Better protect waterways from coal mine wastewater discharges is quite apparent. Currently regulation focuses on water column concentrations of a select few pollutants whilst never measuring the actual impact to stream ecology.
The Coal Mine Impact Grades (CMIG) derived in this study has been developed from presence and absence data collected at eight waterways within the greater Sydney Basin. A total of 12866 individual macroinvertebrates from 55 families were collected from a single upstream and a single downstream sample location at the eight waterways. Ten replicated quantitative macroinvertebrate samples were collected at five of the waterways and 5 identically sampled replicates at each remaining waterways upstream and downstream sample locations.
We have developed a preliminary biotic index to measure ecosystem impacts specifically derived for coal mine wastewater regulation. Although this is preliminary, there is no other index to provide such observations. This index has potential and with its continued development driven by ongoing data collection the index has great potential to increase its robustness and accuracy.
In recent years post coal mining impacts to our waterways are revealing that once mining ceases the impact to a stream ecosystem increases as coal mine wastewater is no longer treated, and Acid Mine Drainage becomes the new pollutant. If coal mines are to cease mining this biotic index may help better management post mining, especially if implemented with post mining Acid Mine Drainage treatment. The biotic index would allow for actual ecosystem monitoring to ensure post mining impacts are mitigated or minimised.