Types, occurrence, and distribution of microplastics and metals contamination in sediments from south west of Kerkennah archipelago, Tunisia

Microplastics (MPs) are one of the most significant solid waste pollutants in the marine environment and accumulate in sediments around worldwide. In this study, the pollution level, the type, occurrence, and distribution of MPs in sediments from the southwestern Kerkennah archipelago, Tunisia, were investigated. Sediment samples were collected from 20 adjacent sites through three lines L1, L2, and L3. MPs were separated from sediment by density flotation (NaCl, 1.2 g cm(-3)) and characterized in terms of shape, size, and color using microscope. The accumulation of toxic chemicals such as trace metals on microplastics was measured by atomic absorption microwave-assisted acid extraction. Polymer types were identified using FTIR-ATR spectroscopy. This study showed that microplastics were found in all samples, which emphasized that their extensive distribution throughout three lines by an average abundance of MPs was 611 items/m(2). Among the shape categories of plastic particles, fiber and fragment were the most dominant frequent shapes (94%). The more frequent colors found were white (52.7%) and transparent (35.1%). Regarding the sizes, the microplastics below 1 mm were the most common accounting for 97% of all plastics. Results of trace metals Zn, Cu, Pb, Cr, and Ni in sediments with concentrations were reported as 3.48 mu g/g, 0.41 mu g/g, 0.38 mu g/g, 0.33 mu g/g, and 0.12 mu g/g, respectively.

Automated summary

Microplastics are a significant solid waste pollutant in marine environments, and this study investigated their presence in sediment samples from the southwestern Kerkennah archipelago in Tunisia. The study found microplastics in all samples, predominantly in the form of fibers and fragments, with white and transparent colors being the most common. Additionally, trace metals such as Zn, Cu, Pb, Cr, and Ni were also detected in the sediments at concentrations ranging from 0.12 to 3.48 μg/g.