Measuring the impact of emissions on the Murujuga rock art

Botanical ecologist Stephen van Leeuwen recalls with joy his decades spent exploring Murujuga’s remote sandy beaches, rock art-filled gorges and mangrove-lined bays.

The Wardandi Noongar man and Curtin University biodiversity and environmental science chairman spent some 20 years either side of the millennium living in Karratha in Western Australia. During the week he’d undertake a wide variety of scientific work on Murujuga; on weekends he’d “play” on the peninsula.

Those memories came to the fore when he was appointed chairman of the Murujuga rock art stakeholder reference group, an offer he accepted without hesitation.

The group will receive analysis from scientists and rangers on the impact of industrial emissions on Murujuga’s 40,000-plus-year-old rock art, which will be used to inform industry and government stakeholders.

On a recent visit to Ngajarli (Deep Gorge) alongside Murujuga Aboriginal Corporation (MAC) chief executive Peter Jeffries and rock art monitoring project scientific lead Ben Mullins, van Leeuwen was struck by how well the area is looked after today.

“When I left Karratha just over 15 years ago, people were running amok and walking all over the rock art, not knowing what they were walking on,” he says. “Where we are sitting at the moment was infested with weeds.

“The Murujuga Aboriginal Corporation rangers are doing a great job managing weeds, and there’s interpretation signs telling people what they’re looking at. It has come a long way in the last 35 years.”

Van Leeuwen would have good reason to be nervous about the task ahead of him. Murujuga has, in the past year, been thrust into the national spotlight over a perceived conflict between industry, environment and culture.

Debate over how much industrial emissions are impacting Murujuga’s rock art has been divisive for decades, but now as a World Heritage bid progresses and more industrial development looms, the issue is more prominent than ever.

Scientists have provided conflicting reports on the matter the Murujuga Rock Art Monitoring Program has now been tasked with providing clarity on.

“I have to start with a clean slate but with an understanding of what’s happened in the past,” van Leeuwen says.

“I was involved with the CSIRO monitoring program, and to some extent I raised some of the issues in the early days with the environmental regulator about the impact on land snails and some of the wetland systems that emissions may be having.

“I’m very much basing decisions on how we manage this particular piece of country – which is really important internationally – on good science and good evidence.”

Who’s involved?

The main industry player on Murujuga is Woodside, whose North West Shelf and Pluto LNG plants can be seen from across Nickol Bay in the Pilbara’s largest town, Karratha.

Norwegian chemicals giant Yara operates two plants on Murujuga producing fertiliser and ammonium nitrate for explosives, and plans to build a renewable hydrogen pilot plant to the north of existing facilities, not opposite Ngajarli or on the way to Hearson Cove as claimed by critics.

Both companies enjoy support from government and the Karratha community, where thousands of their staff live and where they are contributors to clubs, events and infrastructure. But national environment groups are mounting a vocal campaign over industrial emissions and, closer to home, some Traditional Owners are concerned about sacred sites and rock art erosion.

Perdaman Industries plans to build a $4.5bn fertiliser plant to the west of Ngajarli which could see three sacred sites removed. Rio Tinto’s iron ore port facilities sit on the south of the peninsula near Dampier and are largely out of the spotlight when it comes to the politics of Murujuga.

All four companies sit on the reference group alongside Murujuga Aboriginal Corporation, the WA Department of Water and Environmental Regulation (DWER) and van Leeuwen.

As the head of MAC, Peter Jeffries is the man responsible for finding balance between stakeholders.

This includes engaging with the five Traditional Owner groups entrusted to protect Murujuga, a unique situation created by the Flying Foam Massacre in 1868, which all but wiped out the peninsula’s Yaburara custodians.

“I think it’s important we have a committee that can sit down and have a look at how we ensure the monitoring program is undertaken over the next four or five years to be able to provide us with that clear scientific data with regards to the effects on the rock art,” Jeffries says.

