Nitrate release from waste rock dumps in the Elk Valley, British Columbia, Canada
| Autor: | Fazilatun N. Mahmood, C. Kennedy, M. Jim Hendry, S. Lee Barbour |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Environmental Engineering
Denitrification 010504 meteorology & atmospheric sciences Waste management business.industry French drain Humidity chemistry.chemical_element 010501 environmental sciences 01 natural sciences Pollution Nitrogen chemistry.chemical_compound chemistry Nitrate Environmental chemistry Environmental Chemistry Coal Leaching (agriculture) business Waste Management and Disposal Effluent Geology 0105 earth and related environmental sciences |
| Zdroj: | Science of The Total Environment. :915-928 |
| ISSN: | 0048-9697 |
| DOI: | 10.1016/j.scitotenv.2017.05.253 |
| Popis: | The origin, distribution and leaching of nitrate (NO 3 − ) from coal waste rock dumps in the Elk Valley, British Columbia, Canada were defined using chemical and NO 3 − isotope analyses (δ 15 N- and δ 18 O-NO 3 − ) of solids samples of pre- and post-blast waste rock and from thick (up to 180 m) unsaturated waste rock dump profiles constructed between 1982 and 2012 as well as water samples collected from a rock drain located at the base of one dump and effluent from humidity cell (HC) and leach pad (LP) tests on waste rock. δ 15 N- and δ 18 O-NO 3 − values and NO 3 − concentrations of waste rock and rock drain waters confirmed the source of NO 3 − in the waste rock to be explosives and that limited to no denitrification occurs in the dump. The average mass of N released during blasting was estimated to be about 3–6% of the N in the explosives. NO 3 − concentrations in the fresh-blast waste rock and recently placed waste rock used for the HC and LP experiments were highly variable, ranging from below detection to 241 mg/kg. The mean and median concentrations of these samples ranged from 10–30 mg/kg. In this range of concentrations, the initial aqueous concentration of fresh-blasted waste rock could range from approximately 200–600 mg NO 3 − -N/L. Flushing of NO 3 − from the HCs, LPs and a deep field profile was simulated using a scale dependent leaching efficiency (f) where f ranged from 5–15% for HCs, to 35–80% for the LPs, to 80–90% for the field profile. Our findings show aqueous phase NO 3 − from blasting residuals is present at highly variable initial concentrations in waste rock and the majority of this NO 3 − (> 75%) should be flushed by recharging water during displacement of the first stored water volume. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect