Article reprinted with permission from Oceanspace, formerly located at http://www.oceanspace.co.uk

Issue Number 27 dated Monday 30 March 1998
*U.S. Sea Grant Researchers Identify New Ways To Eliminate Zebra Mussels.

Since the discovery of zebra mussels in North American waters 10 years ago, scientists have been investigating ways to control the pesky mollusk that has become famous for clogging boat intakes and electric and water facility intake pipes. One critical point in zebra mussel control is the prevention of settlement of their larvae, called veligers.

Two New York Sea Grant research teams have identified technologies that eliminate the zebra mussel veliger. One method, developed by Linda Chalker- Scott and her team, involves zapping larvae with high-intensity ultraviolet radiation. Chalker-Scott and her colleagues found that, in the lab, brief ultraviolet exposure (1 to 2 seconds) paralyzes the veligers for nearly 20 minutes. This is enough time for the larvae to be swept through most water intake systems, prohibiting settlement and colonization on intake pipes. The researchers also found that a longer exposure of 5 seconds killed the veligers instantly.

According to Chalker-Scott, the UV prototype is currently being used by a private company seeking to market a control device. Another project, led by New York Sea Grant researcher John Van Benschoten, examined what effects coagulants have on controlling zebra mussels. Coagulants are chemicals that cause particles in the water to stick together and form a mass. Van Benschoten and his colleagues recognized early in the study that the coagulants could have potential adverse effects due to the formation and settlement of floc (the mass formed by coagulants) in the intake pipes. They found that coagulants killed veligers largely because they make water more acidic. As a result, the scientists concluded that mild acidification of water at the intake shows great potential for water utilities needing to control mussels.