The Effectiveness of Arsenic Remediation from Groundwater in a Private Home     

Elizabeth Pratson  Avner Vengosh  Gary Dwyer  Lincoln Pratson  Emily Klein 《Ground Water Monitoring & Remediation》2010,30(1):87-93

Private wells are the source of drinking water for approximately 15% of households in the United States, but these wells are not regulated or monitored by government agencies. The well waters can contain arsenic, a known carcinogen that occurs in groundwater throughout the nation at concentrations that can exceed the Maximum Contaminant Level defined by the U.S. Environmental Protection Agency (10 ppb). In order to reduce arsenic exposure, homeowners can either rely on bottled water for drinking or install in-house water treatment systems for arsenic removal. Here, we document the arsenic levels associated with these options. We examined 24 different major bottled water brands and found that all have arsenic levels <1.5 parts per billion (ppb), and more than half have levels below our measurement detection limit of 0.005 ppb. For in-house treatment systems, we examined the performance of arsenic removal by point-of-use reverse osmosis filtration, and by whole-house and point-of-use filters containing granulated ferric oxide. Our results show that long-term (2 years) filtration with granulated ferric oxide reduced arsenic in well water from an initial concentration of 4 to 9 ppb down to <0.005 ppb, validating this technology as an effective form of arsenic remediation for private homes.  相似文献   

Physico-chemical characteristics and pollutants of the benthic environment in the Montevideo coastal zone,Uruguay     

Muniz P  Venturini N  Martínez A 《Marine pollution bulletin》2002,44(9):962-968

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The Continuum Voronoi Block Model for simulation of fracture process in hard rocks     

Erick Rgenes  Mrcio Muniz de Farias  Leandro Lima Rasmussen 《国际地质力学数值与分析法杂志》2022,46(1):89-112

In this paper, a numerical model is presented to represent the fracture process in hard rocks based on a pseudo-discontinuum method called the Continuum Voronoi Block Model (CVBM). To validate this tool, numerical models for one Brazilian test, one unconfined compression test, and multiple triaxial compression tests with different confining stress were calibrated to match laboratory test results for Creighton granite. The model proved robust and matched the following macro-properties: crack initiation (CI) stress, (CD) stress, peak strength, tensile strength, Young's Modulus, and Poisson's ratio. The calibrated model served as a basis for a sensitivity study to analyze how micro-properties influence the rock's macroscopic responses. From the sensitivity study, a calibration methodology was proposed, which shall facilitate the use of the CVBM in future works.  相似文献