Geoff Brumfiel,WashingtonThe number of foreign students enrollingin US universities stagnated last year andmay now be declining for the first time indecades, according to a series of studiesreleased this week.

The annual report of the Institute of Inter-national Education (IIE), a New York-basedorganization that monitors student exchange,shows that the growth in total foreign-studentenrolment at US universities grew by just0.6% in the 2002–03 academic year — thelowest level of growth since 1995. And in a follow-on survey of international studentoffices in 276 universities, most reportedsome decline in international enrolment thisautumn, suggesting that the total number ofstudents may actually fall in the 2003–04 academic year for the first time since 1971.

Such a drop is likely to hit US universitieswhere it hurts: international students spendsome US$12 billion annually on tuition andliving expenses, according to the IIE, and foreign graduate students fill many researchand teaching jobs on campuses, particularlyin science and engineering.

The 2002–03 academic year saw sharp

increases in the number of students comingfrom India and South Korea, the IIE surveyfound,but the number arriving from Europe,Southeast Asia and the Middle East declined.

University administrators and academicgroups attribute the slowing enrolment rateslargely to the strict visa-issuance policiesenacted in the wake of the terrorist attacks of 11 September 2001 (see Nature 422,457–258; 2003). “The US government isdoing more than anyone to deter foreign stu-dents,”says Gail Szenes,director of the Officefor International Students and Scholars at

New York University, whose campus lies just blocks from the World Trade Center,destroyed in the 2001 terror attacks. Con-sular interviews for students whose subjectareas appear on a state department watch listare especially problematic for those studyingin the sciences,Szenes says.

Visa woes are also afflicting scholars com-ing to teach and to do research in the UnitedStates, according to preliminary results ofa separate survey by three major universityassociations. About three-quarters of morethan 200 US universities surveyed by theassociations said that they had problems getting scholars into the country, accordingto Victor Johnson, public-policy director atthe Washington DC-based Association ofInternational Educators, one of the groupsthat conducted the survey.

New visa guidelines have created a percep-tion that it is more difficult for foreign stu-dents and scholars to come the United States,but until now,the evidence for this was largelyanecdotal, according to Johnson. “These arethe first data that confirm our fears,”he says.■

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US loses allure in foreign students’ eyes

Roaming polar bears reveal Arctic role of pollutantsMarika Willerroider,MunichFemale polar bears have providedresearchers with an insight intothe long-term health impact ofpollutants.

In a study published on 1November, a Norwegian teamreveals that bears that roam longdistances in their search for foodtend to accumulate relatively highlevels of industrial pollutants suchas polychlorinated biphenyls(PCBs) in their bodies. This couldbe linked to the exceptional levels ofhermaphroditism seen in some bearpopulations, although thisconnection has yet to be confirmed.

PCBs, which were widely used inelectrical equipment until they were bannedin most countries on health grounds, areextremely resistant to biodegradation. Theyaccumulate in the food chain, even in remotelocations, and then accrue at the chain’s end— in polar bears, for example, which cannoteasily metabolize or excrete the compounds.

The researchers tagged 54 female bearsfrom the Svalbard archipelago and thenearby Barents Sea in the far north ofEurope with satellite transmitters, andmonitored their movements for severalyears. They found that some bears in off-

coast habitats roam huge territories eachyear — up to 270,000 square kilometres —and accumulate significantly higher levels ofPCBs in their fat, blood and milk than bearsin smaller coastal or near-coastal habitats(G. H. Olsen et al. Environ. Sci. Technol. 37,4919–4924; 2003).

“Long-distance migration costs immenseenergy,” says Øystein Wiig, a mammalogistat the University of Oslo’s ZoologicalMuseum and a co-author on the study.“The bears need to consume much moreprey, and thus build up more PCBs.”

Particularly high pollutant concentrationswere found in bears migrating to the Kara

Sea, north of Russia. This indicatesthat there is massive pollution of Siberian rivers fromcontaminated industrial areasupstream, says Wiig.

PCBs are part of a group ofpollutants known as endocrinedisruptors, which may interferewith hormone function in humansand animals at relatively low doses.Earlier research suggests that thePCBs could be the cause of sexualanomalies found in polar bears —hermaphroditism has been seen in about 2% of the roughly 5,000-strong bear population in

Svalbard (Ø. Wiig et al. J. Wildlife Dis. 34,792–796; 1998).

But the link is tentative. “I’d rather notjump to conclusions. Hermaphrodites havealso been found among brown bears that arefree of PCBs,” says Aaron Fisk, a toxicologistat the University of Georgia in Athens, whoinvestigates pollution in arctic wildlife.

The release of PCBs into the arcticenvironment is slowly decreasing, saysSamantha Smith, who directs the arcticprogramme of the WWF, an environmentalgroup. But she warns that a second wave of pollutants, now stored in arctic icereservoirs, may be released if glaciers melt. ■

Learning curve: the changing numbers of foreignstudents coming to the US between 2002 and 2003.

At the end of a food chain, polar bears accumulate toxic chemicals.

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