Nano-plastics that accumulate in marine life may end up on dinner plates, study suggests

06 Jun 2018 --- Plastic nanoparticles – which are tiny pieces of plastic less than 1 micrometer in size – could potentially contaminate food chains, ultimately affecting human health, a study conducted at the National University of Singapore (NUS) has found. The study found that such nanoplastics are easily ingested by marine life and accumulate over time. This creates a risk of transference to the human food chain. They suggest this could threaten food safety and pose health risks.

Using the acorn barnacle Amphibalanus amphitrite as a model organism, the NUS research team demonstrated for the first time that nano-plastics consumed during the larval stage are retained and accumulated inside the barnacle larvae until they reach adulthood.

“We opted to study acorn barnacles as their short life cycle and transparent bodies made it easy to track and visualize the movement of nano-plastics in their bodies within a short span of time,” says Samarth Bhargava, a Ph.D student from the Department of Chemistry at the NUS Faculty of Science, who is the first author of the research paper.

“Barnacles may be at the lower levels of the food chain, but what they consume will be transferred to the organisms that eat them. In addition, plastics are capable of absorbing pollutants and chemicals from the water. These toxins may be transferred to the organisms if the particles of plastics are consumed, and can cause further damage to marine ecosystems and human health,” marine biologist Dr. Neo Mei Lin from the Tropical Marine Science Institute at NUS and one of the authors of the paper, tells FoodIngredientsFirst.

“Barnacles can be found in all of the world’s oceans. This accumulation of nano-plastics within the barnacles is of concern. Further work is needed to better understand how they may contribute to longer term effects on marine ecosystems,” says Dr. Serena Teo, Senior Research Fellow from the Tropical Marine Science Institute at NUS, who co-supervised the research.

The study
The NUS research team incubated the barnacle larvae in solutions of their regular feed coupled with plastics that are about 200 nanometers in size with green fluorescent tags. The larvae were exposed to two different treatments: acute and chronic.

Under the acute treatment, the barnacle larvae were kept for three hours in a solution that contained 25 times more nano-plastics than current estimates of what is present in the oceans. On the other hand, under the chronic treatment, the barnacle larvae were exposed to a solution containing low concentrations of nano-plastics for up to four days.

The larvae were subsequently filtered from the solution and examined under the microscope. The distribution and movement of the nano-plastics were monitored by examining the fluorescence from the particles present within the larvae over time.

“Our results showed that after exposing the barnacle larvae to nano-plastics in both treatments, the larvae had not only ingested the plastic particles, but the tiny particles were found to be distributed throughout the bodies of the larvae,” says Serina Lee from the Tropical Marine Science Institute at NUS, who is the second author of the paper.

Even though the barnacles’ natural waste removal pathways of moulting and excretion resulted in some removal of the nano-plastics, the team detected the continued presence of nanoplastics inside the barnacles throughout their growth until they reached adulthood.

Next steps
The NUS research team seeks to further their understanding of the translocation of nanoparticles within the marine organisms and potential pathways of transfer in the marine ecosystem.

“The lifespan and fate of plastic waste materials in marine environment is a big concern at the moment owing to the large amounts of plastic waste and its potential impact on marine ecosystem and food security around the world. The team would like to explore such topics in the near future and possibly to come up with pathways to address such problems,” explained Suresh Valiyaveettil, Associate Professor from the Department of Chemistry at the NUS Faculty of Science, who co-supervised the research.

The team is currently examining how nano-plastics affect other invertebrate model organisms to understand the impact of plastics on marine ecosystems.

Plastic particles in our food-systems
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). 

Exclusive testing was conducted on more than 250 bottles from nine different countries, with 93 percent found to have contained plastic debris the size of the width of a human hair, including polypropylene, nylon, and polyethylene terephthalate (PET).

These findings sparked concern in the public sphere as researchers were unsure of what the effect on human health may be. This, in turn, sparked the World Health Organization to conduct an investigation into the matter. You can read more about the topic on our sister website, NutritionInsight, here.

In light of the plight of plastic on marine life, The European Commission announced new rules to combat increasing levels of plastic pollution in the oceans. The EU-wide rules aim to target the 10 highest polluting single-use products, which together constitute 70 percent of all marine litter items.

The news rules apply different measures to different products. Where alternatives are readily available and affordable, single-use plastic products will be banned from the market. For products without straight-forward alternatives, the focus is on limiting their use through a national reduction in consumption; design and labeling requirements and waste management/clean-up obligations for producers. Together, the new rules aim to put Europe ahead of the curve on an issue with global implications. However, the rules have been met with a range of responses from industry.

By Laxmi Haigh