Zobrazení zdroje stránky Jakobsenpilegaard5020

River ecosystems are the most important resource of surface freshwater, but they have frequently been contaminated by excessive nutrient input of nitrogen (N) and phosphorus (P) in particular. An efficient and economic river water treatment technology that possesses the capacity of simultaneous N and P removal is urgently required. [https://www.selleckchem.com/products/Acadesine.html find more] In this study, a solar-driven, self-sustainable electrolytic treatment was conducted in situ to intensify N and P removal from eutrophic river water. Solar panel was applied to provide the electrolysis setups with energy (voltage 10 ± 0.5 V), and the current density was controlled to be 0.06 ± 0.02 mA cm-2. Results indicated that the average removal efficiencies of total N (TN) and total P (TP) under electrolysis conditions reached 72.4 ± 11.7 and 13.8 ± 5.3 mg m-2 d-1, which were 3.7- and 4.7-fold higher compared to untreated conditions. Enhanced TN removal mainly reflected the abatement of nitrate N (NO3--N) (80.6 ± 4.1%). The formation of ferric ions through the electro-dissolution of the sacrificial iron anode improved TP removal by coprecipitation with SPS. Combined high-throughput sequencing and statistical analyses revealed that electrolysis significantly reshaped the microbial communities in both the sediment-water interface and suspended sediment (SPS), and hydrogenotrophic denitrifiers (e.g., Hydrogenophaga) were highly enriched under electrolysis conditions. These findings indicated that in situ electrolysis is a feasible and effective technology for intensified nutrient removal from river water.Saltmarshes are global hotspots of carbon sequestration and storage and are known as effective blue carbon ecosystems. However, the role of porewater exchange in saltmarshes as a source of carbon to the nearshore waters is still poorly constrained. Herein, we examined the radium quartet, dissolved inorganic (DIC) and organic (DOC) carbon in the porewater and nearshore surface water of Chongming Dongtan saltmarsh, China. Multiple methods based on the radium quartet were applied to estimate the porewater exchange, including the three-endmember model, mass balance model and time series observation. All methods revealed that the porewater exchange rate in Chongming Dongtan saltmarsh equaled 3.37 ± 1.23 cm d-1. The porewater-derived DIC and DOC fluxes were then estimated to be (1.51 ± 0.64) × 107 and (9.97 ± 6.96) × 105 mol d-1, respectively, which correspondingly made up 64.6% and 35.6%, of the total inputs into the Chongming Dongtan saltmarsh nearshore water. Considering the intertidal area covered by saltmarsh vegetation, carbon export through the porewater exchange was 3.87 ± 1.55 g C m-2 d-1, and was 1.2-fold greater than the carbon burial rate, accounting for approximately 29% of carbon outwelling in Chongming Dongtan saltmarsh. This study highlights the significance of porewater exchange for evaluating carbon sequestration capacity, and suggests that porewater exchange should not be overlooked in blue carbon assessments of saltmarshes.Anthropogenic inputs into the environment may serve as sources of antimicrobial resistant bacteria and alter the ecology and population dynamics of synanthropic wild animals by providing supplemental forage. In this study, we used a combination of phenotypic and genomic approaches to characterize antimicrobial resistant indicator bacteria, animal telemetry to describe host movement patterns, and a novel modeling approach to combine information from these diverse data streams to investigate the acquisition and long-distance dispersal of antimicrobial resistant bacteria by landfill-foraging gulls. Our results provide evidence that gulls acquire antimicrobial resistant bacteria from anthropogenic sources, which they may subsequently disperse across and between continents via migratory movements. Furthermore, we introduce a flexible modeling framework to estimate the relative dispersal risk of antimicrobial resistant bacteria in western North America and adjacent areas within East Asia, which may be adapted to provide information on the risk of dissemination of other organisms and pathogens maintained by wildlife through space and time.Chloride pollution of groundwater and surface water resources is an environmental concern in many regions. While use of road salt for winter road maintenance is known to be a major source of chloride in the environment, limited research has investigated the environmental impacts of chloride discharged from water softeners, particularly in areas with hard water. A chloride budget was developed for the state of Minnesota to estimate the amount of chloride discharged from household water softeners as well as other domestic, agricultural, commercial, and industrial sources. The analysis used multiple data sources, including salt sales records and wastewater monitoring data, and used statistical, spatial, and survey methods to estimate chloride loading from major sources statewide. Annual chloride mass contributions were estimated for the following sources household water softener use; human excretions; household product use; chloride concentrations in drinking water; atmospheric deposition; road salt use; dust su reservoirs, and streams.In this study, the reduction of the emerging organic contaminant atrazine in water, was investigated by adsorption, oxidation and a combination of both technologies. Adsorption tests were performed using method ASTM D3860-98 with two types of activated carbon powdered activated carbon and granular activated carbon. For the oxidation tests, advanced ozone oxidation technology was used. Finally, in the combined tests, firstly adsorption treatment was applied followed by oxidation and then the order was reversed. We studied the contaminant removal percentage using different treatments at various reaction times. Results for the different treatments under study showed that, for an initial atrazine concentration of 0.7 mg L-1 and a dose of 16 mg L-1 of powdered activated carbon, with contact times of 60 min, 24 h and 48 h, percentage reductions of the contaminant of 81%, 92% and 94% respectively were obtained. For the same concentration of contaminant, but instead using granular activated carbon, the percentage reduction of atrazine at 60 min was 2%, this percentage rising to 34% and 35% after 24 and 48 h of contact time, respectively.