Dust is regarded as an important pathway of heavy metal(loid)s to the human body. Health risks posed by metal(loid)s from household dust are of particular concern. However, the contamination and sources of heavy metal(loid)s in household dust environments, as well as source identification of health risks related to heavy metal(loid)s from household dust for vulnerable populations such as children, have not been thoroughly studied in China, particularly for the areas involved with industrial activities such as ore mining. Thus, a cross-sectional study was conducted in a rural area famous for Pb/Zn ore mining, to assess the pollution sources and health risks of heavy metal(loid)s from household indoor and outdoor dust and to identify the contribution of household dust to the health risks for children. The results indicated that household environment was heavily contaminated by metal(loid)s, which were mainly attributed to mining activity. Meanwhile, the indoor/outdoor ratio and the redundancy analysis indicated that there were other pollution sources in indoor environments such as coal combustion, materials for interior building and decoration. Vapor inhalation was the main exposure pathway for Hg, while ingestion was the predominant pathway for other metal(loid)s. Although the cancer risks were relatively low, the HIt from household indoor and outdoor dust (2.19) was about twice the acceptable limit (1) and was primarily from Pb (64.52%) and As (23.42%). Outdoor dust was a larger contributor to the HI of Sb, As, Cr, Cd, Zn and Pb, which accounted for 51.37%, 58.63%, 52.14%, 59.66%, 52.87% and 64.47%, respectively, and the HIt was mainly from outdoor dust (60.76%). These results indicated that non-cancer health risks were largely from outdoor dust exposure, and strengthened the notion that concern should be given to the potential health risks from metal(loid)s in household dust both originating from mining activity and indoor environmental sources.

Association between long-term exposure to ambient air pollution and obesity remains inconclusive, and the evidence from rural areas was limited. Thus, this study aimed to assess the association between ambient air pollution and obesity based on different anthropometric indices in Chinese rural adults, and further to compare the effect sizes of different air pollution types. A total of 38,824 participants (aged 18–79 years) were recruited from the Henan Rural Cohort Study. Logistic and multivariable linear regression model were used to examine the association between ambient air pollution exposure (including particulate matter with aerodynamic diameters ≤ 1.0 μm (PM₁), ≤2.5 μm (PM₂.₅), and ≤10 μm (PM₁₀), and nitrogen dioxide (NO₂)) and obesity as well as obese anthropometric indices (including body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), body fat percentage (BFP), and visceral fat index (VFI)). The potential effect modifications were also examined. Positive associations were found between long-term exposure to PM₁, PM₂.₅, PM₁₀ and NO₂ and obesity regardless of how obesity was defined (false discovery rate (FDR) < 0.05). Moreover, BMI, WC, WHR, WHtR, BFP, and VFI displayed increased trends with PM₁, PM₂.₅, PM₁₀ and NO₂ concentrations increasing (all FDR<0.05). PM₁₀ had the largest effects on obesity among the four types of air pollution. The elderly, women, individuals with low level of education and income, and those who had high fat diet were more vulnerable to the adverse effects of air pollution. In addition, the results of the sensitivity analysis showed that those associations between ambient air pollution and obesity remained robust. These findings suggest that long-term exposure to ambient air pollutant (particularly PM₁₀) may be positively associated with obesity in Chinese rural adults, especially among the elderly, women, individuals with low education and income, as well as unhealthy lifestyles.

This study was designed to investigate the seasonal characteristics and apportion the sources of organic carbon during non-haze days (<75 μg m⁻³) and haze (≥75 μg m⁻³) events at Pinggu, a rural Beijing site. Time-resolved concentrations of carbonaceous aerosols and organic molecular tracers were measured during the winter of 2016 and summer 2017, and a Chemical Mass Balance (CMB) model was applied to estimate the average source contributions. The concentration of OC in winter is comparable with previous studies, but relatively low during the summer. The CMB model apportioned seven separate primary sources, which explained on average 73.8% on haze days and 81.2% on non-haze days of the organic carbon in winter, including vegetative detritus, biomass burning, gasoline vehicles, diesel vehicles, industrial coal combustion, residential coal combustion and cooking. A slightly lower percentage of OC was apportioned in the summer campaign with 64.5% and 78.7% accounted for. The other unapportioned OC is considered to consist of secondary organic carbon (SOC). During haze episodes in winter, coal combustion and SOC were the dominant sources of organic carbon with 23.3% and 26.2%, respectively, followed by biomass burning emissions (20%), whereas in summer, industrial coal combustion and SOC were important contributors. Diurnal contribution cycles for coal combustion and biomass burning OC showed a peak at 6–9 pm, suggesting domestic heating and cooking were the main sources of organic aerosols in this rural area. Backward trajectory analysis showed that high OC concentrations were measured when the air mass was from the south, suggesting that the organic aerosols in Pinggu were affected by both local emissions and regional transport from central Beijing and Hebei province during haze episodes. The source apportionment by CMB is compared with the results of a Positive Matrix Factorization (PMF) analysis of ACSM data for non-refractory PM₁, showing generally good agreement.

