The US Environmental Protection Agency has ruled that ship ballast water – often a witches’ brew of microbes, eggs, plants and creatures (some as much as a foot long) – must be treated before it is released.
Environmentalists sued the EPA over ballast’s exemption from the Clean Water Act.
Cruise ships, which use ballast water to stabilize their ride, dump as much as 70 thousand liters of the nasty cocktail every day. But they are not the biggest culprits. There are huge tankers and cargo ships that must be weighed down when they are empty and thousands of rust-buckets that don’t really care about the rules. Most cruise ships are fairly modern and can be retrofitted with treatment systems.