South Gyeongnam governor orders tighter oversight of full water supply chain

South Gyeongnam Province has activated a high-intensity water quality management system after algae alerts at the Nakdong River's Chilseo and Mulgeum-Maeri stations were raised to the "Alert" level. Gov. Park Wan-su received a briefing on the algae situation Monday and issued a special directive — titled "Special Directive for Safe Tap Water Supply" — ordering thorough management of the entire process from water intake and purification through to supply.

Acting on the directive, the province Tuesday activated algae barriers and water-spraying devices at eight mainstream Nakdong River intake stations and optimized advanced purification processes using ozone and activated carbon to significantly strengthen the removal of algae toxins and odor-causing substances. Water quality monitoring was also expanded to at least once a week, exceeding the legally required frequency.

The measures come amid a separate incident in which geosmin — an earthy-odor compound — was detected in tap water in the Changwon area. Geosmin is a metabolic byproduct of harmful cyanobacteria; while harmless to humans, it triggers a musty, soil-like smell even in trace amounts and is classified as a monitored substance.

Geosmin concentrations at the Nakdong River's Chilseo station surged to 43 nanograms per liter on June 18 — more than double the reference threshold of 20 ng/L — prompting Changwon city to issue an advisory recommending that residents boil tap water for at least three minutes before drinking for now.

Environmental groups pushed back immediately. The Masan-Changwon-Jinhae branch of the Korea Federation for Environmental Movement held a press conference that day, sharply criticizing the city's credibility, saying geosmin had been detected as early as June 8 yet Changwon did not issue its advisory until June 18 — a delay of nearly 10 days.

South Gyeongnam Province and Changwon city said water quality has since stabilized through an all-out response in the purification process. Cho Hyun-joon, head of the province's balanced development division, made emergency visits Tuesday to the Changnyeong-Haman Weir and the Changwon Chilseo water purification plant for on-site inspections. The inspections confirmed that intensive operation of advanced purification processes — including ozone treatment and activated carbon filtration — had brought geosmin levels to "undetected" status in tests conducted Monday, indicating stable management.

"Geosmin evaporates easily when heated, so boiling tap water as advised is safe until the algae situation fully subsides," a provincial official said. "We will maintain elevated standards for chemical dosing and advanced purification in preparation for the possibility of worsening algae blooms as the heat wave continues, and will concentrate the province's capabilities on water quality management together with relevant agencies."