A surprising jump in lead levels in Washington, D.C., drinking water is being blamed on corrosive water resulting from a regimen of treatments needed to address contaminants.
The levels have forced EPA to reexamine how it sets acceptable lead levels and treatment protocols for municipal drinking water, said Benjamin H. Grumbles, EPA acting assistant administrator for water, at a congressional hearing on March 5.
Last week, the agency also announced a plan that is likely to make the District's water system the nation's most studied.
The scheme creates a 32-member expert team to examine the city's water treatment program and propose a treatment plan by mid-April. It also requires free bottled water or filters to be provided to 23,000 homes and businesses with lead service pipes; replacement of lead pipes; and a water sampling program for homes without lead pipes since they, too, have shown high lead levels.
The city has a history of water problems with lead, but the severity of the current levels was discovered in routine tests in July 2002, EPA says. Further testing showed high lead levels for two-thirds of some 6,000 homes--in some cases, more than 20 times above action levels of 15 ppb.
The discovery resulted in rounds of finger pointing by EPA; elected District officials; the Army Corps of Engineers, which is responsible for water treatment; and the District's Water & Sewer Authority, which sells and distributes the water. Adding to the agencies' woes is a lack of public trust, the result of their failure to announce the problem, which was made public only last month in news accounts.
District Mayor Anthony Williams told reporters that he blames the corrosion on the addition of chloramines to the city's drinking water. Chloramines began to be added in November 2000 to reduce carcinogenic disinfection by-products created when high levels of chlorine, the primary bacterial disinfectant, is added to drinking water.
In the 1990s, the District faced several incidents of bacterial contamination, which led briefly to EPA recommendations that residents boil drinking water. The chloramines are required by EPA, says Thomas P. Jacobus, the Army Corps water treatment manager, who says that chloramines are not responsible for the corrosion.
However, other water experts disagree and recommend that phosphate-based corrosion inhibitors be added, a path chosen by other cities. Jacobus, however, rejected that choice because it would require the District's sewage treatment facility to remove the phosphates before discharging treated sewage to the Potomac River.
Along with water testing, the area has begun a large blood testing program, mostly for children.