Data on fine particulate matter (PM2.5) in China were first announced in 2013. The primary objective of this study was to evaluate the acute effects of PM2.5 on asthma morbidity in Beijing, China. A total of 978,658 asthma hospital visits consisting of 928,607 outpatient visits, 40,063 emergency room visits and 9988 hospital admissions from January 1, 2010, to June 30, 2012, were identified from the Beijing Medical Claim Data for Employees. A generalized additive Poisson model was applied to explore the association between PM2.5 and health service use. The mean daily PM2.5 concentration was 99.5 μg/m3 with a range from 7.2 μg/m3 to 492.8 μg/m3. Ambient PM2.5 concentration was significantly associated with increased use of asthma-related health services. Every 10 μg/m3 increase in PM2.5 concentration on the same day was significantly associated with a 0.67% (95% CI, 0.53%–0.81%), 0.65% (95% CI, 0.51%–0.80%), and 0.49% (95% CI, 0.35%–0.64%) increase in total hospital visits, outpatient visits and emergency room visits, respectively. The exposure–response association between PM2.5 concentration and hospital visits for asthma exacerbations was approximately linear. In conclusion, this study found that short-term elevations in PM2.5 concentration may increase the risk of asthma exacerbations. Our findings contribute to the limited scientific literature concerning the acute effects of PM2.5 on asthma morbidity outcomes in developing countries.

Disinfectant used in drinking water treatment and distribution system can induce culturable bacteria, including various kinds of pathogenic bacteria, into viable but non-culturable (VBNC) state. The loss of cultural state, resuscitation and environmental persistence of VBNC bacteria will severely damage drinking water microbiological safety and thus pose a risk to public health. The manner in which chlorination treatment induced a VBNC state in Escherichia coli and the antibiotic persistence of VBNC bacteria was investigated. It was found that low dosage of chlorine (0.5 mg L−1) disinfection effectively reduced the culturability of E. coli and induced a VBNC state, after which metabolic activity was reduced and persistence to 9 typical antibiotics was enhanced. Furthermore, RT-qPCR results showed that stress resistance genes (rpoS, marA, ygfA, relE) and ARGs, especially efflux genes were up-regulated compared with culturable cells. The intracellular concentration was tested and found to be lower in VBNC cells than in actively growing E. coli, which suggested a higher efflux rate. The data presented indicate that VBNC E. coli are more persistent than culturable counterparts to a wide variety of antibiotics. VBNC E. coli constitute a potential source of contamination and should be considered during monitoring of drinking water networks.

The 22ⁿᵈ Asia-Pacific Economic Cooperation (APEC) Conference was held near Yanqi Lake, Huairou, in Beijing, China during November 10-11, 2014. To guarantee haze-free days during the APEC Conference, the Beijing government and the governments of the surrounding provinces implemented a series of controls. Three months of Aethalometer 880 nm black carbon (BC) measurements were examined to understand the hourly fluctuations in BC concentrations that resulted from emission controls and meteorology changes. Measurements were collected at the University of Chinese Academy of Sciences near the APEC Conference site and in Central Beijing at the Institute of Remote Sensing and Digital Earth of the Chinese Academy of Sciences. Synoptic conditions are successfully represented through analysis of backward trajectories in six cluster groups. The clusters are identified based on air mass transport from various areas such as Inner Mongolia, Russia, three northeastern provinces, and Hebei industrial areas, to the measurement sites. Air pollution control measures during the APEC Conference significantly reduced BC at the conference site (Huairou) and in Central Beijing, with greater reductions in BC concentrations at the conference site than in Central Beijing. The highest BC concentrations in Huairou were associated with air masses originating from Central Beijing rather than from the Hebei industrial region. The success of the control measures implemented in Beijing and the surrounding regions demonstrates that BC concentrations can be effectively reduced to protect human health and mitigate regional climate forcing. This study also demonstrates the need for regional strategies to reduce BC concentrations, since urban areas like Beijing are sources as well as downwind receptors of emissions.

Wheat is one of several cereals that is capable of accumulating higher amounts of Cd in plant tissues. It is important to understand the Cd²⁺ transport processes in roots that result in excess Cd accumulation. Traditional destructive technologies have limited capabilities in analyzing root samples due to methodological limitations, and sometimes may result in false conclusions. The mechanisms of Cd²⁺ uptake into the roots of wheat seedlings (Triticum aestivum L.) were investigated by assessing the impact of various inhibitors and channel blockers on Cd accumulation as well as the real-time net Cd²⁺ flux at roots with the non-destructive scanning ion-selective electrode technique. The P-type ATPase inhibitor Na3VO4 (500 μM) had little effect on Cd uptake (p < 0.05) and the kinetics of transport in the root of wheat, suggesting that Cd²⁺ uptake into wheat root cells is not directly dependent on H⁺ gradients. While, the uncoupler 2,4-dinitrophenol significantly limited Cd²⁺ uptake (p < 0.05) and transport kinetics in the root of wheat, suggesting the existence of metabolic mediation in the Cd²⁺ uptake process by wheat. The Cd content at the whole-plant level in wheat was significantly (p < 0.05) decreased upon pretreatment with the Ca²⁺ channel blockers La³⁺ or Gd³⁺ and Verapamil, but not in case of pretreatment with the K⁺ channel blocker tetraethylammonium (TEA). In addition, the inhibitors of the Ca²⁺ channel, as well as high concentrations of Ca²⁺, reduced the real-time net Cd²⁺ fluxes at the root surface in SIET experiments. These results indicate that Cd²⁺ moves across the plasma lemma of the wheat root via Ca²⁺ channels. In addition, our results suggested a role for protein synthesis in mediating Cd²⁺ uptake and transport by wheat.

