Abstrait

Accumulation of metals in native wheatgrasses and wild ryes when grown on metal-contaminated soil from three mine sites in Montana.

Lan Yun, Kevin B. Jensen*, Steven R. Larson

One of the biggest challenges to successfully phytoremediate contaminated mine land soils is the identification of native plants that possess a broad adaptation to ecological sites and either exclude or uptake heavy metals of interest. This study evaluated forage concentrations of aluminum (Al), arsenic (As), chromium (Cr), cadmium (Cd), copper (Cu), iron (Fe), magnesium (Mn), nickel (Ni), lead (Pb), strontium (Sr), and zinc (Zn) in native wheatgrasses (WG) and wildryes (WR) when grown in soil originating from mine tailings from Clark Fork, Cabbage Gulch, and Keating surface mines in western Montana. Despite having metal concentrations that exceeded the upper limits of normal plant tissue for As, Cd, Sr, and Zn, bioconcentration factors (BCF), an indicator of plants ability to extract metals from the soil, were ≥ 1 only for Cd and Mn and were soil specific. Charleston Peak slender WG appears to have some potential has a Cd accumulator when grown on soils with pH levels of 5.01 and 4.26 compared to a more basic soil found in the Clark Fork (pH = 7.64). Due to BCF values ≥ 1 for Mn uptake, all basin WR cultivars/germplasms studied, First Strike slender and Secar WG could be possible materials for Mn accumulators in a phyto extraction program. However, based on BCF values and soil types used, none of the WG and WR studied could be considered as hyperaccumlulator species for Al, As, Cr, Cd, Cu, Fe, Mn, Ni, Pb, Sr, and Zn.