Bentsenbaird6643

Reducing nitrate leaching may not result in a significant improvement of groundwater quality. The amount of nitrate reaching groundwater depends not only on the hazard related to agricultural activities but also on-site specific groundwater vulnerability. Using national databases and other compiled datasets, the agricultural hazard was calculated as the ratio of (i) the nitrate leached estimated from the N surplus, and (ii) the water surplus, a proxy of the percolating water below the root zone. By combining the hazard with a multi-parameter groundwater vulnerability, a spatially explicit groundwater contamination risk, developed for mainland Portugal, was computed for 1999 and 2009. Results show an increase from 8,800 to 82,679 ha of the territory rated with a very high contamination risk. The priority areas were successfully screened by the Index, coinciding with the current Vulnerable Zones, although additional hotspots were detected in southern Portugal. Percolation, including both irrigation activity and precipitation, was found to be a key driver for the groundwater contamination risk due to its opposite effects in the hazard and in the vulnerability. Reducing nitrogen leaching may be insufficient to reduce the risk of nitrate contamination if there is a relatively larger reduction in precipitation. This index is particularly useful when applied to contrasting situations of vulnerability and hazard, which require distinct mitigation measures to mitigate groundwater contamination.In terms of researching and treating farmland pollution, interactions between organic and inorganic pollutants are very important aspects. Herein, the effects of heavy metals on di(2-ethylhexyl) phthalate (DEHP) adsorption in soil were investigated. The presence of Cd2+/Cu2+ increased the adsorption capacity of DEHP (>23%) in a nonlinear manner. Fourier transform infrared spectroscopy revealed that the stretching vibration of soil functional groups changed under different pollution combinations, while quantum chemical simulation, including an independent gradient model and localized orbital locator, proved that outer-orbital complexes could be formed by electrostatic interaction between Cd2+/Cu2+ and DEHP. The electron transfer process was analyzed by charge decomposition analyses, and these, combined with bond critical point analyses, revealed that metal ions reduced DEHP stability. The binding energy and binding free energy of different combinations were calculated and analyzed, using the key soil organic matter (SOM) information obtained through pyrolysis gas chromatography mass spectrometry. This effectively explained the adsorption behavior, and showed that SOM polar functional groups played an important role in the effect of heavy metals on DEHP adsorption. The study described here has provided a new basis for understanding the multiple interactions, accumulation, and transformation of pollutants in the soil.The conversion of agricultural biomass into hydrochar has enormous potential to improve soil quality. In particular, hydrochar particles introduced into the natural environment readily bind environmental pollutants. The interaction of hydrochar and pollutants will, however, be impacted by long term natural ageing in the earth surface. The adsorption performance and the associated mechanisms that could be affected by physical or chemical ageing are not yet fully understood. To elucidate the influence of different types ageing on the physicochemical properties and sorption capacity of hydrochar, we systematically characterized the elemental composition, specific surface area, total organic carbon, and functional groups of fresh and aged hydrochar. Norfloxacin (NOR), a typical antibiotic as a model in this study, was used for the sorption performance of different aged hydrochars in the presence or absence of Cu2+. Nigericin sodium nmr The various artificial accelerated ageing methods have been employed such as H2O2 oxidation, HNO3/Hreciprocal effects of natural ageing and coexisting pollutants on a long-term use of hydrochar in the field.Supervision zones in a reclaimed coal mine refer to regions where soil properties are being slowly restored but further management is still urgently needed. The important roles of supervision zones in guiding the ecological restoration of degraded mining areas have been widely recognized, but the delimitation of supervision zones needs further examination. To delineate supervision zones for the restoration of poor soil properties, the soil available phosphorus (SAP), soil available potassium (SAK), soil total nitrogen (STN), soil organic matter (SOM), soil particle fractal dimension (SPD), soil electric conductivity (SEC), and soil pH (pH) at a depth of 0-20 cm were measured in a reclaimed dump in the Antaibao coal mine on the Loess Plateau of China. The spatial distribution of the soil properties was analyzed using geostatistical analysis, a fuzzy c-means clustering algorithm, and pedodiversity analysis. Then, the supervision zones were delimited based on the spatial characteristics of the reclaimed soil properties. The results revealed the following (1) reclaimed soil in the study area was clustered into eight classes, and each soil class had one or more well-recovered soil properties, except for class I. Areas covered with only class I soil were delimited as poor-soil property regions. (2) The spatial distribution of the pedodiversity indexes of the reclaimed soil classes showed obvious aggregation characteristics, with extremely low values occurring mainly in the northeast and south of the study area. Two zones with low values of the Shannon index (H) were delimited as low-pedodiversity regions. (3) Four supervision zones with poor land reclamation effects were delimited based on the analysis of the poor-soil property regions and low-pedodiversity regions, and precise reclamation measures, including crop rotation, fertilization, neutralization, irrigation, and plowing, were proposed for each zone to improve the quality of the reclaimed soil.Extensive research has been performed on the utilization of biochar for pollutant removal via sorption. Additionally, the relationship between sorption strength of organic pollutants by organic matter and nanomaterials and their sorption site energy distribution has been studied. However, the linkage between removal efficiency of organic pollutants and the sorption site energy distribution on biochars is unknown. As a first attempt to address this knowledge gap, three biochars were derived from two plant-origin precursors (corn straw-CS; birch sawdust-BS) and one animal-origin precursor (meat and bone meal-MBM) at 500 °C (CS-500, BS-500, and MBM-500). In addition, two biochars were prepared with CS at 300 and 800 °C (CS-300 and CS-800) to examine the relationship between their site energy distribution and removal efficiency of antibiotics including sulfadiazine (SDZ), sulfamethoxazole (SMX), tetracycline (TC) and ciprofloxacin (CFX) by these materials. Our findings showed that the antibiotic-biochar interactions can be well interpreted with site energy distribution and XPS analysis results.