New Tools for sensing Microplastic, an Emerging Food Security Issue

On March 19, Ethan Edson, the developer of the autonomous microplastic sampling instrument “Manta Ray”, gave a talk titled “New Tools for Sensing Microplastic Pollution, an Emerging Food Security Issue”. This was the third lecture of Northeastern University’s Spring 2019 “Contemporary Issues in Security and Resilience Studies” Speaker Series

Awareness of the global plastic crisis is rising as cities pledge to reduce their waste and major media publications like National Geographic campaign for education and action. Single-use plastic pollution has been shown to harm wildlife time and again. Most recently, a whale was found beached in the Philippines with 88 pounds of plastic in its stomach – its death likely caused by starvation due to complications with the plastic. However, plastic pollution extends below the surface, present in small particles that can be ingested by fish and make their way up the food chain. These microplastics are all around us, and Northeastern University alum Ethan Edson has developed a tool to better understand their marine presence.

Origins of the Plastic Problem

Since the 1960s, global production of plastic has grown exponentially. Plastic is lightweight, flexible, moldable, and waterproof, making it the ideal material for all types of consumer and industrial products. It is also extremely cheap to produce, often making it cheaper to make new plastic than to recycle old plastic, which creates a disincentive to do the latter. The properties that make plastic so popular are also what cause trouble when plastic waste is not managed properly. Many plastic products are only intended to be used for a short period of time, but the plastic material itself is designed to last forever. Unlike wood or food scraps, plastic will not decompose (i.e. be broken down into component molecules through bacterial processes, aka biodegradation) and instead can persist for hundreds of years.

When waste is mismanaged, it can end up in the ocean. Ocean circulation patterns result in gyres, which concentrate plastic pollution in the centers of the oceans. While dramatic floating garbage patches capture the public eye, the bulk of the pollution is not obvious at the surface. Microplastics are plastic particles that are smaller than 5mm. They can either be primary microplastics that were produced as small solids (like microbeads and microfibers) or secondary microplastics which have been broken-down from larger pieces. Secondary microplastics are more prevalent in the ocean, where UV exposure and mechanical stresses accelerate the degradation of plastics into smaller pieces.

Health and Environmental Impacts

With so much plastic in the environment, animal interactions are inevitable. To fish and other filter-feeders, microplastics bear an uncanny similarity to plankton, their primary food source. Plastic has no nutritional value to animals that ingest it, and might interfere with digestion. In addition, plastic absorbs toxins from the water. Pollutants in an aqueous environment are attracted to plastic due to its chemical composition, and therefore plastic pieces can have concentrations of toxins that are much higher than in the surrounding water. These toxins will be further concentrated in organisms higher up in the food chain due to the process of biomagnification. This has the potential to harm higher-level consumers, including humans. The human health impacts of microplastics are not entirely known. When ingested, microplastics larger than 100 microns will pass through our digestive system, but the smallest pieces may be able to pass through human tissue – potentially ending up in our bloodstream or causing cancer. Microplastics are not only in our seafood, but are also found in our drinking water and in the air we breathe.

Microplastic Research

To further investigate these environmental and health concerns, more information first needs to be known about the global distribution of marine microplastics. However, the current method of documenting microplastics is expensive and time-consuming, requiring researchers to manually extract plastic pieces from water samples with a microscope and tweezers. In response, Ethan Edson developed “Manta Ray” – a sampling tool that has automated and improved this process. The basic concept involves pumping water through a linear system that scans the composition of microplastic particles and determines the concentration of plastic in the sample. “Manta Ray” uses an optical sensor to determine the type of plastic passing through the system by employing deep learning neural networks to match the spectroscopy profiles of the scanned particle to the type of plastic. Edson’s goal is to produce this tool on a large scale to monitor microplastics across the globe. His ideas for future deployment of Manta Ray include installing it in permanent buoy tracking stations and attaching it to shipping vessels that regularly traverse the oceans to efficiently chart the distribution of microplastics around the world. He is also in the process of commercializing the Manta Ray’s technology so that its hardware or data can be sold to interested parties.

The next lecture in this series will be on April 16: Click here for more information.

For more on this topic, see News at Northeastern’s new article, “This Sensor Won’t Save The Whale With 88 Pounds of Plastic In Its Stomach. But It Might Help The Rest of Us.”
Want to read more about the development of the “Manta Ray’s” technology? Check out this report.