Activity

Karst aquifers are extremely vulnerable to pollution, including from nitrate. This research advances a systematic evaluation of water quality dynamics and processes in a relatively pristine karst flow system impacted by seasonal tourism, in particular migration and transformation of nitrate. Water samples from the Shuifang Spring basin (Jinfoshan Karst World Heritage Site, Chongqing, China) were collected for analysis of ion concentrations and dual nitrate isotopes. The principal sampling sites included untreated tap water from the Jinfoshan Holiday Hotel (JHH), JHH septic system effluent, discharged effluent at Sinkhole #1, and groundwater at Shuifang Spring (SFS, the resurgence of the basin). Sampling from April 2017 through April 2018 showed that higher nitrate concentrations were observed at SFS during busy tourist seasons that occurred in the summer drought and winter dry seasons. Between the septic system and SFS, nitrate was diluted by rainwater and infiltration from the matrix regions of the karst aqua range of karst settings.Extreme weather events are becoming more intense and frequent as a result of climate change. The modulation of hemato-physiological potential as a compensatory response to extreme warm events combined with different salinities is poorly understood. JQ1 Target Protein Ligand chemical This study aimed to assess the hemato-physiological and molecular response of European seabass, Dicentrarchus labrax exposed to extreme warm temperature (33 °C) after prior acclimatization at 32 psu, 12 psu, 6 psu, and 2 psu water. Fish were acclimated to 32 psu, 12 psu, 6 psu, and 2 psu followed by 10 days extreme warm (33 °C) exposure. Along with growth performance and survival, hemato-physiological response and molecular response of fish were recorded. Fish held at 32 psu and 2 psu exhibited significantly lower growth performance and survival than those at 12 psu and 6 psu (p less then 0.05). Red blood cells (RBC), hematocrit, and hemoglobin content were significantly decreased, while white blood cells (WBC), erythrocytic cellular abnormalities (ECA) and erythrocytic nuclear abnormalities (ENA) were found to increase significantly in 32 psu and 2 psu fish (p less then 0.05). Plasma lactate was found to increase significantly in 32 psu fish on day 10 (p less then 0.05). Activities of glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT), and TNF-α expression increased significantly in 32 psu and 2 psu fish (p less then 0.05). Most of the repeated measured parameters indicated limited acclimation capacity during the extreme warm exposure at all four salinity groups. However, overall results indicate that European seabass acclimatized at 12 psu and 6 psu salinities, can cope better during extreme warm exposure (33 °C).Bioaugmentation is an effective technology for treating wastewater containing recalcitrant organic pollutants. However, it is restricted by several technical problems, including the difficult colonization and survival of the inoculated bacteria, and the time-consuming start-up process. Considering the important roles of quorum sensing (QS) in regulating microbial behaviors, this study investigated the effects of N-acyl-homoserine lactones (AHLs)-based manipulation on the start-up of biofilm reactors bioaugmented with a pyridine-degrading strain Paracoccus sp. BW001. The results showed that, in the presence of two specific exogenous AHLs (C6-HSL and 3OC6-HSL), the biofilm formation process on carriers was significantly accelerated, producing thick and structured biofilms. The protein and polysaccharide contents of the extracellular polymeric substances (EPS) and soluble microbial products (SMP) in sludge were also elevated, possibly due to the increased abundance of several EPS-producing bacterial genera. Specifically, the stability and complexity of protein structures were improved. Besides the reactor running time, the AHL-manipulation was proved to be the main factor that drove the shift of bacterial community structures in the reactors. The addition of exogenous AHLs significantly increased the succession rate of bacterial communities and decreased the bacterial alpha diversity. Most importantly, the final proportions of the inoculated strain BW001 were elevated by nearly 100% in both sludge and biofilm communities via the AHL-manipulation. These findings strongly elucidated that AHL-based QS was deeply involved in biofilm formation, sludge characteristics, and microbial community construction in bioaugmented reactors, providing a promising start-up strategy for bioaugmentation technology.The nano-sized zero valent iron assisted biochar from hazelnut shell (nZVI@biochar) was prepared and assessed for the feasibility as the binding agent in diffusive gradients in thin-films (DGT) technique. The 1.5% agarose solution containing the optimal nZVI@biochar dose of 15 g L-1 was used to prepare the nZVI@biochar binding gel which owned a high capacity (1010 ± 50 μg disc-1) and a rapid uptake within 30 min. The elution efficiency of phenol from the loaded binding gel was up to 99.3% using the mixture of 1% hydroxylamine hydrochloride and 0.05 mol L-1 HCl. The phenol uptake of nZVI@biochar-DGT increased linearly with the increase of deployment time (R2 = 0.9938) and was in accord with the theoretical values from DGT equation, while there was no notable interference of the sample matrixes on the phenol uptake of nZVI@biochar-DGT in the spiked freshwaters. The good performance of nZVI@biochar-DGT was found under a range of pH (4.1-10.2), ionic strength (as pNaNO3) (0.155-4), and dissolved organic matter up to 20 mg L-1. In field, the monitoring of nZVI@biochar-DGT was more representative than the results from the grab-sampling with better precision and lower sampling frequency, which can provide reliable information, reduce the cost of human resources, and improve efficiency. These illustrate that the nZVI@biochar is more suitable as the binding agent of DGT for uptake of phenol and nZVI@biochar-DGT is an effective tool to monitor in-situ phenol in waters.Trace metal pollution of coastal sediment is monitored in many countries to control its evolution and the effectiveness of preventive and corrective measures. However, temporal variability of trace metal pollution is not always due to changes in pollution management, as natural processes can induce a significant variability in the trace metal content of sediment and particulate matter, especially in strongly polluted coastal areas. To study this variability, time series of trace metals in particulate matter and bottom sediments were recorded along with hydrographic and hydrodynamic parameters in the most highly polluted zone of the Besòs River prodelta. Two benthic tripods equipped with current meters, turbidimeters and sediment traps were deployed at 20 and 30 m water depth from late-September to mid-June and sediment cores were taken four times at each site during the deployment period. Trace metal content in the trapped particulate matter and the surface sediment increased during storm events, which can resuspend and erode several cm of subsurface sediments with higher pollution levels from earlier industrial times.