Growing Biofuel Feedstocks in Copper-Contaminated Soils of a Former Superfund Site

Abstract

Copper mining in the Upper Peninsula of Michigan in the mid-19th century generated millions of tons of mining waste, called stamp sand, which was deposited into various offshoots of Lake Superior. The toxic stamp sand converted the area into barren, fallow land. Without a vegetative cover, stamp sand has been eroding into the lakes, adversely affecting aquatic life. Our objective was to perform a greenhouse study, to grow cold-tolerant oilseed crops camelina (Camelina sativa) and field pennycress (Thlaspi arvense) on stamp sand, for the dual purpose of biofuel production and providing a vegetative cover, thereby decreasing erosion. Camelina and field pennycress were grown on stamp sands in columns, using compost to supply nutrients. A greenhouse study in wooden panels was also done to evaluate the effectiveness of camelina in reducing erosion. Results show that camelina significantly reduced erosion and can also be used commercially for generating biodiesel. A 25-fold reduction in Cu content in the surface run-off was observed in the panels with camelina compared to those of the control. Stamp sand-grown camelina seeds contained 20% and 22.7% oil and protein respectively, and their fatty acid composition was similar to previous studies performed on uncontaminated soils.