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Assessment of occupational exposure to pesticide mixtures with endocrine-disrupting activity 全文
2019
Wong, Hie Ling | Garthwaite, David G. | Ramwell, Carmel T. | Brown, Colin D.
Occupational exposure to pesticide mixtures comprising active substance(s) and/or co-formulant(s) with known/possible endocrine-disrupting activity was assessed using long-term activity records for 50 professional operators representing arable and orchard cropping systems in Greece, Lithuania, and the UK. Exposure was estimated using the harmonised Agricultural Operator Exposure Model, and risk was quantified as a point of departure index (PODI) using the lowest no observed (adverse) effect level. Use of substances with known/possible endocrine activity was common, with 43 of the 50 operators applying at least one such active substance on more than 50% of spray days; at maximum, one UK operator sprayed five such active substances and 10 such co-formulants in a single day. At 95th percentile, total exposure was largest in the UK orchard system (0.041 × 10⁻² mg kg bw⁻¹ day⁻¹) whereas risk was largest in the Greek cropping systems (PODI 0.053 × 10⁻¹). All five cropping systems had instances indicating potential for risk when expressed at a daily resolution (maximum PODI 1.2–10.7). Toxicological data are sparse for co-formulants, so combined risk from complex mixtures of active substances and co-formulants may be larger in reality.
显示更多 [+] 显示较少 [-]Thermodynamic and kinetic insights into plant-mediated detoxification of lead, cadmium, and chromium from aqueous solutions by chemically modified Salvia moorcroftiana leaves 全文
2019
Salman, Syed Muhammad | Ali, Asad | Khan, Behramand | Iqbal, Mehmood | Alamzeb, Muhammad
Thermodynamic and kinetic aspects for the biosorptive removal of Pb, Cd, and Cr metals from water using Chemically Modified Leaves of Salvia moorcroftiana (CMSML) were determined. Different parameters including pH, temperature, metal’s initial concentration, biomass dosage, and contact time were optimized. Optimum biosorptions of Pb, Cd, and Cr were attained at pH values of 6.0, 7.0, and 3.0 respectively. Batch experiments showed maximum removal of both Pb and Cd at 40 °C and that of Cr at 30 °C. Biosorption capability of CMSML was observed to decrease with raising temperature. Optimal equilibrium times for Pb, Cd, and Cr uptake were 120, 60, and 120 min respectively. Based on the values of regression correlation coefficients (R²), the current data is explained better by applying Langmuir isotherms than the Freundlich model. Maximum biosorbent capabilities (qₘₐₓ) for Pb, Cd, and Cr were approximately 270.27, 100.00, and 93.45 mg/g respectively. Thermodynamically, removal of all the three metal ions was shown to be exothermic and spontaneous.
显示更多 [+] 显示较少 [-]Conversion of organic biomedical waste into potential fertilizer using isolated organisms from cow dung for a cleaner environment 全文
2019
Patil, Pooja M. | Mahamuni, Pranjali P. | Abdel-Daim, Mohamed M. | Aleya, Lotfi | Chougule, Roma A. | Shadija, Prem G. | Bohara, Raghvendra A.
Management of organic biomedical waste is a global quandary, and it is becoming difficult to confront day by day. Conversion of organic biomedical waste into fertilizer is of great concern. In the present research, organic biomedical waste samples (blood swabs, dressing swabs, and used cotton) were collected then after cow dung was collected in sterile container and immediately transported to the laboratory and screened for any gastrointestinal infection by using routine microscopy for intestinal parasitic infection, routine bacterial culture, and fecal occult blood for any intestinal bleeding. Then after, the pure culture of organisms and fungus were prepared, and further samples were subjected to degradation for 288 h by using various organisms and fungus. Then after, the specific quantity of biomedical waste was subjected for incineration. The physicochemical parameters of biomedical waste samples were analyzed. Then treated samples were mixed with soil to confirm a role as potential fertilizer. Then after, tomato plantation was done and phytochemical parameters of tomato plant were analyzed. This study states that organic biomedical waste produces a sanitary and stable fertilizer.
