山火事後も長期にわたりカナダの飲料水が汚染リスクにさらされる可能性―UBC研究(Canadian drinking water at risk long after wildfires, UBC study warns)

2026-03-04 カナダ・ブリティッシュコロンビア大学(UBC)

カナダ・ブリティッシュコロンビア大学(UBC)の研究によると、山火事は鎮火後も長期間にわたり飲料水の安全性に影響を及ぼす可能性がある。研究チームは、山火事後の流域で水質を調査した結果、降雨によって焼失した植生や土壌から灰や有機物、栄養塩、金属などが河川や貯水池へ流入し、水処理施設に大きな負担を与えることを確認した。これらの物質は濁度や有機炭素濃度を高め、水処理過程で有害な消毒副生成物が生成されるリスクもある。さらに山火事の影響は数年にわたり続く可能性があり、気候変動による山火事の増加と相まって水供給の安全性に新たな課題をもたらしている。研究者は、流域管理や早期監視、処理技術の強化など、長期的な水資源管理対策の重要性を指摘している。

<関連情報>

山火事関連化学物質の表層飲料水源への影響:現状と研究のギャップ Impacts of wildfire-related chemicals on surface drinking water sources: Status and research gaps

Raul de Leon Rabago, Loretta Li, Qingshi Tu
Science of The Total Environment  Available online: 3 February 2026
DOI:https://doi.org/10.1016/j.scitotenv.2026.181472

Graphical abstract

山火事後も長期にわたりカナダの飲料水が汚染リスクにさらされる可能性―UBC研究(Canadian drinking water at risk long after wildfires, UBC study warns)

Highlights

  • Post-fire concentrations of TSS, NO₃, TN, PO₄3−, and TOC increased by up to 39,600%.
  • Heavy metals and PAHs increased up to 66,000-fold above environmental standards.
  • Wildfire-derived contaminants reduce treatment efficiency and raise operation costs.
  • Long-term monitoring is scarce but critical to assess post-wildfire water impacts.
  • Models should include air deposition, runoff, erosion, and sediment remobilization.

Abstract

Climate change is driving more severe wildfires, raising urgent concerns about their impact on surface water sources. This critical review, based on 23 studies across 28 watersheds, synthesizes existing knowledge on how wildfires change the concentrations of eight contaminant categories in surface waters: suspended solids and turbidity, nutrients, organic carbon, major ions, trace metals, polycyclic aromatic hydrocarbons (PAHs), persistent organic pollutants (POPs), and wildfire-fighting chemicals (WFFCs). We observed that post-wildfire peak values reached 1142 mg/L for total suspended solids (TSS), ∼145 NTU for turbidity, 6.28 mg/L for nitrate, 31.08 mg/L for TOC, 325 μS/cm for electrical conductivity (EC), and 116 mg/L for trace metals such as zinc, with elevated levels often persisting over five years. Beyond the burned watershed, smoke plumes transport contaminants to distant basins via atmospheric deposition and subsequent runoff. These loads challenge drinking water treatment systems, potentially reducing performance while increasing health risks and operational costs. Although simulation tools exist to assess these risks, they require adaptation to account for wildfire-specific processes like atmospheric deposition and altered hydrology. As a result, further research is required on the persistence and remobilization of wildfire-derived trace metals, PAHs, POPs, and WFFCs, and on treatment performance under wildfire-affected source waters, along with long-term monitoring to supply data that improve modeling.

1102水質管理
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