Air pollution is associated with risks of mortality in China, but the evidence is still limited for morbidity. This study aims to examine overall effects of ambient air pollutants on emergency hospital visits (EHVs) at the national level in China and calculate corresponding attributable risks. We collected daily data for EHVs from 33 largest hospitals in China between Oct 2013 and Dec 2014, as well as daily measurements of particulate matter (PM10 and PM2.5: particles with aerodynamic diameter < 10 μm and 2.5 μm, respectively), nitrogen dioxide (NO2) and sulphur dioxide (SO2) from 31 cities where the hospitals were located. Firstly, quasi-Poisson regression with a constrained distributed lag model (CDLM) was employed to examine city-specific associations of EHVs with each pollutant. Then, the effects at the national scale were pooled with a random-effect meta-analysis. Daily EHVs was significantly associated with a 10 μg/m3 increase in PM2.5 at lag 0–2 days [cumulative relative risk (RR) and 95% confidence intervals (CI): 1.006 (1.002, 1.009)], PM10 at lag 0–1 days [1.004 (1.002, 1.006)], NO2 at lag 0–1 days [1.015 (1.010, 1.019)] and SO2 at lag 0–2 days [1.022 (1.014, 1.030)]. The effect estimates were not modified by sex, but stronger effects were observed among children than adults. Overall, 3.34% of EHVs may result from exposure to ambient PM2.5, 3.96% to PM10, 5.90% to NO2 and 5.38% to SO2. Exposure to outdoor air pollution has acute effects on EHVs. Effective measures to control air pollution levels in China could potentially reduce demands for emergency hospital services.

The exposure to legacy polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDDs) and unrestricted 1,2-bis (2,4,6-tribromophenoxy) ethane (BTBPE), bis (2-ethylhexyl)-2,3,4,5-tetrabromophthalate (BEH-TEBP) and 2-ethylhexyl-2,3,4,5-tetrabromo-benzoate (EH-TBB) was examined in tail feathers of 76 birds belonging to ten predatory species inhabiting Pakistan. In addition, different feather types of six individuals of Black kite (Milvus migrans) were compared for their brominated flame retardant (BFR) levels. Black kite was found to be the most contaminated species with a median (minimum-maximum) tail feather concentration of 2.4 (0.70–7.5) ng g−1 dw for ∑PBDEs, 1.5 (0.5–8.1) ng g−1 dw for ∑HBCDDs and 0.10 (<LOQ-0.1) ng g−1 dw for BTBPE. Among unrestricted BFRs, BTBPE was detected only in Black kite and Little owl (Athene noctua), whereas BEH-TEBP and EH-TBB were not detected in any species. BDE-47 was found to be the most prevalent BFR compound in aquatic species, while BDE-99 and -153 were more abundant in terrestrial species. For HBCDDs, α-isomer was generally recorded as the most prevalent BFR in both terrestrial and aquatic species. The concentrations of BFRs differed significantly (all P < 0.01) among species, trophic guilds and between habitats, the latter for PBDEs only (P < 0.04), whereas differences among taxonomic affiliations and groups with different feeding regimes were not significant (P > 0.05 for both). Similarly, no significant concentration differences were observed among different feather types (all P > 0.05) suggesting their similar exposure. While variables such as species, trophic guild and δ15N values were evaluated as major predictors for BFR accumulation in the studied species, we predict that combined effects of just mentioned factors may govern the intra- and interspecific differences in BFR contamination profiles. We urge for further investigation of BFR exposure and potential toxicological effects in predatory birds from Asia with a more extensive sample size per species and location.

Diverse antibiotic-resistance genes (ARGs) are frequently reported to have high prevalence in veterinary manure samples due to extensive use of antibiotics in farm animals. However, the characteristics of the distribution and transmission of ARGs among bacteria, especially among different species of multiple antibiotic-resistant bacteria (MARB), have not been well explored. By applying high-throughput sequencing methods, our study uncovered a vast MARB reservoir in livestock manure. The genera Escherichia, Myroides, Acinetobacter, Proteus, Ignatzschineria, Alcaligenes, Providencia and Enterococcus were the predominant cultivable MARB, with compositions of 40.6%–85.7%. From chicken manure isolates, 33 MARB were selected for investigation of the molecular characteristics of antibiotic resistance. A total of 61 ARGs and 18 mobile genetic elements (MGEs) were investigated. We found that 47 ARGs were widely distributed among the 33 MARB isolates. Each isolate carried 27–36 genes responsible for resistance to eight classes of antibiotics frequently used in clinic or veterinary settings. ARGs to the six classes of antibiotics other than streptogramins and vancomycin were present in all 33 MARB isolates with a prevalence of 80%–100%. A total of 12 MGEs were widely distributed among the 33 MARB, with intI1, IS26, ISaba1, and ISEcp1 simultaneously present in 100% of isolates. In addition, 9 gene cassettes within integrons and ISCR1 were detected among MARB isolates encoding resistance to different antibiotic classes. This is the first report revealing the general co-presence of multiple ARGs, various MGEs and ARG cassettes in different species of individual MARB isolates in chicken manure. The results highlight a much higher risk of ARGs spreading through livestock manure to humans than we expected.

