Biochars that were produced from three different biomass materials were amended to a soil to elucidate their influence on the fate of carbaryl. Sorption and degradation of carbaryl in soils amended with the biochars were investigated. The results showed that the amendment of biochars to soil enhanced the sorption of carbaryl. The nonlinearity of sorption isotherm and sorption affinity of carbaryl increased with the content and pyrolytic temperature of the biochars. Both chemical and biological degradation of carbaryl were influenced by biochars. The biochars enhanced the chemical hydrolysis of carbaryl in soil, with biochars produced at 700 °C (BC700) exhibiting greater impact, due to their strong liming effect. In contrast, BC350 (produced at 350 °C) promoted the biodegradation of carbaryl in soil by different extents, while BC700 obviously reduced the biodegradation of carbaryl. The enhanced activities of natural microorganisms in the soil and the lowered bioavailability of carbaryl acted together to determine the biodegradation.

Resuspension of bedded sediments was simulated under laboratory-controlled conditions in order to assess the amount of polycyclic aromatic hydrocarbons (PAH) remobilized in the dissolved fraction during one short and vigorous mixing. The desorbed amount of PAH was compared to the exchangeable fraction, the total amount of PAH sorbed on the sediment particles, and the dissolved PAH amount contained in the interstitial pore waters in order to evaluate the contribution of each fraction to the total amount of PAH released. To monitor the desorption of PAH and measure low trace level concentrations, passive samplers were used in an experimental open flow through exposure simulator. Results show that for the selected sediment, a substantial fraction of sorbed PAH (69 % of the total amount) is not available for remobilization in a depleted medium. Obtained data pinpoint that over 9 days, only 0.007 % of PAH are desorbed by passive diffusion through a water-sediment interface area of 415 cm² and that an intense resuspension event of 15 min induces desorption of 0.015 % of PAH during the following 9 days. Results also highlight that during resuspension simulation, modifications of the sediment and the water body occurred since partitioning constants of some pollutants between sediment and water have significantly decreased.

To evaluate the impact of chemical oxygen demand (COD)/total phosphorus (TP) ratio on microbial community characteristics during low-oxygen simultaneous nitrification and denitrification process, three anaerobic-aeration (low-oxygen) sequencing batch reactors, namely R1, R2, and R3, were performed under three different COD/TP ratios of 91.6, 40.8, and 27.6. The community structures of each reactor were analyzed via molecular biological technique. The results showed that the composition of ammonia-oxidizing bacteria (AOB) was affected, indicated by Shannon indexes of the samples from R1, R2, and R3. Nitrosomonas was identified to be the dominant AOB in all SBRs. Moreover, the copy numbers of nitrifiers were more than those of denitrifiers, and the phosphorus-accumulating organisms to glycogen-accumulating organisms ratio increased with the decrease of COD/TP ratio.

Air pollution has become an ever more critical issue in Beijing in more recent years. In this study, we use the air quality index (AQI), corresponding primary pollutant types and meteorological data which are collected at 16 monitoring stations in Beijing between January 2013 and December, 2013 studying the spatial and temporal variations of air quality and air pollutants. The results show that PM₂.₅ was the most serious pollutant, followed by O₃. The average PM₂.₅ mass concentration was 119.5 ± 13.8 μg m⁻³ in Beijing. In addition, the air quality varies across different seasons. More specifically, winter season showed the worst air quality. Moreover, while particulate matter (PM₂.₅ and PM₁₀) concentrations were relatively higher in the spring and winter seasons, gaseous pollutants (O₃ and NO₂) were more serious in the summer and autumn. In terms of spatial heterogeneity, the findings showed that AQI and PM₂.₅ concentrations were higher in south and lower in the north of the city, and the O₃ showed exactly a pattern with the opposite direction—higher in the north and lower in the south. NO₂ was found to have a greater impact on the central region compared with that in other regions. Furthermore, PM₂.₅ was found to be positively correlated with the relative humidity, but negatively correlated with wind speed and atmospheric pressure (P < 0.01). However, the dominant meteorological factors that influence the PM₂.₅ concentrations varied in different seasons. The results in this paper provide additional information for the effective control of the air pollution in Beijing.

Generation of secondary sludge is a major concern of textile dye removal by coagulation process. Combinatorial coagulation-biodegradation treatment system has been found efficient in degradation of coagulated textile dye sludge. Moringa oleifera seed powder (700 mg L⁻¹) was able to coagulate textile dyestuff from real textile wastewater with 98 % color removal. Novel consortium-BBA was found to decolorize coagulated dye sludge. Parameters that significantly affect coagulation process were optimized using response surface methodology. The bench-scale stirred tank reactor (50-L capacity) designed with optimized parameters for coagulation process could efficiently remove 98, 89, 78, and 67 % of American Dye Manufacturer’s Institute (ADMI) in four repetitive cycles, respectively. Solid-state fermentation composting reactor designed to treat coagulated dye sludge showed 96 % removal of dye within 10 days. Coagulation of dyes from textile wastewater and degradation of coagulated dye sludge were confirmed by Fourier transform infrared spectroscopy (FTIR) analysis. Cell morphology assay, comet assay, and phytotoxicity confirmed the formation of less toxic products after coagulation and degradation mechanism.

