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Distribution of total mercury and methylmercury and their controlling factors in the East China Sea
2020
Liu, Chang | Chen, Lufeng | Liang, Shengkang | Li, Yanbin
Mercury (Hg) is among contaminants of public concern due to its prevalent existence, high toxicity, and bioaccumulation through food chains. Elevated Hg has been detected in seafood from the East China Sea (ECS), which is one of the largest marginal seas and an important fishing region in the northwestern Pacific Ocean. However, there is still a lack of knowledge on the distribution of Hg species and their controlling factors in the ECS water column, thus preventing the understanding of Hg cycling and the assessment of Hg risks in the ECS. In this study, two cruises were conducted in October 2014 and June 2015 in order to investigate the distribution of total Hg (THg) and methylmercury (MeHg) and their controlling factors in the ECS. The concentrations of THg and MeHg were determined to be 4.2 ± 2.8 ng/L (THg) and 0.25 ± 0.13 ng/L (MeHg) in water from the ECS. The level of Hg in the ECS occupied the higher rank among the marginal seas, thus indicating significant Hg contamination in this system. Both the THg and MeHg presented complicated spatial distribution patterns in the ECS, with high concentration areas located in both the nearshore and offshore areas. Statistical analyses suggest that temperature (T) and Hg in sediment may be the controlling factors for THg distribution, while dissolved organic matter (DOM), T, and MeHg in the sediment may be the controlling factors for MeHg distribution in the seawater of the ECS. The relative importance of these environmental factors in Hg distribution depends on the water depth. T-salinity (S) diagram analyses showed that water mass mixing may also play an important role in controlling THg and MeHg distribution in the coastal ECS.
Afficher plus [+] Moins [-]Spatiotemporal variations and driving factors of dust storm events in northern China based on high-temporal-resolution analysis of meteorological data (1960–2007)
2020
Xu, Chuanqi | Guan, Qingyu | Lin, Jinkuo | Luo, Haiping | Yang, Liqin | Tan, Zhe | Wang, Qingzheng | Wang, Ning | Tian, Jing
Northern China is a significant source of dust source in Central Asia. Thus, high-resolution analysis of dust storms and comparison of dust sources in different regions of northern China are important to clarify the formation mechanism of East Asian dust storms and predict or even prevent such storms. Here, we analyzed spatiotemporal trends in dust storms that occurred in three main dust source regions during 1960–2007: Taklimakan Desert (western region [WR]), Badain Jaran and Tengger Deserts (middle region [MR]), and Otindag Sandy Land (eastern region [ER]). We analyzed daily dust storm frequency (DSF) at the 10-day scale (first [FTDM], middle [MTDM], and last [LTDM] 10 days of a month), and investigated the association of dust storm occurrences with meteorological factors. The 10-day DSF was greatest in the FTDM (accounting for 77.14% of monthly occurrences) in the WR, MTDM (45.85%) in the MR, and LTDM (72.12%) in the ER, showing a clear trend of movement from the WR to the ER. Temporal analysis of DSF revealed trend changes over time at annual and 10-day scales, with mutation points at 1985 and 2000. We applied single-factor and multiple-factor analyses to explore the driving mechanisms of DSF at the 10-day scale. Among single factors, a low wind-speed threshold, high solar radiation, and high evaporation were correlated with a high DSF, effectively explaining the variations in DSF at the 10-day scale; however, temperature, relative humidity, and precipitation poorly explained variations in DSF. Similarly, multiple-factor analysis using a classification and regression tree revealed that maximum wind speed was a major influencing factor of dust storm occurrence at the 10-day scale, followed by relative humidity, evaporation, and solar radiation; temperature and precipitation had weak influences. These findings help clarify the mechanisms of dust storm occurrence in East Asia.
