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'Carcinogenic' scandal prompts US drinking water scrutiny

The Environmental Protection Agency (EPA) is likely to tighten drinking water standards in the US after an Environmental Working Group (EWG) study found dangerous chromium-6 in the tap water of 31 US cities.

Chromium-6 is known to be carcinogenic when inhaled, and the EPA labelled it “likely to be carcinogenic” when imbibed. The EWG called for the EPA to establish a legal chromium-6 limit and to make water suppliers to test for it.

“The water utilities are in a very tough position – often overwhelmed, underfunded. They need help from Washington. ”

Ken Cook, EWG

EPA administrator Lisa Jackson said the EPA “will likely revise drinking water regulations” following the completion of its own research into the metal’s health risks. She discussed the EWG report with senators following its publication in late December.

“EPA will issue guidance to all water systems in the country to help them develop monitoring and sampling programs specifically for chromium-6,” said Jackson.

“Significant technical assistance” – including the provision of technical experts to work with water system operators and engineers – will be offered to the communities with the highest levels of chromium-6.

“The water utilities are in a very tough position – often overwhelmed, underfunded and responsible for providing the safest drinking water they can,” said EWG president and co-founder Ken Cook. “They need help from Washington.”

No legal limit

Water companies are currently required to test for chromium to an upper limit of 100ug/l. However, this limit is for total chromium, which includes both chromium-6 (hexavalent chromium) and harmless chromium-3 (trivalent chromium). There is no legal limit for chromium-6 alone.

California public health officials said on 3 January they were lowering their suggested limit, proposed in 2009, from 0.06ug/l of chromium-6 in drinking water to just 0.02ug/l.

“Industry influence has allowed this contaminant to remain in much of the state’s water for years, endangering millions.”

Ken Cook, EWG

Cook praised the move. “The Obama administration should use California as a model and move quickly to give every state, city and community in the nation the same safeguards against this dangerous chemical,” he said.

Jackson said the results of EWG study’s only provide “a snapshot in time” and do not give a full enough picture. She said: “This assessment still needs to be reviewed by independent scientists as an essential step toward tightening drinking water standards for chromium-6.”

The new figures will feed into an ongoing EPA assessment of chromium-6. “The agency … had already begun a rigorous and comprehensive review of its health effects,” said the EPA. “When this human health assessment is finalized in 2011, EPA will … determine if a new standard needs to be set.”

“Industry influence has allowed this contaminant to remain in much of the state’s water for years, endangering millions, especially infants fed powdered formula mixed with tap water,” said Cook.

Chromium-6 was made famous when legal clerk Erin Brockovich campaigned on behalf of a contaminated California town in 1993, and it is commonly used in industrial processes such as stainless steel and textile dye production.

Chromium-6 in the UK

Like the US, the UK has no legal limit for chromium-6 in drinking water. However, it does have a legal limit for total chromium (chromium-6 together with chromium-3).

Here, the limit is 50ug/l compared with 100ug/l in the US. That looks fairly stringent until you consider that California is pushing for chromium-6 limits to be set at just 0.02ug/l.

However, accurate comparison between the two is rendered almost impossible by the fact that the two countries have very different laws on effluent discharge from the type of industrial factories that produce chromium-6 as a waste product. Even within the US, laws vary from state-to-state as to how much – if any – chromium-6 can be deposited into waterways.

“No water company is permitted to supply a product that is detrimental to public health.”

Drinking Water Inspectorate

Further impacting chromium-6 laws here in the UK is the fact that the concentration limit is accompanied by a vague rule that encourages water companies to stay well below the legal limit.

“The regulations are such that no water company is permitted to supply a product that is detrimental to public health,” said a Drinking Water Inspectorate (DWI) spokesman. For this reason, water companies tend to enforce their own monitoring systems to monitor toxins like chromium-6.

The Environment Agency here in the UK said: “Chromium and its compounds may cause cancer and genetic damage. Excessive exposure may affect the digestive system, kidney, liver, lung, nose, skin and the unborn child. The Environment Agency aims to ensure that environmental exposures are too low to cause such effects.”

The UK legislation controlling releases of chromium are the Surface Waters (Dangerous Substances) (Classification) Regulations, 1997 and Pollution Prevention and Control Regulations.

“The Environment Agency aims to ensure that environmental exposures are too low to cause such effects.”

Environment Agency

At a European and international level, the Pollution of the aquatic environment by dangerous substances EC Directive and the OSPAR Convention for the protection of the marine environment of the North East Atlantic both apply.

The highest level of chromium-6 measured by EWG was in Norman, Oklahoma at 12.9ug/l, which would be low enough to pass under the UK’s 50ug/l limit if chromium-3 levels in the same place were lower than 37.1ug/l – a piece of data that EWG does not supply.

However, whether it would pass the “detrimental to human health” clause is another matter.

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