Acid Mine Drainage
The remediation of stream benthic invertebrate communities in streams impacted by acid mine drainage
Opencast coal mining can have significant long-term impacts on aquatic ecosystems. On the West Coast, South Island, New Zealand, coal measures can be high in sulphur and heavy metals, and mining activities frequently generate acid mine drainage (AMD) in receiving waters. AMD can result in very low pH (e.g., < 4) and high concentrations of metals (e.g., Iron and Aluminium), both of which have toxic effects on aquatic life. Streams receiving AMD often have depauperate communities which may take centuries to naturally recover. Traditionally, restoration of aquatic ecosystems occurs by removing the stressor; in this case removing the AMD through the use of active or passive water treatment systems. However, these remediation strategies have not always resulted in improved benthic communities.
Justin Kitto's MSc research investigates factors that enhance the successful restoration of benthic invertebrate communities in streams recovering from AMD. Justin's research is being conducted within AMD impacted and unimpacted streams on the Stockton Plateau, Buller District, to 1) identify the spatial distribution of aquatic species in streams on the Stockton Plateau; 2) identify sources and sinks of species and populations; 3) investigate the factors affecting adult aquatic insect dispersal across the plateau to determine if source populations can recolonise sink sites; and 4) investigate the effects of in-stream conditions, such as habitat and food resources, in enhancing the recovery of invertebrate communities in AMD impacted waterways.
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Figure 1. Experimental addition of untreated Pinus radiata offcuts (left) and leaf litter and wood additions (right) as habitat for macroinvertebrates in AMD and reference streams.
Figure 2. Justin Kitto (MSc student) using Malaise traps to explore
dispersal of adult aquatic insects along streams impacted by AMD.
People involved in this project
University of Canterbury
Justin Kitto (Completed MSc Student)
Jon Harding
Missouri University of Science & Technology
Dev Niyogi
Solid Energy New Zealand
Phil Lindsay