Publications: Research reports and publications

A review of microplastics risk - implications for Environment Southland

1 July, 2019
Cawthron Report No. 3350. Prepared for Environment Southland

Tremblay LA, Pochon X, Baker V, Northcott GL (2019). A review of microplastics risk - implications for Environment Southland. Prepared for Environment Southland. Cawthron Report No. 3350. 21 pages plus appendices


There is increasing scientific and public concern over the presence and persistence of plastic pollution in the environment. An estimated 5 to 13 million metric tons of plastics enter the oceans annually, and that amount is projected to continue to increase if no mitigation measures are put in place (Burgess & Ho 2017). This is an environmental issue that must be addressed and managed by regional councils. This report was commissioned by Environment Southland to focus on the ecological risk assessment related to microplastics in the environment. It provides an overview of current state of knowledge information to assist Environment Southland to develop risk mitigation and management strategies for plastics and microplastics (defined in Section 2).
Research on marine plastic pollution has been the focal point of scientists, the public and policy makers. However, recent literature on the presence of microplastics in air, soil, sediments, freshwaters, oceans, plants, animals, and parts of the human diet, raise broad concerns of the impacts of plastics and microplastics in complex global ecosystems. It is established that microplastics are a ubiquitous contaminant and their impacts in the environment pose the highest risk from plastic pollution. Plastic debris is usually divided into two categories: macroplastics > 5 mm and microplastics greater than 0.3 mm and less than 5 mm (Moore 2008). The presence of microplastics in all environmental compartments (water, soil, air, and biota) has gained increasing public and political awareness along with the desire to identify sources and reduction / remediation options (Vollertsen & Hansen 2017). The limited investigations completed to date in New Zealand indicate the types and concentration of microplastics entering and persisting in our environment are likely to be similar to those reported in many other countries.

The objectives of this report were to:
• review the national and international research literature on the sources of microplastics, their fate and transport in the environment and current state of knowledge on their risk to ecosystem and human health
• summarise the international research programmes and strategies to assess, characterise and manage the risk of microplastics
• cover current international guidelines and legislation including initiatives to reduce or eliminate plastics and ultimately microplastics
• provide a list of current microplastics research efforts in New Zealand
• provide recommendations to define knowledge gaps and research needs to better manage the risk of microplastics in New Zealand.