Wastewater discharges from dairy industries can cause a range of harmful effects in aquatic ecosystems, including a decline in biodiversity due to species evasion. Therefore, it is important to know the purification potential of rivers for the removal of pollutants released in dairy wastewater (DWW). The hypothesis adopted in this work was that the release of DWW into stretches of the Ribeirão dos Pombos River (São Paulo State, Brazil) might trigger an avoidance response, resulting in fish migrating to other regions, with the response being greater when the self-cleaning potential of the river is smaller. Therefore, the goals of the present study were to: (i) investigate how land use and seasonality of the rainfall regime influence the quality of the water in different areas of the river (P1: river source; P2: urban region; P3: rural region); (ii) assess the potential of the river to purify DWW; and (iii) evaluate the potential toxicity and repellency of DWW to the freshwater fish Danio rerio, using acute toxicity (mortality) and non-forced avoidance tests, respectively. P1 was shown to be the most preserved area. The chemical composition of the river varied seasonally, with higher concentrations of Cl⁻ and SO₄²⁻ at P3 during the rainy period. The river purification potential for DWW was higher at P2, due to greater microbiological activity (associated with higher BOD). The DWW was more acutely toxic in water from P2. The avoidance response was strongly determined by the concentration of DWW, especially for water from P2. The high capacity for self-cleaning at P2 did not seem sufficient to maintain the stability of the ecosystem. Finally, the non-forced exposure system proved to be a suitable approach that can assist in predicting how contaminants may affect the spatial distributions of organisms.

The association between temperature and mortality has been widely reported. However, it remains largely unclear whether inflammation-related diseases, caused by excessive or inappropriate inflammatory reaction, may be affected by ambient temperature, particularly in low-income areas.To explore the association between ambient temperature and clinical visits for inflammation-related diseases in rural villages in the Ningxia Hui Autonomous Region, China, during 2012─2015.Daily data on inflammation-related diseases and weather conditions were collected from 258 villages in Haiyuan (161 villages) and Yanchi (97 villages) counties during 2012─2015. A Quasi-Poisson regression with distributed lag non-linear model was used to examine the association between temperature and clinical visits for inflammation-related diseases. Stratified analyses were performed by types of diseases including arthritis, gastroenteritis, and gynecological inflammations.During the study period, there were 724,788 and 288,965 clinical visits for inflammation-related diseases in Haiyuan and Yanchi, respectively. Both exposure to low (RR: 2.045, 95% CI: 1.690, 2.474) and high temperatures (RR: 1.244, 95% CI: 1.107, 1.399) were associated with increased risk of total inflammation-related visits in Haiyuan county. Low temperatures were associated with increased risks of all types of inflammation-related diseases in Yanchi county (RR: 4.344, 95% CI: 2.887, 6.535), while high temperatures only affected gastroenteritis (RR: 1.274, 95% CI: 1.040, 1.561). Moderate temperatures explained approximately 26% and 33% of clinical visits due to inflammation-related diseases in Haiyuan and Yanchi, respectively, with the burden attributable to cold exposure higher than hot exposure. The reference temperature values ranged from 17 to 19 in Haiyuan, and 12 to 14 in Yanchi for all types of clinical visits.Our findings add additional evidence for the adverse effect of suboptimal ambient temperature and provide useful information for public health programs targeting people living in rural villages.

The atmospheric concentrations of 14 organophosphate esters (OPEs) were monitored by passive air sampling at 33 sites to determine their spatial distributions, and seasonal variations (summer and winter) in Tianjin, North China. The total concentrations of the OPEs (∑₉OPEs) in the summer ranged from 0.08 to 1113 ng/sample with a median of 98.4 ng/sample, which was non-statistically different from the concentrations obtained in the winter (which ranged from 1.93 to 548 ng/sample with a median of 46.2 ng/sample). Among the observed OPEs, the concentrations of TnBP and TCiPP were statistically higher in the summer compared with the winter (p < 0.05). For grouped OPEs, only a significantly higher level of chlorinated OPEs was found in summer than that in winter. In the winter, spatial differences were found to be significantly different between the concentrations of TnBP, TiBP, TCEP, and TEHP in the suburban and rural areas (p < 0.05). Considering the possible point-sources, in the summer, the concentrations of TDCPP, TCiPP, DPEHP, TEHP, and the total concentration of TCPs (denoted as ∑₃TCP, comprised of the concentrations of TCP, TmCP, and ToCP) in an electronic-waste (e-waste) dismantling area were higher than those obtained at the other sampling sites. ∑₉OPEs at the e-waste site and another site located near a manufacturing plant of organophosphate flame retardants (OFRs) were both higher than the median concentrations obtained at the other sampling sites, and TCiPP was the most abundant pollutant. In the winter, the concentrations of ∑₉OPEs at the e-waste site were still higher than their median concentrations at the other sites. Because OPEs are used in aircraft lubricating oils and hydraulic fluids, an airport was thought to be another important source of TiBP and TPhP in the present study. Therefore, the e-waste site, airport, and OFR manufacturing plant may be the major sources of OPEs in the environment.

