Plastic resin pellets also known as pre production plastic or nurdles are the raw material which is heated and chemically treated to mould plastic goods. Huge volumes of plastic resin pellets are produced and shipped around the world each year. An alarming number of these pellets are constantly being lost to the marine environment both from direct cargo loss at sea and from spillage around factories and transport routes on land. A large proportion of these land spillages eventually find their way into drainage systems and out to sea. At sea pellets are circulated throughout the world’s oceans.
Plastic resin pellets contain some toxic chemicals but also accumulate pollutants from the ocean. These absorbed pollutants are organic compounds known as Persistent Organic Pollutants (POP’s), a growing number of which are proving to be Endocrine Disruptors – chemical compounds which interfere in differing ways and rates, with the normal functioning of organisms. While an adult affected by endocrine disrupting chemicals may not show any noticeable effects, significant to devasting effects can occur in its offspring involving one or more of the growth, development, behavioural, reproductive and immune system processes. Organisms potentially affected by persistent organic pollutants range from plankton through to humans.
Plastic resin pellets are mistaken by marine creatures as food or are inadvertently ingested. They are known to be ingested by many forms of sea life thus becoming a conduit into the marine food web for persistent Organic Pollutants. Japanese researchers have established that levels of POP’s can range up to one million times greater on pellets than in surrounding seawater. Plastic debris (post production plastic) also has an array of chemicals including POP’s in its makeup and also absorbs persistent organic pollutants from seawater.
Small and Microscopic Plastic
Plastic resin pellets are one member of a growing family of small plastic pollution. Advances in plastic fabrication technology have given rise to mini pellets which are 2mm or less in size and micro pellets which are 1mm or less. Plastic fragments resulting from the wearing and breakage of intact plastic products reduce down through small to microscopic sizes.
Plastic resin also comes in powder form, the grains of which are around 200 micron and this takes us into the microscopic realm. Photo degradation of plastic items generates a whitish powder – microscopic grains which are still plastic and retain their toxic loads. Another member of this family is plastic scrubbers – as exfoliates in skin care products and also as specialised air blasting media. Scrubbers are around 500 micron in size. As the size of a plastic pollutant decreases, increasing numbers of smaller organisms become exposed to it and the pollutants it carries.
Monitoring the Presence of Plastic Resin Pellets on Coastlines
The occurrence, numbers and condition of plastic resin pellets on a given section of coast can provide clues as to their origin, behaviour, fate and harm potential.
Distribution of the pellets is governed by local coastal features and dynamics and the presence of pellets can seem somewhat illusive. To account for the seasonal variation in their presence monitoring over time is desirable.
The condition of a plastic resin pellet can vary from new looking to worn and some show a range of yellow staining. Staining is a good indicator that the pellet has spent some time circulating in the ocean and hence has had prolonged exposure to Persistent Organic Pollutants in the seawater. Wearing may indicate that a pellet has migrated down a coast undergoing fragmentation and or has been recirculating in a beach debris trap site for some time.
Scientists have only recently begun to closely examine the Persistent Organic Pollutant – Plastic Resin Pellet pollution process and its potential to harm marine organisms. What has been established is that many persistent organic pollutants are endocrine disruptors and their effects have been verified in a range of species. Also established is that many marine creatures are ingesting plastic resin pellets. For example the USEPA has reported species of turtle, seabird, fish and lobster as having ingested plastic resin pellets. Plastic debris including resin pellets now occurs in every marine and coastal environment worldwide. Marine plastic pollution is exacting a heavy toll on many species and in some cases is one of the significant factors threatening their continued existence.
An immediate and practical approach to the plastic resin pellet problem is to curtail the spillages and losses. This needs to be done urgently, however, by itself will not solve the problem. Demand for plastic resin pellets will continue to escalate while plastic production and consumption patterns remain unchanged and unchecked in relation to their environmental impacts. Changing the way polymer based goods are produced from one based on oil and toxic chemicals to one based on natural materials and sustainable production methods is an emerging solution but will take time. In the mean time changing our patterns of use and consumption away from plastic – especially single use containers and wrapping and avoiding known harmful products can have an impact. Becoming actively involved in removing debris from our coastlines is also essential to limit the accumulation of fragmented plastic.
Plastic resin pellets and micro plastic pollution already existing in the ocean will remain there for hundreds and possibly thousands of years, continually circulating throughout the ocean and within the food web. Establishing the extent of distribution of resin pellets along our coast and in our offshore environments is an important step toward understanding the origin, fate and harm potential of this form of marine debris and providing information to assist in the challenge of stopping the occurrence of marine plastic debris including plastic resin pellets.
- Algalita Marine Research Foundation
- International Pellet Watch
- UNEP Information on Persistent Organic Pollutants
- GPA Information on POPs
- Potential for Plastic to Transport Hydrophobic Contaminants
- Californian legislation to curb plastic resin pellet spillage
- Plastic Nurdle Fact Sheet