A turquoise fisherman's net lies coiled on the white sand, amongst other debris

Plastic pollution accumulates on east beach of Henderson Island © Alex Bond

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Over four billion plastic particles found in beach sand of remote paradise island

Scientists explored one of the most isolated islands in the world - Henderson Island - and discovered more than four billion plastic particles in the top five centimetres of sand. 

In 2015, a team of scientists, including Dr Alex Bond, the Senior Curator in Charge of Birds at the Museum, travelled to the Henderson Island to research the impact of plastic pollution on sea birds and other marine animals.

The team found the island's three beaches covered in trash and debris that had travelled hundreds of miles via powerful ocean currents.

Alex says, 'A lot of the rubbish we saw was not new - we found some recognisable toys from the eighties and nineties. Plastic can stay in the ocean for a long time and then end up on a beach.'

The team estimated there were 38 million pieces of plastic, possibly the highest density of plastic pollution reported anywhere in the world.

This was disturbing as Henderson Island was believed to be one of the last remaining pristine places on Earth free from human contact, affording it its UNESCO World Heritage Site status.

Many questions arose from this discovery, but the team did not have the resources to answer them all at the time.

A map of the world with Henderson Island marked as a red dot

Henderson Island, along with Pitcairn, Oeno and Ducie make up the Pitcairn Island Group. Scattered over several hundred kilometres of ocean, Henderson Island is the largest atoll out of the four. Image by Uwe Dedering/wiki, edited by Tammana Begum (CC BY-SA 3.0).

In 2019, Alex returned to the beautiful yet polluted island with a different team, including Dr Jennifer Lavers, a researcher at the University of Tasmania's Institute of Marine and Antarctic Studies. Together, they collected the data used by honours student Emma Nichols.

The aim was to see how the debris had changed since they last visited, compare it with plastic in the South Pacific Ocean and examine the presence of micro and nano plastic on the beach.

The team found the amount of plastic on the beach had increased in over the last four years. They estimated there were over four billion pieces of micro and nano plastic in just the top five centimetres of sand.

How did one of the most isolated places in the world with no direct human contact accumulate such a dense amount of plastic?

Global waste management

Henderson Island is one of four islands that form the Pitcairn Islands in the South Pacific Ocean. The nearest large land mass is South America which is more than 4,828 kilometres away.

Situated in the South Pacific Gyre - one of the five oceanic rotating currents in the world - the island acts like a sink for plastic debris. This also makes it an important indicator of plastic pollution.

'Pitcairn is the only island inhabited with a human population of 50 but none of the trash comes from there,' explains Alex. 'We found pieces of plastic that were from Europe, Africa, North America, South America and Asia. They get into the oceans and are bought here.'

This is a common problem with a lot of small island states, especially in the south Pacific where they don't have the capacity to deal with these challenges.

A crab has it's head trapped in a turquoise piece of plastic on the beach

Micro and nano plastic is worrying for animals that live within sediments such as mussels, and filter feeders such as crabs which may ingest plastic and subsequently experience detrimental effects. © Jennifer Lavers.

There are many sources of plastic pollution such as fishing practices, agriculture and human activities on beaches. However, a lot of the plastic pollution comes from leaks in waste disposal systems.

For example, wastewater disposals are bad at filtering out microplastics before releasing waste water into waterways that connect to the oceans. Open landfills also mean rubbish is blown away by wind or washed off by rain.

Adverse weather can be expected more frequently with climate change, contributing to further leaks in mismanaged waste.

'Plastic pollution is a worldwide issue and needs to be dealt with on a cooperative and global level,' says Alex. 'It's all about plugging those leaks in waste management streams and that's got to happen everywhere.'

A lot of the waste management systems are either outdated or products of current times. Improving and adapting these systems to climate change is needed or else plastic pollution will continue to get worse.

At the very least, having conversations will open up the possibilities of plugging those leaks and reducing the amount of plastic that ends up in the oceans.

Alex says, 'I think we're going to slowly see a shift from cleaning up plastics to treating it like other contaminants like lead and mercury, where we know they're going to persist in the environment for millennia. Then it'll be how we go about managing it that becomes important.'