Environmental ▼ News Researchers find new POP The levels of TPT in the tested fish varied substantially, however: The Lepidion lepidion, or Mediterranean codling, had up to 176.5 ng/g of TPT, while the Alepocephalus rostratus contained less than 1.4 ng/g. Still, the TPT levels found in these
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riphenyltin (TPT) appears to be a persistent organic pollutant (POP), according to scientists at Spain’s Institute of Chemical and Environmental Research (IIQABCSIC). In the October 15 issue of ES&T (pp. 4224–4228), they report
TPT levels in organisms from the northwest Mediterranean M. galloprovincialis R. decussata T. haemastoma L. aurata
Harbors
B. brandaris M. barbatus
Coastal areas
M. moro L. lepidion A. rostratus C. guentheri B. mediterraneus
Deep-sea areas 0
20
40
60
80
100 120 140 160 180 ng/g w.w. as Sn
1430
The deep-sea fish studied by the scientists at Spain’s Institute of Chemical and Environmental Research show that TPT is persisting in the environment and subject to long-range transport. The levels of PCBs, dioxins, and TBT in these deep-sea fish are lower than the levels of those contaminants found in organisms inhabiting harbors and coastal areas, but the TPT levels are much higher.
finding unexpectedly high levels of TPT, a compound used in fungicides and marine antifouling paints, in what they believe is the first evidence of the compound in deep-sea organisms. Overall, the TPT levels in the deep-sea fish were “surprising”, because they were so much higher than the levels of tributyltin (TBT), another organotin compound that has received much more attention because of its toxic properties, says Cinta Porte-Visa, a researcher with IIQAB-CSIS’s Environmental Chemistry Department and the paper’s corresponding author. Mora moro, a species of codfish that lives more than 1000 meters below the Mediterranean Sea’s surface, contained the highest TPT levels, up to 1430 nanograms per gram (ng/g wet weight as tin) of tissue. 400 A
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deep-sea fish are much higher than levels recorded in organisms from the Mediterranean coast, Porte-Visa says, and on a par with the highest levels reported to date, which were recorded in horseshoe crabs on the Japanese coast. The TPT discovery contrasts sharply with the TBT levels in the same fish, Porte-Visa says. TBT levels tend to be highest in those fish living near contamination sources such as harbors and decrease sharply with distance and depth, she explains. Levels of polychlorinated biphenyls (PCBs) and DDT were also low in the deep-sea organisms, showing that these fish are “clearly less contaminated than coastal ones,” she says. The unusual TPT distribution indicates that the chemical persists in the environment and can be trans-
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ported long distances, Porte-Visa explains. In her paper, she notes that TPT has a high sediment–water partition coefficient; the organotin can therefore bind to sediment particles and drift out to the deep sea undiluted. The ability of some organisms to metabolize TPT may also be very low, she adds. “TPTs just haven’t been looked at as much, in terms of their levels,” says Margaret Whalen, an assistant professor at Tennessee State University’s department of chemistry who is studying the impacts of organotin compounds on humans. “People are definitely accumulating TBT in blood,” she says, but she hasn’t found measurable TPT accumulation in the small group of 13 individuals that she has tested thus far. Porte’s study nonetheless implies that TPT may not be breaking down as rapidly as scientists previously believed it would, she adds. Organotins are “considered to be amongst the most toxic chemicals ever released into the marine environment”, according to the World Wild Fund for Nature (WWF International), an environmental group, but most of the regulatory action to date has focused on TBT. The International Maritime Organization has agreed to ban the use of organotins in antifouling paints by 2008, largely because of TBT, but the treaty has yet to enter into force. Moreover, the U.S. EPA reviewed TPT’s use as a fungicide in 2001 and determined that its benefits continue to outweigh its risks. Laboratory exposure studies have shown TPT produces a wide spectrum of toxic effects in aquatic and terrestrial organisms, including effects on the immune system, reproductive/developmental effects, and cancers of the endocrine system organs, according to the United Nations’ Food and Agriculture Organization. Brief exposures to TPT can impair human immune system function, according to stud© 2002 American Chemical Society
