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Comparison of arsenic fractions and health risks in PM2.5 before and after coal-gas replacement Full text
2020
Xie, Jiao-Jiao | Yuan, Chun-Gang | Xie, Jin | Niu, Xiao-Dong | Zhang, Xu-Rui | Zhang, Ke-Gang | Xu, Pei-Yao | Ma, Xiao-Ying | Lv, Xiang-Bing
Coal-Gas replacement project has been implemented to decrease haze pollution in China in recent years. Airborne arsenic (As) mostly originates from coal burning processes. It is noteworthy to compare the distribution of arsenic fraction in PM₂.₅ before and after coal-gas replacement. Eighty PM₂.₅ samples were collected in Baoding in December 2016 (coal dominated year) and December 2017 (gas dominated year) at different functional areas including residential area (RA), industrial area (IA), suburb (SB), roadside (ST) and Botanical Garden Park (BG). The fraction, bioavailability and health risk of As in the PM₂.₅ samples were investigated and compared between these two years. Arsenic was mainly distributed in the non-specifically sorbed fraction (F1) and the residual fraction (F5). However, the proportion of F1 to the total As in 2017 was higher than that in 2016, while the proportion of As in the amorphous and poorly-crystalline hydrous oxides of Fe and Al fraction (F3) in 2017 was lower. The distributions of fraction and bioavailability showed temporal and spatial characteristics. The total concentration and bioavailability of As in SB and IA were significantly higher than those in RA, ST and BG. The BF (Bioavailability Factor) values of As ranged from 0.30 to 0.61. Health risk assessment indicated that the hazard quotient (HQ) and carcinogenic risk (CR) of As in PM₂.₅ significantly decreased after coal-gas replacement.
Show more [+] Less [-]Biodegradation of phthalate esters by Paracoccus kondratievae BJQ0001 isolated from Jiuqu (Baijiu fermentation starter) and identification of the ester bond hydrolysis enzyme Full text
2020
Xu, Youqiang | Minhazul, Karim A.H.M. | Wang, Xiaocheng | Liu, Xiao | Li, Xiuting | Meng, Qi | Li, Hehe | Zhang, Chengnan | Sun, Xiaotao | Sun, Baoguo
Phthalate ester (PAE) pollution is an increasing problem globally. Paracoccus kondratievae BJQ0001 was isolated from the fermentation starter of Baijiu and showed an efficient degradation capability toward PAEs. To our poor knowledge, this is the first report of a P. kondratievae strain capable of degrading PAEs. The first complete genome sequence of P. kondratievae was presented without gaps, and composed of two circular chromosomes and one plasmid. The species simultaneously degraded di-methyl phthalate (DMP), di-ethyl phthalate (DEP), di-butyl phthalate (DBP), di-isobutyl phthalate (DIBP) and di-(2-ethylhexyl) phthalate (DEHP), with DMP and DEP as the preferred substrates. The half-life (t₁/₂) of DMP was only 6.34 h with an initial concentration of 200 mg/L. Combined with gene annotation and metabolic intermediate analysis, a metabolic pathway was proposed for the species. Benzoic acid, the intermediate of anaerobic PAE metabolism, was identified in the aerobic degradation process. Two key enzymes for alkyl ester bond hydrolysis were obtained, and belonged to families IV and VI of hydrolases, respectively. These results will promote the investigation of PAE degradation by P. kondratievae, and provide useful information for improving the quality control of food and environmental PAE treatment.
Show more [+] Less [-]China is implementing “Garbage Classification” action Full text
2020
Tong, Yeqing | Liu, Jiafa | Liu, Sizhe
In recent days, garbage classification has become a hot topic in China, and Shanghai took the lead in the implementation of garbage classification legislation in China. Starting from the current situation of garbage classification in China, this study emphasizes the garbage classification in terms of law, amount, economy, management, resourcing and successful experience of garbage classification in China, so as to provide inspiration and guidance for garbage classification for other countries.
