In preparing ballast treatment standards, which a federal court ruled inadequate in 2015, the EPA turned to some of the country’s best scientists in the field to help establish a safe number of organisms that could be discharged per cubic meter of water while still protecting the Great Lakes and other U.S. waters from new invasions.
The only thing the panel could agree on is that the fewer organisms allowed to survive in a ballast tank, the better. Beyond that, they were at a loss because, they said, you can’t just pick a magic number and call it safe.
Unless the number you pick is zero.
That is the number Isle Royale National Park Superintendent Phyllis Green aimed for when she learned in 2007 that an invasive virus deadly to dozens of freshwater fish species was creeping toward her rugged, forested island in the middle of Lake Superior.
Green went straight to the captain of the Ranger III, the 165-foot-long ship that ferries park passengers to the island, 73 miles from its home port on Michigan’s Upper Peninsula. Worried that the ferry might suck the rapidly spreading virus into its ballast tanks while docked at the mainland, she asked if there were any way to disinfect that ballast before it was released into park waters. The captain said no. “What happens,” Green replied, “if I tell you that you can’t move this ship unless you kill everything in your ballast tanks?”
That’s when the brainstorming started. Green’s goal was to try to figure out how to make the Ranger III safe to sail — not in years or even months, but in a matter of days. She sat down with the captain, the ship’s engineer and David Hand, chair of the Department of Civil and Environmental Engineering at Michigan Technological University. Hand had worked on water purification systems for the International Space Station that can turn sweat and urine into tap water.
“This,” Hand told the group of the ballast problem, “is not rocket science.”
Two weeks later, Isle Royale’s passenger ship had a crude ballast treatment system that used chlorine to fry viruses and other life lurking in its 37,000-gallon ballast tanks, and then vitamin C to neutralize the poison so the water could be harmlessly discharged into the lake.