CRYSTAL QUEST® Double Undersink Arsenic Water Filter. Quick and easy to install and use, stylish, convenient and effectively removes arsenic and hundreds of contaminants from water. Water travels through 7 stages of filtration First, water travels through an Arsenic-selective resin cartridge designed specifically for reducing arsenic. Click here for product data. Second, through a 6-stage cartridge - # Provides (1-3 years) of quality safe and pure water.. Click here for more information Easy to use and install on all standard sinks. Arsenic (As) is not easily dissolved in water. Therefore, if it is found in a water supply, it usually comes from mining or metallurgical operations or from runoff from agricultural areas where materials containing arsenic were used as industrial poisons. Arsenic in water has no color, taste or odor Arsenic and phosphate easily substitute for one another chemically, therefore commercial grade phosphate can have some arsenic in it. Arsenic is highly toxic and has been classified by the US EPA as a carcinogen. which was derived from toxicity considerations rather than carcinogenicity. The current MCL for arsenic is 0.010 mg/l as of 01/23/06. Information about arsenic in water can be found on the US Environmental Protection Agency website: www.epa.gov/safewater/arsenic.html.