In this study, the feasibility of employing an integrated bioremediation approach in contaminated river sediment was evaluated. Sequential addition of co-substrate (acetate) and electron acceptor (NO3−) in a two-phase treatment was capable of effectively removing polycyclic aromatic hydrocarbons (PAHs) in river sediment. The residual concentration of total PAHs decreased to far below effect range low (ERL) value within 91 days of incubation, at which concentration it could rarely pose biological impairment. The biodegradation of high molecular weight PAHs were found to be mainly occurred in the sediment treated with co-substrates (i.e. acetate or methanol), in which acetate was found to be more suitable for PAHs degradation. The role of co-substrates in influencing PAHs biodegradation was tentatively discussed herein. Additionally, the sediment odorous problem and blackish appearance were intensively addressed by NO3− injection. The results of this study demonstrated that integrating two or more approaches/processes would be a helpful option in sediment remediation. It can lead to a more effective remediation performance, handle multiple contamination issues, as well as mitigate environmental risks caused by one of the single methods.

Worsening air pollution is a serious threat to public health in many urban and heavily industrialized areas. Particle size and chemical composition are well known determinants of the pathological response to air pollution. In addition, pathological responses may depend on the exposure profile (or scenario) of air pollution. For instance, we previously demonstrated that repeated exposure to low levels of fine airborne particulate matter (PM2.5) induced distinct epigenetic changes compared to acute high-doses exposure. In the present study, we evaluated the differential pathological responses of BEAS-2B human bronchial epithelial cells to two distinct PM2.5 exposure scenarios: 24-h exposure to high-doses PM2.5 (0, 6, 12, 24, 48, 96 μg/cm2) and 10 days’ repeated exposure to low levels of PM2.5 (0, 1.5, 3, 6 μg/cm2). Acute exposure to high concentrations of PM2.5 caused ROS burst, marked DNA damage, dysfunction of the endoplasmic reticulum (ER) stress response, autophagy and necrotic cell death. In contrast, repeated low levels of PM2.5 led to sustained low-grade ROS accumulation, milder DNA damage, ER stress/unfolded protein response (UPR), S-phase arrest, apoptosis, and autophagy. Notably, most cells surviving repeated low-level exposure showed a series of abnormal adaptive responses, such as inhibition of mitochondria biogenesis and epigenetic dysregulation. These results indicate that different PM2.5 exposure scenarios induce distinct forms cytotoxicity and adaptive response. In addition to particle size and chemical composition, exposure scenario may be a critical factor determining the toxic health effects of PM2.5.

Interactions with pollutants and environmental factors are poorly studied for physiological traits. Yet physiological traits are important for explaining and predicting interactions at higher levels of organization. We investigated the single and combined impact of the pesticide chlorpyrifos, predation risk and warming on endpoints related to oxidative stress in the damselfly Enallagma cyathigerum. We thereby integrated information on reactive oxygen species (ROS), antioxidant enzymes and oxidative damage. All three treatments impacted the oxidative stress levels and for most traits the pesticide interacted antagonistically with warming or predation risk. Chlorpyrifos exposure resulted in increased ROS levels, decreased antioxidant defence and increased oxidative damage compared to the control situation. Under warming, the pesticide-induced increase in oxidative stress was less strong and the investment in antioxidant defence higher. Although both the pesticide and predation risk increased oxidative damage, the effects of the pesticide on oxidative damage were less strong in the presence of predator cues (at 20 °C). Despite the weaker pesticide-induced effects under predation risk, the combination of the pesticide and predator cues consistently caused the highest ROS levels, the lowest antioxidant defence and the highest oxidative damage, indicating the importance of cumulative stressor effects for impairing fitness. Our results provide the first evidence for antagonistic interactions of warming and predation risk with a pollutant for physiological traits. We identified two general mechanisms that may generate antagonistic interactions for oxidative stress: cross-tolerance and the maximum cumulative levels of damage.

Dissolved humic acid (HA) is ubiquitous in natural waters. Its presence significantly changes the photo-and bio-degradation of some organic pollutants in natural waters. The effects of photobleaching on the composition, photosensitizing property and bioavailability of HA were investigated here along with the subsequent influence on its photochemical and biological reactivity in mediating 17α-ethynylestradiol (EE2) degradation. Photobleaching transformed the refractory HA into some small molecules, including organic acids and aliphatics. Along with composition alteration, the photochemical reactivity of HA towards EE2 was slightly depressed, with 9% of the removal rate inhibited by a 70-h photobleaching. Contrarily, the reactivity of HA in mediating EE2 biodegradation by E. coli was significantly promoted by a short-term photobleaching. Compared to the biodegradation of EE2 in the pristine HA, the 10-h photobleached HA increased the biodegradation removal rate of EE2 by 25%, reaching its peak value of about 60%. However, the EE2 biodegradation was inhibited by further irradiation, and the removal rate of EE2 decreased to that in the pristine HA systems. Because no substrate competition was found between EE2 and formate or glucose, EE2 biodegradation mediated by HA in natural waters may not be affected by coexistent organics. Photodegradation and biodegradation of EE2 mediated by HA thus can be combined together by photobleaching to remove pollutants from natural waters. The results reported here could assist environmental risk assessment with respect to EE2 in natural aquatic systems.

