Growth response and metals uptake of native bunchgrasses during organic amendment-assisted phytostabilization of alkaline mine tailings

Tailings management is one of several challenges faced by mines operating in dry environments. If tailings are exposed, with no vegetative cover, dust from mine sites can spread over long distances through eolian dispersion and water erosion, posing a risk to human and environmental health. Phytostabilization is a remediation technique which involves promoting vegetation growth on mine sites in order to prevent erosion and stabilize metals belowground. Here we report the results of a greenhouse study in which two native bunchgrasses (bluebunch wheatgrass and rough fescue) were evaluated for their ability to grow on alkaline mine tailings from the historic Afton mine when amended with a range of concentrations of locally available soil amendments (compost and wood ash). The addition of compost lowered tailings pH and increased organic matter content. A positive correlation between compost concentration and total biomass was observed, likely due to improved soil conditions. Shoot and root biomass of bluebunch wheatgrass was significantly greater than that of rough fescue on all treatments. Both candidates minimized shoot accumulation of metals with the exception of Mo which exceeded the domestic animal toxicity limit. The results revealed that compost is a promising amendment for promoting bunchgrass growth on these tailings.Non UBCUnreviewedOthe