Stomach flushing technique applied to quantify microplastics in Crocodilians

The impact of microplastics on wildlife is a recent problem for which methods to evaluate exposure still need development. Being able to identify and quantify microplastics (particles < 5 mm) in the gastric contents of live crocodiles allows us to evaluate exposure, at both individual and population level, and also its contribution as transporter of other contaminants. The method was validated to determine and quantify microplastics in crocodile stomach contents recovered during an experiment where a known amount of this contaminant was given to crocodiles via oral administration. Through stomach flushing we were able to recover more than 80 % of the total volume of microplastic administrated to each crocodile. In summary, the method used during the experiment consists of 1) immobilization of the crocodile; 2) extraction of microplastics from stomach contents obtained through stomach flushing; 3) separation, identification and quantification of recovered microplastic fragments using microscopy and FTIR. Low cost method that uses a small number of materials, does not take long to produce results and can easily be performed in the field or the laboratory. Effective in extracting stomach contents (95 %). High (>80 %) and good (>60 %) recovery efficiencies within two and four days after ingestion of microplastics by crocodiles (C) 2019 The Authors. Published by Elsevier B.V.