As residents find ways to use ash following the volcanic eruption in Tonga, an assistant geologist says they were not sure about the chemical makeup yet

In the days following the eruption of the Huga-Tonga Hunga-Ha’apai volcano, everything was covered in ash.

Tevita Hafoka, a resident from Nuku’alofa who works at the Ministry of Land and Resources, said the landscape completely changed.

“It was like a monotone picture. Everything was grey or brown,” he said.

The clean-up has been difficult. Men and women have been sweeping roads to get rid of the ashfall, only to have it fall again from the surrounding tree tops and roof tops.

Some businesses haven’t been able to operate because of the thick ash blanketing their offices and stores.

The fine dust gets everywhere, and Hafoka said people were slowly coming to terms with the associated health risks.

“We’re no longer wearing masks for COVID, it’s masks for the ash,” he said.

But despite the risks, people are coming up with ways to make use of the ash.

Some are piling it on the roads to stop cars from driving too fast.

Others are even turning a profit, selling bags of the ash for $5(US$2.18). It can be used as fertiliser or in concrete.

Pupunu Tukuafu, an assistant geologist from Tonga’s land and resources department, said they were not sure about the chemical make-up yet, but have warned the fine particles can be harmful if breathed in.

But he said the water supply was still safe to drink if boiled.

Researchers in New Zealand have been analysing the composition of ash from the eruption to find out its toxicity.

Associate Professor Scott Bryan from the School of Earth & Atmospheric Sciences at the Queensland University of Technology, says some compounds in volcanic ash, like silica and fluorine, can be harmful, though he remains optimistic.

“Thankfully, the nature of the eruption where there’s a lot of steam produced by the explosion may have helped wash a lot of the ash,” he said.

“But it’s certainly worthwhile trying to analyse the waters and just check on the chemistry of the waters to make sure there’s no sort of nasty elements of chemicals in them.”

It is expected that recovery from the debris and ashfall of the volcano could take several months, if not years.

The Food and Agricultural Organisation (FAO) estimates that 60 to 70 percent of livestock will be at least partially harmed by the ash.

Xiangjun Yao, FAO’s sub-regional coordinator for the Pacific, said her team was planning a survey to find to gauge the damage.

“If that ashfall is very thick, then this harvest would become difficult,” she said.

“Ashfall can be disruptive to the health, and also to the growth of those crops.”

But despite the dire predictions, there’s some good news.

Though the ash may be too fine for commercial use, Professor Scott Bryan said there was potential for the volcanic ash to be used as a fertiliser.

“The Tonga main islands are limestone. So the soils are generally quite poor. So [the ash] is gonna be the most used to them,” he said.

In more good news, it’s expected that reefs and marine life affected by the volcanic blast will soon recover.

Tonga’s waters are perfect for migrating whales that use its bays and oceans to care for young calves.

Damage to this important ecosystem could be devastating to these endangered animals.

But Professor Mark Orams, from Auckland University of Technology, said that was unlikely.

“Humpback whales, because of their seasonal migration are not in Tongan waters at present, they won’t arrive back and Tonga until around June,” Professor Orams said.

“So in many ways, the volcanic eruption and subsequent tsunami and changes are not impactful for humpback whales directly, because they’re not currently located in Tongan waters.”

It is expected most of the ash will be cleaned up by this week.

This story was produced by Prianka Srinivasan, originally published at ABC on 31 January 2022, reposted via PACNEWS.