臺灣消毒副產物之時序趨勢分析與極端高溫對土壤逕 流中前驅物的影響

Abstract

由於消毒副產物（DBPs）的廣泛存在及其相關的健康風險，尤其是在環境和氣候條件變化的情況下，DBPs仍然是飲用水安全的主要隱患。本研究利用台灣水務公司和台灣環境部（原環保署）的資料集，分析了台灣各地（包括本島和離島）水處理廠的長期監測資料（2007-2024年）。整體而言，總三鹵甲烷（THMs）、鹵乙酸（HAA5）和溴酸鹽的濃度基本上符合國家監管標準；然而，空間差異顯著。台灣北部和南部地區的平均THM和HAA5濃度較高，這與源水中總有機碳（TOC）含量較高相對應，而台灣東部地區的DBP濃度最低。相較之下，近海島嶼系統顯示出不成比例的高溴化消毒副產物濃度，平均溴化三鹵甲烷和溴化鹵乙酸水平分別為 19.05 μg/L 和 5.28 μg/L，這主要是由於受海水入侵影響的富含溴化物的源水所致。經驗模型表明，溴代三鹵甲烷可根據常規監測的總三鹵甲烷可靠預測（r = 0.85，R² = 0.725），而溴代鹵乙酸與HAA5的相關性較弱。溴取代因子分析進一步揭示了各溴代三鹵甲烷物種之間的非線性關係，顯示在高溴化物條件下，各物種的優勢度發生了變化。 為了探討氣候相關因素對消毒副產物（DBP）生成的影響，實驗室實驗研究了短期極端土壤升溫（25、45 和 65 °C）對徑流水質和 DBP 生成潛力的影響。高溫顯著增強了土壤微生物活性，增加了徑流中溶解性有機碳和氮的含量，並促進了多種 DBP 的生成，包括鹵乙酸（HAAs）、鹵代乙腈（HAN）和鹵代酮（HK）。在 65 °C 下，DBP 相關的細胞毒性比常溫條件增加了約 1.3 倍。強化混凝可有效降低三鹵甲烷（THM）（降低 41–47%）、HAA（降低 47–50%）、HAN（降低 22–28%）和三氯硝基甲烷（TCNM）（降低 49–61%）的生成，但在高溫下，HK 的生成量增加了高達 54%。這些發現強調了在未來的氣候情境下，有必要考慮極端土壤表面溫度對 DBP 前驅物生成和處理效果的影響。

Disinfection by-products (DBPs) remain a major concern for drinking water safety due to their widespread occurrence and associated health risks, particularly under changing environmental and climatic conditions. This study analyzed long-term monitoring data (2007–2024) from water treatment plants across Taiwan, including the main island and offshore islands, using datasets from the Taiwan Water Corporation (TWC) and the Ministry of Environment Taiwan, formerly the Environmental Protection Administration (EPA). Overall, total trihalomethanes (THMs), haloacetic acids (HAA5), and bromate concentrations generally complied with national regulatory standards; however, pronounced spatial variability was observed. Higher mean THM and HAA5 concentrations occurred in Northern and Southern Taiwan, corresponding to elevated total organic carbon (TOC) levels in source waters, while Eastern Taiwan exhibited the lowest DBP levels. In contrast, offshore island systems showed disproportionately high brominated DBP (Br-DBP) concentrations, with mean brominated THM (Br-THM) and brominated HAA (Br-HAA) levels of 19.05 μg/L and 5.28 μg/L, respectively, primarily driven by bromide-rich source waters influenced by seawater intrusion. Empirical modeling demonstrated that Br-THMs could be reliably predicted from routinely monitored total THMs (r = 0.85, R² = 0.725), whereas Br-HAAs showed weak relationships with HAA5. Bromine substitution factor analysis further revealed non-linear relationships among individual Br-THM species, indicating shifts in species dominance under high-bromide conditions. To address climate-related drivers of DBP formation, laboratory experiments investigated the effects of short-term extreme soil heating (25, 45, and 65 °C) on runoff quality and DBP formation potential. Elevated temperatures significantly enhanced soil microbial activity, increasing dissolved organic carbon and nitrogen in runoff and promoting the formation of multiple DBP classes, including HAAs, haloacetonitriles (HAN), and haloketones (HK). At 65 °C, DBP-associated cytotoxicity increased by approximately 1.3-fold compared with ambient conditions. Enhanced coagulation effectively reduced THM (41–47%), HAA (47–50%), HAN (22–28%), and trichloronitromethane (TCNM) (49–61%) formation, but increased HK formation by up to 54% at elevated temperatures. These findings underscore the need to consider extreme soil surface temperatures in DBP precursor formation and treatment performance under future climate scenarios.