Preliminary results of a study show a tracer chemical put into sewage treatment injection wells in Lahaina has been detected in nearshore waters.

But federal officials said the bacteria levels in the ocean there are low or nonexistent, and well within the range for safe swimming.

A final study by the U.S. Environmental Protection Agency is expected by June.

The preliminary study said officials were doing limited sampling of nutrient seepage along the shoreline as a result of the injection wells.

But the study will not provide an estimate of the amount of nutrients entering the ocean from the injection wells, the agency said.

Critics have argued that nutrient loading from the injection wells has contributed to algae blooms.

Other factors being studied include the temperature, salinity and concentration of nutrients.

The county has been injecting partially treated sewage into injection wells at the Lahaina Wastewater Treatment Plant, about a third of a mile from Kahekili Park, where some water samples were taken.

Earlier this year four groups filed a $60 million lawsuit calling for the county to stop injecting partially treated sewage into the injection wells.

Maui Mayor Alan Arakawa said the study confirms the ocean is safe and clean.

Arakawa said the county will continue to work to obtain "best science" to make decisions.