The U.S. Environmental Protection Agency released preliminary findings Friday that confirm liquid flows through injection wells at the Lahaina Wastewater Reclamation Facility and into West Maui coastal waters via underwater springs close to shore.
But it added that the state Department of Health "has detected no bacterial indicators."
The EPA said Health Department monitoring near the injection wells found bacterial levels that "are low or nonexistent, and well within the range considered safe for swimming."
University of Hawaii researchers conducted the study amid concerns coral reefs and the ocean are being harmed by treated wastewater pumped into the injection wells by the Lahaina plant.
EPA Pacific Southwest Region ground water office manager David Albright said Friday that the study doesn't say the wells are the cause of coral reef decline. He said more research is needed on the issue.
The EPA said researchers put a tracer dye substance into the injection wells near the Kaanapali coast. They later detected the tracer coming out of underwater springs less than 30 yards from the shoreline. It took fewer than three months for the tracer dye to appear at ocean checkpoints.
"However, the results suggest an average travel time (underground) from the injection wells to the submarine seeps in excess of seven months," the EPA reported.
Other results included the temperature, salinity, acid levels, nutrient concentrations and the discharge rate into the ocean.
Mayor Alan Arakawa said that the results from the Health Department "confirm that our ocean water is clean and safe."
"The County of Maui, State of Hawaii Department of Health and the Environmental Protection Agency continue to work cooperatively to obtain the best science to inform our decisions, a process that is ongoing."
The EPA reported that in 2011 Maui County was required to increase its level of wastewater disinfection before it pumps the effluent into the injection wells. It said the county is on schedule to meet EPA requirements to achieve full ultraviolet disinfection of all wastewater at the Lahaina facility by December 2013.
"We now have a much better understanding of the movement of the wastewater injected in Lahaina," said Jared Blumenfeld, EPA's regional administrator for the Pacific Southwest. "Although we continue to collect and analyze data, the findings underscore the need for EPA and the Hawaii Department of Health to consider any and all regulatory tools to ensure protection of public health and the marine habitat, including nearby reefs, in West Maui."
University of Hawaii researchers conducted the study amid concerns from officials and environmentalists that coral reefs and the ocean are being harmed by treated wastewater pumped into the injection wells by the Lahaina plant.
Earlier this year, four community groups sued Maui County, saying millions of gallons of wastewater injected into wells at the facility each day surface off Kahekili Beach Park, killing coral and triggering outbreaks of invasive algae.
The Lahaina Wastewater Reclamation Facility disposes of 3 million to 5 million gallons of treated wastewater daily through four injection wells that send fluid deep underground. The injection wells have a permit from the EPA, which expired but was administratively extended.
The study began in July 2011 and was funded by the EPA, the U.S. Army Corps of Engineers and the state Health Department. Researchers will continue to collect data from water samples from effluent discharge points until the end of this year. A final report is expected in June.
To see the interim report, go online to www.epa.gov/region9/water/groundwater/uic-permits.html#lahaina.