The Catskill Mountains have been adversely impacted by decades of acid deposition, however, since the early 1990s, levels have decreased sharply as a result of decreases in emissions of sulfur dioxide and nitrogen oxides. This study examines trends in acid deposition, stream-water chemistry, and soil chemistry in the southeastern Catskill Mountains. We measured significant reductions in acid deposition and improvement in stream-water quality in 5 streams included in this study from 1992 to 2014. The largest, most significant trends were for sulfate (SO42−) concentrations (mean trend of −2.5 μeq L−1 yr−1); hydrogen ion (H+) and inorganic monomeric aluminum (Alim) also decreased significantly (mean trends of −0.3 μeq L−1 yr−1 for H+ and −0.1 μeq L−1 yr−1 for Alim for the 3 most acidic sites). Acid neutralizing capacity (ANC) increased by a mean of 0.65 μeq L−1 yr−1 for all 5 sites, which was 4 fold less than the decrease in SO42− concentrations. These upward trends in ANC were limited by coincident decreases in base cations (−1.3 μeq L−1 yr−1 for calcium + magnesium). No significant trends were detected in stream-water nitrate (NO3−) concentrations despite significant decreasing trends in NO3− wet deposition. We measured no recovery in soil chemistry which we attributed to an initially low soil buffering capacity that has been further depleted by decades of acid deposition. Tightly coupled decreasing trends in stream-water silicon (Si) (−0.2 μeq L−1 yr−1) and base cations suggest a decrease in the soil mineral weathering rate. We hypothesize that a decrease in the ionic strength of soil water and shallow groundwater may be the principal driver of this apparent decrease in the weathering rate. A decreasing weathering rate would help to explain the slow recovery of stream pH and ANC as well as that of soil base cations.

With China as the study area, MODIS MOD14A1 and MCD12Q1 products were used to derive daily crop residue burning spots from 2014 to 2015. After vectorization of crop residue burning pixels and with the use of fishnet, burning density distribution maps were eventually completed. Meanwhile, the daily air quality data from 150 cities in 2014 and 285 cities in 2015 were used to obtain daily and monthly PM2.5 distribution maps with the Kriging interpolation. The results indicate that crop residue burning occurs in a seasonal pattern, and its spatial distribution is closely related to farming activities. The annual PM2.5 in China decreased 11.81% from 2014 to 2015, and the distribution of PM2.5 in China's east and north is always higher than in China's west and south. Furthermore, the changes in PM2.5 exhibit a hysteresis after crop residue burning in summer and autumn-winter. Regarding summer crop residue burning in China's middle–east, the r between crop residue burning spots and PM2.5 is 0.6921 (P < 0.01) in 2014 and 0.5620 (P < 0.01) in 2015, while the correlation coefficient of autumn-winter crop residue burning in China's northeast is slightly lower with an r of 0.5670 (P < 0.01) in 2014 and 0.6213 (P < 0.01) in 2015. In autumn-winter, crop residue burning can induce evident PM2.5 increase in China's northeast, and that is more obvious than summer crop residue burning in China's middle–east. Furthermore, when data of summer and autumn-winter crop residue burning from 2014 to 2015 are compared, we can see that the change in number of crop residue burning spots significant changes PM2.5 in these regions. Both the summer and autumn-winter crop residue burning areas presented spatial consistency with high PM2.5. By contrast, the results from many aspects indicated that the crop residue burning in spring did not cause a notable change of PM2.5.

