Chapter 14 - Occurrence and ecological health risks of microplastics

Abstract

An increasing body of evidence exists on the occurrence of (micro)plastics in various environmental compartments including soils, aquatic systems, and as air-borne particulates. (Micro)plastics and their associated chemical additives pose potential environmental and ecological health risks. Information on the environmental and ecological health risks of microplastics remains scattered in several articles, while the few available reviews often focus on one environmental compartment such as soils or aquatic systems. Here, we applied the eco-hierarchical or ecosystem cascade framework to examine the evidence, and present a comprehensive synthesis of the environmental and ecological health risks of microplastics. First, the eco-hierarchical or ecosystem cascade framework and its principles are presented. Second, the impacts of microplastics and their chemical additives on the soil physico-chemical properties and ecological processes, including biogeochemical cycling are discussed. This is then followed by a discussion of the ecological impacts of microplastics on aquatic ecology, including behaviour, physiology, feeding habits, and growth-related parameters. Using the eco-hierarchical or ecosystem cascade framework, under-studied aspects of the ecological impacts of microplastics were identified. These include the impacts of microplastics and their chemical additives on: (1) trophic interactions, (2) ecosystem goods, services, and benefits, and (3) interactions of microplastics with other ecological health stressors such as legacy and emerging chemical and biological contaminants such as synthetic chemicals and antibiotic resistance. Lastly, future research directions including several knowledge gaps and the application of emerging research tools are presented.