"Activists and news media often claim that Americans use 500 million plastic straws per day, for example, which sounds awful"

Bloomberg:

But the source of this figure turns out to be a survey conducted by a nine-year-old. Similarly, two Australian scientists estimate that there are up to 8.3 billion plastic straws scattered on global coastlines. Yet even if all those straws were suddenly washed into the sea, they'd account for about .03 percent of the 8 million metric tons of plastics estimated to enter the oceans in a given year.

...

at least 46 percent of the plastic in the garbage patch by weight comes from a single product: fishing nets. Other fishing gear makes up a good chunk of the rest.