Posted on: Thursday, December 12, 2002

Maui cuts level of zinc additive

By Christie Wilson
Advertiser Neighbor Island Editor

WAILUKU, Maui — The Maui County Department of Water Supply yesterday began reducing levels of a chemical used to remove lead in the Upcountry water system that some residents blame for skin and eye irritations.

The department already was planning to cut back the amount of zinc orthophosphate once it had done its job, but the schedule is being moved up because of the concerns, said spokeswoman Jacky Takakura.

About 50 complaints have been received since June 2001, when the department began adding the chemical to the Upcountry system by order of the Department of Health. The source of the complaints has not been confirmed and there appears to be no pattern in the location of the affected homes or the type of plumbing used, she said.

The Upcountry area relies on surface water from rainfall, which does not have the naturally occurring minerals contained in groundwater that coat the inside of water pipes and prevent leaching, Takakura said. Rainwater also is more acidic and more likely to corrode metals.

The water department tried other methods of controlling lead contamination — a serious health threat to children and pregnant women — but nothing else was effective, she said.

Zinc orthophosphate is commonly used in large water systems throughout the country. Takakura said she conferred with other water utilities and found no reports of itchy skin or eye irritations.

National standards set safe use of the chemical at 15.6 parts per million. Zinc orthophosphate was added to the Maui water at a concentration of 3 parts per million, Takakura said. Now that the department is in compliance with the order to reduce lead levels, it began flushing the system yesterday and lowering the amount of zinc to 2.5 ppm. Over the next five to six months, that amount will be reduced to 1 or 1.5 ppm, she said.

"We've got to walk a fine line because we don't want to fall out of compliance with lead levels," she said.

Water consumers can request free lead testing by calling the department's lab at (808) 270-7550.