Remediation of a mine soil with insoluble polyacrylate polymers enhances soil q...

• Author(s): Guiwei, Q. ; Varennes, A. ; Cunha-Queda, C.
• Date: 2008
• Persistent ID: http://hdl.handle.net/10400.5/5951
• Origin: Repositório da UTL
• Subject(s): orchardgrass; mine soils; polyacrylate polymers; remediation; soil quality; enzymatic activities
• Document Type: Article
• Language: English

Description

We investigated the effects of different application rates of insoluble hydrophilic polyacrylate polymers on plant growth and soil quality from a Pb-contaminated mine soil. The polymer increased the waterholding capacity of the soil from about 250 g ⁄ kg in unamended soil to almost 1000 g ⁄ kg in soil with 0.6% polymer. However, the capacity of the polymer to retain water decreased progressively, presumably as the polymer sorbed Pb. Growth of orchardgrass (Dactylis glomerata L. cv. Amba) was stimulated in the polymer-amended soil. The greatest accumulated biomass over four cuts was obtained in soil amended with 0.4% of polymer. After orchardgrass had been growing for 101 days, the amounts of CaCl2-extractable Pb present in the polymer-amended soil were 15–66% of those in the unamended soil, depending on polymer application rate. The number of bacteria culturable on agar enriched with ‘Nutrient’ and yeast extract, and the activities of dehydrogenase, phosphatase, b-glucosidase, protease and cellulase increased following polymer application. In contrast, urease activity was impaired by polymer application, presumably due to the presence of ammonium as a counter ion. Principal component analysis was used to compare the effects of the different rates of polymer application. Overall, the application of 0.2 or 0.4% polymer resulted in closer values for the indicators of soil quality used than the treatment with 0.6% polymer.