needed to determine which ones. Metallothioneins certainly have a role in sequestering metals, she says, but it is as yet unclear how much of a role they play with organometallics like organotins. Although most of the fish evaluated in the study are not widely consumed, a recent study by The Irish Republic’s National Food Center ranked M. moro as a goodtasting fish that could be acceptable to the country’s population to replace the dwindling supplies of coastal species. —KELLYN S. BETTS
Sequestration experiment is drowning Plans to run large-scale trials of ocean sequestration of carbon dioxide (CO2) are being hampered by growing opposition. In August, the Norwegian environment minister refused permission for an experiment in the Norwegian Sea, and in June, local opposition foiled attempts to secure permits in Hawaii. The international scientific team that is planning the sequestration experiment says that it is still hopeful of finding a suitable test site. In 1997 at Kyoto, Norway, the United States, Australia, Japan, and Canada signed an agreement under the OECD’s Climate Technology Initiative to undertake ocean sequestration trials. Nevertheless, environment minister Børge Brende cancelled a permit issued by the Norwegian Pollution Control Agency to conduct the experiment after environmental groups appealed. Instead, he said that ocean sequestration should first be “discussed internationally and the legal implications clarified”. In particular, Brende is concerned that the project could conflict with the 1992 OSPAR Convention, formerly the Oslo and Paris Conventions, which sets out to protect the marine environment of the northeast Atlantic Ocean. He is awaiting an evaluation
by the OSPAR Commission’s legal group, scheduled for their next meeting in June 2003. “We are very disappointed about this denial to conduct fundamental research on climate mitigation technologies, but we will find somewhere to do our experiments,” says Lars Golmen, who is the project manager for the consortium in Norway. Eleven researchers from the project have signed a letter protesting Norway’s decision (p. 399A). The research consortium, which includes teams from Norway, the United States, Australia, Japan, and Canada, has only one year’s funding left. Meanwhile, environmental organizations are relieved. “We regard the project as dead in Norway,” says Truls Gulowsen of Greenpeace, adding that injecting CO2 into the seas is an unsustainable way of solving the climate problem. Greenpeace also cites concerns about the effects on marine life and whether oceans can store large amounts of CO2 for long periods. The project involved injecting 5.4 metric tons of liquid CO2 800 meters below sea level and then studying the behavior of the dispersing plume and its impacts on marine life. —MARIA BURKE
News Briefs Diesel engine exhaust is a likely human lung cancer hazard if inhalation exposure is long-term and chronic, according to a 10year assessment developed by the U.S. EPA. In this review, EPA staff evaluated the health effects literature on diesel exhaust, identified the most important exposure hazards to humans, and evaluated the exposure–response characteristics of key health effects. EPA staff relied on the 10-year assessment to support the agency’s recent decision to control emissions from heavy-duty highway engines. Health Assessment Document for Diesel Engine Exhaust, released on Sept. 4, is available at http:// cfpub.epa.gov/ncea.
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ies conducted using human blood, reported Sharnise Wilson, one of Whalen’s students, at the spring 2002 American Chemical Society meeting. Very low levels—on the order of a few nanograms per liter— of TPT (and TBT) can induce reproductive disorders, Porte says. Unlike many other POP chemicals, TPT does not appear to be bioaccumulating in the fatty tissue of the tested fish. Instead, it is concentrating in the liver, Porte says. She suspects that it has an affinity for proteins, but more study will be
Aggregate emissions of six pollutants tracked nationally have declined by 25% since 1970, according to the 2001 air quality trends report, released Sept. 4 by the U.S. EPA. The report includes data on the ambient levels of carbon monoxide, lead, nitrogen oxide, ground-level ozone, particulate matter, sulfur dioxide, and volatile organic compounds. These emissions dropped at the same time that energy consumption increased 42%, vehicle miles traveled shot up 149%, and the overall Gross Domestic Product rose 161%, the report notes. Despite progress, more than 170 million tons of pollution are emitted each year, and as many as 133 million people live in areas where the monitored air exceeded national levels. Latest Findings on National Air Quality: 2001 Status and Trends is available at www.epa.gov/oar/aqtrnd01.
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