Chemical’s Safe Level Based on 2 Weeks’ Exposure
Morgantown Dominion Post
23 April 2014
CHARLESTON — When federal officials decided what chemical levels
West Virginians could safely consume in water tainted by a January
spill, their standard assumed people would be exposed for two
weeks, not 100-plus days.
Months later, Centers for Disease Control and Prevention (CDC)
officials see no reason to adjust a chemical benchmark they
quickly created off limited lab rat research. However, a local
health official argues the CDC needs to account for ongoing
chemical exposure, even if it’s minimal.
Until Democratic U.S. Sen. Joe Manchin asked last week, CDC never
revealed how long its safety mark assumed everyday contact with
chemical-laden water. For months, the CDC said the level accounted
for the “short-term,” but hadn’t conveyed a firm timeframe. Gov.
Earl Ray Tomblin told The Associated Press on Monday he wasn’t
informed what “short-term” meant.
Richard Denison, a scientist with the Environmental Defense Fund,
cautioned that even a new, more protective long-term standard
would have the same flaw: No one knows exactly how much people
were exposed to the chemical, and little toxicity data is
available on long-term implications.
For four to 10 days, starting Jan. 9, 300,000 people in nine
counties faced a tap-water ban until the regional water plant and
various hydrants met the CDC’s mark. Only 11 people’s homes were
tested, all more than a month after the spill.
In tests in late March, chemical traces well below the safe level
were leaching off the water plant’s filters and flowing to
people’s home taps. West Virginia American Water started changing
the first of its contaminated filters April 1, but the full slate
of 16 might not be replaced until late May. Small chemical levels
will keep entering the water system until then, researchers say.
The longer someone is exposed to a chemical, the lower the safe
level should be, local health officials have argued.
CDC spokeswoman Bernadette Burden said there’s no reason to
believe anyone will have adverse health effects from trace
chemicals in their taps, including at previous lab detection
limits that were 100 times lower than the safe drinking mark.
Comparatively, the chemical found leaving the water plant last
month was 2,000 times lower than the safe standard.