Method for Quantifying and Characterization of Microplastics in Sand Beaches

In recent years microplastics have become an issue of global concern due to the negative effects that they cause in the environment, such as their ingestion by marine species and their capacity to adsorb pollutants from water. To face this problem research has been performed around the world to study the presence of microplastics in marine environments. However, the use of different on-field sampling and laboratory characterization techniques, sometimes difficult to replicate, hinders the possibility to compare results. This paper proposes a methodology for sampling and characterization of microplastics on the 1 -5 mm range present on sand beaches. First, a comparison is made between the different techniques used for sampling, extraction, classification and identification of microplastics on studies performed on the last five years. Then the proposed methodology, which involves sampling in the high tide zone, at 5 cm depth, is explained in detail. The method has a low cost, as it uses simple equipment available in most of the labs. It can be easily replicable and allows presenting results in different units. The decision criteria, materials and steps in each of its seven stages (identification of sampling zone, selection of sampling points, sampling, drying, extraction, quantification and classification of microplastics) are described. Also, it explains a process to eliminate false positives caused by organic matter or shells. This work aims to improve the efficiency, replicability and homogeneity in the study of microplastics.