A study has measured the amount of plastic debris found in a region of the Atlantic Ocean over a 22-year period.
US researchers, writing in Science, suggest the volume of plastic appeared to have peaked in recent years.
One reason could be tighter marine pollution rules that prevent vessels dumping their waste at sea.
The team said monitoring the free-floating plastic also provided an insight into the behaviour of ocean surface currents.
They found plastic, most pieces measuring no more than a few millimetres, in more than 60% of 6,136 samples collected by dragging fine-meshed nets along the ocean’s surface.
“Plastic marine pollution is a significant environmental concern, yet a quantitative description of the scope of this problem is the open ocean is lacking,” they wrote.
UN Secretary General Ban Ki-moon has described as “heart-wrenching” the destruction he witnessed on a visit to flood-devastated Pakistan.
Mr Ban said the scale of the disaster was greater than anything he had seen before.
He again urged the world to speed up aid to the country, saying shelter and medicine were desperately needed.
The Pakistani government says up to 20 million people have now been affected by the monsoon floods.
At least 1,500 are known to have lost their lives.
(CNN) — Remnants of what was Tropical Depression Five will likely reach the northern Gulf Coast late Wednesday or early Thursday and will stall the crucial work of permanently sealing BP’s ruptured oil well.
Permanently sealing the well in the Gulf of Mexico will have to wait about four days after the storm passes the site, the government’s point man in the Gulf said Wednesday.
As the heavy rains and gusty winds associated with the weakening tropical depression moved closer to the Gulf Coast Wednesday, retired Coast Guard Adm. Thad Allen told reporters crews were preparing for whatever weather was to come.