Afficher plus [+] Moins [-]Short-term associations between size-fractionated particulate air pollution and COPD mortality in Shanghai, China
2020
Peng, Li | Xiao, Shaotan | Gao, Wei | Zhou, Yi | Zhou, Ji | Yang, Dandan | Ye, Xiaofang
Particulate air pollution is a continuing challenge in China, and its adverse effects on chronic obstructive pulmonary disease (COPD) have been widely reported. However, epidemiological evidence on the associations between size-fractionated particle number concentrations (PNCs) and COPD mortality is limited. In this study, we utilized a time-series approach to investigate the associations between PNCs of particles at 0.25–10 μm in diameter and COPD mortality in Shanghai, China. Quasi-Poisson regression generalized additive models were applied to evaluate these associations, with adjustment of time trend, day of week, holidays, temperature and relative humidity. Stratification analyses were performed by season and gender. There were a total of 3238 deaths due to COPD during the study period. We found that daily COPD deaths were significantly associated with PNCs of particles <0.5 μm, and the magnitude of associations increased with decreasing particle size. An interquartile range (IQR) increase in PNC₀.₂₅—₀.₂₈, PNC₀.₂₈—₀.₃, PNC₀.₃—₀.₃₅, PNC₀.₃₅—₀.₄, PNC₀.₄—₀.₄₅ and PNC₀.₄₅—₋₀.₅ was associated with increments of 7.51% (95%CI: 2.45%, 12.81%), 7.22% (95%CI: 2.16%, 12.53%), 6.95% (95%CI: 1.81%, 12.35%), 6.26% (95%CI: 1.25%, 11.52%), 5.24% (95%CI: 0.56%, 10.13%) and 4.15% (95%CI: 0.14%, 8.32%), respectively. The associations remained robustness after controlling for the mass concentrations of gaseous air pollutants. In stratification analyses, significant associations between PNCs and COPD mortality were observed in the cold seasons, and in males. Our results suggested that particles <0.5 μm in diameter might be most responsible for the adverse effects of particulate air pollution on COPD mortality, and COPD patients are more susceptible to PM air pollution in the cold seasons, especially for males.
Afficher plus [+] Moins [-]Incorporation of solar-thermal energy into a gasification process to co-produce bio-fertilizer and power
2020
Ansari, Shahid H. | Ahmed, Ashfaq | Razzaq, Abdul | Hildebrandt, Diane | Liu, Xinying | Park, Young-Kwon
Biomass integrated gasification combined cycle (IGCC) is attracting increased interest because it can achieve high system energy efficiency (>50%), which is predicted to increase with the increase in the solar share in biomass IGCC. This study evaluated the potential of crop residues numerically for the co-production of power and bio-fertilizer using ASPEN Plus® simulation software. The results showed that the gas yield increases with increasing temperature and decreasing pressure while the yield of bio-fertilizer is dependent on the biomass composition. The biomass with a low ash content produces high bio-fertilizer at the designated gasification temperature. The IGCC configuration conserves more energy than a directly-fired biomass power plant. In addition, the solar-assisted IGCC attains a higher net electricity output per unit of crop residue feed and achieves net thermal efficiencies of around 53%. The use of such hybrid systems offer the potential to produce 0.55 MW of electricity per unit of solar-thermal energy at a relatively low cost. The ASPEN Plus model predicted that the solar biomass-based IGCC set up is more efficient in increasing the power generation capacity than any other conversion system. The results showed that a solar to electricity efficiency of approximately 55% is achievable with potential improvements. This work will contribute for the sustainable bioenergy production as the relationship between energy production and biomass supplies very important to ensure the food security and environmental sustainability.
Afficher plus [+] Moins [-]Effects of L-Glufosinate-ammonium and temperature on reproduction controlled by neuroendocrine system in lizard (Eremias argus)
2020
Zhang, Luyao | Chen, Li | Meng, Zhiyuan | Jia, Ming | Li, Ruisheng | Yan, Sen | Tian, Sinuo | Zhou, Zhiqiang | Diao, Jinling
In the context of global warming, an important issue is that many pesticides become more toxic, putting non-target organisms at higher risk of pesticide exposure. Eremias argus (a native Chinese lizard) was selected as animal model in this study. As a kind of poikilothermic vertebrate, E.argus is sensitive to temperature change. The experimental design [(with or without L-Glufosinate-ammonium (L-GLA) pollution × two temperatures (25 and 30 °C)] was used in this study for 90 days to identify the chronic effects of the pesticide–temperature interaction on the lizards’ neuroendocrine-regulated reproduction. Survival rate, body weight, clutch characteristics, testicular histopathology, the content of neurotransmitters and related enzyme activity, the level of sex steroid, the expression of Heat shock protein 70 (HSP70), antioxidant system, the accumulation and degradation of L-GLA were examined. Results showed that L-GLA disrupt reproduction of lizards through hypothalamus-pituitary-gonad (HPG) axis. In addition, temperature can not only change the environmental behavior of pesticides, but also alter the physiological characteristics of lizards. Thus, our results emphasized that temperature is an essential abiotic factor that should not be overlooked in ecotoxicological studies.
