Assessment of microplastics in gastrointestinal tract of cattle egret (Bubulcus ibis) from a metropolitan city Lahore, Pakistan

Ingestion of microplastic (MPs) in birds and its subsequent health effects has become one of the major environmental concerns. The current study is, therefore, designed to investigate the level of MPs in gastrointestinal tract of a semi-aquatic bird species, the cattle egret (Bubulcus ibis) and characterize their types, color and chemical composition. Samples (n = 5) from dead individuals were first digested then separated on the basis of density followed by vacuum filtration prior to quantification of MPs through stereomicroscopy. Fourier Transform Infrared Spectroscopy (FTIR) was used to identify the chemical composition of MPs. Our results showed the highest level (mean ± S.D items/sample) of sheets (37.2 ± 9.6) followed by fibers (28.8 ± 15.3), fragments (12.8 ± 16.2), and microbeads (0.4 ± 0.5) in gastrointestinal tract of cattle egret. The most frequently detected color was transparent (23%), followed by brown (19%), white (18%), black (15%), and orange (10%), respectively. Polyvinyl alcohol (PVA), polyisobutylene, polyaramid, fiberglass and PTFE coated fiberglass fiber were characterized as the major constituent compounds of MPs in gastrointestinal tracts of cattle egrets. Highest concentrations of sheets and fibers MPs in gastrointestinal tract of cattle egrets reflect their greater sources and lowest degradation. Our results depict the elevated level of MPs in the gastrointestinal tract of cattle egrets which might be posing some serious health effects. The ingestion of MPs by birds is evidently associated with their declining populations which should be mitigated effectively to avoid future worst consequences.