Rapidly growing global population adds significant strains on the fresh water resources. Consequently, saline water is increasingly tapped for crop irrigation. Meanwhile, rapid advancement of nanotechnology is introducing more and more engineered nanoparticles into the environment and in agricultural soils. While some negative effects of ENPs on plant health at very high concentrations have been reported, more beneficial effects of ENPs at relatively low concentrations are increasingly noticed, opening doors for potential applications of nanotechnology in agriculture. In particular, we found that cerium oxide nanoparticles (CeO2NPs) improved plant photosynthesis in salt stressed plants. Due to the close connections between salt stress tolerance and the root anatomical structures, we postulated that CeO2NPs could modify plant root anatomy and improve plant salt stress tolerance. This study aimed at testing the hypothesis with Brassica napus in the presence of CeO2NPs (0, 500 mg kg−1 dry sand) and/or NaCl (0, 50 mM) in a growth chamber. Free hand sections of fresh roots were taken every seven days for three weeks and the suberin lamellae development was examined under a fluorescence microscope. The results confirmed the hypothesis that CeO2NPs modified the formation of the apoplastic barriers in Brassica roots. In salt stressed plants, CeO2NPs shortened the root apoplastic barriers which allowed more Na+ transport to shoots and less accumulation of Na+ in plant roots. The altered Na+ fluxes and transport led to better physiological performance of Brassica and may lead to new applications of nanotechnology in agriculture.

Microcystin-leucine arginine (MC-LR) causes testicular inflammation and hinders spermatogenesis. However, the molecular mechanisms underlying the immune responses to MC-LR in the testis have not been elucidated in detail. In this study, we show that MC-LR induced immune responses in Sertoli cells (SC), germ cells (GC), and Leydig cells (LC) via activating phosphatidylinositol 3-kinase (PI3K)/AKT/nuclear factor kappa B (NF-κB), resulting in the production of pro-inflammatory cytokines and chemokines including tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and chemokine (C-X-C motif) ligand 10 (CXCL10). The observed effects were attributed to reduced activity of protein phosphatases 2A (PP2A) as a result of binding of MC-LR to the catalytic subunit of PP2A in SC and GC. By contrast, innate immune responses were triggered by Toll-like receptor 2 (TLR2) in LC because MC-LR could not enter into the LC and subsequently inhibit the PP2A activity. PI3K/AKT/NF-κB were also activated in SC, GC, and LC in vivo, with the enrichment of TNF-α, IL-6, MCP-1, and CXCL10 in the testis. Following chronic exposure, MC-LR-treated mice exhibited decreased sperm counts and abnormal sperm morphology. Our data demonstrate that MC-LR can activate innate immune responses in testicular cells, which provides novel insights to explore the mechanism associated with MC-LR-induced orchitis.

An increasing number of studies have been conducted to determine a possible linkage between maternal exposure to ambient fine particulate matter and effects on the developing human fetus that can lead to adverse birth outcomes, but, the present results are not consistent. A total of 23 studies published before July 2016 were collected and analyzed and the mean value of reported exposure to fine particulate matter (PM2.5) ranged from 1.82 to 22.11 We found a significantly increased risk of preterm birth with interquartile range increase in PM2.5 exposure throughout pregnancy (odds ratio (OR) = 1.03; 95% conditional independence (CI): 1.01–1.05). The pooled OR for the association between PM2.5 exposure, per interquartile range increment, and term low birth weight throughout pregnancy was 1.03 (95% CI: 1.02–1.03). The pooled ORs for the association between PM2.5 exposure per 10 increment, and term low birth weight and preterm birth were 1.05 (95% CI: 0.98–1.12) and 1.02 (95% CI: 0.93–1.12), respectively throughout pregnancy. There is a significant heterogeneity in most meta-analyses, except for pooled OR per interquartile range increase for term low birth weight throughout pregnancy. We here show that maternal exposure to fine particulate air pollution increases the risk of preterm birth and term low birth weight. However, the effect of exposure time needs to be further explored. In the future, prospective cohort studies and personal exposure measurements needs to be more widely utilized to better characterize the relationship between ambient fine particulate exposure and adverse birth outcomes.

Antibiotics are added to agricultural fields worldwide through wastewater irrigation or manure application, resulting in antibiotic contamination and elevated environmental risks to terrestrial environments and humans. Most studies focused on antibiotic detection in different matrices or were conducted in a hydroponic environment. Little is known about the transfer of antibiotics from antibiotic-contaminated irrigation wastewater and animal manure to agricultural soil and edible crops. In this study, we evaluated the transfer of five different antibiotics (tetracycline, sulfamethazine, norfloxacin, erythromycin, and chloramphenicol) to different crops under two levels of antibiotic-contaminated wastewater irrigation and animal manure fertilization. The final distribution of tetracycline (TC), norfloxacin (NOR) and chloramphenicol (CAP) in the crop tissues under these four treatments were as follows: fruit > leaf/shoot > root, while an opposite order was found for sulfamethazine (SMZ) and erythromycin (ERY): root > leaf/shoot > fruit. The growth of crops could accelerate the dissipation of antibiotics by absorption from contaminated soil. A higher accumulation of antibiotics was observed in crop tissues under the wastewater treatment than under manure treatment, which was due to the continual irrigation that increased adsorption in soil and uptake by crops. The translocation of antibiotics in crops mainly depended on their physicochemical properties (e.g. log Kow), crop species, and the concentrations of antibiotics applied to the soil. The levels of antibiotics ingested through the consumption of edible crops under the different treatments were much lower than the acceptable daily intake (ADI) levels.