RESUMEN
Coated fertilizers have been widely used to improve fertility in barren land. However, improving soil structure and water-retention capacity is also essential for arid and semi-arid areas with sandy soils to promote crop growth. Most currently available coated fertilizers rarely meet these requirements, limiting their application scope. Therefore, this study "tailored" pectin-montmorillonite (PM) multifunctional coatings for arid areas, featuring intercalation reactions and nanoscale entanglement between pectin and montmorillonite via hydrogen bonding and electrostatic and van der Waals forces. Notably, PM coatings have demonstrated an effective "relay" model of action. First, the PM-50 coating could act as a "shield" to protect urea pills, increasing the mechanical strength (82.12 %). Second, this coating prolonged the release longevity of urea (<0.5 h to 15 days). Further, the remaining coating performed a water-retention function. Subsequently, the degraded coating improved the soil properties. Thus, this coating facilitated the growth of wheat seedlings in a simulated arid environment. Moreover, the cytotoxicity test, life cycle assessment, and soil biodegradation experiment showed that the PM coating exhibited minimal environmental impact. Overall, the "relay" model of PM coating overcomes the application limitations of traditional coated fertilizers and provides a sustainable strategy for developing coating materials in soil degradation areas.
Asunto(s)
Bentonita , Preparaciones de Acción Retardada , Fertilizantes , Pectinas , Suelo , Agua , Pectinas/química , Agua/química , Suelo/química , Bentonita/química , Preparaciones de Acción Retardada/química , Biodegradación Ambiental , Triticum/química , Urea/químicaRESUMEN
To control the concentrations of pharmaceutical and personal care products (PPCPs) in the surface water of urban and rural areas, it is important to explore the spatial variation in source-specific ecological risks and identify critical sources. Here, we focused on 22 PPCPs found in the effluent from wastewater treatment plants and surface water in Tianjin, and source-specific risk was quantitatively apportioned combining positive matrix factorization with ecological risk assessment. Results showed that rural areas exhibited a more severe contamination level than urban areas. Medical wastewater (30.1 %) accounted for the highest proportion, while domestic sewage posed the greatest threat to aquatic ecosystems. The incidence of potential risks (RQ > 0.01) caused by domestic sewage in urban areas (88.9 %) was higher than that in rural areas (75.9 %). However, PPCP risks caused by farmland drainage, aquaculture, and livestock discharge were mainly distributed in rural areas. The critical source identified in the entire region was domestic sewage (weight, 0.36), and its weight (0.51) in urban areas was greater than that in rural areas (0.32). The impact of aquaculture (weight, 0.16) in rural areas was noteworthy. These findings may contribute to developing environmental management strategies in key areas to help alleviate PPCP contamination worldwide.
Asunto(s)
Cosméticos , Contaminantes Químicos del Agua , Aguas del Alcantarillado , Agua , Monitoreo del Ambiente/métodos , Ecosistema , Contaminantes Químicos del Agua/análisis , Medición de Riesgo , Cosméticos/análisis , Preparaciones Farmacéuticas , ChinaRESUMEN
Compiling information concerning changes in ecological space quality (ESQ) is imperative for urban management and restoration, as proper management promotes sustainable development. Most previous studies have lacked a comprehensive model for evaluating ESQ and are thus unable to provide effective support for decision-makers. Based on the purpose of policy and needs of the public, this paper constructs a comprehensive adaptive evaluation model for mapping ESQ using the Pearl River Delta (PRD) urban agglomeration as an example, and the analysis uncovers the driving forces of urbanization indicators of ESQ change. From 2000 to 2017, the overall ESQ was considered as good, but the overall value decreased slightly, from 52.8 to 51.5. ESQ in the central PRD exhibited a notable downward trend, while coastal cities exhibited an upward trend. There was an approximate negative correlation between ESQ and the urbanization indexes, except for education level and the proportion of primary industry. In the PRD, rural population density, the proportion of primary industry, and education level were the important drivers of magnitude and direction in most cities, but their impacts differed across cities. The ecological management lacked control of in areas good and moderate ESQ, and this was the main factor resulting in the decline of regional ESQ. By quantifying ESQ and the spatially explicit urbanization drivers, the potential for ecological management in the urban agglomeration is also discussed.