Trace levels of selenium have been detected for the first time in the Lahaina Water System during routine water testing, according to the Maui County Department of Water Supply.

The system serves Lahaina, Honokowai and Napili. Samples collected Sept. 29 and Oct. 23, at the point where treated water enters the distribution system, detected selenium levels ranging from 6 micrograms to 7.4 micrograms per liter.

According to the EPA and the Hawaii Department of Health, the maximum contaminant level for selenium in drinking water is 50 micrograms per liter — the highest concentration considered safe for lifelong consumption based on known health risks.

“The levels of selenium detected are very small and far below safety limits,” water director John Stufflebean said Monday. “Our community’s health and well-being are at the heart of everything we do, and we will continue monitoring water quality to ensure it remains safe for daily use.”

Selenium is a naturally occurring mineral found in soil, rocks and certain mineral deposits. It can enter drinking water resources naturally through erosion and human activities, such as irrigated agriculture.