Phytoremediation and revegetation of mine tailings and bio-ore production: progress report on plant growth in amended tailings and metal accumulation in seedlings planted at Central Manitoba (Au) minesite (NTS 52L13)

Summary This report summarizes the results of the 2004 field season for a study initiated in 2000 to determine the potential for revegetation, phytoremediation and phytomining of gold mine tailings at Central Manitoba (Au) minesite in southeastern Manitoba. Metal accumulation was recorded in plant tissues of woody seedlings harvested after three growing seasons. None of the studied plant species accumulated enough metals to be suitable for phytomining and phytoremediation; however, significant accumulations of Cu were recorded in tamarack, dogwood, Jack pine and white spruce growing on site 1. Vegetation naturally growing close to site 1 accumulated very low levels of Cu suggesting that the seeds of the adapted existing vegetation would be the best candidates for revegetation purposes. A new field experiment was designed in 2003 to test the benefits of amendments (humic material, peat and fertilizer) on survival and growth of alfalfa, slender wheatgrass and meadow fescue. The results of the 2004 experiment showed that the selected species responded differently to the addition of humic material to the tailings. While alfalfa showed an increase in growth with the highest concentration of humic amendment, slender wheatgrass and meadow fescue showed decreased growth and survival rates with increased application rates.