“Murujuga Aboriginal Corporation has always been of the opinion around a partnership with industry but more importantly, what we call coexistence. That’s an important part – to be able to sit down and have robust discussions with our industry partners.

“We have an (emissions) limit with regards to where we would like the industry not to go over and I think that’s been clearly articulated to industry.”

Data from the monitoring program will start flowing through in mid-2023, which will give the group information on pollutants that may require regulation. Consultants Calibre and Curtin University are training Murujuga rangers, who will eventually take on project management and fieldwork roles.

“Ultimately, the rangers will be fully trained in any technique that’s going to be implemented as part of the ongoing monitoring,” project scientific lead Ben Mullins says.

“In the previous monitoring that was done, the sites were largely selected out of convenience or out of some perception of where the effects might have been higher and lower.

“We had some of the best statisticians in Australia, if not the world, both at Curtin University and the University of Wollongong, and some of the biggest supercomputers in the world, designing the approximate locations that we needed to use in the study.

“Then we went out with the rangers and elders from MAC to select culturally appropriate regions to study within that framework.”

“It’s important we have a committee that can sit down and have a look at how we ensure the monitoring program is undertaken over the next four or five years to be able to provide us with that clear scientific data with regards to the effects on the rock art.”

Peter Jeffries

A DWER spokesperson says any new regulations would complement existing safeguards for the rock art.

“Conditions placed on Perdaman Chemicals & Fertilisers include compliance to ensure no air emissions from the proposal have an adverse impact accelerating the weathering of rock art within Murujuga beyond natural rates, compliance with the future standards set by the Murujuga Rock Art Strategy and the maintenance of regional air quality,” the spokesperson says.

“The Minister for Environment may consider contemporising conditions for other industry already operating on Murujuga when data from the monitoring program becomes available.

“Studies to date have been unable to provide conclusive information on the impacts to the rock art from industrial emissions.”

Plenty of science, but no fiction

A “police speed radar”, “season one Star Trek phaser”, “laser tag blaster” – Mullins has heard it all when it comes to the high tech gear he carries around Murujuga.

The real name – portable X-ray fluorescence spectrometer – sounds straight out of a space opera too, but its real-world use in understanding the chemical composition of surfaces is all science, no fiction. On Murujuga, it is being used to establish the chemical makeup of rocks to understand whether emissions from nearby industry are having an effect on the archipelago’s 40,000-year-old rock art.

Curtin University professor Mullins says using the spectrometer is as simple as pointing and holding at any surface.

“It is used … to check plastics and other things that are imported into the country to make sure they don’t have inappropriate levels of heavy metals,” he says. “In our case, it will tell us all sorts of things that are on the surface of the rock all the way down to chlorine, chloride and sodium and then all of the other heavy minerals like manganese.

“There are theories manganese is possibly one of the most susceptible elements as an indicator of change on the surface of the rocks. That’s yet to be determined.”

The portable tool is one element of the work underway to paint an accurate picture of how rock art is reacting to industrial emissions. With an extensive sensor network, cultural backing and super-computers at hand, scientists hope they can give a definitive answer to the big question: are emissions eroding Murujuga’s rock art?

Mullins says previous research has relied on sites selected out of convenience and perceptions as to where emission impacts may be felt at a greater or lesser rate. But this time the study area’s been refined to a set of precise locations: 54 rock-art panels for observation, 65 sample rocks and 26 spatial mapping areas across Murujuga, spanning five rock types on the archipelago.

Twenty-one air quality sensors have also been set up from Karratha to the northern islands of the Dampier Archipelago to complement nine existing industry sensors.

A DWER spokesperson says consultants Calibre and Curtin University were training the Murujuga rangers to take on leadership and fieldwork roles, with an eye to one day handing project management over to Indigenous rangers.

“Calibre has been engaged to the end of 2025 to develop and implement the monitoring program,” the spokesperson says. “The overall monitoring program will be implemented over a much longer term to ensure there is ongoing protection of the Murujuga Rock Art.”

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