Toxicity degradation of waste soil from a chlor-alkali factory byAzolla pinnata Lam

Cultures ofAzolla pinnata Lam., grown in various mixtures of soil plus industrial waste from a chlor-alkali factory for 30 to 60 days, resulted in the addition of significant amounts of nitrogen and organic carbon to the growing medium. A considerable decrease in the alkaline pH of the waste/soil was also recorded. On transplantation of rice seedlings into the waste/soil mixtures, after 60 days of Azolla culture it was observed that the rice survived and continued to grow in mixtures containing 30% waste whereas, in control conditions, seedlings failed to survive in above 15% waste/soil combinations.