Sri Lanka is facing what some are calling the worst human-made disaster in its maritime history. A container ship carrying oil, toxic chemicals and tons of plastic pellets sank off of the country’s main port Wednesday. It caught fire two weeks ago and couldn’t be towed to shore. Authorities are prepared in case oil starts seeping from the sunken vessel. Already, tons of plastic pellets are washing up on long stretches of Sri Lankan beach, along about a third of its western coast. The pellets, which can harm marine life, will persist in the environment for decades, and be swept by the ocean currents around the region. The World’s environment correspondent Carolyn Beeler reports on their lasting environmental impact.