Biosolids as a long-term solution for soil development on mine tailings

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In most regions in Canada, mine sites must be reclaimed after the mining has ceased. Biosolids from municipal waste treatment plants have been shown to assist in site restoration by improving soil biophysical properties. However, the use of biosolids is controversial with the Canadian public because of concern regarding the leaching of heavy metals from the biosolids into the restored ecosystem. For example, there have been recent protests by residents within the Nicola Valley, British Columbia, regarding the application of biosolids near Merritt, BC. Therefore, mine companies, such as Teck Highland Valley Partnership (HVC), require information on the short and long-term impacts of biosolids on mine reclamation sites. With this information the company can make informed decisions on the effectiveness and safety of biosolids in restoring disturbed sites. In 1998, two study sites were established at the HVC mine on reclaimed tailings areas. The objective was to assess the impacts of different levels of biosolids application on soil physical and chemical properties and on plant growth and chemistry. Past research on these sites reported that 2 years after biosolids application the availability of essential plant nutrients were improved, biosolids were more effective than fertilizers at improving soil quality and carbon sequestration, concentrations of Mo were elevated in plant tissues and changes in soil hydrology were inconclusive. The initial study only reported on the short term impacts, but it is essential that the longer term changes in soil and plant nutrients, heavy metal concentrations, carbon content and hydrology be quantified. These study sites still remain but there is a possibility that new mining in this area may result in these plots being destroyed. Therefore, if the mining industry is to be more informed on the long-term impacts of biosolids, we must measure the long-term impacts on physical soil properties and plant tissue immediately. The objective of this study is to assess the impact of biosolids on soil and plant characteristics 17 years after the application of biosolids to a mine reclamation site.