SINGAPORE - Microplastics have been found in marine animals across Singapore’s coastal areas in a new study, with researchers discovering these plastic bits not just in the animals’ digestive tracts, but also in their respiratory organs and bodily fluid.

Microplastics enter the animals not just through the food they consume, but also when they breathe or move through water, said the researchers from the NUS Tropical Marine Science Institute (TMSI).

The study also showed that microplastics are widespread across Singapore’s coastal habitats – including mangroves, coral reefs and seagrass beds – and they could potentially be transferred from one organism to the next.

Previous studies had focused mostly on the presence of microplastics – referring to tiny plastic particles smaller than 5mm – in Singapore’s environment, said the study’s co-principal investigator Neo Mei Lin, a senior research fellow at TMSI.

For example, a recent study had found that 97 per cent of macro- and microplastics on Singapore’s shores came from marine-based sources.

The TMSI researchers wanted to find out more about the presence, distribution, abundance and composition of microplastics in local marine organisms. Their study is part of a larger project that examines the impacts and hazards of marine plastics in the coastal environments.

As an emerging field of study, not a lot is known about microplastics and their impacts yet, according to the US National Oceanic and Atmospheric Administration (NOAA).

However, laboratory studies have shown that microplastics and chemicals in plastics may impact animals by delaying their developmental stages, cause problems with reproduction, and may even make it difficult for them to fight off disease, NOAA noted on its website.

Four marine species were selected for TMSI study: the orange fidd...