Resíduos de microplásticos em camarão de água doce Macrobrachium amazonicum no município de Itacoatiara (AM)

Abstract

Contamination by microplastic (MPs) in the aquatic environment has attracted attention due to its various effects in biotic and abiotic environemnets. Therefore, the aim of this study was to evaluate the occurrence of plastic debris in freshwater shrimp Macrobrachium amazonicum, surface Waters, sediments and macrophytes from Itacoatiara, AM, Brasil. A total of 600 specimens of M. amazonicum were captured in two collection sites Jauary (urban area) and Centenário (rural area). Initially, the sex and size of shrimp were recorded. The samples were grouped into the gastrointestinal tract, cephalothorax and abdomen and weighed. Chemical solutions were used in the samples to extract the MPs. These MPs were analyzed and characterized according to their physical and chemical properties. Data analysis was performed using analysis of variance. Regarding the presence of plastic debris in surface waters, sediments and macrophytes, a total of 11 points were applied in rural 1 (upstream of the Amazon River), urban and rural 2 (downstream of the Amazon River) in the municipality of Itacoatiara (AM). The surface water samples were filtered. The sediments were submitted to chemical solutions to extract the MPs. The solid residues collected in the sediments were analyzed qualitatively and quantitatively. The percentage of coverage of each species was performed, as well as the percentage of associated plastic debris. The identification of plastic debris was performed through the physical characteristics of the contaminants. Data analysis was performed using analysis of variance. The results showed that shrimp from urban areas have higher accumulations of MPs than from rural areas, with a predominance of MPs in females and in the gastrointestinal tract of shrimp. Fibers from 1 to 5 mm, in blue color, were abundant in the shrimp in the present study. Two polymers were identified, with polypropylene present in the dark blue fibers and nylon in the light blue fragments. In addition, it was observed the presence of accumulation of plastic waste in the urban area, being different for the rural area. The presence of MPs in surface waters was more evident in rural area 1, while for sediments, it was accumulating in urban areas. Dark blue fibers with sizes from 1 to 5 mm were present in surface water and sediment samples. The macrophyte species Paspalum repens and Pontederia rotundifolia were predominant. These same species presented accumulations of plastic debris in the rural area 1. Fragments of 1 to 5 mm in white and dark blue were abundant in the macrophyte species. The results presented in this study show the presence of plastic debris on the left bank of the Amazon River, in the municipality of Itacoatiara, which may be the source of entry of MPs contaminants into the Amazon ecosystem, which may cause several damages to aquatic animals in the Amazon region and, even in the transfer to humans through consumption of contaminated animals.