One of the biggest global environmental problems right now is that millions of tons of plastic waste are being dumped in our oceans. Plastics take thousands of years to decay and marine animals and birds that ingest these materials often get intoxicated and die. But these plastics also pose a significant threat to human health as they are passed up the food chain.
Plastics contain lead, cadmium, and mercury that are toxic to humans and these toxins have already been found in fish in the ocean. Some plastic also contain diethylhexyl phthalate, which is a carcinogen. Many toxins in plastics are directly linked to cancers, birth defects, immune system problems and childhood developmental issues. Plastics also act like sponges and soak up other toxins that might be floating in the ocean and carry them through the food chain as well.
A scientist has now filmed one exact moment when plastic in the ocean enters the food chain. Dr Richard Kirby who studies planktons has recorded a tiny arrow worm ingesting plastic microfibre. Speaking to the BBC, Kirby observed how the fibre makes a loop inside the animals body and blocks anything from moving down the animals gut below its head. He said that although this is the first time the action has been filmed, the sight of plankton ingested plastic is disturbingly common.
Researchers have documented the growth of islands of plastic in the middle of oceans and conducted post-mortems on whales, seals and birds to find large plastic bags and bottles in their stomachs. But a large part of plastic pollution is in the form of microplastics – either particles left behind in the ocean when larger plastic materials break down over time or from tiny objects like microbeads from shower gels that get flushed into water bodies. The United Nations estimates that there are about 51 trillion particles of microplastic are in the world’s seas and oceans.
Other researchers have also demonstrated that zooplankton do indeed ingest microbeads, that the microbeads ingest in their digestive tracts giving chemicals present in the microbeads plenty of time to enter the tissues of animals and, subsequently enter the systems of larger animals that consume them.