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Vulture mortality resulting from illegal poisoning in the southern Balkan Peninsula Texte intégral
2018
Parvanov, Dimitar | Stoynov, Emilian | Vangelova, Nadya | Peshev, Hristo | Grozdanov, Atanas | Delov, Ventseslav | Iliev, Yavor
A study was carried out to determine the incidents of illegal poisoning of griffon vulture (Gyps fulvus), Egyptian vulture (Neophron percnopterus), black vulture (Aegypius monachus), and bearded vulture (Gypaetus barbatus) in the southern Balkan Peninsula between 1982 and 2017. A total of 38 poisoning cases affecting 224 vultures were analyzed to identify their causes and the primary target species for poisoning. Nine different compounds were used in these incidents and the most frequently applied were strychnine, carbamate, and organophosphoros compounds. The poison used to kill gray wolf had the most significant collateral damage to the vulture populations in comparison to the other investigated reasons. It was the primary cause of 60% of all registered vulture poisoning events in the southern Balkan Peninsula during the last 36 years. Establishing permanent feeding sites for vultures in areas with wolves appears to be an effective way to minimize the risk of poisoning. There is a pressing need for the development of an appropriate conservation practice taking into consideration relationships among the main and casual target species for poisoning as an essential element in conjunction with the human activities.
Afficher plus [+] Moins [-]Electric bicycle cost calculation models and analysis based on the social perspective in China Texte intégral
2018
Yan, Xuetong | He, Jie | King, Mark | Hang, Wen | Zhou, Bojian
Electric bicycles (EBs) are increasingly popular around the world. In April 2014, EB ownership in China reached 181 million. While some aspects of the impact of EBs have been studied, most of the literature analyzing the cost of EBs has been conducted from the buyer’s point of view and the perspective of social cost has not been covered, which is therefore the focus of this paper. From the consumer’s point of view, only the costs paid from purchase until retirement are included in the cost of EBs, i.e., the EB acquisition cost, battery replacement cost, charging cost, and repair and maintenance cost are included. Considered from the perspective of the social cost (including impact on the environment), costs that are not paid directly by consumers should also be included in the cost of EBs, i.e., the lead-acid battery scrap processing cost, the cost of pollution caused by wastewater, and the traffic-related costs. Data are obtained from secondary sources and surveys, and calculations demonstrate that in the life cycle of an EB, the consumer cost is 6386.2 CNY, the social cost is 10,771.2 CNY, and the ratio of consumer to social cost is 1:1.69. By comparison, the ratio for motor vehicles is 1:1.06, so that the share of the life cycle cost of EBs that is not borne by the consumer is much higher than that for motor vehicles, which needs to be addressed.
Afficher plus [+] Moins [-]Influence of Mn2+ ions on the corrosion mechanism of lead-based anodes and the generation of heavy metal anode slime in zinc sulfate electrolyte Texte intégral
2018
Zhang, Chenmu | Duan, Ning | Jiang, Linhua | Xu, Fuyuan | Luo, Jin
The influence of Mn²⁺ ions on the generation of heavy metal anode slime during zinc electrolysis industry was extensively investigated using several electrochemical methods, electron microscope technologies, and particle size analysis. Results showed that the Mn²⁺ could obviously promote oxygen evolution reaction (OER) and thereby weaken oxidation efficiency of Mn²⁺ (ηMₙO₂) and dissolution of Pb²⁺. The significant improvement in kinetic parameters for OER was found in electrolytes of 1 and 3 g/L Mn²⁺, but became unstable as the Mn²⁺ concentration increased to 10 g/L. This result was correlated with much different properties of oxide layers that its changes of microstructure are involved in, since it confirmed that the positive role of compact oxide layers in contributing to high corrosion resistance and activity for OER, but excessive Mn²⁺, resulted in its micromorphology of overthickness and instability. Such differences resulted from the effect of the Mn²⁺ concentration fluctuation on kinetic rates of the nucleation growth process. The formation and adsorption of intermediate MnO₂–OHₐdₛ identified as the controlled step for Mn²⁺ catalyzing OER was also recommended. The generation mechanism of anode slime was found to be changed in essence due to varying Mn²⁺ concentrations. In electrolyte of 1 g/L Mn²⁺, results revealed that the root cause of excessive small suspended anode slime (around 20 μm) was the change of the initial pathway of Mn²⁺ electro-oxidation, whereas, it showed great improvement in the settling performance as the Mn²⁺ concentration was increased to 10 g/L. Considering the potential of optimizing Mn²⁺ concentrations as a cleaner approach to control anode slime, deepening the understanding of the impact mechanism of Mn²⁺ can provide new insights into intervention in the generation of anode slime.
