Disturbingly high levels of microplastic contamination were recently discovered in Indus River dolphins’ gastrointestinal tracts. The International Union for Conservation of Nature (IUCN) currently lists this species as endangered. The study, published in the journal PLOS One, documents the alarming environmental conditions these dolphins face in their natural environment. The Indus River — the river home of these fish — is one of the most polluted rivers on the planet.
From 2019 to 2022, researchers examined the cause of death in great detail on five stranded dolphins, each identified as Platanista minor, scientifically. Microplastics were present in all samples, with an average of 286.4±109.1 pieces per dolphin. This important finding surfaces a major concern. Pollution in the Indus River should be addressed as a priority, where microplastic fibers constitute the majority of pollution.
Microplastic Findings in Indus River Dolphins
Analysis showed that a jaw-dropping 94.76% of the microplastics detected in the dolphins were fibers. The vast majority of these fibers were blue or clear in color. These microplastic textile fibers differ in diameter and length, going from 5 mm down to 300 µm. This opens up huge implications for marine organisms that might eat them. Polyethylene terephthalate (PET) was the most prevalent polymer, making up 58.16% of all the microplastics detected.
The presence of such a high concentration of microplastics in these endangered dolphins sheds light on the broader implications for aquatic ecosystems. Indus River dolphins, like all apex predators, play an integral role in their ecosystem. Such organisms frequently build up toxic substances through the consumption of contaminated prey species.
“Polymers emanate from plastic ropes, fishing nets, plastic bottles and bags, and agricultural runoff, suggesting their accumulation by intensive anthropogenic interventions. The detection of identical polymers in both prey fishes and IRD guts suggests trophic transfer and indicates that local prey species are primary vectors for IRD exposure.” – Ahsaan Ali et al.
The Pollution Crisis in the Indus River
The Indus River, known for having the most polluted waters in the world, is known for these pollution problems, mainly with the high amount of plastic. This contamination poses serious risks to the health of the river’s ecosystem and our communities. It subjects the wildlife that calls the region home to grave danger. The sheer amount of plastics found throughout the environment increases ingestion rates, even for animals such as the endangered Indus River dolphin. This increases the burden of stressors these dolphins are already encountering.
Science has proven that microplastics are more than just an environmental irritant. They have a large effect on health and survival of dolphins. Ingesting other polymers such as PET, polyvinyl chloride (PVC), and polyethylene (PE) can harm human health. These toxic chemicals can harm your health in a number of ways.
“Microplastics are transferred up the food chain, and IRDs, as apex predators, accumulate them along with additives including bisphenols and phthalates, which are proven to be endocrine-disrupting chemicals. Frequent ingestion of PET, PVC, PE, and related polymers may cause digestive dysfunction, oxidative stress, immune disruption, and reproductive toxicity, collectively threatening the health, survival, and resilience of IRD populations.” – Ahsaan Ali et al.
Implications for Conservation Efforts
Our results from this study are essential for informing conservation actions to protect the recovery Indus River dolphin population. First of all, they are the world’s most endangered species. To develop effective pollution offsetting plans nationwide, we need to know the true effects of air pollution on their health.
Addressing these root causes of pollution that have made microplastic contamination so widespread will be key. Efforts must focus not only on reducing plastic waste entering waterways but on educating local communities about sustainable practices to protect this vulnerable species.