The occurrence and distribution of microplastic contamination in Qara-sou river, Iran: incidence, quantification, and qualification.

In the current study to investigate the characte - rization of Microplastic - released into the Qara-Sou river, Kermanshah, Iran, 12 sampling sites were surveyed along a 100 km stretch of the river. The maximum and minimum numbers of MPs were about 10,000 and 45,000 items per m3. The average concentration of MPs in the Qara-sou river was 23,666 ± 12147 items per m3. The dominant size and shape of MPs ranged from 0.025 to 1 mm (~44%) and fiber shapes (~78%). In addition, SEM-EDS analyses confirmed the presence of carbon-dominant peaks with O, Ca, Fe, Al, and Si. FTIR spectra have identified some MPs in the PVC, PU, PS, PE, and nylon polymer categories. A high level of MPs was discharged into the Qara-sou river, which should be attracting the attention of the community and decision-makers to reduce damage to the environment and human health.

Occurrence and characterization of microplastic content in the digestive system of riverine fishes.

In the present study, the occurrence and characterization of microplastics (MPs) content in the fishes of the river was studied. Therefore, six sampling stations were considered for fishing. Then, the entire stomach of fishes was investigated by visual stereomicroscope, FTIR, SEM, and EDX to analyze the content of the samples, by MPs type, shape, color, and size. The most frequency of MPs was observed in Ghazanchi (Siii) and Kermanshah (Siv) stations which were close to urban and industrial areas. Most types of detected MPs included polystyrene, polyethylene, and nylon with the highest frequency observed in Luciobarbus caspius and Alburnus chalcoides fishes. Overall, the frequency of detected MPs in the caught fishes was 93.8%. Indeed, MPs with a size of 0.025-1 mm (25-1000 µm) were the most frequency of MPs in fishes. The frequency of MPs shapes was fiber (85.12%), fragment (12.32%), foam (0.77%), film (1.21%), and microbead (0.56%), respectively. The highest and lowest percentage of MPs belonged to black and green with an abundance of 63% and 2%, respectively. The result implies that lots of riverine fishes are polluted with MPs, those which can move into the food chain.