Chemical transportation of heavy metals in the constructed wetland impacted by acid drainage was investigated seasonally using a combination of the selective sequential extraction of the sediments with elemental analysis of the emergent vegetation in the wetland. Manganese was dissolved from sediments in the constructed wetland by the contact with acid drainage, and then precipitated again as ion-exchangeable forms. It was expected that a part of Mn and Fe bound to oxides were flown out of the wetland as suspended particulate matters. It was observed that there is passive absorption of Mn in leaves of Phragmites austlaris in the upstream of the wetland. The transportation of Cu clearly showed the seasonal variation: there was the decomposition of organic substances with high molecular weights by soil microorganisms in summer. Therefore, Cu was complexed to the humic substances, and dramatically adsorbed onto the roots of Phragmites austlaris in down stream of the wetland. It was also observed that there is active absorption of Fe in roots and leaves of Phragmites austlaris. Most of the zinc was strongly bounded to the sediments, therefore, scarcely uptaken to the vegetation. It was also found that there were heavy metal distributions between plant organs.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering