Debris at Pasir Ris Park mangroves.
Until now it was thought that plastic rubbish is relatively stable chemically and, apart from being unsightly, its principle threat to living creatures came from its ability to choke or strangle any animals that either got caught in it or ingested it thinking it was food.
But the latest research suggests that plastic is also a source of dissolved substances that can easily become widely dispersed in the marine environment. Many of these chemicals are believed to toxic to humans and animals.
The scientists found that when plastics decompose in the ocean they release a range of chemicals, such as bisphenol A and substances known as polystyrene-based (PS) oligomers, which are not found naturally. Bisphenol A has been implicated in disrupting the hormonal system of animals.
A common form of plastic rubbish is styrofoam, which soon gets crushed into small pieces in the sea. However, it also releases substantial quantities of a toxic substances called styrene monomer, which is known to cause cancer, as well as styrene dimers and trimer, which are suspected of being carcinogenic. The trimer also breaks down into the toxic monomer form.
This study clearly shows new micro-pollution by compounds generated by plastic decomposition to be taking place out of sight in the ocean. Thus, marine debris plastics in the ocean will certainly give rise to new sources of global contamination that will persist long into the future.
Full articles on the wildsingapore news blog.