In the chilly gloom of the Californian seabed, thousands of barrels ooze a banned chemical. Some date back to the 1940s when the first was dumped off the coast. In March this year, researchers found that the chemical, DDT, has barely broken down, remaining as toxic as it was 80 years ago.
DDT (dichlorodiphenyltrichloroethane) is an insecticide that was widely used in agriculture until being banned – in the United States in 1972 and globally in 2001 – due to concerns about health impacts on wildlife and people. Its dense chemical bonds can resist degradation for decades.
Researchers now worry that dredging or storms could cause this polluted stretch of seafloor off the Los Angeles coast to release toxic plumes, threatening sea life and those who eat it.
Plastic gets the limelight when it comes to ocean pollution, but chemicals pose “a major threat, one that we’re probably consistently underestimating,” says Alex Rogers, a marine ecologist at the University of Oxford, and science director with REV Ocean, a research non-profit working on solutions to ocean challenges. The problem goes far beyond legacy pollutants like those barrels of DDT. Today, around 350,000 synthetic chemicals are widely used in manufacturing. They are embedded in our everyday lives in pharmaceuticals, cosmetics, cleaning products, electrical goods, textiles, furniture and other products. Ninety-five percent of all manufactured items now contain synthetic chemicals of some kind. Read on.