Show more [+] Less [-]Evaluation of particulate matter (PM10) emissions and its chemical characteristics during rotary harrowing operations at different forward speeds and levelling bar heights Full text
2020
Maffia, Jacopo | Balsari, Paolo | Padoan, Elio | Ajmone-Marsan, Franco | Ricauda Aimonino, Davide | Dinuccio, Elio
Particulate matter (PM) is an air pollutant which poses a considerable risk to human health. The agricultural sector is responsible of the 15% of the total anthropogenic emissions of PM₁₀ (PM fraction with aerodynamic diameter below 10 μm) and soil preparation activities have been recognized as one of the main drivers of this contribution. The emission factors (EF) proposed by European environmental agency (EEA) for tilling operations are based on very few studies, none of which has been made in Italy. Moreover, few studies have considered the influence of operative parameters on PM₁₀ emissions during tilling. The aim of this work was to assess PM₁₀ emission and dispersion during rotary harrowing and to understand how operative parameters, such as forward speed and implement choice may affect PM release. A further objective was to assess the near field dispersion of PM₁₀ to address exposure risks. Emission factors (EFs) were determined during two different trials (T1 and T2). During T1, the effect of tractor speeds (0.6, 1.1 and 1.7 m s⁻¹) on PM₁₀ emissions was investigated, while in T2 a comparative essay was made to study the influence of levelling bar height on emissions. The average ground level downwind concentrations of PM₁₀ during harrowing operation was estimated through dispersion modelling. The observed PM₁₀ EFs for rotary harrowing were 8.9 ± 2.0 mg m⁻² and 9.5 ± 2.5 mg m⁻² on T1 and T2, respectively. The heavy metal content of soil-generated PM₁₀ was also assessed. In the generated PM, the elemental concentrations were higher than ones in soil. As, Cd and Ni concentration levels, determined in PM₁₀ near to the tractor path, were also high, being several times higher than the annual average regulatory threshold levels in ambient air, as defined by the European regulation.
Show more [+] Less [-]Hazardous impact of diclofenac exposure on the behavior and antioxidant defense system in Nauphoeta cinerea Full text
2020
Adedara, Isaac A. | Awogbindin, Ifeoluwa O. | Afolabi, Blessing A. | Ajayi, Babajide O. | Rocha, Joao B.T. | Farombi, Ebenezer O.
Environmental pollution by pharmaceuticals such as diclofenac (DCF) is globally acknowledged to be a threat to the ecosystems. Nauphoeta cinerea is an important insect with valuable ecological role. The present investigation aimed to elucidate the impact of DCF on insects by assessing the behavior and antioxidant defense response in nymphs of N. cinerea exposed to DCF-contaminated food at 0, 0.5, 1.0 and 2.0 μg kg⁻¹ feed for 42 successive days. Subsequent to exposure period, neurobehavioral analysis using video-tracking software in a novel apparatus was performed before estimation of biochemical endpoints in the head, midgut and hemolymph of the insects. Results indicated that DCF-exposed insects exhibited marked reduction in the maximum speed, total distance traveled, mobile episodes, total mobile time, body rotation, absolute turn angle and path efficiency, whereas the total freezing time was increased compared with the control. The diminution in the exploratory activities of DCF-exposed insects was substantiated by heat maps and track plots. Additionally, DCF elicited marked diminution in antioxidant enzyme and acetylcholinesterase (AChE) activities along with increase in nitric oxide (NO), reactive oxygen and nitrogen species (RONS), and lipid peroxidation (LPO) levels in the head, midgut and hemolymph of the insects. Taken together, DCF elicited neurotoxicity and oxido-inflammatory stress in exposed insects. N. cinerea may be a suitable model insect for environmental risk assessment of pharmaceuticals in non-target insect species.