Persistent organic pollutants (POPs) including PCDD/Fs, PCBs and organochlorine pesticides (OCPs) are among the most important and hazardous pollutants of soil. Food producing animals such as chicken, beef, sheep and goats can take up soil while grazing or living outdoors (free-range) and this can result in contamination.In recent decades, large quantities of brominated flame retardants such as polybrominated diphenyl ethers (PBDEs), short-chain chlorinated paraffins (SCCPs) and per- and polyfluorinated alkylated substances (PFAS) have been produced and released into the environment and this has resulted in widespread contamination of soils and other environmental matrices. These POPs also bioaccumulate and can contaminate food of animal origin resulting in indirect exposure of humans.Recent assessments of chicken and beef have shown that surprisingly low concentrations of PCBs and PCDD/Fs in soil can result in exceedances of regulatory limits in food. Soil contamination limits have been established in a number of countries for PCDD/Fs but it has been shown that the contamination levels which result in regulatory limits in food (the maximum levels in the European Union) being exceeded, are below all the existing soil regulatory limits. ‘Safe’ soil levels are exceeded in many areas around emission sources of PCDD/Fs and PCBs. On the other hand, PCDD/F and dioxin-like PCB levels in soil in rural areas, without a contamination source, are normally safe for food producing animals housed outdoors resulting in healthy food (e.g. meat, eggs, milk).For the majority of POPs (e.g. PBDEs, PFOS, PFOA, SCCP) no regulatory limits in soils exist.There is, therefore, an urgent need to develop appropriate and protective soil standards minimising human exposure from food producing animals housed outdoors. Furthermore, there is an urgent need to eliminate POPs pollution sources for soils and to control, secure and remediate contaminated sites and reservoirs, in order to reduce exposure and guarantee food safety.

Polycyclic aromatic hydrocarbons (PAHs) remain a focal concern of the air pollution in China. To discriminate the sources of airborne PAHs in Chinese rural regions, a national-scale tree bark sampling campaign and emission inventory estimation were conducted. The concentrations of the sum of 16 U.S. EPA priority PAHs in rural bark ranged from 6.30 to 3803 ng/g, with the dominance of 3- and 4-ring PAHs. Bark residual PAH concentration correlated significantly with emission flux rate, bark lipid content, ambient PM₂.₅, precipitation and sampling location. Based on the information of emission data, bark PAH congener profiles, principal component analysis, diagnostic ratios and compound-specific isotope analysis, solid fuel combustion was identified as the major source and could explain 40.3%–46.4% of bark PAH residues in rural China. The δ¹³C values of most individual PAHs were more negative at sites with lower longitude and latitude, suggesting a greater contribution of biomass combustion to PAH residues. Our results suggest the importance of regulating solid fuel combustion to significantly improve the air quality in China, and bark samples can provide a wealth of information on effectively monitoring and controlling the sources of PAH emission in rural China.

Anthropogenic Pb emitted from East Asia, particularly China, is often long-range transported to the east by the prevailing westerlies. To characterize the geographical properties of varying atmospheric Pb concentrations by transboundary and domestic source(s)-related Pb in Korea, closely adjacent to China, the Al and Pb concentrations and the stable Pb isotopic composition were determined in the total suspended particles (TSP) collected at urban (IC), rural (TA), and remote background (JJ) sites in western Korea from August 2015 to October 2016. The annual average Pb concentrations were significantly higher in urban and rural areas (IC, 16.2 ng m⁻³ and TA, 11.1 ng m⁻³) than in remote area (JJ, 6.41 ng m⁻³), showing pronounced seasonal variations with relatively higher concentrations in winter and spring and lower concentrations in summer and autumn. Significantly high enrichment factors (EF) for Pb indicate that anthropogenic contributions are important for this toxic element in TSP. Coupling the Pb isotopic signatures with the air mass back trajectories identified the major potential source regions for individual samples. The results show that during winter, China was the dominant contributor, accounting for 92%, 82%, and 100% of the sampling periods at IC, TA, and JJ, respectively. The Chinese contribution decreased in summer and autumn, whereas the Korean contribution increased, according to the East Asian monsoon system. The Pb concentrations increased by 2.2 (IC), 1.2 (TA) and 1.4 (JJ) times when the Chinese contribution was dominant, compared to the Korea-dominant periods. The Pb isotopic systematics for the samples characterized by the dominant Korean contribution differed substantially between the three sites, implying that the relative importance of various domestic sources varied with geographical areas in western Korea.