The Environmental Protection Administration (EPA) said the results of its first phase of water quality tests at 318 tap water treatment plants across the nation had a pass rate of 99.97 percent.
The administration said it commissioned local environmental protection bureaus to conduct water quality tests using more difficult criteria this year.
Out of the total of 357 tap water treatment plants across the nation, the test results from 318 plants and 38 small water treatment facilities, finished before last month, showed a high qualification rate, an agency official said.
A total of 7,723 water samples were collected and tested for certain substances, said Tung Hsiao-yin (董曉音), a section chief at the Department of Environmental Sanitation and Toxic Substances.
There were only two unqualified water samples, one from a water treatment plant in Hsinyi (信義), Nantou County, which contained an excessive amount of trihalomethanes at 0.0868 milligrams per liter, while the maximum contamination level is set at 0.08mg/L, Tung said.
The other sample came from the Guguan (谷關) water treatment plant in Greater Taichung, which contained excessive levels of bromate at 0.02mg/L, while the permitted level is only 0.1mg/L, she said.
Both plants were fined between NT$60,000 and NT$600,000 and instructed to improve the situation within a given time period, under the Drinking Water Management Act (飲用水管理條例), she said.
It was speculated that the excessive trihalomethanes level resulted from organic substances such as leaves that fell into the water during the chlorine disinfection process, and the excessive level of bromate may be caused by miscalculation of added chlorine, department Director-General Yuan Shao-ying (袁紹英) said.
The EPA has already listed several substances as first-priority test items for a draft filtering test for drinking water — aluminum, DEHP (a plasticizer) and haloacetic acids — while second-priority items include four types of microorganisms such as E. coli and 26 types of chemical substances, such as formaldehyde.
“Although most of the aluminum intake in the human body is from food, not from drinking water, we still list it as a prioritized substance for examination,” Yuan said.
“Many vendors in night markets still use aluminum cooking pots to hold soup or other foods, which may increase consumers’ aluminum intake, so we must enforce stricter standards on drinking water to reduce the public’s health risks,” he said.
Management of DEHP is emphasized in international standards because it does not readily decompose in water, he said.
The draft filtering test is scheduled to be proposed for government approval between late this year and next year, and will guarantee the safe quality of drinking water, he said.