EPA's Chromium-6 Guidance Said to Raise More Questions for Water System Operators

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The Environmental Protection Agency needs to advise water systems about how to inform the public about the levels of hexavalent chromium in drinking water and say how it plans to use the data collected by the water systems, representatives of public and rural water utilities told BNA.

During interviews Jan. 13-14, public water groups such as the American Water Works Association said they recognize the need for monitoring hexavalent chromium, also known as chromium-6.

However, EPA's recently released guidance on enhanced monitoring of hexavalent chromium in drinking water supplied by community and nontransient noncommunity water systems raises more questions than answers, representatives of the water systems say.

“What do utilities do with this data once we have collected it?” Alan Roberson, AWWA's regulatory affairs director, asked. “… If you do decide to collect the sample what do you tell your customers?”

EPA released guidance Jan. 11 for enhanced monitoring of hexavalent chromium that asks water systems--be they public or private, urban or rural--to take quarterly samples at three different stages:

• untreated water at intakes or wells,

• treated water by drinking water treatment plants prior to their entry into the distribution system, and

• during the time the water circulates through the distribution system.

It also seeks sampling of groundwater systems on a semiannual basis. The regulatory guidance does not require sampling, however (8 DEN A-4, 1/12/11).

Determination on Chromium-6 Due in 2011.

EPA said it issued the guidance in response to recent concerns, including a report by the Environmental Working Group, that hexavalent chromium could pose health concerns if consumed over long periods of time. It comes as EPA works to finalize a report assessing the health effects of hexavalent chromium, which is scheduled to be completed in June.

EPA is proposing to classify chromium-6 as likely to be carcinogenic to humans via ingestion. The agency expects to complete the health risk assessment and make a final determination about the carcinogenicity of chromium-6 in 2011.

Hexavalent chromium enters water from metal-plating facilities, steel mills, pulp mills, and some other industrial activities. The metal also occurs naturally but typically it is converted into trivalent chromium, a less harmful metal, in plants and animals, including in humans.

An EPA spokesman was unavailable to respond to questions about how it would use the data utilities collect.

Roberson said EPA is asking utilities to monitor “voluntarily” for hexavalent chromium at the parts-per-trillion (ppt) level, while it currently requires total chromium levels, which include hexavalent chromium, to not exceed 100 parts per billion in drinking water.

In its guidance, EPA said laboratories can use a modified analytical ion chromatography method for detecting hexavalent chromium at 20 ppt and reporting limits of 60 ppt. It said “the analytical instrumentation required for EPA Method 218.6 is not uncommon in drinking water laboratories; however, many laboratories may not be 'set-up' to offer this analysis.”

Public water organizations said they are concerned about the lack of laboratories available to conduct this level of testing.

EPA has provided a link to laboratories in California that are certified and equipped to detect hexavalent chromium at the suggested levels, but it said it is reaching out to laboratories across the country to establish a national drinking water laboratory capability.

Risk Communication Absent.

Public drinking water utilities are not only concerned about the low detection limits that would stretch the capabilities of the detection instruments, but also about how to communicate the level of risk posed by detection levels as low as 20 ppt to the public.

“The risk communication piece is missing from this guidance,” Roberson said.

Besides, Roberson and other groups representing the public drinking water utilities are concerned about the data's utility.

“The utilities will have the data. There's no centralized place to send this data,” Roberson said.

Currently, community water systems and nontransient community water systems, such as schools and factories supplying their own water, are only required to test for total chromium at the entry points to the distribution systems. But these systems are now being asked to monitor for hexavalent chromium at entry points prior to being treated, after being treated, and while the water is flowing through the distribution systems.

EPA Should Provide Health Analysis Data.

Diane VanDe Hei, executive director for the Association of Metropolitan Water Agencies (AMWA), noted that hexavalent chromium is regulated under EPA's maximum contaminant level (MCL) for total chromium, which was developed based on a health-effect endpoint for hexavalent chromium that is allergic dermatitis.

VanDe Hei said EPA is completing a health risk assessment of hexavalent chromium. A health risk assessment under the Safe Drinking Water Act is required before the agency can regulate a contaminant.

“Under the SDWA, there is a scientific process EPA must follow to develop drinking water regulations, and that process is already under way,” VanDe Hei said, adding that the Environmental Working Group, which raised the alarm about this toxic metal, ought to share the data and the methodology upon which it found that hexavalent chromium in 31 samples taken from 35 states were above the levels proposed by California.

“This data ought to be made public so that it can be corroborated and verified as are other studies that inform regulations,” VanDe Hei said. “So far, EWG has been unwilling to do so.”

Mike Keegan, analyst for the National Rural Water Association, agreed with VanDe Hei that EPA and EWG should make the health-effects data and chemical analysis data available for public review. Like AMWA, NRWA has had no luck obtaining the data.

Moreover, Keegan said small, particularly rural, communities are already chafing under the burden of existing set of drinking water regulations.

“We believe EPA should change their current drinking water standards and enforcement policy so it is not unfair and harmful to small and rural communities before adding to the number of regulations,” Keegan wrote in an e-mail to BNA.

Keegan was referring to a provision in the Safe Drinking Water Act, as amended in 1996, that allows states to grant variances to small public water systems that have difficulty complying with national drinking water standards, if EPA determines that affordability is a problem. Variances have not been granted, however, under the criteria EPA put in place in 1998. That has been a sore point for the National Rural Water Association, which has advocated that EPA adopt criteria that allow for workable variances before imposing additional laws (108 DEN A-7, 6/9/09).

By Amena H. Saiyid

EPA's Guidance for Public Water Systems on Enhanced Monitoring for Chromium-6 (Hexavalent Chromium) in Drinking Water is available at http://water.epa.gov/drink/info/chromium/guidance.cfm.