ENVIRONMENTAL SURVEY UPDATE ARTICLES

REVIEW PANEL EXPECTED TO CAST DOUBT

An upcoming report by an independent panel of scientists is expected to cast doubt on EPA’s proposed revisions to its drinking water standard for arsenic, and may add to the arsenal of industry and municipal pressure to change the standard. A discussion draft of the upcoming report, written by the panel, expresses concerns regarding the proposed standard of 5 parts per billion (ppb), which sources say stem from uncertainties in the risk data the agency used to set the standard, as well as flaws in the agency’s cost determination.

The Science Advisory Board’s (SAB) Drinking Water Committee (DWC) met in late summer to discuss final revisions to a report the committee is developing concerning EPA’s proposed reduction of the maximum contamination level (MCL) for arsenic from 50 ppb to 5 ppb. The SAB was established by Congress to provide independent scientific and engineering advice to EPA on the technical basis for agency regulations.

One source familiar with the issue says that most committee members are coming to the conclusion that it’s difficult to believe 5 parts per billion: is the defensible standard because of uncertainties in the risk data EPA used to arrive at the proposed standard.

The draft raises concerns about a Taiwanese study, which is one of the studies EPA used to arrive at its proposed MCL. According to the draft, the portion of the Taiwanese population that made up the study area had significantly different nutritional and socioeconomic conditions from the rest of Taiwan and from the United States. Due to these and similar concerns, the draft recommends that EPA sponsor its own formal risk assessment for arsenic.

The draft notes, "The DWC also has some reservations related to the agency’s cost projection for the arsenic rule."

(Superfund Report, 9/4/00)