The British Royal Air Force bombed the V-1302 John Mahn on Feb. 12, 1942, sending it to its watery grave in the North Sea. But the ship is not slumbering silently. A study published in Frontiers in Marine Science has found the wreck continues to leak hazardous pollutants and impact its nearby marine environment some 80 years on, proving "a historic shipwreck can still significantly steer the surrounding sediment chemistry and microbial ecology." CNN reports the researchers analyzed samples taken from the ship's steel hull as well as from the sediment around it. Heavy metals, explosive compounds, and polycyclic aromatic hydrocarbons—naturally occurring chemicals found in crude oil and gasoline—were detected, with concentrations higher nearer the ship.
The highest metal and metalloid concentrations were identified in the sample taken outside the coal bunker, with nickel, copper, and arsenic identified, per the study. "The general public is often quite interested in shipwrecks because of their historical value, but the potential environmental impact of these wrecks is often overlooked," study author Josefien Van Landuyt notes in a press release, which adds that there is a lack of information about the location of these wrecks. And yes, wrecks plural: There are thousands at the bottom of the North Sea, and it's estimated that WWI and WWII shipwrecks across the planet collectively hold as much as 20.4 million tons of petroleum products.
Van Landuyt suggests it's possible the problem has worsened, not improved, with time, as corrosion can cause holes to develop in the ship, potentially opening formerly enclosed spaces, reports Gizmodo. "As such, their environmental impact is still evolving," notes Van Landuyt. She acknowledges her team explored the impact of "one ship, at one depth, in one location. To get a better overview of the total impact of shipwrecks on our North Sea, a large number of shipwrecks in various locations would have to be sampled." (Read more discoveries stories.)