WAILUKU, Maui — Assurances from a panel of experts appeared to do little yesterday to quell the debate over whether water from two pesticide-contaminated wells in Pa'ia can be safely filtered for drinking.

The panel was convened by Mayor Alan Arakawa to assure residents that the water is safe.

Residents who would be using the water question what amount, if any, constitutes a "safe" level of contamination, and why the wells are being put into regular service when there would appear to be other, cleaner sources available.

In response to their concerns and Arakawa's determination to use Hamakuapoko wells No. 1 and No. 2, the Maui County Council passed an ordinance earlier this month prohibiting the county from using the water for human consumption.

Arakawa, who has not said whether he will veto the bill, yesterday accused critics of stirring up "hysteria that has no basis in science," since treated water from the two wells meets federal and state safe drinking water standards.

"The county is not in the business of killing off the residents of Maui County ..." the mayor said during a public briefing at the Kalana O Maui county building. "If anyone thinks all water should be absolutely pure and clean, that is not reality."

The two Hamakuapoko wells tap into groundwater that contains the carcinogen DBCP, which has the chemical name 1,2dibromo-3-chloropropane, which was used in Hawai'i until 1984. Other chemicals used on pineapple fields that are found in the wells are EDB (ethylene dibromide) and TCP, chemical name 1,2,3trichloropropane.

A granulated activated carbon system is being employed to remove harmful chemicals from the well water, a proven technology already in use on Maui and the O'ahu central plain, which also has a long history of groundwater contamination from pesticides.

One member of the panel experts, University of Hawai'i engineering professor Roger Babcock, said granulated activated carbon — or GAC — has been in use since the 1930s and is the only approved treatment for the pesticides in the Maui wells.

The carbon pulls the contaminants from the water, and once absorbed, the chemicals are not easily released, Babcock said. Water is run through two large tanks containing GAC and monitored at different points in the system to determine when the material is saturated and must be replaced.

Another panel member, Erwin Kawata, water quality director for the Honolulu Board of Water Supply, said GAC filtration has been in use in Central O'ahu for 20 years without incident. The system processes 30 million gallons a day for 200,000 consumers in 'Ewa, Kapolei and Makaha.

"Activated carbon is a simple process and we have found it to be reliable," he said.

Kawata said Central O'ahu has little choice but to use treated water from contaminated wells since virtually all the groundwater sources in the region are tainted from decades of pineapple and sugar farming. He said piping in water from distant, cleaner sources would be unfeasible.

Stuart Yamada of the state Department of Health's Safe Drinking Water Branch joined Kawata and Babcock in endorsing GAC filtration, with all three saying they have no qualms about drinking treated water originating from contaminated wells.

Maui County Councilwoman Michelle Anderson, chair of the Water Resources Committee and the council's most vocal critic of administration plans to use the Hamakuapoko wells, pointed out that Environmental Protection Agency studies to determine "maximum contaminant levels" for various chemicals don't take into account the effects on infants, children, the elderly and infirm, or the cumulative health impacts of ingesting a mix of toxins such as those contained in the two Maui wells.

Yamada agreed that scientific concerns have been raised about the multiple effects of multiple contaminants, but that few studies have been done.

Central O'ahu may not have a choice about its water sources, Anderson said, but Maui does. She and others suggested that money for the Hamakuapoko pipeline and the additional $1.5 million to $3 million to be spent on a separate filtration system to remove nitrates from the well water could be used instead to develop water sources at higher elevations where pesticide contamination is not a problem.

"All things considered, we do have other choices, so why are we putting our population at risk?" Anderson said.

There is also resentment among Pa'ia residents that the water they are now getting from uncontaminated wells at the 'Iao Aquifer in the West Maui Mountains will be taken away to be used for new development in Central and South Maui.

"This is our water and nobody else's," said Frank Domingo, 77, of Pa'ia.

Work began in recent weeks on a $3.9 million project to build 3 miles of pipeline from the Hamakuapoko wells to the Upper Pacia tank, with the water eventually to flow from taps in Pa'ia, Spreckelsville and Ku'au. The intent of the pipeline was to send the 'Iao water back to the Central Maui system, but Arakawa yesterday reassured Domingo that Pa'ia would not be cut off from its current water source.

Department of Water Supply officials seemed taken aback by the mayor's statement. Water Director George Tengan later told the Advertiser that although plans call for returning the 'Iao water to Central Maui, "it would depend on how we run the wells. We could still continue with 'Iao water (in Pa'ia)."

Tengan also said Anderson's notion of using other "clean" wells in the area instead of the Hamakuapoko wells is not practical, since they don't produce enough water to make necessary distribution improvements cost-effective. And since there are few areas in the region that weren't used for farming, drilling of new wells would have to take place at such great distances as to make transmission cost-prohibitive.

Arakawa and others say the ban on use of the two wells would have unintended consequences for the rest of the island. Kula farmer Warren Watanabe, president of the Maui County Farm Bureau, has said that prohibiting use of the two wells could cut off a valuable and safe source of water at a time when Upcountry residents and farmers are facing a water shortage.

The Upcountry water system will be getting an additional 1.3 million gallons a day from the new Po'okela well in Makawao scheduled to go into operation by the end of the year, but water officials said that will provide only temporary relief as demand continues to grow.