In the Hsinchu area, most of the drinking water comes from the Touqian Creek. As early as 1983, over 90% of the Touqian Creek watershed was designated as a "drinking water quality and quantity protection zone" under the Water Supply Act, with the aim of effectively protecting water resources and regulating related development and land use activities.
However, for Professor Chou Hsiu-Chuan, director of the Institute of Environmental Sciences at National Chiao Tung University, "Touqian Creek is like a glamorous warrior with deep scars." Although its water quality test results seem clean, significant hidden concerns exist, and it is even facing a "wolf in front and tiger behind" situation, much like a warrior about to face a life-and-death struggle.
Chou noted that it is hard to believe that the water quality testing results for Touqian Creek have consistently ranked among the best nationwide regarding river quality. This is because the Environmental Protection Administration measures river pollution indicators (River Pollution Index, RPI), focusing on ammonia nitrogen, dissolved oxygen, biochemical oxygen demand, suspended solids, and other organic substances, without including emerging pollutants or heavy metals.
Under Chou's leadership, a research team from National Chiao Tung University began work on sediment testing and biological toxicity studies related to Touqian Creek in June 2023. They sampled surface and deep sediments from various locations along the creek, including the Machhai section of Youluo Creek, Luliao Creek, Long'en Weir, and the Nanya water intake, conducting relevant pollutant and bio-toxicity analyses.
Chou stated that although the team previously conducted research on the Kejia Creek for many years, the pollution situation in Touqian Creek is more severe. Testing revealed that the sediment contained eight heavy metals, with "nickel" exceeding the lower limit of domestic sediment quality standards, thus requiring increased testing frequency. Compared to U.S. Environmental Protection Agency (US EPA) sediment standards, nickel is classified as heavily polluted, while zinc, chromium, and arsenic fall under moderate pollution.
Moreover, in terms of biological toxicity analysis, the team used extracts from river sediments to test cell survival rates and found them to be very poor, particularly noting that renal cells "suffered greatly," which could pose threats to human health through the food chain.
Chou pointed out a unique aspect of sediment: it acts as a repository for environmental pollutants. Pollutants from air, water, or soil will accumulate in the sediment, where they can both adsorb and desorb, making it a composite indicator of environmental pollution rather than merely a drinking water indicator. Sediment and water quality tests have different standards; for heavy metals, the sediment standard must exceed the water standard by 1000 times to be considered polluted.
Some may argue, "I drink water, I don’t eat dirt," but Chou emphasized that the desorption of pollutants remains a concern. Once these pollutants desorb, they can still come into contact with aquatic organisms, crops, or irrigation water.
The NCTU team compared these pollutants across different seasons and found that whether testing wet soil, dry soil, or leachate from centrifuged soil, the heavy metal content during the wet season is higher than in the dry season, indicating that water disturbances can stir up these heavy metals.
Chou believes that contamination factors (CF) and pollution load index (PLI) can complement the existing river pollution indicators (RPI) to effectively quantify the potential risk levels of heavy metals (toxicity coefficients), thereby enhancing the reflection of current water quality pollution status.
She also suggested that invisible hazards may return to the human body through drinking water and food. Hsinchu is a major hub for the semiconductor industry, which could generate emerging pollutants and heavy metal contamination, presenting a serious issue that must be addressed. "The government needs to take the initiative and accelerate improvement efforts; in addition to constructing public sewage systems, there should also be independent and stricter measures for water source testing."