Washington (ISJ) - Oceans are at great risk of turning into trash bins. Pollution caused by plastic waste has reached alarming levels, especially in the oceans, posing unprecedented threat to marine life. It pollutes oceans and waterways severely impacting the environment and economy.
Plastic constitutes approximately 90 percent of all trash floating on the ocean's surface, with 46,000 pieces of plastic per square mile. The hazardous nature of plastic trash can be gauged from the fact that it does not biodegrade. Instead it photo-degrades with sunlight, breaking down into smaller pieces.
Seabirds, whales, sea turtles and other marine life are eating these smaller pieces and dying from choking, intestinal blockage and starvation. All these marine mammals have been found entangled in plastics or with ingested pieces of plastics, impacting their movement, ability to feed and reproduce, ultimately leading to premature deaths.
Plastic wastes are not only physically harmful but chemically harmful also because they are inherently toxic, or because they absorb other pollutants that are toxic. They can cause abrasions and blockages.
A team of researchers at University of California Davis, and University of California, San Diego, found that fish exposed to a mixture of polyethylene with chemical pollutants absorbed from the marine environment bioaccumulate these chemical pollutants and suffer liver toxicity and pathology. Fish fed virgin polyethylene fragments also showed signs of stress, although less severe than fish fed marine polyethylene fragments.
The fish were exposed to three treatments. Significantly, fish exposed to virgin and marine plastic showed signs of stress in their liver, including glycogen depletion, fatty vacuoles and single cell death.
Studies showed severe glycogen depletion was seen in 74% of fish from marine plastic treatment, 46% from virgin plastic and 0% from controls. Fatty vacuolation was seen in 47% of fish from marine plastic treatment, 29% of fish from virgin plastic and 21 % from controls. Single cell necrosis was 11% of fish from marine plastic treatment compared to 0% from virgin plastic treatment and controls.
Studies concluded that waste plastics in the ocean were a menace to all marine life. Especially insidious are the invisible micro- and nano-plastics that can be taken up by microorganisms at the bottom of the food web and bio-accumulate in top predators with profound effects on their feeding behaviour, metabolism and morphology.
Scientists are also investigating the effects on human health from the existing data on the disrupting effects of numerous chemicals associated with waste plastics. It is high time, the government enacts laws to reduce plastic pollution by classifying plastic wastes as hazardous.
Source: Institute of Science in Society
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