What causes discoloration on sinks, tubs, and toilets? If the stains or water are blue-green in color, then most likely, corrosion of copper is occurring within the household plumbing. Stains that are various shades of yellow, tan, brown, black, orange, or red can indicate the presence of metals other than copper. Two other metals that are typically to blame for staining are iron and manganese. While these minerals serve as essential nutrients for your body, they aren’t so kind to plumbing fixtures, appliances and even clothing. Reddish and yellow-tan discoloration is often caused by iron, while black or dark brown discoloration points to manganese. Due to their similarities and their frequent occurrence in tandem, iron and manganese are generally treated in much the same way. Discoloration usually results from the exposure of these metals to oxygen, known as oxidation. In your plumbing, water often has limited exposure to oxygen, keeping any s...
Aqueous chlorine reacts with certain organic materials present in water sources to form trihalomethanes (THMs). Long-term exposure to these harmful byproducts of disinfection has been linked to an increased risk of cancer and infant birth delivery problems. It is estimated that THMs in drinking water are responsible for as many as 2-17 percent of the bladder cancers diagnosed each year in the United States. To protect the public, the U.S. Environmental Protection Agency has established a maximum contaminant level of 0.08 milligrams per liter (mg/L) for THMs. To conform to these regulations, many municipal water supplies have switched to an alternative method of disinfection using chloramination; more than 1 in 5 Americans uses drinking water treated with chloramines. Chloramination involves the addition of anhydrous or aqueous ammonia (NH 3 ) before or after the addition of chlorine (HOCl) to produce monochloramine (NH 2 Cl). This reaction is as follows: N...
Health Advisories! EPA has established health advisories for PFOA and PFOS based on the agency’s assessment of the latest peer-reviewed science to provide drinking water system operators, and state, tribal and local officials who have the primary responsibility for overseeing these systems, with information on the health risks of these chemicals, so they can take the appropriate actions to protect their residents. EPA is committed to supporting states and public water systems as they determine the appropriate steps to reduce exposure to PFOA and PFOS in drinking water. As science on health effects of these chemicals evolves, EPA will continue to evaluate new evidence. To provide Americans, including the most sensitive populations, with a margin of protection from a lifetime of exposure to PFOA and PFOS from drinking water, EPA has established the health advisory levels at 70 parts per trillion. What's a health advisory? Health advisories provide information on contaminants ...
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