Sixty-five percent of Taiwan’s reservoirs were eutrophic during a water shortage last year, the Environmental Protection Administration (EPA) said this week.
Eutrophication affected 35 of Taiwan’s 55 reservoirs last year, while the oligotrophic Feitsui Reservoir (翡翠水庫), which supplies the Taipei metropolitan area, had the best water quality, the EPA said.
Eutrophication is caused by an excess of nutrients, which results in a buildup of plant life that limits the benefits of light and oxygen in water.
Photo: Lin Ching-hua, Taipei Times
Mesotrophic water contains a moderate amount of nutrients, encouraging the growth of submerged aquatic plants, while oligotrophic water is clear and of higher quality.
The EPA regularly analyzes water samples from reservoirs, including 20 major reservoirs and six minor ones on Taiwan proper, and 26 on outlying islands. It monitors the water quality of key reservoirs monthly and general reservoirs quarterly.
Eight major reservoirs on Taiwan proper were eutrophic — Shihmen Reservoir (石門水庫) in Taoyuan, Baoshan Reservoir (寶山水庫) in Hsinchu County, Mingde (明德水庫) and Liyutan (鯉魚潭水庫) reservoirs in Miaoli County, Baihe (白河水庫) and Jingmian (鏡面水庫) reservoirs in Tainan, and Chengching Lake (澄清湖水庫) and Fengshan Reservoir (鳳山水庫) in Kaohsiung — while 11 reservoirs were mesotrophic, the EPA said, citing its water quality report for last year.
Among the six minor reservoirs on Taiwan proper, Dapu Reservoir (大埔水庫) in Hsinchu County, Toushe Reservoir (頭社水庫) in Nantou County and Agongdian Reservoir (阿公店水庫) in Kaohsiung were eutrophic, while the other three were mesotrophic, the report said.
All of the reservoirs on the outlying islands were affected by eutrophication, it said.
Hou Chia-hung (侯嘉洪), a professor at National Taiwan University’s (NTU) Graduate Institute of Environmental Engineering, on Monday said that precipitation levels can affect a reservoir’s water quality.
If there is not much rain, an excess of nutrients such as nitrogen and phosphorous stimulates algal growth, a phenomenon called “algal bloom,” Hou said.
Eutrophication causes concern, as algae can produce toxins that might be harmful to human health, although algae can be completely removed in water treatment processes, he said.
However, eutrophication makes tap water more difficult to process, especially when it comes to deciding how much algae remover is needed, he said.
Taiwan Water Resources Protection Union director Jennifer Nien (粘麗玉) said that last year’s shortages almost dried up some reservoirs and caused serious algal blooms.
Due to eutrophication, water purification plants would add more chemicals to water to remove the algae, Nien said.
EPA Office of Water Quality Protection head Yen Hsu-ming (顏旭明) said that eutrophication is evaluated using the Carlson trophic state index, which is determined by the level of suspended chlorophyll-a solids and the transparency of the water.
If the chlorophyll-a levels are too high, it can be inferred that eutrophication is due to an algal bloom, which can be resolved by removing the algae, Yen said.
However, if the eutrophication is caused by “reservoir killer” microcystis, ingesting the water might cause acute gastroenteritis, dermatitis, hepatitis or cancer, he said.
However, the possibility of contracting such diseases from drinking tap water is low and the EPA checks water quality regularly to ensure it is safe, he said.
The EPA tests water before and after it is treated, he said.
Lin Yi-pin (林逸彬), a professor at NTU’s Graduate Institute of Environmental Engineering, said that people should not worry too much about water quality, as it is carefully monitored at multiple stages.
Considering that most countries issue more than five denominations of banknotes, the central bank has decided to redesign all five denominations, the bank said as it prepares for the first major overhaul of the banknotes in more than 24 years. Central bank Governor Yang Chin-lung (楊金龍) is expected to report to the Legislative Yuan today on the bank’s operations and the redesign’s progress. The bank in a report sent to the legislature ahead of today’s meeting said it had commissioned a survey on the public’s preferences. Survey results showed that NT$100 and NT$1,000 banknotes are the most commonly used, while NT$200 and NT$2,000
The Centers for Disease Control (CDC) yesterday reported the first case of a new COVID-19 subvariant — BA.3.2 — in a 10-year-old Singaporean girl who had a fever upon arrival in Taiwan and tested positive for the disease. The girl left Taiwan on March 20 and the case did not have a direct impact on the local community, it said. The WHO added the BA.3.2 strain to its list of Variants Under Monitoring in December last year, but this was the first imported case of the COVID-19 variant in Taiwan, CDC Deputy Director-General Lin Ming-cheng (林明誠) said. The girl arrived in Taiwan on
South Korea is planning to revise its controversial electronic arrival card, a step Taiwanese officials said prompted them to hold off on planned retaliatory measures, a South Korean media report said yesterday. A Yonhap News Agency report said that the South Korean Ministry of Foreign Affairs is planning to remove the “previous departure place” and “next destination” fields from its e-arrival card system. The plan, reached after interagency consultations, is under review and aims to simplify entry procedures and align the electronic form with the paper version, a South Korean ministry official said. The fields — which appeared only on the electronic form
The Ministry of Foreign Affairs (MOFA) is suspending retaliation measures against South Korea that were set to take effect tomorrow, after Seoul said it is updating its e-arrival system, MOFA said today. The measures were to be a new round of retaliation after Taiwan on March 1 changed South Korea's designation on government-issued alien resident certificates held by South Korean nationals to "South Korea” from the "Republic of Korea," the country’s official name. The move came after months of protests to Seoul over its listing of Taiwan as "China (Taiwan)" in dropdown menus on its new online immigration entry system. MOFA last week
RSS