The Ecotoxicological Effects of Microplastics on Trophic Levels of Aquatic Ecosystems

Spatial and temporal variations of microplastics (MPs) studies in both fresh water and seawater ecosystems have produced many results that support the adsorption of toxic pollutants to the microplastic surface. In addition, small-sized polymer fragments have increased their participation in the food web since phytoplanktonic organisms. This situation causes consequences that can severely limit the growth and/or development of many aquatic species. In this part of the book, the toxicity studies results examined in the last 10 years show that the properties of microplastics (polymer type, shape, size, colour, etc.), the exposed dose, the forms of exposure and the way in which functional disorders occur afterwards are addressed; methodically and conceptually. In the methodology studies of toxicity studies, it was determined that the most preferred microorganism was Daphnia magna. Many factors taken into account due to the ease of operation of the organism, the clarity of the test procedures, its comparability and the purpose of the studies carried out are effective in these choices. In addition, Danio rerio, Mytilus galloprovincialis, Mytilus edulis and Scrobicularia plana were found to be among the other organisms of frequent choice. Toxicology studies focus more on the effect of exposure to a single concentration or independent chemicals. Therefore, researchers have struggled to find answers to the type of interaction. The movement and dynamic of microplastics in water, the similarity of MP colour to nutrients for the organism or pollutant absorption due to surface load affect the accumulation of pollutants in the organism. In addition, it has been observed that polymer type is an important factor in determining microplastic toxicity, while polypropylene (PP) is the most common type of microplastic in detection and analysis studies, toxicology and MP studies have shown that studies on polyethylene (PE) and polystyrene (PS) are high. The pressure of these polymers on each step in the food web, when additives used in the plastic manufacturing process are added, leading to toxicology results reach to a toxic or very toxic level.