. The significant impact of OCSB emissions on ozone is mainly characterized by localized and episodic (e.g., daily) changes in ozone concentration, up to 20 µg/m3 in North China and Yangtze River Delta region and even more in Northeast China during the burning season. With the implementation of straw burning bans, VOCs and NOx emissions from OCSB dropped substantially by 46.9%, particularly over YRD (76%) and North China (60%). Consequently, reduced OCSB emissions result in an overall decrease in annual averaged MDA8 ozone, and reductions in monthly MDA8 ozone could be over 10 µg/m3 in North China. The number of avoided premature death due to reduced OCSB emissions (considering both PM2.5 and ozone) is estimated to be 6120 (95% Confidence Interval: 5320-6800), with most health benefits gained over east and central China. Our results illustrate the effectiveness of straw burning bans in reducing ozone concentrations at annual and national scales and the substantial ozone impacts from OCSB events at localized and episodic scales.
There is a growing concern about human health of residents living in areas where mining and smelting occur. In order to understand the exposure to the potentially toxic elements (PTEs), we here identify and examine the cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) in scalp hair of residents living in the mining area (Bayan Obo, n = 76), smelting area (Baotou, n = 57) and a reference area (Hohhot, n = 61). In total, 194 hair samples were collected from the volunteers (men = 87, women = 107) aged 5-77 years old in the three areas. Comparing median PTEs levels between the young and adults, Ni levels were significantly higher in adults living in the smelting area while Cr was highest in adults from the mining area, no significant difference was found for any of the elements in the reference area. From the linear regression model, no significant relationship between PTEs concentration, log10(PTEs), and age was found. The concentrations of Ni, Cd, and Pb in hair were significantly lower in the reference area when compared to both mining and smelting areas. In addition, Cu was significantly higher in the mining area when compared to the smelting area. Factor analysis (FA) indicated that men and women from the smelting area (Baotou) and mining area (Bayan Obo), respectively, had different underlying communality of log10(PTEs), suggesting different sources of these PTEs. Multiple factor analysis quantilized the importance of gender and location when combined with PTEs levels in human hair. The results of this study indicate that people living in mining and/or smelting areas have significantly higher PTEs (Cu, Ni, Cd, and Pb) hair levels compared to reference areas, which may cause adverse health effects. Remediation should therefore be implemented to improve the health of local residents in the mining and smelting areas.
This study was conducted to: (1) assess the role of wetland vegetation in the removal of oxygen demand and nitrogen under tropical conditions, (2) estimate the uptake of nitrogen and copper by wetland plants and (3) investigate the speciation of Cu in wetland media among four operationally defined host fractions, namely exchangeable, carbonate, reducible and organically bound. Four laboratory-scale wetland units, two free-water-surface (FWS) and two subsurface-flow (SF) with one of each planted with cattails (Typha augustifolia), were fed with primary-treated sewage and operated at nominal retention times of 0.6-7 days. The influent and effluent BOD/COD and nitrogen concentrations were monitored to assess the performance of the wetland units for various mass loading rates. At the end of the study, all cattail plants were harvested and analyzed for total Kjeldahl nitrogen (TKN). Four other wetland units, which were identical to the first four, were fed with domestic wastewater spiked with copper in increasing concentrations. Copper speciation patterns in the sand layer were determined at the end of the study. The results showed that wetland vegetation did not play an important role in oxygen demand removal but were capable of removing about 22% and 26% of the nitrogen input in the FWS and SF wetland units, respectively. Mass balance analysis indicated that less than 1% of copper introduced was taken up by the cattails. Copper speciation patterns in the sand media showed that the exchangeable fraction contributed 30-57% and 63-80% of the nonresidual copper in the planted and unplanted FWS wetlands, respectively. For SF units, the percentages were 52-62% and 59-67%, respectively. This indicates that large amount of copper in the media were potentially remobilizable.
This paper discusses heavy metal removal from wastewater by batch study and filtration technique through low-cost coarse media. Batch study has indicated that more than 90% copper (Cu) with concentration up to 50 mg/l could be removed from the solution with limestone quantity above 20 ml (equivalent to 56 g), which indicates the importance of limestone media in the removal process. This indicates that the removal of Cu is influenced by the media and not solely by the pH. Batch experiments using limestone and activated carbon indicate that both limestone and activated carbon had similar metal-removal efficiency (about 95%). Results of the laboratory-scale filtration technique using limestone particles indicated that above 90% removal of Cu was achieved at retention time of 2.31 h, surface-loading rate of 4.07 m3/m2 per day and Cu loading of 0.02 kg/m3 per day. Analyses of the limestone media after filtration indicated that adsorption and absorption processes were among the mechanisms involved in the removal processes. This study indicated that limestone can be used as an alternative to replace activated carbon.
