Current environmental literature provides insufficient information and analysis on how today’s environmental state was shaped by countermeasures to pollution taken in the last century, which could be characterized as a century of environmental degradation. Such a look back is crucial to better understand and predict how policy and countermeasure choices today may shape the world in the future. Following this line of reasoning, the present work conducted a post audit on the long-term consequence of a countermeasure against a major heavy metal pollution case caused by the operation of the Ashio Copper Mine in Japan. It examined this issue from both environmental and societal perspectives by document analysis, field investigation on the heavy metal concentration in the soils of a heavy mental catchment area and questionnaire survey on the public knowledge with regard to the copper mining contamination case as well. It shed new light on how environment may evolve via the interaction with human activities by identifying drivers behind major changes. It also revealed a gap between the reality and the public perception towards the consequence of the copper contamination. Such insights will deepen the discussion on what is sustainability and motivate further study to pursue sustainable development.

渡良瀬遊水地周辺はかつて、足尾銅山から流出した重金属による被害を受けた地域である。この重金属による汚染は、地域の自然環境や生物に多大な影響を与えたことが報告されている。近年、政府やボランティアなどの活動により重金属汚染の状況は劇的に改善され、2012年には渡良瀬遊水地はラムサール条約湿地に登録された。しかし、周辺の土壌では、基準値以下ではあるものの依然として重金属が検出されることもあり、より詳細な現状把握と、さらなる浄化が求められている。