IMO will ban the use of a popular biocide The International Maritime Organization (IMO) agreed in November to ban the application of organotin antifouling paints on ships by 2003, despite studies showing that existing regulations have significantly reduced concentrations of the biocide in water columns worldwide. Organotin-based paints, such as the self-polishing copolymer tributyltin (TBT), kill or repel nuisance organisms that encounter ship hulls, but the paints also diffuse into adjacent waters, where other plants and animals may be exposed. Signs of endocrine-disrupting effects were noticed in nontarget species, such as oysters, shellfish, and snails in many different countries during the late 1970s and 1980s said Stewart Evans a biologist at England's Dove Marine Laboratory. However, since mandatory measures were taken in France, England, and the United States during the 1980s to ban TBT use on yachts and other small vessels under 25 meters in length that spend most of their time docked in marinas, monitoring studies have shown a dramatic recovery of marine life in coastal waters. "The incidence of imposex [the tendency of marine snails to develop masculine characteristics] has decreased, the abundance of dogwhelks [a common marine snail] has increased and the levels of TBT in tissues has down in these animals " Evans said Likewise, monitoring studies by the U.S. Navy and Parametrix, Inc,, an engineering and consulting firm in Kirkland, Wash., whose studies are funded by the organotin industry, have found significant reductions of TBT concentrations in water columns, sediments, and aquatic life in U.S. coastal waters since the application restrictions took effect. But a few hot spots still exist, particularly in sediments within closed bodies of water, shipyards, and commercial harbor areas where ships are dry docked for maintenance and paint application. "We believe that these sediments are a significant and longterm source of TBT, and even
though levels in the water column have dropped, we believe that they're still too high and pose a hazard to various species," said Jill Bloom, a review officer in EPA's Office of Prevention, Pesticides, and Toxic Substances. In a 1997 report on the effectiveness of existing laws on reducing risks from organotin compounds, EPA concluded that "existing laws and rules have been effective in reducing levels of environmental TBT, but greater U.S. restrictions in concert with greater international restrictions and development of safer ciltem stives cire needed to further reduce risks" In light of such pressure, Chamber of Shipping of America, which represents owners, operators, and charterers of ocean-going vessels, has opted not to fight the TBT phaseout, said Kathy Metcalf, the organization's director of maritime affairs. "Our position is that by banning the use of mat material on small hulls, you got rid of die problem, but we also recognize that the political status of this is such that it's going to go forward whether there's a scientific justification for it or not" Metcalf said. "The driving force [behind die U.N. body's decision] was simply a growing awareness of the need to protect the environment," said Alex Bilney, marine manager for the International Chamber of Shipping. And the precautionary principle, which pushes governments to control dangerous substances even before a definitive causal link has been established between chemicals and healtii and environmental effects played no small role in the
IMO's decision, Bilney added. The goal now is to find an environmentally sound alternative that is as effective against fouling as TBT. Alternatives currently on the market include self-polishing antifoulant paints without biocides; nontoxic, nonstick coatings; hard coatings in combination with special cleaning procedures; electrochemical methods; and self-polishing antifoulant paints with biogenic biocides. But tfiese products have not yet undergone the rigorous testing that TBT has, leaving the shipping industry concerned suitable alternative might not be available by the time the ban kicks in Moreover, the existing alternative paints cost up to four times more than TBT, according to a 1998 cost-benefit analysis conducted by Parametrix, Inc., and Princeton Economic Research, Inc., of Rockville, Md. Also, these alternatives require more frequent dry docking intervals—ships must be repainted every two to two-and-ahalf years as opposed to the fiveyear intervals guaranteed by TBTbased paints. Overall the analysis indicates additional annual costs to the worldwide fleet to switch to existing tin-free products to be $0 5-10 billion In spite of the enormous cost, "there is agreement [at the IMO] that the harmful effects of TBT outweigh the beneficial effects," Bilney said. But, there is concern that a ban imposed too early could lead to other environmental problems. "One of the things that seriously worries me is that we'll throw out TBT and actually introduce untested substances in antifouling paints," Evans said. —KRIS CHRISTEN
World Bank inspection panel weakened The World Bank's three-member inspection panel has increased the transparency and accountability of bank lending practices, but the bank's board of directors, which created the panel, has weakened its power considerably, say environmental advocacy groups and panel members themselves. Instances in which the panel's work is preempted occur because
board members represent the very countries that do the borrowing and view the panel's independent investigations as an infringement on their national sovereignty, said David Hunter, vice president of the Center for International Environmental Law. The World Bank formed the independent panel in 1993 in response to outside criticism that
JAN. 1, 1999/ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS * 1 1 A