显示更多 [+] 显示较少 [-]Regenerable bagasse-based carbon activated by in situ formation of zero-valent zinc microparticles for high-performance degradation of amoxicillin in water 全文
2019
Yu, Zengcheng | Cai, Yixin | Lu, Yuqin | Liu, Chao | Yang, Zhennai | Liu, Shilin | Luo, Xiaogang
Increasing degradation of amoxicillin in water by low-cost advanced functional activated carbon-based materials derived from bagasse is an effective and economic way to remove the antibiotic residue pollutant and for high-valued utilization and transformation of plant wastes. In this work, bagasse was pyrolyzed and Zn²⁺ was activated for designing a high-efficiency bagasse-based activated carbon, which was characterized by FTIR, XRD, XPS, SEM, EDS, and ζ potential analyses. These analyses illustrated the mechanism of amoxicillin degradation, and microscale zero-valent zinc in bagasse-based activated carbon has a key role in amoxicillin degradation. Amoxicillin was broken down by reductive degraded radicals, which were produced by microscale zero-valent zinc corrosion in water. After the amoxicillin degradation, the byproduct of zinc hydroxide being adsorbed onto the used bagasse-based activated carbon can provide possibility of sustainable regeneration. Mass spectra analysis illustrated the main degradation products of amoxicillin. The kinetic experiments were adopted to observe the process of amoxicillin degradation, followed by the pseudo-first-order kinetic model. The isotherm experiments demonstrated that the maximum amoxicillin degradation capacity of bagasse-based activated carbon was about 46 mg g⁻¹. The bagasse wastes were used as carbon source to design potential advanced activated carbon materials for increasing degradation of amoxicillin in water.
显示更多 [+] 显示较少 [-]Sludge nematodes, cestodes, and trematodes eggs variation from lagooning, activated sludge and infiltration-percolation wastewater treatment system under semi-arid climate 全文
2019
El Fels, Loubna | El Hayany, Bouchra | El Faiz, Abdelouahed | Saadani, Mustapha | Houari, Mustapha | Hafidi, Mohamed
The prevalence and the identification of the helminth eggs load of raw sewage sludge was assessed of three different wastewater treatment systems. The results showed a variety of parasite species with following average concentrations; five taxa belonging to three classes nematodes, cestodes and trematodes were inventoried. The class of nematodes is the most diverse with 5 taxa. It is represented by the eggs of Ascaris sp., Capillaria sp., Trichuris sp., Toxocara sp., and Ankylostome sp., then comes the cestodes class, this is represented by the eggs of Tænia sp. The trematode class is represented by Schistosoma sp. The lagooning station of Chichaoua shows the highest load 7 species with Ascaris 21 eggs/g; Capillaria sp., 11 eggs/g; Trichuris sp., 6 eggs/g; Toxocara sp., 2 eggs/g and Ankylostome sp., 1 egg/g; Taenia sp., 2eggs/g; and Schistosoma sp., 1 egg/g. Infiltration-percolation sludge show the presence of 4 species of helminths eggs in sludge from anaerobic settling with different rates: 15 eggs/g for Ascaris sp., 15 eggs/g for Trichuris sp., 13 eggs/g for Capillaria sp., and 8 eggs/g for Taenia sp. However, in sand filter pool, the sludge helminth eggs load was decreased by 47% of Ascaris sp., 85% of Capillaria sp., and 75% of Taenia sp., Nevertheless, an increase of Trichuris eggs load was noted in the second sludge by 17%. Five helminth eggs was detected in primary sludge coming from decantation pools in activated sludge plant in Marrakech, that is Ascaris sp., with a load of 16 eggs/g; Capillaria sp., with 3 eggs/g, Trichuris eggs with 2 eggs/g; Taenia sp., with 4 eggs/g; and Schistosoma sp., with 2 eggs/g. The abatement load of Ascaris sp. with 81% and Schistosoma and Taenia sp., with 100% was noted in biological sludge. Nevertheless, an increase load of Capillaria and Trichuris eggs 81% and 75% respectively was observed in this sludge coming from biological pools. The distribution of parasitic helminth eggs is linked to the differences in demographic and socio-economic status, seasonal variation, physico-chemical characteristic of helminth eggs, and the purification wastewater system performance.
