Oyster beds off the UAE coast contain elevated concentrations of microplastics, according to a new study that highlights the contamination of the marine environment.
Old fishing gear, shipping waste and plastics discarded on land could all be contributing to the microplastic pollution found in the research, according to scientists.
The study by the American University of Sharjah (AUS) in collaboration with other organisations looked at oysters, and sediments from oyster beds, at five sites several kilometres off the coast of Sharjah, Ajman and Umm Al Quwain.
The research found that all of the sediment samples analysed and 51 per cent of the oyster samples analysed contained microplastics between 0.1mm and 5mm in size.
Levels of microplastics varied considerably between the sites, averaging 101.2 particles per kilogram of oysters, and 191.7 particles per kilogram of dry weight of oyster-bed sediment.
Having found microplastics in the oyster beds, a source of food for local fisheries, Dr Fatin Samara, professor in biology, chemistry and environmental sciences at AUS and the study’s lead researcher, said that their research findings suggest that fish in the area may also be affected.
“Are fish in the area exposed if we’re finding these levels of microplastics in oysters? Will we find these levels in fish?” she said.
“The point of this research, like any other conducted on issues impacting our environment, is to call for action, as these pollutants, whether they are consumed or are present throughout the environment, could eventually present a health risk.”
Dr Samara said that the microplastics could have come from material discarded at sea that had degraded over time.
Potential sources include fishing equipment, clothing containing synthetic microfibres, which release particles when washed that move through the sewage treatment system and into the local coastal waters, and cosmetics, which may contain plastic microbeads.
"Microplastics do not necessarily come from one source. There are a lot of possibilities. We have tourist activities, we have fishing activities, we have shipping activities, we have direct releases. More research can determine the sources and risks involved,” she said.
Dr Samara said that microplastics were something that the UAE authorities were taking seriously, citing the recent announcement that single-use plastic bags would be banned in Abu Dhabi from June 5.
She also said that the UAE had set its own sustainability agenda to align with the UN’s Sustainable Development Goals to ensure healthy ecosystems.
"Microplastics are a global problem,” Dr Samara said.
“It’s not something that the UAE is looking into alone, and governments can be encouraged to take measures over the use of plastic.”
Titled "Microplastic Pollution in Oyster Bed Ecosystems: An Assessment of the Northern Shores of the United Arab Emirates", the study was published in the journal Environmental Advances.
The research involved lead author and AUS graduate Meera Al Hammadi, and co-authors Dr Sandra Knuteson, a senior lecturer in biology, chemistry and environmental sciences at AUS, and Dr Sofian Kanan, a professor in biology, chemistry and environmental sciences at the university.
“Investigating the presence of microplastics in oyster beds in the UAE is very important because this allows us to understand the threats facing our marine life and our lives,” Ms Al Hammadi said.
"Our findings may be considered as a baseline for future research. Now I want to continue to investigate microplastics and go beyond oyster beds and look into the marine environment as a whole.”
The research is part of a wider project on marine ecosystems involving Emirates Nature – WWF, the Sharjah Environment and Protected Areas Authority and AUS.
Microplastic contamination can affect marine ecosystems as a whole, according to Dr Dannielle Green, director of the Applied Ecology Research Group at Anglia Ruskin University in the UK, who was not part of the AUS study.
“In my own research on oysters I found that microplastics could decrease their filtration rates and affect their immune system,” Dr Green said.
“I also found that microplastics in a simulated benthic [sea bed] habitat decreased the overall biodiversity and abundance of organisms. So there is potential for them to alter whole marine ecosystems.”
Dr Green said there was little data to indicate that microplastics at the level found in marine organisms could affect human health, but there remained “a lot of research to do” to fully understand their effects.