Concerning PM2.5 concentrations, rapid industrialization, along with increase in cardiovascular disease (CVD) were recorded in Pakistan, especially in urban areas. The degree to which air pollution contributes to the increase in the burden of CVD in Pakistan has not been assessed due to lack of data. This study aims to describe the characteristics of PM2.5 constituents and investigate the impact of individual PM2.5 constituent on cardiovascular morbidity in Karachi, a mega city in Pakistan. Daily levels of twenty-one constituents of PM2.5 were analyzed using samples collected at two sites from fall 2008 to summer 2009 in Karachi. Hospital admission and emergency room visits due to CVD were collected from two large hospitals. Negative Binominal Regression was used to estimate associations between pollutants and the risk of CVD. All PM2.5 constituents were assessed in single-pollutant models and selected constituents were assessed in multi-pollutant models adjusting for PM2.5 mass and gaseous pollutants. The most common CVD subtypes among our participants were ischemic heart disease, hypertension, heart failure, and cardiomyopathy. Extremely high levels of PM2.5 constituents from fossil-fuels combustion and industrial emissions were observed, with notable peaks in winter. The most consistent associations were found between exposure to nickel (5–14% increase per interquartile range) and cardiovascular hospital admissions. Suggestive evidence was also observed for associations between cardiovascular hospital admissions and Al, Fe, Ti, and nitrate. Our findings suggested that PM2.5 generated from fossil-fuels combustion and road dust resuspension were associated with the increased risk of CVD in Pakistan.

In this study, reactive pyrite (FeS2) particles were prepared through a modified hydrothermal method and tested for immobilization of Cr(VI) in contaminated soil and synthetic groundwater. The addition of a NaAc buffer in the synthetic process resulted in pyrite particles of greater specific surface area, more uniform size, and more crystalline structure. The particles can effectively immobilize Cr(VI) in both water and a model Chinese loess soil. Over 99.9% of Cr(VI) was rapidly removed from water at pH 6.0 (Initial Cr(VI) = 25 mg/L, FeS2 dosage = 0.48 g/L), and the removal remained high (>82%) even at pH 9.5. Both adsorption and reductive precipitation were found operative in the Cr(VI) immobilization, with ∼66% of Cr immobilized due to reduction. Fe(II) ions associated on the FeS2 surface played a key role in the reduction of Cr(VI) to Cr(III), and S22− also facilitated the reductive removal of Cr(VI). The presence of humic acid enhanced Cr(VI) removal at pH 4.0, but the effect was negligible at pH 6.0. Batch kinetic tests showed that treating a Cr(VI)-laden soil with 0.48 g/L (as Fe) of FeS2 decreased the equilibrium water-leachable Cr(VI) by >99.0% at pH 6.0 and by >70.0% at pH 9.0. The distribution coefficient (Kd) value of the pyrite-amended soil was 1477.8 at pH 6.0, which is 306 times higher than for the untreated soil. Column elution tests showed that installation of a 3-cm reactive layer of FeS2 in a soil column was able to capture the leachable Cr(VI) from the soil, and the retardation factor (Rd) for the 3-cm FeS2 layer sample was 381 times higher than that for the plain soil. The synthetic pyrite particles may serve as an reactive material for effective removal or immobilization of Cr(VI) in contaminated water or soil.

A total of 152 groundwater samples were collected around a contaminated site to evaluate the carcinogenic and noncarcinogenic risks of exposure to twelve volatile chlorinated hydrocarbons (VCHs) by oral ingestion, dermal contact and inhalation absorption during showering. Although toxicity data of some VCHs are fragmentary, the results showed that the carcinogenic and noncarcinogenic risks of exposure to VCHs in contaminated drinking groundwater for local residents needs immediate attention. The main risk contributors for the carcinogenic and noncarcinogenic risks are carbon tetrachloride and 1,1,2-trichloroethane through inhalation exposure pathway, respectively. The health risk contribution rates associated with three exposure pathways for a specific VCH were intrinsic to the compound, and the dermal contact corresponded to a negligible contribution for almost every VCH species. Although most of the evaluated VCHs had a higher risk contribution by inhalation than by oral ingestion pathway, the integrated multi-VCH health risk contributions of the three exposure pathways were mainly dependent on the VCH compositions. Drinking boiled water not only decreased the exposure risk but also affected the risk contribution rates of three exposure pathways, which indicates that it is feasible to reduce the risk of VCH exposure during daily activities based on the risk contribution of the exposure pathways. In addition to the VCHs included in the drinking water standards, species such as 1,1,2,2-tetrachloroethane and hexachloroethane also showed a remarkable exposure health risk according to the standardized health risk calculation, which implied that improved drinking water standards are urgently required.

