Microplastics in Cauvery affecting fish: IISc study

BENGALURU: A recent study by the Indian Institute of Science (IISc) found the presence of microplastics in the Cauvery river which may have been contributing to growth defects in fish. Research believe that microplastics in the river might lead to a negative impact on humans in the long-term. 

The study titled ‘Evaluation of cytogenotoxic potential and embryotoxicity of KRS-Cauvery River water in zebrafish’ was done by a team of researchers headed by Prof Upendra Nongthomba of IISc’s Molecular Reproduction, Development and Genetics Department (MRDG). 

After noticing deformities in fried fish sold on the river’s bank, Nongthomba set out to find the cause.
The study found that the water in the KRS Cauvery river was hypoxic or oxygen-deficient. They had also found the presence of microplastics that are at least 5mm small. 

Following experiments done on zebrafish embryos with water collected from the river, the researchers found that the fish had suffered early cell death, heart damage, skeletal deformities, an increased mortality rate and DNA damage.

Some studies have shown that microplastics also lead to a decrease in oxygen levels in water, which causes the presence of Reactive Oxygen Species (ROS), unstable oxygen-based chemicals. ROS were also found in the zebrafish following experiments, with a build-up of the chemicals proven to damage DNA and have similar effects that were found in the fish. However, Nongthomba believes that the level of microplastics in the water is not at a dangerous level.