The use of optical microscope remains the most commonly used technique for microplastic identification and quantification despite major limitations with misidentifications and biases. We evaluated the use of the 1% Rose Bengal stain in improving the identification of microplastics after a standard microplastic isolation process. The stain discriminated organic materials from potential microplastics with significant differences between numbers observed before (6.65 ± 5.73) and after staining (2.91 ± 3.43). Numbers of potential microplastics observed under the conventional method (without staining) in sediment, feacal matter of shorebirds and the lagoon water were respectively 3.55 g-1, 0.8 g-1 and 0.13 ml-1 but reduced to 1.85 g-1 of sediment, 0.35 g-1 of feacal material and 0.09 ml-1 of water after staining. Colour composition of potential microplastics under the conventional method was brown (31.0%), black (26.5%), white (20.2%), translucent (16.7%) and red (5.6%). After staining, brown (49,2%), black (30.5%) white (2.3%) and translucent (18.0%) were retained but distinction could not be made between stained organic items and red-coloured microplastics. It was clear that the stain has the potential in improving microplastic identification but requires further investigations.
Coloring Agents Environmental Monitoring