Selection of appropriate interpolation methods for the conversion of discrete samples into continuous maps is a controversial issue in the environmental researches. The main objective of this study was to analyze the suitability of three interpolation methods for the discrimination of groundwater with respect to the water quality index (WQI). The groundwater quality data consisted of 17 variables associated with 65 wells located in Andimeshk-Shush Plain. Three spatial interpolation methods including ordinary kriging (OK), empirical Bayesian kriging (EBK), and inverse distance weighting (IDW) were utilized for modeling the groundwater contamination. In addition, different cross-validation indicators were applied to assess the performance of different interpolation methods. The results showed that the performance differed slightly among different methods, although the best performed interpolation method in this study was the empirical Bayesian kriging. Among the interpolation methods, IDW with weighting power of 4 estimated the most contaminated area, while OK estimated the lowest contaminated area. The weighting power of IDW had a significant influence on the estimation, meaning that the estimated contaminated area was increased when a greater weighting power was selected. The subtraction results indicated that there are slightly spatial differences among the contamination assessment results. Results of both standard deviation (SD) and coefficient of variation (CV) also showed that uncertainty was highest in the southern part of the study area, where the distribution of wells were more intensive than that of the northern part.

In the present study, a two-hybrid yeast bioassay and a T-screen were used to screen for the thyroid receptor (TR)-disrupting activity of select metallic compounds (CdCl₂, ZnCl₂, HgCl₂, CuSO₄, MnSO₄, and MgSO₄). The results reveal that none of the tested metallic compounds showed TR-agonistic activity, whereas ZnCl₂, HgCl₂, and CdCl₂ demonstrated TR antagonism. For the yeast assay, the dose–response relationship of these metallic compounds was established, and the concentrations producing 20 % of the maximum effect of ZnCl₂, HgCl₂, and CdCl₂ were 9.1 × 10⁻⁵, 3.2 × 10⁻⁶, and 1.2 × 10⁻⁶ mol/L, respectively. The T-screen also supported the finding that ZnCl₂, HgCl₂, and CdCl₂ decreased the cell proliferation at concentrations ranging from 10⁻⁶ to 10⁻⁴ mol/L. Furthermore, the thyroid-disrupting activity of metallic compounds in environmental water samples collected from the Guanting Reservoir, Beijing, China was evaluated. Solid-phase extraction was used to separate the organic extracts, and a modified two-hybrid yeast bioassay revealed that the metallic compounds in the water samples could affect thyroid hormone-induced signaling by decreasing the binding of the thyroid hormone. The addition of ethylenediaminetetraacetic acid (30 mg/L) could eliminate the effects. Thus, the cause(s) of the thyroid toxicity in the water samples appeared to be partly related to the metallic compounds.

The high chroma of cellulosic ethanol production wastewater poses a serious environmental concern; however, color-causing compounds are still not fully clear. The characteristics of the color compounds and decolorization of biologically treated effluent by electro-catalytic oxidation were investigated in this study. Excitation-emission matrix (EEM), fourier transform infrared spectrometer (FTIR), UV-Vis spectra, and ultrafiltration (UF) fractionation were used to analyze color compounds. High chroma of wastewater largely comes from humic materials, which exhibited great fluorescence proportion (67.1 %) in the biologically treated effluent. Additionally, the color compounds were mainly distributed in the molecular weight fractions with 3–10 and 10–30 kDa, which contributed 53.5 and 34.6 % of the wastewater color, respectively. Further decolorization of biologically treated effluent by electro-catalytic oxidation was investigated, and 98.3 % of color removal accompanied with 97.3 % reduction of humic acid-like matter was achieved after 180 min. The results presented herein will facilitate the development of a well decolorization for cellulosic ethanol production wastewater and better understanding of the biological fermentation.

This study is part of our investigations about the release of persistent organic pollutants from melting Alpine glaciers and the relevance of the glaciers as secondary sources of legacy pollutants. Here, we studied the melt-related release of polychlorinated biphenyls (PCBs) in proglacial lakes and glacier streams of the catchment of the Silvretta glacier, located in the Swiss Alps. To explore a spatial and temporal distribution of chemicals in glacier melt, we combined two approaches: (1) analysing a sediment record as an archive of past remobilization and (2) passive water sampling to capture the current release of PCBs during melt period. In addition, we determined PCBs in a non-glacier-fed stream as a reference for the background pollutant level in the area. The PCBs in the sediment core from the Silvretta lake generally complied with trends of PCB emissions into the environment. Elevated concentrations during the most recent ten years, comparable in level with times of the highest atmospheric input, were attributed to accelerated melting of the glacier. This interpretation is supported by the detected PCB fractionation pattern towards heavier, less volatile congeners, and by increased activity concentrations of the radioactive tracer ¹³⁷Cs in this part of the sediment core. In contrast, PCB concentrations were not elevated in the stream water, since no significant difference between pollutant concentrations in the glacier-fed and the non-glacier-fed streams was detected. In stream water, no current decrease of the PCBs with distance from the glacier was observed. Thus, according to our data, an influence of PCBs release due to accelerated glacier melt was only detected in the proglacial lake, but not in the other compartments of the Silvretta catchment.

A modified polar organic chemical integrative sampler (POCIS) could provide a convenient way of monitoring perfluorinated chemicals (PFCs) in water. In the present study, the modified POCIS was calibrated to monitor PFCs. The effects of water temperature, pH, and dissolved organic matter (DOM) on the sampling rate (R ₛ) of PFCs were evaluated with a static renewal system. During laboratory validation over a 14-day period, the uptake kinetics of PFCs was linear with the POCIS. DOM and water temperature slightly influenced POCIS uptake rates, which is in consistent with the theory for uptake into POCIS. Therefore, within a narrow span of DOM and water temperatures, it was unnecessary to adjust the R ₛ value for POCIS. Laboratory experiments were conducted with water over pH ranges of 3, 7, and 9. The R ₛ values declined significantly with pH increase for PFCs. Although pH affected the uptake of PFCs, the effect was less than twofold. Application of the R ₛ value to analyze PFCs with POCIS deployed in the field provided similar concentrations obtained from grab samples.