title: Assessment of a reclamation cover system for phosphogypsum stacks in Central Alberta, Canada.
abstract: Phosphogypsum (PG), a byproduct of the phosphate fertilizer industry, was produced and stockpiled at the Agrium Fort Saskatchewan facility from 1965 to 1991. Upon decommissioning, the outer slopes of the PG stacks were reclaimed by applying 15 cm of topsoil and planting a non-native seed mix. Physical, chemical, and hydrologic evaluations of the cover system confirmed that plants were successfully growing in various soil capping depths and were often rooting more than 200 mm into the PG. Percolation past the substrate into PG during a typical storm event was low (< 10 mm), and runoff from the stacks was negligible. Runoff quality met most guidelines, but some parameters, including fluoride, were up to 18 times higher than provincial or federal guidelines for soil and water quality. However, the cover system, when applied appropriately, does meet basic reclamation objectives. The exceedances are found in areas where the cover system has been compromised by erosion or mixing or in areas where the cover system has not been fully applied, such as roads or the inner basin. In areas where the cover system has been applied successfully, basic reclamation requirements are met.
authors.affiliation: Swansea Univ., School of Engineering, Grove Building 333, Singleton Park, Swansea, UK SA2 8PP. ihallin@hotmail.com
authors.forename: Ingrid L
authors.initials: IL
authors.lastname: Hallin
authors.forename: M Anne
authors.initials: MA
authors.lastname: Naeth
authors.forename: David S
authors.initials: DS
authors.lastname: Chanasyk
authors.forename: Connie K
authors.initials: CK
authors.lastname: Nichol
mesh_terms: D000416:Alberta; D002133:Calcium Sulfate / Q000737:chemistry*; D005308:Fertilizers; D007220:Industrial Waste; D010758:Phosphorus / Q000737:chemistry*; D011891:Rain; D012037:Refuse Disposal; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D005308:Fertilizers; D007220:Industrial Waste; D014874:Water Pollutants, Chemical; D014867:Water; C077769:phosphogypsum; D010758:Phosphorus; D002133:Calcium Sulfate