NSF International is a not-for-profit organization that develops standards, product testing procedures, and certification services for products including water treatment devices. NSF has certified point-of-use reverse osmosis and distillation devices for the reduction of arsenic in drinking water. Pretreating water through chlorination or oxidation and filtration may be necessary to make reverse osmosis devices effective for arsenic removal. For more information or a list of NSF-certified devices, contact the organization at (800) 673-8010, or visit the Web site at www.nsf.org.
Because of arsenic’s tendency to bind to and precipitate with iron oxide minerals, water treatment installed specifically to oxidize and filter out iron can also remove arsenic to safe levels. Cartridge filters are not sufficient for this purpose. If iron is being removed with water treatment filtration, a treatment device specific to arsenic removal may not be needed. Where iron is present along with arsenic, As levels may fluctuate up and down with Fe content, effective Fe removal is highly recommended upstream of arsenic removal devices such as RO.
Some of the treatment technologies may not be amenable to point-of-entry, or whole-house, treatments. In these cases, point-of-use units, which treat water at the tap, may be the best option.
Following installation of a treatment device, water quality should again be tested to verify the operation of the device. After that, water should be tested at least annually to confirm treatment effectiveness. A maintenance agreement for such devices is highly recommended.
Again, since water quality varies greatly, be sure to have your water tested and consult a local water professional for advice before purchasing a water treatment system.