Phytoextraction of selenium from soils irrigated with selenium-laden effluent

This two-part study compared the efficacy of different plant species to ext ract Se from soils irrigated with Se-laden effluent. The species used were: Brassica napus L. (canola), Brassica juncea Czern L. and Coss (Indian must ard), and Hordeum vulgare L. (barley). In Study 1 we irrigated the plants w ith a saline effluent containing 0.150 mg Se L-1, while in Study 2, the sam e species were planted in a saline soil selenized with 2 mg Se L-1. Plants were simultaneously harvested 120 days after planting. In Study 1, there we re only slight effects of treatment on dry matter (DM) yield. Plant Se conc entrations averaged 21 mug Se g(-1)DM for the Brassica species, and 4.0 mug Se g(-1) DM for barley. Total Se added to soils via effluent decreased by 40% for Brassica species and by 20% for barley. In Study 2, total DM decrea sed for all species grown in saline soils containing Se. Plant Se concentra tions averaged 75 mug g(-1) DM for Brassica species and 12 mug Se g(-1) DM for barley. Total Se added to soils prior to planting decreased by 40% for Brassica species and up to 12% for barley. In both studies, plant accumulat ion of Se accounted for at least 50% of the Se removed in soils planted to Brassica and up to 20% in soils planted to barley. Results show that althou gh the tested Brassica species led to a significant reduction in Se added t o soil via use of Se-laden effluent, additional plantings are necessary to further decrease Se content in the soil.