Afficher plus [+] Moins [-]Metals in bones of the middle-aged inhabitants of Sardinia island (Italy) to assess nutrition and environmental exposure Texte intégral
2018
Bocca, Beatrice | Forte, Giovanni | Giuffra, Valentina | Serra, RitaMaria | Asara, Yolande | Farace, Cristiano | Milanese, Marco | Tognotti, E. (Eugenia) | Montella, Andrea | Bandiera, Pasquale | Madeddu, Roberto
Metals in bones of 72 subjects lived between the twelfth and eighteenth century AC and collected in four Sardinian (Italian insular region) burial sites (Alghero, Bisarcio, Geridu, and Sassari) were determined and used as biomarkers to evaluate diet and potential social-environmental differences. Concentrations of Ba, Ca, Cd, Cu, Hg, Pb, Sr, and Zn were quantified in different types of compact bone (femur, fibula, humerus, radius, tibia, ulna) by sector field inductively coupled plasma mass spectrometry previous acidic digestion and differences among the various burial sites, centuries, types of bone, gender, and age were explored by univariate and multivariate analyses. Results indicated differences between sites in terms of diet: Bisarcio (inland village) had increased ratios of Ba/Ca and Zn/Ca due to higher incidence of vegetables, cereals, and animal foods in the diet; Geridu (coastal village) showed increased Sr/Ca ratio indicating foods of plant and marine origin that were predominant; Alghero (coastal site) and Sassari (inland site) displayed prevalently a mixed diet reflecting a higher economy and food imports. In addition, these latter sites showed increased levels of Hg/Ca (fish, drugs, cosmetics) and Pb/Ca (coins, utensils, pipeline for water). In conclusion, the elemental Ba/Ca, Sr/Ca, and Zn/Ca ratios were indicative of provenance and diet, while Hg/Ca and Pb/Ca ratios were associated to various forms of environmental exposure.
Afficher plus [+] Moins [-]Origin and effect factors of sedimentary organic carbon in a karst groundwater-fed reservoir, South China Texte intégral
2018
Huang, Siyu | Pu, Junbing | Cao, Jianhua | Li, Jianhong | Zhang, Tao | Jiang, Feng | Li, Li | Wu, Feihong | Pan, Moucheng | Bai, Bing
Reservoirs are commonly recharged by groundwater that is rich in bicarbonate ions in karst regions of South China, and the recharge of this groundwater to the reservoir can affect the biogeochemical processes of carbon sedimentation at the reservoir bottom. In this study, Dalongdong Reservoir, which is mainly recharged by two subterranean streams, was investigated based on a 42-cm-thick sedimentary core and the ²¹⁰Pb/¹³⁷Cs dating technique and isotope analyses to understand the sedimentary history and identify the carbon sources. The ²¹⁰Pb/¹³⁷Cs age model showed that the sediments were accumulated over the last 60 years. The annual increase precipitation and temperature showed no obvious change compared with trends of δ¹³C in total organic carbon (δ¹³Cₒᵣg), δ¹⁵N values in total nitrogen, and the carbon and nitrogen ratio (C/N). This shows that climate was not the main control of the variation in sediment factors. Based on δ¹³Cₒᵣg, δ¹⁵N, C/N, and isotopic mixing modeling, sources of organic carbon in the sediments were derived from plankton (60.84%), soil (22.93%), waste water (14.56%), and terrestrial plants (1.67%). From 1958 to 1978, reservoir establishment and leakage affected the contribution of the four sources. The contribution of the plankton source increased from 1978 to 2015, resulting from change of water level and continued input of external nitrogen. However, because of the revegetation supplied by an economic aid project the contribution of soil showed a considerable decreasing trend from 1978 to 2002. After 2002, For “Grain for Green” project, the contribution from soil further decreased. After reservoir construction, the contribution of waste water stabilized. The contribution of terrestrial plants started increased rapidly after 2002. Karst groundwater, which contains more dissolved inorganic carbon containing lower δ¹³CDIC than the water sources of other lakes or reservoirs, makes the δ¹³Cₒᵣg value of sediment more negative by phytoplankton photosynthesis in the reservoir.
