Rock art report rejects acid rain theory

The Western Australian State Government and the Murujuga Aboriginal Corporation (MAC) have released the latest report from a major scientific program monitoring the condition of rock art on Murujuga in the Burrup Peninsula and Dampier Archipelago, in northern WA.

Led by the MAC and the Department of Water and Environmental Regulation (DWER), the Murujuga Rock Art Monitoring Program has delivered the largest and most reliable data set on rock art globally, tracking air quality, rock surface chemistry, rainfall, and pH levels affecting the area’s ancient rock art.

Findings from the program have informed the development of interim Environmental Quality Criteria (EQC), which are now being used to guide regulation of industrial emissions on the peninsula.

The monitoring program and EQC form part of the Murujuga Rock Art Strategy, which has been implemented by MAC and the WA Government since 2019.

Regular public reporting against the interim criteria will begin in 2025, alongside continued research and data collection.

The WA Government, in partnership with MAC, will continue routine monitoring and assessment of air quality against the EQC, with management responses to be implemented if thresholds are exceeded.

“Protection of Murujuga’s cultural heritage, including the rock art, is vital to our Members, and critical to achieving our long-held aspiration to achieve World Heritage Listing for the Murujuga cultural Landscape,” MAC Chairperson, Mr Peter Hicks said.

“The latest findings show that past emission levels may have affected some of the rock types. We are confident that we have got a robust scientific program, that is clarifying these processes so that we can achieve lasting protection of the rock art.

“While research is ongoing, we are excited to be at a stage where we have interim EQC for the first time. MAC will continue to hold government to their commitment to protecting the rock art.”

Data gathered over the next two years will be used to establish scientifically robust final criteria to ensure long-term protection of the rock art.

Key findings from the research include:

• the program’s data does not support earlier theories suggesting acid rain or deposition is
• contributing to damage of the rock art; and
• an initial determination of ambient air quality levels considered safe for Murujuga’s rock art has
• been made and will be refined as the program continues.
• Air quality and emissions trends
• Air quality data collected over the past 18 months aligns with previous modelling

Levels of key pollutants such as nitrogen dioxide and sulphur dioxide have declined since 2014.

Rock surface analysis

The upper layer of granophyre – one of five rock types under study – shows elevated porosity in an area near Dampier. Current evidence suggests this occurred during periods of significantly higher industrial emissions in the 1970s.

Further research will investigate these processes, including the role of microbial activity and chemical or chemo-microbial interactions.

MAC Vice-Chairperson Belinda Churnside said the rock art depicted the everyday living of ancestors “and we still have strong connection and cultural ties to it”.

“MAC has been involved in every aspect of establishing and implementing the Rock Art Monitoring Program, through our Board and Rangers, guided by the senior, cultural, knowledgeable Elders,” she added.

“The collection of data by cultural and scientific experts will allow us to better understand and manage the ngurra (country) today, tomorrow and forever.”

Environment Minister Matthew Swinbourn thanked all involved and looked forward to the continued collaboration and co-operation with MAC and the scientific community over the final years of the studies.

“The successful development of these interim EQCs could not have been achieved without the knowledge and support of the Murujuga Circle of Elders, MAC Board, rangers and other personnel; a large team of 55 highly-credentialed scientists; a panel of independent, expert peer reviewers; and the Murujuga Rock Art Stakeholder Reference Group,” he said.

“The approach of the program is to achieve a transparent, risk-based and adaptive framework for monitoring and managing environmental quality to successfully protect the rock art on Murujuga from anthropogenic emissions into the long-term.”