Afficher plus [+] Moins [-]Effects of multi-year biofumigation on soil bacterial and fungal communities and strawberry yield
2020
Zhang, Daqi | Yan, Dongdong | Cheng, Hongyan | Fang, Wensheng | Huang, Bin | Wang, Xianli | Wang, Xiaoning | Yan, Yue | Ouyang, Canbin | Li, Yuan | Wang, Qiuxia | Cao, Aocheng
Biofumigation is an effective, non-chemical method to control soil-borne pests and diseases and to maximize crop yield. We studied the responses of soil bacterial and fungal communities, the soil’s nutritional state and strawberry yield, when the soil was biofumigated each year for five consecutive years using fresh chicken manure (BioFum). BioFum significantly increased the soil’s NH4+-N, NO3−-N, available P and K and organic matter. Fusarium spp. and Phytophthora spp. which are known to cause plant disease, were significantly decreased after BioFum. In addition, Biofum increased the soil’s temperature, enhanced chlorophyll levels in the leaves of strawberry plants, and the soluble sugar and ascorbic acid content in strawberry fruit. We used high-throughput gene sequencing to monitor changes in the soil’s bacterial and fungal communities. Although BioFum significantly decreased the diversity of these communities, it increased the relative abundance of some biological control agents in the phylum Actinobacteria and the genera Pseudomonas, Bacillus and Chaetomium. An increase in these biological control agents would reduce the incidence of soil-borne pathogens and plant disease. Although strawberry marketable yield using BioFum was higher in the first three years, the decline in the final two years could be due to the accumulation of P and K which may have delayed flowering and fruiting. Methods to overcome yield losses using BioFum need to be developed in the future. Our research, however, showed that BioFum enhanced soil fertility, reduced the presence of soil pathogens, increased the relative abundance of beneficial bacteria and fungi and improved strawberry quality. Unlike chemical soil treatments that can cause pest and disease resistance when used continuously over many years, our multi-year research program on BioFum showed that this treatment provided significant benefits to the soil, plant and strawberry fruit.
Afficher plus [+] Moins [-]Heterogeneity of influential factors across the entire air quality spectrum in Chinese cities: A spatial quantile regression analysis
2020
Han, Xiaodan | Fang, Wei | Li, Huajiao | Wang, Yao | Shi, Jianglan
Most of the previous researches estimate influencing factors impact on air quality average without considering the heterogeneity of influential factors on different levels of air quality. In order to detect the different effects of influencing factors on air quality index (AQI) between lower-AQI and higher-AQI cities, this study applies a spatial quantile regression model (SQRM) to investigate heterogeneity of influential factors on AQI, while accounting for spatial autocorrelation of AQI. The results show that heterogeneity effects of windspeed, terrain slope, urbanization sprawl and spatial autocorrelation on AQI are large across the entire AQI spectrum, while heterogeneity effects of precipitation, temperature, relative humidity, terrain fluctuation and urbanization intensity on AQI are not obvious. The spatial positive autocorrelation of AQI in higher-AQI cities is greater than that in lower-AQI cities. Compared with higher-AQI cities, the negative impact of terrain slope on AQI is lager in lower-AQI cities. One unit increase in wind speed contributes AQI to decrease 9.31 to 5.64 then to 5.39 for lower, medium and higher-AQI cities. One unit increase in urbanization sprawl would lead AQI increase 25.6 to 15.6 then to 10.5 for lower, medium and higher-AQI cities. The heterogeneity analysis of meteorological, topographic and socioeconomic factors effects on air quality are of guiding significance for realizing the differentiation of policy measures for air pollution prevention and control.
