Title: Platypus Disappearance Linked to Pollution in NSW River

The platypus, an egg-laying mammal first observed by Charles Darwin nearly 190 years ago, appears to be vanishing from the Cox's River in New South Wales. This river, located near Lithgow on the western side of the Blue Mountains, has seen a significant decline in platypus sightings, primarily due to high salinity levels and pollution.

According to Associate Professor Ian Wright from Western Sydney University, the current environmental conditions in the river are unsuitable for the platypus. "There are no platypus in that section of the Cox's now because it is heavily polluted with salt and other metal pollutants," he stated. Wright has been studying the waterways in the area for over a decade and noted that his water quality tests have shown no platypus upstream of Lake Wallace. He emphasized that the absence of key food sources, such as yabbies and mayflies, is detrimental to the platypus population.

Salinity, which measures the concentration of dissolved salts in water, has been found to be alarmingly high in the Cox's River. This is often linked to mining activities, particularly from the Mount Piper Ash Repository. Wright explained that while water quality improves downstream, the pollution from the repository is a significant concern. "Platypus reappear and this continues ... as the Cox's River drains down towards Warragamba Dam," he said.

The Cox's River is crucial as it is the second largest river feeding into Warragamba Dam, which supplies most of Sydney's drinking water. Local residents, organized under the Gardens of Stone Alliance (GSA), have been monitoring salinity levels in the river for decades. Their testing, part of the Greater Sydney Landcare program 'Stream Watch', has revealed elevated salinity levels at multiple sites.

In September, testing by Water NSW and the GSA indicated concerning levels of electrical conductivity (EC) at Wangcol Creek, located about 1.6 kilometers downstream from the Mount Piper power station. Water NSW recorded an EC level of 1656.1, while GSA testing showed an even higher level of 2350.2. Further downstream, EC levels remained elevated, with readings of 991.5 and 1130, respectively.

Dr. Gilad Bino, a researcher at the University of NSW, expressed serious concern over these findings. He stated, "[You would want EC levels] ideally under 350. Once it passes that then you start losing the sensitive species, they start disappearing." He added that high salinity levels can disrupt food webs, which are essential for the survival of species like the platypus.

Bino also pointed to evidence suggesting that toxic brine is leaking from the Mount Piper Power Station's ash dump, posing a significant risk to local freshwater ecosystems and platypus populations. Since its opening in 1994, the power station has generated brine waste, which has been deposited in the Mount Piper Ash Repository since 2019.

GSA member Julie Favell highlighted the potential for brine toxins to seep into the groundwater, exacerbating the salinity issue. "The leakage of brine toxins into the water table is the most plausible reason for elevated salinity levels," she said.

In response to these concerns, a spokesperson for Energy Australia stated that the company is working to understand and manage the salinity levels associated with the ash repository. They noted that a NSW planning approval is in place to cap the repository, which aims to mitigate potential salinity migration.

An EPA spokesperson acknowledged the long history of coal mining in the area, which has led to various environmental challenges. They assured that the agency is actively working to minimize these impacts. Centennial Coal has been contacted for further comment on the situation.