Pollution refers to the presence of environmental contaminants in quantities large enough to cause damage, deterioration, or toxicity. Such contaminants are known as pollutants. While some forms of pollution have natural causes, the term is used almost exclusively to refer to pollution caused by human activity.
Marine pollution is the detrimental alteration of a portion of an ocean or ocean coastline. Pollution is often a threat to any organism living in or depending upon the ocean. Human impact on coastal and open ocean habitats comes in many forms: nutrient loading from agricultural runoff and sewage discharges, toxic chemical inputs from industry and agriculture, petroleum spills, and inert solid wastes.
The team calculated how much plastic makes its way into the ocean each year by looking at World Bank reports, finding out how much garbage one person produces per day in 192 coastal countries, and how much of that garbage is plastic.