According to the Netherlands Times, estimates for how much plastic has entered the oceans over the previous 20 years range from 50 million tons to 300 million tons, but the actual quantity is estimated to be about 3.2 million tons. 20,000 "reliable" observations influenced oceanologist Mikeal Kaandorp and his team's calculations, with highlights including rivers bringing far less plastic into the oceans than previously assumed, and microplastics accounting for a lot smaller percentage of plastic pollution.
According to the NL Times, huge estimates on the quantity of plastic entering the oceans are based on how much plastic is produced, how much is recycled, how much is buried or cremated, and how much goes missing. According to these estimates, environmental organizations estimate that 10 million tons of waste wind up in the oceans each year, the majority of which comes from river systems. However, Kaandorp emphasizes that unaccounted-for plastic has never been found, and it is incorrect to assume that every piece ends up in the water.