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581.
Cecilia Cullen Daniel B. Abrams Devin H. Mannix Walton R. Kelly 《Journal of the American Water Resources Association》2023,59(3):539-553
Winter deicers are a major source of chloride contamination to shallow aquifers in northern latitudes. In the greater Chicago area of northeast Illinois, chloride has been accumulating for decades and in many places now exceeds the United States Environmental Protection Agency secondary standard of 250 mg/L. MODFLOW-NWT and MT3D-USGS were used to simulate the accumulation of chloride with 30 years of data in the shallow aquifer of Will County in northeast Illinois. This aquifer is composed of unconsolidated sediments, largely from glacial deposits, overlying a fractured dolomite bedrock. To calibrate to observed heads and chloride, the model needed refined geologic features, higher chloride concentrations on cells representing commercial or industrial lands, lower chloride concentrations on cells representing roads, and point source areas to speed chloride's emergence in the aquifer. These point sources are locally significant and could represent different anthropogenic or geologic features, such as municipal stormwater infrastructure. Future simulations indicate that chloride is not at steady state in the shallow aquifer and wells are at risk of exceeding the secondary standard if winter deicing applications are not reduced. It may take decades for the full impacts of reduced deicing rates to be observed in wells, owing to the long residence time of water in the aquifer. This transient model calibration was possible because of the 30-year dataset collected by communities and government agencies. 相似文献
582.
Inorganic pollution comprises both major and minor constituents, although only 12 chemical elements may be considered major components. Twenty‐eight elements constitute a group of common minor elements and an additional 13 elements comprise a group of less common minor constituents. Reliable quantitative data are required on the occurrence of these substances in a wide variety of water types, usually at extremely low concentrations. The analysis of standard reference water samples provides information on the overall reliability of water‐quality data. Although most major constituents may be determined with acceptable reliability, determinations of certain minor constituents lack comparable precision; for example, determinations of boron, nickel, and chromium. Few precision data are available on the determination of the less common trace elements. Several comparatively new analytical techniques, such as flameless atomic absorption spectrophotometry, voltammetry, and emission spectroscopy with plasma excitation, appear capable of providing improved sensitivity. 相似文献
583.
584.
随着科技进步和经济发展,地下卤水和岩盐矿床逐步得到开发利用,该类矿床开采引起的环境影响日益受到关注。本文在分析水溶开采岩盐矿钻探工艺和采输工程基础上,重点分析了岩盐矿水溶开采项目环境影响评价中的污染源及源强,着重阐述了重点污染源的环境影响。并针对特征环境影响因素提出了指导性的环境防护措施。 相似文献
585.
泌盐盐生植物研究进展 总被引:39,自引:1,他引:38
根据盐生植物的抗盐生理机制及其形态结构和生态学特征 ,可将盐生植物区分为真盐生植物 (euhalophyte)、泌盐盐生植物 (recretohalophyte)和假盐生植物 (pseudohalophyte)三种类型[1 ] ,每一种类型都有其独特的形态结构、生理功能和生态特征 .泌盐盐生植物体中具有特殊的泌盐结构———盐腺或盐囊泡 ,可将植物体内过多的盐分排到体外 ,故能很好地适应盐渍生境 ,在多种盐渍生境中皆能生存 ,如盐湖、盐漠、盐渍草甸、盐沼等 .中国地域广阔 ,存在各种盐生植物生境 ,但是 ,由于我国专门从事研究盐生… 相似文献
586.
生物有机肥料对温室蔬菜硝酸盐和土壤盐分累积的影响 总被引:1,自引:0,他引:1
探讨了 3种有机肥料对温室苋菜、芹菜硝酸盐和土壤盐分累积的影响。结果表明 :施用有机肥可显著降低蔬菜硝酸盐含量。用 3种有机肥料处理栽培的芹菜NO3- 含量平均值为 2 133mg/kg ,比用蔬菜专用肥 (对照 )的低 1617mg/kg ,其中施用大三元生物有机肥的芹菜NO3- 值最低 ,为 180 3mg/kg,比对照低 1947mg/kg。施用大三元生物有机肥的土壤盐分 (EC)含量也最低 ,0~ 10cm耕层的盐分为 0 0 79S/m ,比对照低 0 0 2 4S/m ;10~ 2 0cm耕层的盐分为 0 0 5 5S/m ,比对照低 0 0 10S/m。 相似文献
587.
This study gives a brief demonstration of impurity removal efficiency upon salt solution treatment of phosphogypsum (PG). The experimental set up has been designed according to a multi-variable Box–Behnken Design (BBD) with stirring time, solid: liquid (PG:salt solution) ratio and temperature as the conducted in various salt solutions. PG sample has been treated with sea water, 5% NaCl and 10% NaCl solutions according to the BBD matrix. Fluoride (F), copper (Cu), manganese (Mn), and nickel (Ni) amounts in the PG sample have been measured upon pre- and post-treatment with salt solutions. Among other operating conditions, temperature has been the dominant factor on fluoride removal efficiency, and responses for the factors determined in the experiment runs indicated that a significant correlation could be established between temperature and fluoride removal, sea water being the most efficient salt solution. Higher copper, manganese, and nickel removal efficiencies have been observed in single salt NaCl solution systems however no significant correlation could be established between factors. Results indicate that pre-treatment of PG located near coastal regions with sea water can be a cost-effective approach and applicable on industrial scale when fluoride removal is of importance. 相似文献
588.
The threatened Marsh Grassbird (Locustella pryeri) first appeared in the salt marsh in east China after the salt marsh was invaded by cordgrass (Spartina alterniflora), a non‐native invasive species. To understand the dependence of non‐native Marsh Grassbird on the non‐native cordgrass, we quantified habitat use, food source, and reproductive success of the Marsh Grassbird at the Chongming Dongtan (CMDT) salt marsh. In the breeding season, we used point counts and radio‐tracking to determine habitat use by Marsh Grassbirds. We analyzed basal food sources of the Marsh Grassbirds by comparing the δ13C isotope signatures of feather and fecal samples of birds with those of local plants. We monitored the nests through the breeding season and determined the breeding success of the Marsh Grassbirds at CMDT. Density of Marsh Grassbirds was higher where cordgrass occurred than in areas of native reed (Phragmites australis) monoculture. The breeding territory of the Marsh Grassbird was composed mainly of cordgrass stands, and nests were built exclusively against cordgrass stems. Cordgrass was the major primary producer at the base of the Marsh Grassbird food chain. Breeding success of the Marsh Grassbird at CMDT was similar to breeding success within its native range. Our results suggest non‐native cordgrass provides essential habitat and food for breeding Marsh Grassbirds at CMDT and that the increase in Marsh Grassbird abundance may reflect the rapid spread of cordgrass in the coastal regions of east China. Our study provides an example of how a primary invader (i.e., cordgrass) can alter an ecosystem and thus facilitate colonization by a second non‐native species. Efectos de Spartina alterniflora Invasora Sobre Locustella pryeri en un Área Donde No Es Nativa 相似文献
589.
通过改变石英砂表面的物理化学性质,提高滤料的吸附效率,并考察其对废水中Zn2+的去除效果。以石英砂为载体,用碱性沉积法制备了镁盐改性砂,测定了镁盐改性砂的比表面积,考察了镁盐改性砂对锌的吸附性能及其影响因素。结果表明,镁盐改性砂的比表面积为1.475 m2/g,比石英原砂比表面积提高了6.12倍;在pH值为中性的条件下... 相似文献
590.