High water level fluctuations (WLFs) lead to periodic drying and re-inundation of sediments in the littoral area of eutrophic lakes. In this study, a series of littoral sediment cores were dried for different periods (5–30 d) and rewetted for 48 h. The sediment cores that dried for 30 d were then re-inundated for 90 d. The exchanges of nitrogen (N) and phosphorus (P) across the sediment–water interface (SWI) and the mechanisms were studied. The results showed that ammonium nitrogen (NH4+–N) fluxes increased after 5–25 d of drying, which was followed by an obvious decrease after 30 d of drying. The decreased NH4+–N fluxes remained at low levels during the 90 d re-inundation period. The soluble reactive P (SRP) fluxes decreased significantly after 15 d of drying. However, further re-inundation increased the SRP fluxes to their initial levels. The decreased water content and porosity, the oxidation of the sediment during drying, and the associated transformations of the N and P fractions in the sediment from drying to re-inundation influenced the exchanges of NH4+–N and SRP across the SWI. The decrease of labile NH4+–N in the sediment during drying was non-reversible, while the transformations between redox sensitive P (Fe-P) and aluminum-bound P were more likely to be reversible from drying to re-inundation. The increase of Fe-P during drying and dissolution of Fe-P during the re-inundation were responsible for the development of SRP fluxes from drying to re-inundation. Therefore, the periodic drying and re-inundation of the littoral eutrophic sediments reduced the release of NH4+–N but accelerated the release of SRP from the sediment. This should be given more consideration for the remediation and management of eutrophication in the lake and other similar lakes with high WLFs.

Metals in indoor dust pose potential health risks to humans. Dust deposition on air conditioner filters can represent the resuspended particulate matter in indoor air. However, few studies have examined this until now. This study investigated the total concentrations and different chemical fractionations of Cd, Cr, Mn, Ni, Pb, Sb, V, and Zn in indoor dust from three different functional zones (the Chief District, Commercial District (CmD), and Industrial District) in Hefei. The mean metal concentrations in indoor dust decreased in the following order: Zn > Mn > Pb > Cr > Ni > V > Cd > Sb. Cd, Pb, and Zn mainly existed in the mobile fraction. Cr and V mainly existed in the residual fraction. The enrichment factor and geo-accumulation index values of heavy metals were all ranked in the order of Cd > Zn > Pb > Sb > Ni > Cr > V, and these values in indoor dust were larger than those in outdoor dust. In addition, the enrichment patterns of these elements were similar in the three functional areas. The orders of non-carcinogenic risk (hazard index; HI) for the different functional areas for children were roughly the same, but there were clear differences for adults. In general, all the HIs were less than 1, which were within the internationally recognized safe range. The total carcinogenic risk (TR) was in the order of Cr > Pb > Cd for both children and adults in the three functional zones. The TRs from Cr exposure were not negligible. The TRs were significantly higher in the CmD.

Di(2-ethylhexyl) phthalate (DEHP), as a widely used plasticizer, is reported to have widespread environmental and global health hazards. Trace amounts of phthalates in the environment are sufficient to disrupt ecological balance and affect human health. However, DEHP-induced splenic toxicity remains in an unknown state. Therefore, to explore the mechanism of DEHP-induced splenic toxicity, male quail were employed with 0, 250, 500 and 750 mg/kg body weight DEHP by daily gastric perfusion for 45 days. Notably, splenic corpuscular border and cell gap enlargement were observed in the spleen tissue of DEHP-exposed quail under the histopathological analysis. Furthermore, DEHP induced dysregulation of oxidative stress markers by increasing malondialdehyde (MDA) content and decreasing superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activities. Low concentration of DEHP (≤250 mg/kg) exposure suppressed nuclear factor-E2-related factor 2 (Nrf2) signaling pathway, while high concentration of DEHP (≥500 mg/kg) exposure activated Nrf2-mediated defense response. DEHP induced splenic oxidative stress via interfering Nrf2 signal pathway and altering the transcription of its downstream genes. In conclusion, this study suggested that DEHP induced splenic toxicity.

China has one of the highest PM2.5 (particulate matter with an aerodynamic diameter smaller than 2.5 μm) pollution levels in the world. It might still be long before air quality reaches the National Class II standard of 35 μg/m3.We aim to estimate the potential reduction in premature mortality by reducing indoor PM2.5 levels in the Beijing-Tianjin-Hebei (BTH) region and compare it with reducing outdoor levels.We combined PM2.5 transport model and the Global Burden of Disease (2016) methodology to estimate potential reductions in premature mortality attributable to PM2.5 by reducing indoor PM2.5 to National Class I standard of 15 μg/m3, and compared with reducing outdoor PM2.5 to Government 2020 Interim target of 64 μg/m3 or National Class II standard of 35 μg/m3.A total of 74,000 (95% confidence interval (CI): 43,000–111,000) premature deaths were attributable to PM2.5 exposure in 2013. Thirty percent, or 22,000 (95% CI: 17,000–32,000) deaths, would have been averted if indoor PM2.5 had reached the National Class I standard. The benefit is greater than that from reaching the Government 2020 Interim target for outdoor PM2.5 [22%, or 16,000 (95% CI: 12,000–23,000), deaths], although still smaller than that from reaching the National Class II standard [42%, or 31,000 (95% CI: 24,000–45,000), deaths].Reaching the National Class I level of indoor PM2.5 at current outdoor pollution levels could bring considerable health benefits, which are comparable to those from reaching the Government 2020 Interim target for outdoor PM2.5.The avertable premature deaths gained from cleaning indoor PM2.5 to National Class I standard level would be greater than reducing outdoor PM2.5 to Government 2020 Interim target.