Show more [+] Less [-]Analysis of wintertime O3 variability using a random forest model and high-frequency observations in Zhangjiakou—an area with background pollution level of the North China Plain Full text
2020
Liu, Huazhen | Liu, Junfeng | Liu, Ying | Ouyang, Bin | Xiang, Songlin | Yi, Kan | Tao, Shu
The short-term health effects of ozone (O₃) have highlighted the need for high-temporal-resolution O₃ observations to accurately assess human exposure to O₃. Here, we performed 20-s resolution observations of O₃ precursors and meteorological factors to train a random forest model capable of accurately predicting O₃ concentrations. Our model performed well with an average validated R² of 0.997. Unlike in typical linear model frameworks, variable dependencies are not clearly modelled by random forest model. Thus, we conducted additional studies to provide insight into the photochemical and atmospheric dynamic processes driving variations in O₃ concentrations. At nitrogen oxides (NOₓ) concentrations of 10–20 ppb, all the other O₃ precursors were in states that increased the production of O₃. Over a short timescale, nitrogen dioxide (NO₂) can almost track each high-frequency variation in O₃. Meteorological factors play a more important role than O₃ precursors do in predicting O₃ concentrations at a high temporal resolution; however, individual meteorological factors are not sufficient to track every high-frequency change in O₃. Nevertheless, the sharp variations in O₃ related to flow dynamics are often accompanied by steep temperature changes. Our results suggest that high-temporal-resolution observations, both ground-based and vertical profiles, are necessary for the accurate assessment of human exposure to O₃ and the success and accountability of the emission control strategies for improving air quality.
Show more [+] Less [-]Extracellular polymeric substances alter cell surface properties, toxicity, and accumulation of arsenic in Synechocystis PCC6803 Full text
2020
Naveed, Sadiq | Yu, Qingnan | Zhang, Chunhua | Ge, Ying
Arsenic (As) contamination of water poses severe threats to human health and thus requires effective remediation methods. In this study, Synechocystis PCC6803, a model cyanobacterium common in aquatic environments, was used to investigate the role of extracellular polymeric substances (EPS) in As toxicity, accumulation, and transformation processes. We monitored the growth of Synechocystis with As exposure, measured the zeta potential and binding sites on the cell surface, and analysed As accumulation and speciation in Synechocystis cells with and without EPS. After EPS removal, the binding sites and zeta potential of the cell surface decreased by 44.43% and 31.9%, respectively. The growth of Synechocystis decreased 49.4% and 43.7% with As⁽ᴵᴵᴵ⁾ and As⁽ⱽ⁾ exposure, and As accumulation in the cells decreased by 12.8–44.5% and 14–42.7%, respectively. As absorption was enhanced in cells with EPS removed. The oxidation of As⁽ᴵᴵᴵ⁾ and reduction of As⁽ⱽ⁾ were significantly greater in cells with intact EPS compared to those with EPS removed. Fourier transform infrared spectroscopy (FTIR) showed that functional groups of EPS and Synechocystis cells, including –NH, –OH, CO, and CC, interacted with As species. Together the results of this work demonstrate that EPS have significant impacts on cell surface properties, thereby affecting As accumulation and transformation in Synechocystis PCC6803. This work provides a basis for using EPS to remedy As pollution in aquatic environments.
Show more [+] Less [-]Bisphenol A exposure induces gut microbiota dysbiosis and consequent activation of gut-liver axis leading to hepatic steatosis in CD-1 mice Full text
2020
Feng, Dan | Zhang, Hongmin | Jiang, Xin | Zou, Jun | Li, Qingrong | Mai, Haiyan | Su, Dongfang | Ling, Wenhua | Feng, Xiang
Interactions between the intestine and the liver, the so-called ‘gut-liver axis’, play a crucial role in the onset of hepatic steatosis and non-alcoholic fatty liver disease. However, not much is known about the impact of environmental pollutants on the gut-liver axis and consequent hepatic steatosis. Bisphenol A (BPA), a widely used plasticiser, is an important environmental contaminant that affects gut microbiota. We hypothesised that BPA induces hepatic steatosis by promoting gut microbiota dysbiosis and activating the gut-liver axis. In this study, male CD-1 mice were fed with diet containing BPA (50 μg/kg body weight/day) for 24 weeks. Dietary exposure to BPA increased lipid contents and fat accumulation in the liver. Analysis of 16 S rRNA gene sequencing revealed that the diversity of gut microbiota reduced and the composition of gut microbiota was altered in the BPA-fed mice. Further, the abundance of Proteobacteria, a marker of dysbacteria, increased, whereas the abundance of Akkermansia, a gut microbe associated with increased gut barrier function and reduced inflammation, markedly decreased. Expression levels of intestinal tight junction proteins (zona occludens-1 and occludin) also decreased drastically, leading to increased intestinal permeability and elevated levels of endotoxins. Furthermore, BPA up-regulated the expression of Toll-like receptor 4 (TLR4) and phosphorylation of nuclear factor-kappa B (NF-κB) in the liver and increased the production of inflammatory cytokines, including interleukin-1β, interleukin-18, tumour necrosis factor-α, and interleukin-6. Take together, our work indicated that dietary intake of BPA induced hepatic steatosis, and this was closely related to dysbiosis of gut microbiota, elevated endotoxin levels, and increased liver inflammation through the TLR4/NF-κB pathway.
