Effect of irrigation water contaminated with uranium mill tailings on Sudan grass, Sorghum vulgare var. sudanense, and fourwing saltbush, Atriplex canescens

A greenhouse experiment was carried out to estimate the effects of irrigation water quality on chemical uptake and productivity of Sudan grass (Sorghum vulgare var. sudanense) and fourwing saltbush (Atriplex canescens). Water and soil were obtained from an inactive U ore processing site near Tuba City, Arizona. Two observation wells provided the irrigation water. One was located upgradient from the contaminated site, and was located in the center of the plume downgradient from the area contaminated by the milling operations. A 50/50 mix of the two well waters was used as a third treatment. Concentrations of Se and U in aboveground tissues of saltbush were significantly (P < 0.05) elevated when irrigated with the undiluted contaminated water, but not to unacceptable levels. In the case of Sudan grass, Mo, Se, U, NO3-N, and S were significantly (P < 0.05) elevated in the contaminated water treatment, and all except NO3--N were elevated with the diluted contaminated water, but again within acceptable limits. Saltbush productivity was not significantly (P > 0.05) affected by the three irrigation treatments. Sudan grassaboveground biomass results suggest that the undiluted contaminated plume water could be used for effective crop production, although productivity was significantly better with the nutrient-amended baseline water and the diluted contaminated water. Root biomass was significantly greater in the baseline water irrigation.