Microplastics (MPs) are now one of the major environmental problems due to the large amount released in aquatic and terrestrial ecosystems, as well as their diffuse sources and potential impacts on organisms and human health. Still the molecular and cellular targets of microplastics’ toxicity have not yet been identified and their mechanism of actions in aquatic organisms are largely unknown. In order to partially fill this gap, we used a mass spectrometry based functional proteomics to evaluate the modulation of protein profiling in zebra mussel (Dreissena polymorpha), one of the most useful freshwater biological model. Mussels were exposed for 6 days in static conditions to two different microplastic mixtures, composed by two types of virgin polystyrene microbeads (size = 1 and 10 μm) each one. The mixture at the lowest concentration contained 5 × 105 MP/L of 1 μm and 5 × 105 MP/L of 10 μm, while the higher one was arranged with 2 × 106 MP/L of 1 μm and 2 × 106 MP/L of 10 μm.Proteomics’ analyses of gills showed the complete lack of proteins’ modulation after the exposure to the low-concentrated mixture, while even 78 proteins were differentially modulated after the exposure to the high-concentrated one, suggesting the presence of an effect-threshold. The modulated proteins belong to 5 different classes mainly involved in the structure and function of ribosomes, energy metabolism, cellular trafficking, RNA-binding and cytoskeleton, all related to the response against the oxidative stress.

Because of its analgesic properties, acetaminophen (AAP) is widely used to relieve headache. AAP is generally considered safe for humans, but its effects on aquatic organisms are not well known. Here, we have hypothesis that effects of AAP on aquatic organisms would be environmental temperature dependent, because their physiological function depend on the temperature. To test this hypothesis, we used medaka (Oryzias latipes) as a model, because they can live at a wide range of temperatures (0–40 °C). We exposed medaka larvae to 0 (control), 50, or 150 mg/L of AAP at 15, 25 (optimal temperature), or 30 °C for 4 days. Egg yolk absorption was accelerated with raising temperature at any AAP dose. AAP exposure did not have biologically significant effects on survival ratio and body length of larvae at any tested temperature or dose, but heart rate decreased as the dose of AAP and environmental temperature increased. In addition, as the temperature increased, amount of ATP in individual larvae increased in control group, but decreased in AAP exposed group. Subsequently, exposure to 150 mg/L of AAP at 30 °C decreased the number of red blood cells in the gills; we used 150 mg/L of AAP in subsequent hematological and histological analyses. Hematological analysis showed that rising temperature increased the proportion of morphologically abnormal red blood cells in AAP-exposed larvae, suggesting that AAP induced anemia-like signs in larvae. Histological observation of the kidney, which is a hematopoietic organ in fish, revealed no abnormalities. However, in the liver, which is responsible for drug metabolism, the proportion of vacuoles increased with increasing temperature. Although the exposure concentration we tested was higher than environmentally relevant concentrations, our data indicated that rising temperature enhances the toxicity of AAP to medaka larvae, suggesting an ecological risk of AAP due to global warming.

Biomass burning (BB) is one of the largest sources of carbonaceous aerosols with adverse impacts on air quality, visibility, health and climate. BB emits a few specific aromatic acids (p-hydroxybenzoic, vanillic, syringic and dehydroabietic acids) which have been widely used as key indicators for source identification of BB-derived carbonaceous aerosols in various environmental matrices. In addition, measurement of p-hydroxybenzoic and vanillic acids in snow and ice cores have revealed the historical records of the fire emissions. Despite their uniqueness and importance as tracers, our current understanding of analytical methods, concentrations, diagnostic ratios and degradation processes are rather limited and scattered in literature. In this review paper, firstly we have summarized the most established methods and protocols for the measurement of these aromatic acids in aerosols and ice cores. Secondly, we have highlighted the geographical variability in the abundances of these acids, their diagnostic ratios and degradation processes in the environments. The review of the existing data indicates that the concentrations of aromatic acids in aerosols vary greatly with locations worldwide, typically more abundant in urban atmosphere where biomass fuels are commonly used for residential heating and/or cooking purposes. In contrast, their concentrations are lowest in the polar regions which are avoid of localized emissions and largely influenced by long-range transport. The diagnostic ratios among aromatic acids can be used as good indicators for the relative amounts and types of biomass (e.g. hardwood, softwood and herbaceous plants) as well as photochemical oxidation processes. Although studies suggest that the degradation processes of the aromatic acids may be controlled by light, pH and hygroscopicity, a more careful investigation, including closed chamber studies, is highly appreciated.