Environmental ▼News Fish transport toxins hundreds of miles ushed hundreds of miles across migration route by tracking the fish ified fatty acids could have other the globe, pollutants often set400 km upstream into a pristine consequences. “We have research tle far from their origin beAlaskan lake. Once they reached that now shows that the fish can’t cause of wind, rain, or fire. Add to their lake, the salmon spawned and utilize these fatty acids because the that salmon. A study published in died. Ewald’s group then analyzed chlorine blocks enzyme digestion,” this issue of ES&T (pp 5548–5554) the levels of chlorinated fatty acids reports Ewald. has found that organohalogens in in Arctic grayling, which live in the Ewald has not done follow-up salmon migrating upstream to lakes. In the lakes where the salmstudies to see whether salmon mispawn in a lake can end up in on spawned, the grayling had 5 grations are causing chlorinated the lake’s resident fish. How compounds to build up in the this transfer occurs is still a lake, but Frank Wania, an enmystery. vironmental analytical chem“These fish spend about ist at the University of Toronto three years out at sea before (Canada), says the finding is their migration,” says Göran already important. “Studying Ewald, a professor of environthe transport process is itself mental science at the Techvery interesting, whether it nical University of Denmark leads to an enrichment of the and the corresponding author pollutants or not,” he says. for the new study. Once they While biotransport is probbegin migrating, the salmon ably not significant to the stop eating and deplete their movement of large amounts of Salmon migrate hundreds of miles from the ocean to fat stores by almost 95%, for pollutants on a global scale, it spawn in their natal rivers and lakes, but they also energy use. Previous studies may have important local eftransport any pollutants that have built up in their bodby Ewald and a report pubfects on pollution levels. And ies during years spent at sea. lished as an ASAP article in biotransport may be more September (es049607w) (and times the levels of chlorinated fatty prevalent in the environment than scheduled to be printed in the acids of graylings from a lake 2 km suspected. Ongoing research in December 1 ES&T special ecotoxiaway where salmon are not found. Norway has found that seabird cology issue) found that fat-soluble Ewald is not certain whether the droppings can contaminate lakes pollutants, such as PCBs and digraylings are acquiring the chloriunderneath a rookery with organobenzo-p-dioxins, become magninated fatty acids by consuming the chlorines, and an earlier paper (Enfied in salmon during this time of salmon roe or from feeding on the viron. Sci. Technol. 1993, 27, 2198– migration. For example, PCB levels dead fish themselves. 2206) reported that eels transport in the fat increase up to 9.7 times, “It has to be a direct transfer of large quantities of the pesticide Midepending on the migration run. fatty acids,” he says. He adds that rex out of the Great Lakes and up In the newest research, Ewald the levels of chlorine in the grayling the Saint Lawrence River, which adand his colleagues followed the were about 1 µg/g of fish, which is joins both Canada and the United salmon one step further along their not a toxic level. However, the modStates. —PAUL D. THACKER PHOTODISC
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Easing traffic and air pollution in London London is a city of superlatives: best theater, worst traffic, and most polluted air in Europe. However, “congestion charging”, which has been in effect for almost two years, may be improving the city’s air while re-
ducing traffic, encouraging purchases of energy-efficient automobiles, and funding public transportation, according to preliminary results presented at the World Clean Air and Environmental Protection
408A ■ ENVIRONMENTAL SCIENCE & TECHNOLOGY / NOVEMBER 1, 2004
Congress held in London in August. As of February 1, 2003, drivers who venture within an 8-squaremile area of Central London, bordered by the Inner Ring Road, on weekdays between 7 a.m. and 6:30 p.m. must pay a £5 fee. Signs emblazoned with a red and white C mark the pay-as-you-go streets. © 2004 American Chemical Society
