[20220203]IF11302_控制公共饮用水供应中的铅.pdf

https:/crsreports.congress.gov Updated February 3, 2022Controlling Lead in Public Drinking Water SuppliesCommunities may face a range of issues associated with aging water infrastructure, including elevated lead levels in tap water. Because of leads toxicity, even at low levels, reducing lead exposures from drinking water and other sources remains a public health priority. Other sources of lead exposure include lead-based paint and contaminated soil and dust from deteriorated lead-based paint. Nationally, the phaseouts of leaded gasoline and lead-based paint, along with regulatory controls and technical changes, have reduced lead exposures. Since the late 1970s, overall blood lead levels in children (ages one to five) have declined an estimated 94%. Sources of Lead in Drinking Water Most contaminants, when found in public water supplies, are detected and treated at the water treatment facility. In contrast, lead occurs in tap water after treated water enters the distribution system, where water is corrosive and lead can leach from pipes, plumbing materials, and fixtures (e.g., faucets). Corrosion is a chemical reaction between the water and the plumbing materials. Factors affectin