まとめ
遠い湖への大気中の水銀の堆積は,1850年以来3倍に増加し,大気中の水銀の25%が周辺の土地から湖に輸出されています. これは,水銀の源が広く存在していたことを示唆している.
科学分野:
- 環境科学 環境科学
- 地質化学 地質化学
- エコロジー エコロジー エコロジー
背景:
- 遠く離れた湖の水銀汚染は,ますます懸念される問題となっています.
- 歴史的な水銀の堆積率と地上からのインプットはほとんど理解されていません.
- 大気中の水銀の堆積が主な疑わしい源である.
研究 の 目的:
- 遠い湖の水銀堆積率を再構築するために.
- 大気中の水銀の陸上からの湖への輸出を定量化するために.
- 水銀の汚染源を特定するために.
主な方法:
- ミネソタ州とウィスコンシン州の7つの河頭湖の湖堆積物の分析.
- 堆積物核の年代測定は,歴史的なタイムラインを確立するために行われます.
- 盆地全体の水銀流の計算.
主要な成果:
- 1850年以来,年間大気中の水銀堆積量は3.7μg/m2から12.5μg/m2に増加しました.
- 流域への大気中の水銀堆積の25%が湖に輸出されています.
- 各地における同様の堆積量の増加は,地域的またはグローバルな源を示唆している.
結論:
- リモート湖への水銀の堆積は,工業化以前の時代から大幅に増加しています.
- 陸上の生態系は,水銀が湖に入るための重要な経路として機能します.
- 地域または世界の大気プロセスが,これらの遠い湖の水銀汚染を誘発している可能性が高い.
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