Effect of episodic rainfall on aqueous metal mobility from historical mine sites

• DOI: 10.1071/en17133
• Publication Date: 2018-03-20T23:46:44Z
• Authors: Magaly Valencia-A...; Rebecca Slack; Anthony Stockdale; Robert John Georg...
• Keywords: Ephemeral key; Bedrock

Environmental contextEpisodic extreme rainfall events may affect metal dynamics in rivers flowing within historical mining areas. This study provides an analysis of the water chemistry and geochemical processes associated with mobilisation metals during episodic events. Findings could be used to assess environmental quality streams draining spoil waste areas similar conditions, thereby guide future management strategies. AbstractThe increasing frequency magnitude by remobilisation deposition metal-rich sediments enhancing run off, impacting river quality. assesses effects a Carboniferous headwater catchment contaminated Pb Zn mining. Comprehensive hourly measurements combined modelling using PHREEQC, WHAM/Model VII WHAM-FTOX were this assessment. For event, we measured flow increases from baseline 0.05 2.12 m3 s−1 at peak flow. Changes concentration most marked for ephemeral tributary, 55 μg L−1 576 L−1. Behaviour showed great affinity form organic complexes or bind colloidal Al Fe oxides, whereas tributary subsurface more complex behaviour was observed. example, dissolution secondary carbonate minerals (e.g. smithsonite (ZnCO3)) is likely constrained higher concentrations bicarbonate derived increased bedrock weathering under conditions induced rainfall. The abundance mineral sources circumneutral pH present are important factors controlling Zn. Furthermore, enhance toxicity but there aggravating mitigating that depend on site-specific chemical changes. Overall, highlighted complexity mobility these