Going with the flow in search of macroinvertebrates

While the mere thought of seeking out bugs sounds rather unappealing to most people, Mount Isa Mines’ Environment team have been actively looking for macroinvertebrates to collect data and monitor the health of our local waterways.

Our Environment team invest significant time throughout the year, particularly during the wet season, sampling and surveying the surrounding ecosystems as part of our Receiving Environment Monitoring Program (REMP).

Since 2012, the REMP has been undertaken as part of our responsibilities under our Environmental Authority to monitor water quality, sediment quality and aquatic ecology values to ensure our operations are not impacting the environment.

A key component of the REMP is the use of macroinvertebrate surveys as a bio indicator of ecosystem health.

For those unfamiliar, macroinvertebrates are water ‘bugs’ which live in many types of aquatic habitats, including in sediment at the bottom of a lake, shallow ponds, on the algae on rocks and other areas.

At Glencore’s Mount Isa Mines, our macroinvertebrate samplers are trained in the Queensland AUSRIVAS methodology and, because of the often fleeting nature of the waterways, surveys are conducted during and post wet season.

Different macroinvertebrates can tolerate a range of aquatic environments and different concentrations for a range of parameters, so their presence, or absence, can be used to indicate whether water is clean or potentially impacted.

The REMP results are then compared against reference sites, which are monitoring sites located upstream known to have no interference from our operations, and are used to provide a benchmark for comparisons with the receiving environment.

Glencore’s Mount Isa Mines Environmental Advisor, Andrew Koerber, says the Environment team recently collected water bug samples at a number of sites across the Leichhardt River, Spring Creek and Waterfall Hole.

“Essentially, we go to designated sites along the local waterways using a sweep net to collect samples along the edges,” says Andrew.

“Three samples are collected from each site and are taken from both the water and the water edges to ensure they are representative, for the robustness of the program.”

“The samples are placed into white sorting trays and we have a 30-minute time limit to sort and pick the macroinvertebrates before preserving them in ethanol or methylated spirits so they can be identified in the laboratory,” Andrew says.

This process requires a high degree of patience to meticulously find and sort the macroinvertebrates. Once collected, the Environment team send the macroinvertebrate samples to a consultant to identify and analyse any differences across the sites.

“We then determine any variation in the level of macroinvertebrates between the reference sites and receiving environment.”

“These REMP sampling surveys are an excellent way to compare differences between the local waterways and monitor any potential impacts from our operations and the overall health of our surrounding ecosystems,” says Andrew.