Afficher plus [+] Moins [-]Ecotoxicological assessment of oil-based paint using three-dimensional multi-species bio-testing model: pre- and post-bioremediation analysis Texte intégral
2018
Phulpoto, Anwar Hussain | Qazi, Muneer Ahmed | Haq, Ihsan Ul | Phul, Abdul Rahman | Ahmed, Safia | Kanhar, Nisar Ahmed
The present study validates the oil-based paint bioremediation potential of Bacillus subtilis NAP1 for ecotoxicological assessment using a three-dimensional multi-species bio-testing model. The model included bioassays to determine phytotoxic effect, cytotoxic effect, and antimicrobial effect of oil-based paint. Additionally, the antioxidant activity of pre- and post-bioremediation samples was also detected to confirm its detoxification. Although, the pre-bioremediation samples of oil-based paint displayed significant toxicity against all the life forms. However, post-bioremediation, the cytotoxic effect against Artemia salina revealed substantial detoxification of oil-based paint with LD₅₀ of 121 μl ml⁻¹ (without glucose) and > 400 μl ml⁻¹ (with glucose). Similarly, the reduction in toxicity against Raphanus raphanistrum seeds germination (%FG = 98 to 100%) was also evident of successful detoxification under experimental conditions. Moreover, the toxicity against test bacterial strains and fungal strains was completely removed after bioremediation. In addition, the post-bioremediation samples showed reduced antioxidant activities (% scavenging = 23.5 ± 0.35 and 28.9 ± 2.7) without and with glucose, respectively. Convincingly, the present multi-species bio-testing model in addition to antioxidant studies could be suggested as a validation tool for bioremediation experiments, especially for middle and low-income countries. Graphical abstract ᅟ
Afficher plus [+] Moins [-]Residue behavior and risk assessment of thifluzamide in the maize field ecosystem Texte intégral
2018
Ma, Cong | Liu, Zhongdong | Qi, Yan | Wang, Shanshan | Cao, Xiaolin | Wang, Jing | She, Yongxin | Shao, Yong | Shen, Jitai | Zhang, Chao | Jiang, Zejun
In the present work, the dissipation kinetics and final residue levels of thifluzamide in the maize field ecosystem were investigated. Using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction combined with liquid chromatography-tandem mass spectrometric detection (LC-MS/MS), a rapid, sensitive, efficient, and reliable method for extraction and quantitative analysis of thifluzamide residues in maize grain, maize plant, and soil was developed. Satisfactory recoveries of 78.7–97.0% were achieved with relative standard deviations (RSDs) in the range of 1.6 to 8.2%. The limits of detection (LODs) and the limit of quantification (LOQ) were 0.002–0.005 and 0.010 mg kg⁻¹, respectively. The dissipation kinetics of thifluzamide in maize plant was well fitted by the first-order kinetic model with short half-lives of 0.19–0.22 days, while thifluzamide degraded slowly in soil with half-lives of 4.56–15.85 days. The final residues in maize grain, maize plant, and soil samples collected at the milk stage and the physiological maturity stage were no more than 0.010, 0.807, and 0.278 mg kg⁻¹, respectively. Given that no maximum residue limit (MRL) for thifluzamide in maize has been established, the safety of this fungicide application was estimated by a dietary risk assessment. The hazard quotient was 0.03%, which was substantially less than 1, indicating that the long-term risk induced by the thifluzamide application on maize at the recommended dose is negligible. These results help governments to develop regulations for the safe use of thifluzamide.
Afficher plus [+] Moins [-]Nuclear magnetic resonance-based metabolomic investigation reveals metabolic perturbations in PM2.5-treated A549 cells Texte intégral
2018
Huang, Dacheng | Zou, Yajuan | Abbas, Anees | Dai, Bona
Exposure to PM₂.₅ is associated with an increased risk of lung diseases, and oxidative damage is the main reason for PM₂.₅-mediated lung injuries. However, little is known about the early molecular events in PM₂.₅-induced lung toxicity. In the present study, the metabolites in PM₂.₅-treated A549 cells were examined via a robust and nondestructive nuclear magnetic resonance (NMR)-based metabolic approach to clarify the molecular mechanism of PM₂.₅-induced toxicity. NMR analysis revealed that 12 metabolites were significantly altered in PM₂.₅-treated A549 cells, including up-regulation of alanine, valine, lactate, ω-6 fatty acids, and citrate and decreased levels of gamma-aminobutyric acid, acetate, leucine, isoleucine, D-glucose, lysine, and dimethylglycine. Pathway analysis demonstrated that seven metabolic pathways which included alanine, aspartate and glutamate metabolism, aminoacyl-tRNA biosynthesis, taurine and hypotaurine metabolism, arginine and proline metabolism, starch and sucrose metabolism, valine, leucine and isoleucine biosynthesis, and tricarboxylic acid cycle were mostly influenced. Our results indicate that NMR technique turns out to be a simple and reliable method for exploring the toxicity mechanism of air pollutant.
