Identification, Abundance, and Distribution of Microplastics in Surface Water Collected from Luruaco Lake, Low Basin Magdalena River, Colombia

There are few studies on microplastic (MP) contamination in Colombia, and little is known about its impacts on continental aquatic ecosystems. This study evaluated, for the first time, the identification, abundance, and distribution of MP particles in the surface water of Luruaco Lake, in the low basin of the Magdalena River, Colombia, included in national programs in marine sciences and hydrobiological resources. Six stations and four samplings were established in the dry and rainy seasons. A total of 72 water samples were collected for microplastic extraction using hydrogen peroxide (H2O2) digestion, density separation with sodium chloride solution (NaCl), and filtration. The abundance of MPs ranged from 0 to 3.83 MPs·L−1, with an average of 1.90 MPs·L−1 in the rainy season and 0.25 MPs·L−1 in the dry season. According to the calculated coefficient of microplastics impact, the contamination in the surface water of Luruaco Lake is “maximum” to “extreme” for fibers with an average length of 2.05 mm and “minimum” to “average” for fragments that are 0.35 mm in size on average. Polyester (PES, 57.9%), polystyrene (PS, 47.0%), and polyethylene terephthalate (PET, 35.3%) polymers were more abundant in surface water. The temporal variation of the MPs indicates contamination related to the discharges of the tributary streams to the lake in the rainy season.