Monday, December 20, 2010

Milwaukee Water Works Statement On Chromium, National Water Analysis

The Milwaukee Water Works, responding to inquiries and reporting this weekend about a toxic metal showing up in a sample of drinking water in Milwaukee and other communities (Madison, according to the national report, seems to have a worse situation), has sent me this statement and will post it on its website.

Consumer Information about Chromium-VI -- Dec. 20, 2010

There is a news story today about a study by an environmental advocacy group that says America’s drinking water is contaminated with Chromium-VI or Hexavalent Chromium, a chemical that came to national attention in the 2000 feature film Erin Brockovich.  The Environmental Working Group (EWG) released a report on its recent study of Chromium-VI, as found in water samples the EWG gathered from many cities that have previously detected Total Chromium. The EWG wants the U.S. Environmental Protection Agency (EPA) to set a legal limit for Chromium-VI and require water utilities to test for the chemical.

Consumers can be assured Milwaukee drinking water meets all EPA regulatory requirements for safe and healthful drinking water. The Milwaukee Water Works (MWW) is committed to protecting public health.

The EPA, in its Safe Drinking Water Act (SDWA), regulates Total Chromium in the finished water leaving the treatment plants. The allowable limit per EPA is 100 micrograms/L or parts per billion. The EPA does not currently regulate Chromium-VI.

The Milwaukee Water Works tests annually for Total Chromium as required by the SDWA. The most recent test in 2010 found no Total Chromium. The detection limit for MWW analyses for Total Chromium is 2 micrograms/L, so MWW reports <2 micrograms/L (less than 2 micrograms/L). In previous years, Total Chromium was measured between none detectable and 9 micrograms/L. MWW has not previously tested specifically for Chromium-VI, but has arranged to test for it in the finished water and distribution system. 

EPA is evaluating new health effects data on Chromium-VI. The evaluation is expected to be completed in late 2011. MWW is prepared to respond in a way that protects public health and meets federal and state standards.

The Milwaukee Water Works tests source and treated drinking water for over 500 contaminants even though the EPA requires tests for only 90. This is done as a precaution to ensure safe water, to collect baseline data for study and to meet future regulations. To ensure the public is fully aware of all water quality monitoring data, MWW publicizes it in the annual consumer confidence report and on its website.

The Milwaukee Water Works treats Lake Michigan water in a multiple-step process to remove illness-causing microorganisms and contaminants. The water is disinfected with ozone, a highly reactive gas that destroys microorganisms, removes taste and odor, and reduces byproducts from chlorine disinfection. Coagulation, settling, and biologically active filtration remove additional particles. Fluoride is added for dental health. Final chloramine disinfection ensures safe drinking water throughout the distribution system and at consumer faucets.


Riverkeeper said...

I'm glad that MWW responded so quickly, but they really don't address many of the issues raised in the report. MWW states its results for total chromium of less than 2 ppb (ug/l). Total chromium is largely made up of trivalent chromium (which is needed for metabolism of glucose) and chromium-6, which is cancer causing.
EPA is pondering whether putting in standards for chromium-6, and that should be supported. CA is proposing a limit of .06 ppb for chromium-6 to protect public health. The study here found our chromium-6 limit to be .18 ppb, which is triple that standard. Given our total chromium limit of 2, this seems like a plausible number as we are not required to test for this yet. Most studies I've seen suggest that 50-70% of total chromium is generally chromium-6 depending on local conditions and source of drinking water (groundwater being more sensitive to this pollution). I find it concerning that levels from Lake Michigan seem so high (Chicago had same .18 ppb). Clearly, we have a heavy history of tanneries, mills, etc that used chrom-6, but am still pretty surprised by that number given mass dilution of lake. If numbers are confirmed low in plant, than seems to make sense to look at the collection system. Its good to hear that MWW is already looking into this!

James Rowen said...

Thank you, Riverkeeper. And I agree - - props to the utility for a fast response and intention to test further.

Its the feds who have dropped the ball.

Anonymous said...

Given the mass dilution and the level detected, one can only imagine the environmental damaged that potentially could have been caused by midnight dumping from industries all around Lake Michigan over the last century.

Frightning thought, isn't it?

Anonymous said...

Riverkepper, how do you remove chrome-6 from a public water utility? Does anybody currently do this or is it uncharted territory?

Thanks for the science lesson! I always enjoy your informative talking points.