The CDC has released a study titled “Lead in Drinking Water and Human Blood Lead Levels in the United States” in its Morbidity and Mortality Weekly Report. The report, dated August 10, 2012, reviews publications on childhood lead poisoning, sources of lead exposure for adults and children, and the Safe Drinking Water Act Lead and Copper Rule (LCR) of 1991. Tap water as a source of lead exposure is the focus of the report.
Lead is a common metal that accumulates in the body with disastrous results. In the 1970s, the United States government started to reduce lead concentrations in air, tap water, food, dust, and soil. As a result, blood lead levels (BLLs) in children have been substantially reduced. But children are still being exposed to lead, since many live in housing built before the 1978 ban on lead-based residential paint. Drinking water lines used to be made from lead, and lead solder was used in plumbing. Most of the public water utilities in the country are now in compliance with the LCR.
The effects of lead exposure in children reduces IQ and increases the risk of cancer. BLLs of children in this country increased sharply during the period 1900 to 1975. Regulations that reduced lead exposure included reducing lead in gasoline, foods, food packaging, house paint, water pipes, plumbing fixtures, and solder used in plumbing and beverage containers.
Since the lead bans put in place in the 1970s and 1980s, the average BLL has decreased from almost 16.0 micrograms per decaliter to less than 2.0 micrograms per decaliter. As a point of reference, the BLL for Native Americans before European settlement was 0.016 micrograms per decaliter. That means lead in the blood of children in 2012 is about 100 times higher than ancient background levels, “indicating that substantial sources of lead exposure exist in the environment.”
Lead exposure also affects adults, suppressing the immune system, acting as a carcinogen, and causing peripheral neuropathy and motor nerve dysfunction. Lead exposure can also cause renal failure, gout, and hypertension, as well as suppressing and adversely affecting reproduction.
The Environmental Protection Agency (EPA) has the primary responsibility for ensuring the safety of drinking water, but state and local programs must help ensure that the public is protected from lead exposure. Current water sampling assesses water treatment efficacy, not lead content. The report found that partially replacing lead service lines actually increases lead levels in drinking water. Full replacement of lead service lines should be considered. And information about lead in plumbing should be routinely provided to homebuyers and renters.
And the report recommends that home inspections should focus on the sources of lead, and drinking water in older housing should be tested as a source of lead exposure. The report states that “all sources of lead in the environments of children should be controlled or eliminated.”