Microplastics Exposure Routes and Toxicity Studies to Ecosystems: An Overview

Microplastics (MPs) are now ubiquitous in global ecosystem, therefore all biota is at risk of exposure and potential toxicity. In this study, we presented an overview of information based on literature concerning exposure to MPs and the toxicity of such exposure. Currently, four major routes of exposure have been identified including entanglement, contact, ingestion and inhalation. Humans maybe the most exposed organism because they are at the peak of the food chain. Toxicology effect to marine and freshwater organisms are classified based on exposure dosage as either high (mortality, decreased reproductive output, organ damage) or low (changes in behavior with time). On plants, reports have shown that MPs exposure can affect negatively the growth and depending on exposure concentration and types of MPs and oxidative activities. However, effects on plants maybe short-term and transient. Although, toxicity studies regarding human are still ongoing as per reports, plants and animals are still scantly studied. Animal toxicity studies have widely used D. magna as model specie. MPs pollution may have a knock-on effect on trophic structure and functioning of ecosystems by affecting the base of the food chain. We concluded by identifying the gap in knowledge and give recommendations for future research.