Afficher plus [+] Moins [-]Predicting microalgae growth and phosphorus removal in cold region waste stabilization ponds using a stochastic modelling approach Texte intégral
2018
Schmidt, Jordan J. | Gagnon, Graham A. | Jamieson, Rob C.
A stochastic ecological model with an integrated equilibrium temperature model was developed to predict microalgae growth and phosphorus removal in cold region waste stabilization ponds (WSPs). The model utilized a Monte Carlo simulation to account for parameter uncertainty. The equilibrium temperature model was parameterized using field data collected from two WSPs in Nunavut, Canada, from 2012 to 2014. The equilibrium temperature model provided good agreement with field data on a daily time step. The full model was run using historic (1956–2005) temperature and solar radiation data from five communities (Baker Lake, Cambridge Bay, Coral Harbour, Hall Beach, Resolute) in Nunavut, Canada. The communities represented a range of geographical locations and environmental conditions. Logistic regression on pooled model outputs showed that mean July temperature and mean treatment season temperature (June 1–September 15, ice-free period) provided the best predictors for microalgae growth. They had a predictive success rate of 93 and 88%, respectively. The modelled threshold (50% probability from the Monte Carlo simulation) for microalgae growth was 8.7 and 5.6 °C for the July temperature and mean treatment season temperature, respectively. The logistic regression was applied to each community (except Sanikiluaq) in Nunavut using historic climate data and a probability of microalgae growth was calculated. Based on the model results, soluble phosphorus concentrations consistent with secondary treatment could be achieved if WSP depth is less than 2 m. The model demonstrated a robust method to predict whether a microalgae bloom will occur under a range of model parameters.
Afficher plus [+] Moins [-]Natural and synthetic estrogens in leafy vegetable and their risk associated to human health Texte intégral
2018
Adeel, Muhammad | Zain, Muhammad | Shah, Fahad | Rizwan, Muhammad | Ameen, Asif | Yi, Hao | Baluch, Mansoor A. | Lee, Jie Yinn | Rui, Yukui
Since the inception of global industrialization, the growth of steroid estrogens becomes a matter of emerging serious concern for the rapid population. Steroidal estrogens are potent endocrine-upsetting chemicals that are excreted naturally by vertebrates (e.g., humans and fish) and can enter natural waters through the discharge of treated and raw sewage. Steroidal estrogens in plants may enter the food web and become a serious threat to human health. We evaluated the uptake and accumulation of ethinylestradiol (EE2) and 17β-estradiol (17β-E2) in lettuce plants (Lactuca sativa) grown under controlled environmental condition over 21 days growth period. An effective analytical method based on ultrasonic liquid extraction (ULE) for solid samples and solid phase extraction (SPE) for liquid samples with gas chromatography-mass spectrometry (GC/MS) has been developed to determine the steroid estrogens in lettuce plants. The extent of uptake and accumulation was observed in a dose-dependent manner and roots were major organs for estrogen deposition. Unlike the 17β-E2, EE2 was less accumulated and translocated from root to leaves. For 17β-E2, the distribution in lettuce was primarily to roots after the second week (13%), whereas in leaves it was (10%) over the entire study period. The distribution of EE2 at 2000 μg L⁻¹ in roots and leaves was very low (3.07% and 0.54%) during the first week and then was highest (12% in roots and 8% in leaves) in last week. Bioaccumulation factor values of 17β-E2 and EE2 in roots were 0.33 and 0.29 at 50 μg L⁻¹ concentration as maximum values were found at 50 μg L⁻¹ rather than 500 and 2000 in all observed plant tissues. Similar trend was noticed in roots than leaves for bioconcentration factor as the highest bioconcentration values were observed at 50 μg L⁻¹ concentration instead of 500 and 2000 μg L⁻¹ spiked concentration. These findings mainly indicate the potential for uptake and bioaccumulation of estrogens in lettuce plants. Overall, the estrogen contents in lettuce were compared to the FAO/WHO recommended toxic level and were found to be higher than the toxic level which is of serious concern to the public health. This analytical procedure may aid in future studies on risks associated with uptake of endocrine-disrupting chemicals in lettuce plants.
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