显示更多 [+] 显示较少 [-]Effect of phosphate and silicate on selenite uptake and phloem-mediated transport in tomato (Solanum lycopersicum L.) 全文
2019
Wang, Mengke | Yang, Wenxiao | Zhou, Fei | Du, Zekun | Xue, Mingyue | Chen, Tao | Liang, Dongli
The ambiguous mechanism that selenite seems to be absorbed by roots via phosphorus (P) and silicon (Si) transporters signifies P and Si may affect selenite uptake. However, the role of P and Si in phloem-mediated selenium (Se) transport within plant tissue is unknown. Therefore, in this work, tomato (Solanum lycopersicum L.) seedlings were exposed to selenite under different hydroponic conditions firstly. And then, split-root experiments were conducted. Results showed that Se uptake decreased as external pH increased. At pH 8, more selenite in the form of SeO₃²⁻ was assimilated under P-deficient conditions than under P-normal conditions. Silicate inhibited Se uptake only at pH 3 (27.5% H₂SeO₃ +72.5% HSeO₃⁻). The results of split-root experiments showed that Se concentrations in seedlings increased under heterogeneously high P or Si. Selenium transport from shoots to roots immersed in solution without selenite was also enhanced. This study illustrated that the affinity of tomato roots to assimilate selenite species followed the order of H₂SeO₃ >HSeO₃⁻ >SeO₃²⁻. H₂SeO₃ was absorbed into roots via Si transporters, whereas HSeO₃⁻ and a portion of SeO₃²⁻ were absorbed via low- and high-affinity P transporters, respectively. In addition, heterogeneously high P or Si concentrations in environmental media could enhance phloem-mediated Se redistribution.
显示更多 [+] 显示较少 [-]The impact of environmental regulation on environmental pollution in China: an empirical study based on the synergistic effect of industrial agglomeration 全文
2019
Zhang, Kangkang | Xu, Deyi | Li, Shiran
In recent years, as environmental degradation has become more and more serious, the Chinese government has formulated a series of environmental policies and regulations aimed at improving environmental quality. Does environmental regulation significantly inhibit environmental pollution? Environmental regulation will not only directly affect environmental pollution but also have an indirect impact on environmental pollution. This paper uses Bayesian posterior probability, the optimal model structure selection method, based on join 112 kinds of spatial econometric model structure, and the panel data of 30 provinces in China from 2003 to 2016 to study the effects of environmental regulation on environmental pollution base on the industrial agglomeration mechanism of synergy effect. The research covers the national level and four regions, including the eastern, central, western, and northeastern regions of China. The research shows that: (1) environmental regulation at the national level and in the eastern, central and northeastern regions can significantly curb environmental pollution, but the environmental pollution in the western region shows a significant trend of enhancement. (2) Increased industrial agglomeration across China has significantly worsened environmental pollution. (3) Environmental regulation and industrial agglomeration form a significant synergy effect, which has a significant positive impact on environmental pollution in regions other than northeast China, and a significant negative impact on environmental pollution intensity in northeast China.
显示更多 [+] 显示较少 [-]The dispersion, stability, and resuspension of C60 in environmental water matrices 全文
2019
Ding, Guanghui | Li, Xueyao | Zhang, Jing | Zhang, Nannan | Li, Ruijuan | Wang, Yingying | Yang, Zhanning | Peijnenburg, Willie J. G. M.
Environmental waters cover a range of water quality characteristics which could greatly affect the behavior and fate of C₆₀ in the aquatic environment. In this study, the dispersion and stability of C₆₀ in several environmental water matrices during a 70-day extended mixing period were investigated to better understand its environmental behavior and fate in environmental waters. Relatively stable nanoscale aggregates in water (aqu/nC₆₀) could be formed in wastewater influent, while unstable suspensions were obtained in river water, wastewater effluent, seawater, and estuarine water. During the extended mixing under sunlight, oxygen-containing moieties were produced on the surface of the C₆₀ aggregates, independent of the kind of environmental water matrices. Once the mixed system went under quiescent condition, aggregation and sedimentation of aqu/nC₆₀ occurred. However, an extremely short-time disturbance could easily resuspend the C₆₀ aggregates deposited and increase the concentration of aqu/nC₆₀ in the overlying water column. Therefore, the effects of resuspension should be considered when investigating the environmental behavior and fate of C₆₀.
