Influence of a One Time Biosolids Application on Elemental and Nutrient Concentrations on Mine Tailings

Mine tailings are nutrient deficient, contain no organic matter, and have high metal concentrations preventing the long term establishment of vegetation. The use of organic amendments, including biosolids, can help the revegetation of mine tailings by adding organic matter and nutrients but can increase metals in the receiving soil. There is also uncertainty if biosolids provide a long term benefit, or if the benefits diminish with time. To test this, a study was conducted on two tailings storage facilities, a sand and a silt loam, on a copper mine in the southern interior of British Columbia, Canada. In 1998, biosolids were applied at rates between 50 and 250 Mg ha-1 and compared to a control and fertilizer treatment. Plots were sampled in 2000 and 2015 for total and available nutrients and metals. This study showed that 17 years after a one-time biosolids application at different rates, the tailing storage facilities that received biosolids had higher carbon, nitrogen, phosphorus, and biomass compared to tailings that did not receive biosolids or received conventional fertilizer. Many elements such as C did not change from 2000 to 2015 in biosolids treated plots indicating a long-term benefit to the tailings. Additionally, biosolids did not result in increased concentrations of metals above the national regulatory limits for agriculture. This study suggests that a one-time biosolids application can provide a long-term benefit to tailings, while proper application rates can reduce the risks of metal exceedances.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author