Show more [+] Less [-]Personal black carbon and ultrafine particles exposures among high school students in urban China Full text
2020
Zhou, Ying | Shao, Yijun | Yuan, Yue | Liu, Jian | Zou, Xiaoli | Bai, Pinqing | Ming, Zhan | Zhang, Peng | Vlaanderen, Jelle | Vermeulen, Roel | Downward, George S.
Air pollution is a major public health challenge in the highly urbanized megacities of China. However, knowledge on exposure to ambient unregulated air pollutants such as black carbon (BC) and ultrafine particles (UFP) among the Chinese population, especially among urban high school students who may have highly variable time-activity patterns, is scarce. To address this, the personal exposures to BC and UFP of high school students (aged 17 to 18) in Chengdu, China were measured at 1-min intervals via portable samplers. Monitoring lasted for 2 consecutive 24-h periods with days classified as “school days” or “non-school days”. Time-activity diaries and measurements were combined to explore spatial, temporal, and behavioral factors that contribute to different exposure profiles. The overall geometric means of BC and UFP were 3.60 μg/m³ and 1.83 × 10⁴p/cm³, respectively with notable spatiotemporal variation in exposures observed. In general, the household and transport microenvironments were the predominant contributors to total BC (74.5%) and UFP (36.5%) exposure. However, the outdoor public microenvironment was found to have significantly higher overall average levels of BC than the household and transport microenvironments (p < 0.001) while also presenting the greatest exposure dose intensity (EDI – a measure of exposure in a microenvironment in proportion to time spent in that environment) of 4.79. The largest overall average level of UFP occurred in the indoor public microenvironment followed by transport. The outdoor public microenvironment also presented the greatest EDI of UFP (4.17). This study shows notable spatiotemporal variety in exposure patterns and will inform future exposure and population health studies. The high EDI outdoors may mean that health positive activities, such as exercise, may be being undermined by ambient pollution.
Show more [+] Less [-]Associations between selected perfluoroalkyl acids in serum and hemoglobin in whole blood, a biomarker of anemia: Impact of deteriorating kidney function Full text
2020
Jain, Ram B.
Data (N = 11251) from National Health and Nutrition Examination Survey (NHANES) for 2003–2016 for US adults aged ≥20 years were stratified by gender and anemia and analyzed to evaluate the associations between the concentrations of whole blood hemoglobin (WBHGB) and selected perfluoroalkyl acids (PFAAs) in serum by stages of glomerular filtration (GF). Investigated PFAAs were perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorodecanoic acid (PFDA), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA). Females with whole blood hemoglobin concentrations <12 g/dL and males with whole blood hemoglobin concentrations <13 g/dL were classified as being anemic. Regression models with log10 transformed concentrations of whole blood hemoglobin as dependent variable and age, poverty income ratio, body mass index, serum cotinine, daily alcohol intake, survey year, and log10 concentrations of one of the PFAA as independent variables were fitted. For anemic females, association between WBHGB and PFAA concentrations were uniformly positive across worsening stages of renal failure and percent increases for 10% increases in PFAAs varied between 0.03% and 0.39%. For anemic males, association between WBHGB and PFAA concentrations were positive except at GF-3A (45 ≤ eGFR<60 mL/min/1.73 m²) and percent increases for 10% increases in PFAAs varied between 0.02% and 0.53%. Thus, more often than not, presence of positive associations between WBHGB and PFAA among anemics imply elevated levels of PFAA are associated with higher levels of WBHGB. Similar results were observed for non-anemic males and females, however strengths of associations between whole blood hemoglobin and PFAAs were several fold higher among anemic compared to non-anemic participants. Hemoglobin is consistently associated with serum PFAAs.
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