Cities are complex adaptive systems whose responses to policy initiatives emerge from feedback interactions between their parts. Urban policy makers must routinely deal with both detail and dynamic complexity, coupled with high levels of diversity, uncertainty and contingency. In such circumstances, it is difficult to generate reliable predictions of health-policy outcomes. In this paper we explore the potential for low-order system dynamics (LOSD) models to make a contribution towards meeting this challenge. By definition, LOSD models have few state variables (≤5), illustrate the non-linear effects caused by feedback and accumulation, and focus on endogenous dynamics generated within well-defined boundaries. We suggest that experience with LOSD models can help practitioners to develop an understanding of basic principles of system dynamics, giving them the ability to 'see with new eyes'. Because efforts to build a set of LOSD models can help a transdisciplinary group to develop a shared, coherent view of the problems that they seek to tackle, such models can also become the foundations of 'powerful ideas'. Powerful ideas are conceptual metaphors that provide the members of a policy-making group with the a priori shared context required for effective communication, the co-production of knowledge, and the collaborative development of effective public health policies.
Health has been the main driver for many urban environmental interventions, particularly in cases of significant health problems linked to poor urban environmental conditions. This paper examines empirically the links between climate change mitigation and health in urban areas, when health is the main driver for improvements. The paper aims to understand how systems of urban governance can enable or prevent the creation of health outcomes via continuous improvements in the environmental conditions in a city. The research draws on cases from two Indian cities where initiatives were undertaken in different sectors: Surat (waste) and Delhi (transportation). Using the literature on network effectiveness as an analytical framework, the paper compares the cases to identify the possible ways to strengthen the governance and policy making process in the urban system so that each intervention can intentionally realize multiple impacts for both local health and climate change mitigation in the long term as well as factors that may pose a threat to long-term progress and revert back to the previous situation after initial achievements.
The presence of microplastics in the marine environment poses a great threat to the entire ecosystem and has received much attention lately as the presence has greatly impacted oceans, lakes, seas, rivers, coastal areas and even the Polar Regions. Microplastics are found in most commonly utilized products (primary microplastics), or may originate from the fragmentation of larger plastic debris (secondary microplastics). The material enters the marine environment through terrestrial and land-based activities, especially via runoffs and is known to have great impact on marine organisms as studies have shown that large numbers of marine organisms have been affected by microplastics. Microplastic particles have been found distributed in large numbers in Africa, Asia, Southeast Asia, India, South Africa, North America, and in Europe. This review describes the sources and global distribution of microplastics in the environment, the fate and impact on marine biota, especially the food chain. Furthermore, the control measures discussed are those mapped out by both national and international environmental organizations for combating the impact from microplastics. Identifying the main sources of microplastic pollution in the environment and creating awareness through education at the public, private, and government sectors will go a long way in reducing the entry of microplastics into the environment. Also, knowing the associated behavioral mechanisms will enable better understanding of the impacts for the marine environment. However, a more promising and environmentally safe approach could be provided by exploiting the potentials of microorganisms, especially those of marine origin that can degrade microplastics.
CAPSULE: The concentration, distribution sources and fate of microplastics in the global marine environment were discussed, so also was the impact of microplastics on a wide range of marine biota.
Kuala Lumpur has been undergoing rapid urbanisation process, mainly in infrastructure development. The opening of new township and residential in former tin mining areas, particularly in the heavy mineral- or tin-bearing alluvial soil in Kuala Lumpur, is a contentious subject in land-use regulation. Construction practices, i.e. reclamation and dredging in these areas are potential to enhance the radioactivity levels of soil and subsequently, increase the existing background gamma radiation levels. This situation is worsened with the utilisation of tin tailings as construction materials apart from unavoidable soil pollutions due to naturally occurring radioactive materials in construction materials, e.g. granitic aggregate, cement and red clay brick. This study was conducted to assess the urbanisation impacts on background gamma radiation in Kuala Lumpur. The study found that the mean value of measured dose rate was 251±6nGyh-1(156-392nGyh-1) and 4 times higher than the world average value. High radioactivity levels of238U (95±12Bqkg-1),232Th (191±23Bqkg-1,) and40K (727±130Bqkg-1) in soil were identified as the major source of high radiation exposure. Based on statistical ANOVA, t-test, and analyses of cumulative probability distribution, this study has statistically verified the dose enhancements in the background radiation. The effective dose was estimated to be 0.31±0.01mSvy-1per man. The recommended ICRP reference level (1-20mSvy-1) is applicable to the involved existing exposure situation in this study. The estimated effective dose in this study is lower than the ICRP reference level and too low to cause deterministic radiation effects. Nevertheless based on estimations of lifetime radiation exposure risks, this study found that there was small probability for individual in Kuala Lumpur being diagnosed with cancer and dying of cancer.
