Environmental Science and Pollution Research - This study investigated the changes of toxic compounds in coking wastewater with biological treatment (anaerobic reactor, anoxic reactor and... 相似文献
As the most important fishery medicines, sulfonamides are widely used to prevent diseases caused by pathogens in aquaculture. However, relatively little is known about the residues and dietary risks associated with cultured fish around Tai Lake. In the present study, a sampling strategy for a complete aquaculture period was conducted. Specifically, 12 selected sulfonamide antibiotics were measured among 116 fish samples recruited from four sampling periods, four species, four areas, and 18 fish ponds. All 12 antibiotics were detected at detection frequencies of 4.31–28.45%. Total sulfonamides were detected in 77.59% of the fish samples, with 57.76% of fish samples containing from 0.1 to 10 μg kg?1. Sulfadiazine (SDZ), sulfamethoxazole (SMZ), sulfamethazine (SDD), and sulfamonomethoxine (SMM) were the main types of antibiotics used, and these were present at high concentrations (>100 μg kg?1) with high occurrences, especially in the middle of the aquaculture season. Dietary assessment showed that residual antibiotics in all fish that were being sent to market were far below the maximum residue limit (MRL) of total sulfonamides and that there was almost no risk associated with fish consumption. The results of the present study will facilitate development of effective measures to produce safe aquatic products and meaningful suggestions for consuming aquatic products. 相似文献
The interprovincial trade embodied carbon emissions plays an important role in the national emission reduction target among China’s provinces. Furthermore, it will affect the smooth start-up of the national carbon trade market as well as the implementation of targets in 2030 for dealing with the climate change. Based on constructed MRIO model, this paper analyzes the embodied carbon emission trade flows among Beijing, Tianjin, Hebei and surrounding regions such as Shanxi, Shaanxi, and Inner Mongolia. The results indicate that six provinces have formed different patterns of carbon trade balance, where Beijing, Tianjin, and Hebei provinces are in a deficit position, while the other three provinces are in a surplus position. Beijing, Tianjin, and Hebei have transferred part of the carbon emissions to the other three provinces, which shows greater heterogeneity among various provinces and provincial different sectors. On basis of the conclusions, this paper puts forward some suggestions on provincial decomposition, responsibility distribution, and provincial collaborative reduction for national emission reduction targets. 相似文献
A novel superhydrophobicelectroactive fluorinated polyimide (HEFPI) was first synthesized from aniline trimer and 4,4′-(Hexafluoroisopropylidene) diphthalic anhydride. The HEFPI could be fabricated as superhydrophobicfilm by replicated the surface of the Xanthosomasagittifolium leaves. The water contact angle of HEFPI film reaches as high as 157 ° and the superhydrophobic property of HEFPI could coat on cold-rolled steel (CRS) to prevent the metal corrosion. Electroactivity of EFPI was evaluated by performing electrochemical cyclic voltammetry study. Besides, redox catalytic capabilities of aniline trimer units existed in HEFPI main chain may induce the formation of passive metal oxide layers on the CRS electrode. The synergistic effects (hydrophobic property and passive metal oxide layers) make the HEFPI coating has great potential for advanced anticorrosion material. 相似文献
Chelant-enhanced phytoextraction method has been put forward as an effective soil remediation method, whereas the heavy metal leaching could not be ignored. In this study, a cropping-leaching experiment, using soil columns, was applied to study the metal leaching variations during assisted phytoextraction of Cd- and Pb-polluted soils, using seedlings of Zea mays, applying three different chelators (EDTA, EDDS, and rhamnolipid), and artificial rainfall (acid rainfall or normal rainfall). It showed that artificial rainfall, especially artificial acid rain, after chelator application led to the increase of heavy metals in the leaching solution. EDTA increased both Cd and Pb concentrations in the leaching solution, obviously, whereas EDDS and rhamnolipid increased Cd concentration but not Pb. The amount of Cd and Pb decreased as the leaching solution increased, the patterns as well matched LRMs (linear regression models), with R-square (R2) higher than 90 and 82% for Cd and Pb, respectively. The maximum cumulative Cd and Pb in the leaching solutions were 18.44 and 16.68%, respectively, which was amended by EDTA and acid rainwater (pH 4.5), and followed by EDDS (pH 4.5), EDDS (pH 6.5), rhamnolipid (0.5 g kg−1 soil, pH 4.5), and rhamnolipid (pH 6.5).
Column experiments and numerical simulation were conducted to test the hypothesis that iron material having a high corrosion rate is not beneficial for the long-term performance of iron permeable reactive barriers (PRBs) because of faster passivation of iron and greater porosity loss close to the influent face of the PRBs. Four iron materials (Connelly, Gotthart-Maier, Peerless, and ISPAT) were used for the column experiments, and the changes in reactivity toward cis-dichloroethene (cis-DCE) degradation in the presence of dissolved CaCO3 were evaluated. The experimental results showed that the difference in distribution of the accumulated precipitates, resulting from differences in iron corrosion rate, caused a difference in the migration rate of the cis-DCE profiles and a significant difference in the pattern of passivation, indicating a faster passivation in the region close to the influent end for the material having a higher corrosion rate. For the numerical simulation, the accumulation of secondary minerals and reactivity loss of iron were coupled using an empirically-derived relationship that was incorporated into a multi-component reactive transport model. The simulation results provided a reasonable representation of the evolution of iron reactivity toward cis-DCE treatment and the changes in geochemical conditions for each material, consistent with the observed data. The simulations for long-term performance were also conducted to further test the hypothesis and predict the differences in performance over a period of 40 years under typical groundwater conditions. The predictions showed that the cases of higher iron corrosion rates had earlier cis-DCE breakthrough and more reduction in porosity starting from near the influent face, due to more accumulation of carbonate minerals in that region. Therefore, both the experimental and simulation results appear to support the hypothesis and suggest that reactivity changes of iron materials resulting from evolution of geochemical conditions should be considered in the design of iron PRBs. 相似文献