Canadian researchers are studying whether ballast water should be heated, said Chris Wiley, manager of ballast water research for the Canadian government. For instance, a special steam-producing ship could be anchored offshore. Inbound freighters would anchor next to the ship while steam and six inches of boiling water were pumped into the freighter's ballast tanks. In the United States, the National Research Council said that filtration and chemical treatment of ballast water have promise, but are probably too expensive. The agency's report urged the government to introduce national voluntary guidelines requiring ships to exchange ballast water and encourage further research into the matter.
Some laws already are on the books.
Because of the zebra mussel invasion in the Great Lakes, the Coast Guard requires ships to exchange their ballast before entering the lakes. The government recently enacted a similar requirement for ships sailing in New York's Hudson River. Chuck Jennings of the Coast Guard's marine safety office. But, he predicts that additional laws are in the wind. Ship ballast may be partly responsible for a global epidemic of algae blooms and can spread killer microbes like Pfiesteria piscicida.