To date, experimental and epidemiological evidence of endocrine disrupting compounds (EDCs) adversely affecting human and animal populations has been widely debated. Notably, human health risk assessment is required for risk mitigation. The lack of human health risk assessment and management may thus unreliably regulate the quality of water resources and efficiency of treatment processes. Therefore, drinking water supply systems (DWSSs) may be still unwarranted in assuring safe access to potable drinking water. Drinking water supply, such as tap water, is an additional and crucial route of human exposure to the health risks associated with EDCs. A holistic system, incorporating continuous research in DWSS monitoring and management using multi-barrier approach, is proposed as a preventive measure to reduce human exposure to the risks associated with EDCs through drinking water consumption. The occurrence of EDCs in DWSSs and corresponding human health risk implications are analyzed using the Needs, Approaches, Benefits, and Challenges (NABC) method. Therefore, this review may act as a supportive tool in protecting human health and environmental quality from EDCs, which is essential for decision-making regarding environmental monitoring and management purposes. Subsequently, the public could have sustainable access to safer and more reliable drinking water.
Long-term exposure to air pollution has been associated with several adverse health effects including cardiovascular, respiratory diseases and cancers. However, underlying molecular alterations remain to be further investigated. The aim of this study is to investigate the effects of long-term exposure to air pollutants on (a) average DNA methylation at functional regions and, (b) individual differentially methylated CpG sites. An assumption is that omic measurements, including the methylome, are more sensitive to low doses than hard health outcomes. This study included blood-derived DNA methylation (Illumina-HM450 methylation) for 454 Italian and 159 Dutch participants from the European Prospective Investigation into Cancer and Nutrition (EPIC). Long-term air pollution exposure levels, including NO2, NOx, PM2.5, PMcoarse, PM10, PM2.5 absorbance (soot) were estimated using models developed within the ESCAPE project, and back-extrapolated to the time of sampling when possible. We meta-analysed the associations between the air pollutants and global DNA methylation, methylation in functional regions and epigenome-wide methylation. CpG sites found differentially methylated with air pollution were further investigated for functional interpretation in an independent population (EnviroGenoMarkers project), where (N=613) participants had both methylation and gene expression data available. Exposure to NO2 was associated with a significant global somatic hypomethylation (p-value=0.014). Hypomethylation of CpG island's shores and shelves and gene bodies was significantly associated with higher exposures to NO2 and NOx. Meta-analysing the epigenome-wide findings of the 2 cohorts did not show genome-wide significant associations at single CpG site level. However, several significant CpG were found if the analyses were separated by countries. By regressing gene expression levels against methylation levels of the exposure-related CpG sites, we identified several significant CpG-transcript pairs and highlighted 5 enriched pathways for NO2 and 9 for NOx mainly related to the immune system and its regulation. Our findings support results on global hypomethylation associated with air pollution, and suggest that the shores and shelves of CpG islands and gene bodies are mostly affected by higher exposure to NO2 and NOx. Functional differences in the immune system were suggested by transcriptome analyses.
Rapid development and industrialization in Southeast (SE) Asia has led to environmental pollution, potentially exposing the general population to environmental contaminants. Human biomonitoring (HBM), measurement of chemical and/or their metabolites in human tissues and fluids, is an important tool for assessing cumulative exposure to complex mixtures of chemicals and for monitoring chemical exposures in the general population. While there are national HBM programs in several developed countries, there are no such national programs in most of the SE Asian countries. However, in recent years there has been progress in the field of HBM in many of the SE Asian countries. In this review, we present recent HBM studies in five selected SE Asian countries: Bangladesh, Indonesia, Malaysia, Myanmar and Thailand. While there is extensive HBM research in several SE Asian countries, such as Thailand, in other countries HBM studies are limited and focus on traditional environmental pollutants (such as lead, arsenic and mercury). Further development of this field in SE Asia would be benefited by establishment of laboratory capacity, improving quality control and assurance, collaboration with international experts and consortiums, and sharing of protocols and training both for pre-analytical and analytical phases. This review highlights the impressive progress in HBM research in selected SE Asian countries and provides recommendations for development of this field.