Mediterranean microplastics: Researchers uncover “extreme pollution” on beaches

26 Sep 2018 --- Record high levels of microplastics for the Mediterranean region have been found deep in the sand where sea turtles lay their eggs by University of Exeter researchers. The study identified an average of 5,300 particles of plastic per cubic meter at depths of 60cm on beaches in Cyprus used by green turtles and loggerheads. Researchers say that if conditions worsen such pollution could eventually begin to affect hatching success and even the ratio of male and female turtle hatchlings.

Microplastics – defined as less than 5mm in diameter – come from numerous sources including discarded plastic items that have broken apart, microbeads from cosmetics and microfibres from clothes. Landmark discoveries from New Orb Media earlier this year found potentially harmful microplastics in the water bottles of 11 leading global brands, including Dasani (Coca-Cola), Epura (PepsiCo), Aqua (Danone) and Nestlé Pure Life and San Pellegrino (Nestlé), potentially highlighting the pervasiveness of plastics that have broken down.

“We sampled 17 nesting sites for loggerhead and green turtles and found microplastics at all beaches and all depths,” says Dr. Emily Duncan, of the Centre for Ecology and Conservation on the University of Exeter's Penryn Campus in Cornwall.

“Microplastics have different physical properties to natural sediments, so high levels could change the conditions at hatching sites, with possible effects on turtle breeding. For example, the temperature at which the egg incubates affects the sex of the hatchling – with females more likely in warmer conditions,” she adds.

Of the microplastics categorized in this research, nurdles (pellets used in the production of plastic products) and hard fragments broken from larger items were the most common.

“Unlike the beaches in China where the highest levels of microplastics have been recorded, these beaches in Cyprus are located far from industrial practices and aren't visited by large numbers of people,” says Professor Brendan Godley, Leader of the University of Exeter's marine strategy.

“Therefore it seems that microplastics are arriving on ocean currents. In this case, our analysis suggests most of it came from the eastern Mediterranean basin. This is also true of the large plastic items found on the beaches in Cyprus in large numbers,” he adds.

The findings support the theory that beaches act as a “sink” for marine microplastics, becoming key areas for contamination, as well as strengthening potential concerns that microplastics can have effects on animal and human life.

“Although we knew the beaches were highly polluted with plastic to find microplastics in every location and at very depth was surprising and worrying,” Dr. Emily Duncan tells PackagingInsights.

“The presence of microplastics in the sand could potentially change the incubation environment for the marine turtle eggs. Further experimental studies are needed to evaluate the impact of the plastic presence in the sand column using environmentally relevant plastic concentrations to further understand if these changes to temperature and permeability that may occur,” she concludes.

The paper, published in Marine Pollution Bulletin, is entitled: “The true depth of the Mediterranean plastic problem: Extreme microplastic pollution on marine turtle nesting beaches in Cyprus.”

This is not the first study to identify worrying levels of microplastics in nature. 

Research published in Nature Communications discovered high levels of microplastics in Arctic Sea ice. Overall, 17 different types of plastics were discovered in the ice, including those commonly used in packaging materials, paint particles from ships and fishing nets, and cellulose acetate from cigarette filters. The microplastics could remain frozen in the ice for up to 11 years before melting into the sea. The researchers are unaware of what happens at this point, although a popular theory is that the particles end up on the seafloor. 

Despite the World Health Organization (WHO) launching an investigation into the effects of microplastics on human health, definitive answers are not yet known. You can read PackagingInsights special report on the topic here. 

By Laxmi Haigh