Smelly tap water supplied to residents

By Kim Tae-jong

A harmful algal bloom has been detected in the water system of the Bukhan River, a source of piped water for residents in Seoul, affecting the taste and smell of tap water in many parts of the capital and surrounding areas, environmental authorities said Friday.

Due to the bloom, there have been a slew of complaints about an earthy taste and odor from the tap water. As of Dec. 7, 307 complaints from Seoul and 1,519 from Gyeonggi Province have been received by the water quality control authorities.

The algal bloom was spotted early last month, and is due to the unusually warm weather and decreased amount of rainfall in the past few months, according to the Ministry of the Environment.

“It is a really rare occurrence in the winter season,” an official from the ministry said. “A small algal bloom is usually detected for a short time between June and August. The decreased precipitation and unusually warm weather seems to have led to the current algal bloom.”

The country has witnessed unusually warm weather in the past few months, as the average November temperature hit the highest level on record, according to the weather agency.

The average temperature for November reached 11 degrees centigrade, and it consequently led to an increase in the water temperature of the river to over 8 degrees, up from the average of 5.6 degrees during this time of year.

The total precipitation in September and October dropped to 95 millimeters, down from 521 millimeters from the same period last year.

The ministry said the earthy taste and smell stem from a high concentration of geosmin, which is produced in the bloom.

The concentration in sampled water stood at 45 to 270 parts per million, higher than the permitted level of 20, it said.

But it does not pose any health hazard, and it is also possible to remove the bad taste and smell by boiling the water for more than 3 minutes, it said.

“People can be assured that the taste and odor issues they may be experiencing in their tap water do not pose any health risks,” the official said.

But the ministry will keep monitoring water quality and continue efforts to tackle the problem in cooperation with other government bodies such as the Korea Water Resources Corporation and Korea Environment Corporation, he said.

As one of the measures, they have now increased the total amount of discharged water reserved in the dams located on the upper part of the river.