Microplastic pollution in the digestive tract of western Pacific shrimp (Litopenaeus vannamei Boone, 1931) in farms in the southern provinces of Iran

Microplastics enter the food chain of aquatic animals; they cause damage to the digestive system, disruption of the reproductive cycle, and finally their death. The present study was conducted to investigate the microplastic pollution in the digestive system of Vanami shrimps cultivated in some shrimp farms in Bushehr, Khuzestan, and Hormozgan provinces.

Sampling was done from two shrimp farms in each port including Bandar Rig in Bushehr province, Bandar Choebdeh in Khuzestan province, and South Tiab located in Hormozgan province. 90 shrimp samples were randomly collected from each breeding farm from June to October 2019. The identification method of microplastics was done by FT-IR spectrophotometer.

The highest frequency of microplastics related to farmed shrimps was 41.11% in the fields of Khuzestan province, and a lower amount of microplastic pollution was observed in Hormozgan and Bushehr provinces with 28.88% and 17.70%, respectively. According to one-way ANOVA, the mean of microplastics in the digestive tract of shrimp had a significant difference in the studied stations (p<0.05). The most type and colors of microplastics in the digestive system of shrimps in the farms of all provinces belonged to fiber and black color. Polypropylene and polystyrene were detected in microplastics found in the digestive system of shrimps.

Microplastics were observed in some of digestive tracts of the shrimps of the breeding farms examined in this research in all three provinces of Bushehr, Khuzestan, and Hormozgan. The highest frequency of microplastics in the digestive tract of shrimps is related to the breeding farms of Khuzestan province, and Hormozgan and Bushehr respectively have a lower amount.