Afficher plus [+] Moins [-]Mollusk shell alterations resulting from coastal contamination and other environmental factors
2020
Harayashiki, Cyntia Ayumi Yokota | Márquez, Federico | Cariou, Elsa | Castro, Ítalo Braga
Effects of contamination on aquatic organisms have been investigated and employed as biomarkers in environmental quality assessment for years. A commonly referenced aquatic organism, mollusks represent a group of major interest in toxicological studies. Both gastropods and bivalves have external mineral shells that protects their soft tissue from predation and desiccation. These structures are composed of an organic matrix and an inorganic matrix, both of which are affected by environmental changes, including exposure to hazardous chemicals. This literature review evaluates studies that propose mollusk shell alterations as biomarkers of aquatic system quality. The studies included herein show that changes to natural variables such as salinity, temperature, food availability, hydrodynamics, desiccation, predatory pressure, and substrate type may influence the form, structure, and composition of mollusk shells. However, in the spatial and temporal studies performed in coastal waters around the world, shells of organisms sampled from multi-impacted areas were found to differ in the form and composition of both organic and inorganic matrices relative to shells from less contaminated areas. Though these findings are useful, the toxicological studies were often performed in the field and were not able to attribute shell alterations to a specific molecule. It is known that the organic matrix of shells regulates the biomineralization process; proteomic analyses of shells may therefore elucidate how different contaminants affect shell biomineralization. Further research using approaches that allow a clearer distinction between shell alterations caused by natural variations and those caused by anthropogenic influence, as well as studies to identify which molecule is responsible for such alterations or to determine the ecological implications of shell alterations, are needed before any responses can be applied universally.
Afficher plus [+] Moins [-]Handling uncertainty in optimal design of reservoir water quality monitoring systems
2020
Pourshahabi, Shokoufeh | Rakhshandehroo, Gholamreza | Talebbeydokhti, Nasser | Nikoo, Mohammad Reza | Masoumi, Fariborz
In the present paper, a scenario-based many-objective optimization model is developed for the spatio-temporal optimal design of reservoir water quality monitoring systems considering uncertainties. The proposed methodology is based on the concept of nonlinear interval number programming and information theory, while handling uncertainties of temperature, reservoir inflow, and inflow constituent concentration. A reference-point-based non-dominated sorting genetic algorithm (NSGA-III) is used to deal with the many-objective optimization problem. The proposed model is developed for the Karkheh reservoir system in Iran as a real-world problem. The results show excellent performance of the optimized water quality sampling locations instead of all potential ones in providing adequate information about the reservoir water quality status. The presented uncertainty-based model leads to a 55.73% reduction in the radius of the uncertain interval caused by different scenarios. Handling uncertainties in a spatio-temporal many-objective optimization problem is the main contribution of this study, yielding a reliable and robust design of a reservoir monitoring system that is less sensitive to various scenarios.
Afficher plus [+] Moins [-]Thermal discharge influences the bioaccumulation and bioavailability of metals in oysters: Implications of ocean warming
2020
Lan, Wang-Rong | Huang, Xu-Guang | Lin, Lu-xiu | Li, Shun-Xing | Liu, Feng-Jiao
Human-induced temperature changes influence coastal regions, both via thermal pollution and ocean warming, which exerts profound effects on the chemistry of metals and the physiology of organisms. However, it remains unknown whether the increased temperature of discharged water or ocean warming, as a result of climate change, lead to an increase of human health risks associated with the consumption of sea foods. In this study, the influence of temperature on metal accumulation by oysters was studied in individuals collected from a coastal area affected by the thermal water discharge of the Houshi Power Plant, China. The bioaccumulation factor (BAF) and oral bioavailability (OBA) of metals in oysters was determined. Elevated temperatures led to an increase in BAF for Cu, Zn, Hg, and Cd (p < 0.05), but no change was observed for As and Pb (p > 0.05). The OBA for Cd, As, and Pb correlated positively to elevated temperatures (p < 0.05). However, for Cu and Zn, OBA was negatively correlated with increasing temperature (p < 0.05). As, Pb, and Cd in the trophically available metal (defined as a sum of heat-stable proteins, heat-denaturable proteins, and organelles) was significantly elevated at the highest temperature seawater site (site A) compared to the lowest seawater site (site B). Thus, the irregular variation of OBA for each metal may be the result of variations in the subcellular distribution of metals and the protein quality influenced by the increased temperature. Moreover, the increased temperature and increased the hazard quotient values of As and Cd (p < 0.05 for As, n = 6, p < 0.05 for Cd, n = 6), which provided an indication of the potential risks of the consumption of oysters or other seafood to future warming under climate change scenarios.
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