Hazardous ash from Tonga’s volcano eruption is significant enough to impact the health of residents in the coming days, experts warn.
With radio communications largely cut between the tiny Pacific nation and the rest of the world, the situation on the ground remains uncertain.
Preliminary estimates suggest 2cm of volcanic ash has fallen across the island of Tongatapu, following the eruption of the Hunga-Tonga-Hunga-Ha’apai volcano, 65km north of the capital Nuku’alofa.
Associate Professor Carol Stewart is an environmental health expert at New Zealand’s Massey University, with extensive experience in island disaster recovery.
Looking to explain what it's like living under the cloud of a volcano eruption, she said it is vastly different to the bushfire smoke that Australians and New Zealanders may be familiar with.
On Tonga, much of the thick cloud of ash has now settled on the ground, compared with smoke which can linger in the air for an extended period.
“The ash-fall consists of coarse little stones… and finer volcanic ash, and while it’s on the ground it’s not a breathing hazard in the same way that smoke is,” Assoc Prof Stewart told Yahoo News Australia.
“It's only when it gets stirred up into the air, which is often by traffic, or when people start cleaning up the ash that it really becomes a breathing hazard.”
Concern volcano ash could inflame respiratory conditions
Across Tonga, rainfall is believed to have helped clear the air and dampen down the ash.
Remaining finer ash particles can inflame respiratory issues like asthma and chronic bronchitis, while larger ones will irritate the nose and throat, causing coughing.
"Fresh ash particles typically have an acidic surface coating, and if they get in the eyes they can sting and cause scratching damage and can irritate skin,” Assoc Prof Stewart said.
She recommends people in the area wear face-masks, particularly if they are undertaking cleanup activities.
Why Covid-19 will complicate aid support on Tonga
Covid can make providing aid in disaster situations more complicated for health workers.
In April 2021, while responding to the St Vincent volcano in the Caribbean, Assoc Prof Stewart said it was initially difficult to distinguish between patients suffering the effects of the virus and those impacted by the ash.
When it came to moving people around the islands, vaccination status also had to be considered to avoid spreading disease.
Unlike St Vincent, Tonga is Covid-free and the nation has not been keen on outside aid workers visiting its shores.
Assoc Prof Stewart foresees that much of the aid assistance will be undertaken remotely to help protect locals from illness.
“It's really important that they stay Covid-free,” she said.
“Just look at what we’ve seen in places like Fiji, where the virus has caused huge damage and stressed their systems terribly.”
Biggest health concern on Tonga revealed
Based on the limited information at hand, Assoc Prof Stewart’s major concern is the contamination of water supplies in the region.
Outside of urban areas, communities which are reliant on rainwater tanks could be impacted in several ways.
Advice has been sent to the island, advising locals to cover their tanks and disconnect them from their roofs to avoid ash impacting water supply.
Contaminated water will make the water “cloudy and taste nasty”, making the water unpalatable and potentially unsafe to drink without boiling or treatment.
Long term, Assoc Prof Stewart’s concern is that gutters will have snapped under the weight of the ash fall, meaning repairs will be needed to collect rain in future.
“They need to have enough water for drinking, hygiene, hand cleaning, washing dishes, cooking, all those sorts of things,” she said.
“If you don't have enough water the health risks start to accelerate quite rapidly.”
Tonga could quickly bounce back from volcano impact
Despite the concern, nations like Tonga – which have evolved around the threat of volcanoes – are often fast to bounce back.
Looking at the island of Ambae in Vanuatu, all sources of livelihood were affected by volcano activity in 2017 and 2018.
Traditional buildings collapsed, crops were lost, and locals had to temporarily leave the island until conditions improved. That surprisingly happened quite quickly.
"Tropical systems do recover quite quickly," Assoc Prof Stewart said.
"We visited about a month after one of the ash falls, and were actually amazed at all the new growth.
"Some types of vegetation are more susceptible to damage than others, but there were quite a few crops that had actually regrown.
"It is likely that the plantation side of Tonga's economy will get recover pretty quickly in the absence of further activity."
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