A study of 16 United States Environmental Protection Agency (USEPA) priority listed PAHs associated with particulate matter ≤ 10 μm (PM10) was conducted in Singapore during the period 29th May 2015 to 28th May 2016. The sampling period coincided with an extensive, regional smoke haze episode (5th September to 25th October) that occurred as a result of forest and peat fires in neighboring Indonesia. Throughout this study, 54 atmospheric PM10 samples were collected in 24 h periods using a high volume sampler (HVS) and quarts fiber filters (QFF) as the collection medium. Hysplit software for computing 3-D backward air mass trajectories, diagnostic ratio analysis and ring number distribution calculations were used to examine the sources of PAHs in the atmosphere in Singapore. Under normal conditions the total PAH concentrations were in a range from 0.68 ng m−3 to 3.07 ng m−3, while for the high haze period the results showed approximately double the concentrations with a maximum value of 5.97 ng m−3. Diagnostic ratio (DR) and principal component analysis (PCA) were conducted and indicated the contribution of the traffic as a dominant pyrogenic source of PAHs during normal periods, while results from the haze dataset showed relatively strong influence of smoke from peat and forest fires in Indonesia. Environmental and health risk from PAHs were assessed for both regular and hazy days.

Aquatic ecosystems of the Bolivian Altiplano (∼3800 m a.s.l.) are characterized by extreme hydro-climatic constrains (e.g., high UV-radiations and low oxygen) and are under the pressure of increasing anthropogenic activities, unregulated mining, agricultural and urban development. We report here a complete inventory of mercury (Hg) levels and speciation in the water column, atmosphere, sediment and key sentinel organisms (i.e., plankton, fish and birds) of two endorheic Lakes of the same watershed differing with respect to their size, eutrophication and contamination levels. Total Hg (THg) and monomethylmercury (MMHg) concentrations in filtered water and sediment of Lake Titicaca are in the lowest range of reported levels in other large lakes worldwide. Downstream, Hg levels are 3–10 times higher in the shallow eutrophic Lake Uru-Uru than in Lake Titicaca due to high Hg inputs from the surrounding mining region. High percentages of MMHg were found in the filtered and unfiltered water rising up from <1 to ∼50% THg from the oligo/hetero-trophic Lake Titicaca to the eutrophic Lake Uru-Uru. Such high %MMHg is explained by a high in situ MMHg production in relation to the sulfate rich substrate, the low oxygen levels of the water column, and the stabilization of MMHg due to abundant ligands present in these alkaline waters. Differences in MMHg concentrations in water and sediments compartments between Lake Titicaca and Uru-Uru were found to mirror the offset in MMHg levels that also exist in their respective food webs. This suggests that in situ MMHg baseline production is likely the main factor controlling MMHg levels in fish species consumed by the local population. Finally, the increase of anthropogenic pressure in Lake Titicaca may probably enhance eutrophication processes which favor MMHg production and thus accumulation in water and biota.

Information on naturally occurring thyroid disease in wild animals in general and in small mammals specifically is extremely limited. In the present field-based work, we investigated the structure and function of thyroid glands of deer mice (Peromyscus maniculata) studied as sentinels of ecosystem sustainability on reclaimed areas post-mining on the oil sands of northeastern Alberta, because of their greater sensitivity to contaminants relative to meadow voles (Microtus pennsylvanicus) on the same sites. Extraction of bitumen in the oil sands of northeastern Alberta, results in the release of contaminants including polycyclic aromatic compounds (PACs), metals, and metalloids to the environment that have a measurable biological cost to wildlife living in the affected areas. In previous investigations, deer mice exposed to pollution at reclaimed areas showed compromised ability to regenerate glutathione indicating oxidative stress, together with decreased testicular mass and body condition during the breeding season. In the present study, thyroid glands from those deer mice from the reclaimed site had markedly increased follicular cell proliferation and decreased colloid compared to animals from the reference site. This pathology was positively associated with the greater oxidative stress in the deer mice. Thyroid hormones, both thyroxine and triiodothyronine, were also higher in animals with greater oxidative stress indicating increased metabolic demands from contaminant related subclinical toxicity. This work emphasizes the value of using a combination of endocrinological, histological and oxidative stress biomarkers to provide sensitive measures of contaminant exposure in small mammals on the oil sands.