显示更多 [+] 显示较少 [-]Nitrogen isotope composition of ammonium in PM2.5 in the Xiamen, China: impact of non-agricultural ammonia 全文
2019
Wu, Shui-Ping | Zhu, Heng | Liu, Zhe | Dai, Lu-Hong | Zhang, Ning | Schwab, James J. | Yuan, Chung-Shin | Yan, Jin-Pei
Since NH₃ is a significant precursor to ammonium in PM₂.₅ and contributes significantly to atmospheric nitrogen deposition but largely remains unregulated in China, the insight into the source of NH₃ emissions by the isotopic investigation is important in controlling NH₃ emissions. In this study, atmospheric concentrations of NH₃ and water-soluble ion composition in PM₂.₅ as well as nitrogen isotope ratios in NH₄⁺ (δ¹⁵N-NH₄⁺) in Xiamen, China, were measured. Results showed that average NH₃ concentration for the five sites in Xiamen was 7.9 μg m⁻³ with distinct higher values in the warm season and lower values in the cold season, and PM₂.₅ concentration for the two sites (urban and suburban) was 59.2 μg m⁻³ with lowest values in summer. In the PM₂.₅, NH₄⁺ concentrations were much lower than NH₃ and showed a stronger positive correlation with NO₃⁻ than that with SO₄²⁻ suggesting the formation of NH₄NO₃ and equilibrium between NH₃ and NH₄⁺. Although the concentrations of NH₃ at the urban site were significantly higher than those at the suburban site, no significant spatial difference in NH₄⁺ and δ¹⁵N-NH₄⁺ was obtained. The distinct heavier δ¹⁵N-NH₄⁺ values in summer than in other seasons correlated well with the equilibrium isotopic effects between NH₃ and NH₄⁺ which depend on temperature. The initial δ¹⁵N-NH₃ values were in the range of waste treatment (− 25.42‰) and fossil fuel combustion (− 2.5‰) after accounting for the isotope fractionation. The stable isotope mixing model showed that fossil fuel–related NH₃ emissions (fossil fuel combustion and NH₃ slip) contributed more than 70% to aerosol NH₄⁺. This finding suggested that the reduction of NH₃ emissions from urban transportation and coal combustion should be a priority in the abatement of PM₂.₅ pollution in Xiamen.
显示更多 [+] 显示较少 [-]Associations between mercury exposure and the risk of nonalcoholic fatty liver disease (NAFLD) in US adolescents 全文
2019
Chen, Runsen | Xu, Yang | Xu, Cheng | Shu, Yaqin | Ma, Siyu | Lu, Changgui | Mo, Xuming
Little is known regarding the effects of environmental mercury (Hg) exposure on liver dysfunction in adolescents. We aimed to explore the association between Hg exposure and the risk of nonalcoholic fatty liver disease (NAFLD) in the adolescent population. The cross-sectional associations between blood Hg concentrations and serum alanine aminotransferase (ALT) levels, a surrogate for suspected NAFLD, were evaluated using data from adolescents (aged 12–17 years old) who participated in the National Health and Nutrition Examination Survey (NHANES), 1999–2014. A final sample of 6389 adolescents was analysed. Elevated ALT was defined as > 25 IU/L and > 22 IU/L for boys and girls ≤ 17 years old, respectively. Odds ratios (ORs) of Hg levels in association with serum ALT levels were estimated using a logistic regression after adjusting for gender, age, ethnicity, serum cotinine, body mass index, the poverty income ratio, and NHANES cycles. The median blood Hg level was 0.73 ± 0.91 μg/L amongst US adolescents. In the adjusted model, the ORs of elevated ALT levels of those in the 4th quartile were higher amongst non-Hispanic white adolescents (OR = 1.76, 95% CI 1.20, 2.59; P = 0.035) and those who were normal or underweight (OR = 1.41, 95% CI 1.08, 1.85; P = 0.020). No association was observed for the other variables. Our results indicate that the positive association between blood Hg exposure and the risk of NAFLD in US adolescents is the highest amongst non-Hispanic white and those who are normal or underweight, regardless of ethnicity. More research is necessary to confirm this association and to clarify the potential mechanisms.
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