Spatio-temporal patterns of occurrence of microplastics in the freshwater fish Gambusia affinis from the Brantas River, Indonesia.

The first investigation of microplastics in G. affinis from the Brantas River was carried out in this study. Microplastics were found at higher concentrations in gambusia fish captured downstream (209.18 ± 48.85 particles/gram) than upstream (24.44 ± 0.14 particles/gram). Microplastic particle concentrations in G. affinis have a positive linear relationship with fish length. The fiber was the most prominent shape at Sites 1 and 2, whereas the fragment was dominant at Sites 3 and 4. With a value of 45-48%, black dominates the entire site, followed by blue (29-38%), transparent colors (7-11%), red (2-4%), purple (1-3%), and other colors (5-7%). Microplastics measuring <0.1 mm are commonly found in fish bodies. Cyclohexylmethyl octyl ester (phthalic acid) is the most abundant component found in microplastics, accounting for 30.11% of the total. This study provides evidence that G. affinis can be used to monitor the presence of microplastic pollution in the Brantas River but further studies are needed regarding the effects of microplastics and their health hazards on fish.

Oxidative stress responses of microplastic-contaminated Gambusia affinis obtained from the Brantas River in East Java, Indonesia.

The biological impact of microplastic (MP) contamination on freshwater biota has sparked interest. Microplastics are thought to have a high potential for toxicity, affecting organism metabolism. The goal of this study was to investigating the antioxidant indicators on the gills and digestive tract of Gambusia affinis fish in the Brantas River reacted to microplastic pollution. The obtained data was evaluated using path analysis. The digestive tract had much greater levels of superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) than the gill. SOD concentration in the gills was 13.7 ± 5.3 U/mL, while SOD concentration in the digestive tract was 16.3 ± 3.6 U/mL. The CAT concentration in the gills (5.3 ± 2.9 ng/mL) was higher than the CAT concentration in the digestive tract (10.5 ± 2.8) ng/mL, while the MDA concentration in the gills (690.8 ± 135.6 mU/mL) was higher than the MDA concentration in the digestive tract (869.6 ± 122.2) mU/mL. MP abundance has a direct effect on SOD and MDA in the gills. Meanwhile, the quantity of MP in the digestive tract has a direct effect on SOD and CAT, which affects the development of the MDA response.