Accumulation and Depuration of Microplastics by Oysters Upon the Laboratory Conditions

Abstract

This study aimed to (i) monitor on the 1st, 5th, and 10th days the microplastics (MP) presence and bioaccumulation in different organs (gill, digestive tract, remaining tissue) of the oysters exposed to 100 MP L⁻¹; and (ii) evaluate the MP elimination proportion out of the oysters after 1, 5, 10, and 30 days of the depuration experiment. We found that the accumulation of MP was higher in the digestive tract and remaining tissues than in the gills of the oysters. The average bioaccumulation factors were 10.11, 14.25, and 40.92 for 1, 5, and 10 days of incubation, respectively. Generally, the longer the time of MP exposure, the higher the MP bioaccumulation is in the organs and tissue of the oysters. High elimination proportion of MP in the gill (77.4%), digestive tract (74.4%), remaining tissue (62.3%), and the whole body (70.2%) of the oysters was observed after the 1st day of the depuration experiment. The elimination proportion in each tissue continued to increase linearly with time during the depuration period. After 1 month of depuration, the elimination rate in the gill, digestive tract, remaining tissue, and whole body of the oysters was 83.9%, 91.0%, 91.3%, and 89.9%, respectively. This work contributes to a better understanding of the uptake and distribution of MP in different organs and tissues of the oysters. At least 10 days of MP depuration out of the MP-contaminated oysters is suggested to minimize the MP exposure via food consumption.