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Biomedical scientist concerned about effects of tar balls and orange sheen on human health

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  • Biomedical scientist concerned about effects of tar balls and orange sheen on human health

    Industry updates: Jun 24 2010

    Biomedical scientist concerned about effects of oil spill on human health

    Contact: Dave Lavallee
    University of Rhode Island

    KINGSTON, R.I. June 21, 2010

    University of Rhode Island Pharmacy Professor Bongsup Cho knows there are cancer-causing chemicals in diesel fumes and cigarette smoke.

    The biomedical scientist also knows that some of the same chemicals are found in the gooey tar balls that are being produced as a result of the oil spill in the Gulf of Mexico, which began April 20 when a rig exploded and caught fire.

    But what he and other scientists have little knowledge of is the long-range impact of the spill on humans and wildlife at the cellular level.

    Cho studies the effects of environmental toxins such as cigarette smoke, diesel fumes and charred meat on DNA mutation as potential triggers for cancer.

    For close to 20 years, the National Institutes of Health and the American Cancer Society have funded Cho's research on mechanistic understanding of DNA damage and its consequences on mutation and repair. "Such research is crucial in the development of effective strategies for chemoprevention and drug development, as well as risk assessment," he said.

    Cho said the saturated hydrocarbons found in crude oil, such as methane, hexane and octane, evaporate quickly once in the ocean because they have low boiling points.

    "These are the chemicals that can cause the respiratory problems in people involved in cleanup operations, but they are not the ones necessarily known as carcinogens," Cho said.

    In many cases, these volatile organic compounds evaporate quickly when exposed to sunlight and heat. "Most would evaporate before people would suffer effects from them," Cho said.

    But the tar balls and remaining thick ooze washing ashore and into marshes cause more worry for Cho.

    "The tar balls contain the non-volatile, benzene-like, heavily unsaturated hydrocarbons with high boiling points," Cho said. "That's where there are a lot of toxins, such as benzo[a]pyrene. This is a known human carcinogen, and it is used as a biomarker to detect human exposure to toxins."

    The researcher said a carcinogen usually has mutagenic and teratogenic effects on cells, meaning it can cause mutations in DNA and cause birth defects.

    A study of the blood of individuals who worked on the Exxon Valdez cleanup following the spill in March of 1989 found DNA damage in those subjects. "DNA damage in certain functionally important areas of the genome can be a precursor to various human cancers," Cho said.

    While individuals can get sick when volatile organic compounds evaporate, they would have to absorb the non-volatile compounds through ingestion or actual physical contact, he added.

    "It has been reported that the size of the Gulf oil spill is unprecedented, much greater than that of the the (land mass) of New England area combined. You have to wonder about the fate of the crude oil that has not come ashore and recovered and what long term effects such toxins will have on the food chain," Cho said. "The pollutants from these toxins are going to be there for a long time."

    Cho is worried about another phenomena from the spill-- the orange sheen seen on the surface of the gulf.

    "That orange sheen is a result of a chemical reaction involving the sun, the crude oil and the oil dispersants," Cho said. "But nobody knows what's in that color and how toxic the chemicals are. Companies keep the chemical makeup of the dispersants secret.

    "Crude oil, like diesel fuel and cigarette smoke, contain thousands of chemicals, and we have studied only a few, so the big worry is the unknown activity of those chemicals we have not studied. According to the recent Cancer Advisory Board report to President Barack Obama, Americans are constantly exposed to chemicals. There are 80,000 of them, and we only know a little about them."
    "Safety and security don't just happen, they are the result of collective consensus and public investment. We owe our children, the most vulnerable citizens in our society, a life free of violence and fear."
    -Nelson Mandela

  • #2
    Re: Biomedical scientist concerned about effects of tar balls and orange sheen on human health

    benzene primarily affects the CNS and hematopoietic system.
    Effects may be acute or chronic : aplastic anemia ( high doses ) leukemia etc.


    • Benzene-induced aplastic anemia is caused by chronic exposure at relatively high levels.
    Aplastic anemia is caused by bone marrow failure, resulting in hypoplasia with an inadequate number of all cell lines. Severe aplastic anemia typically has a poor prognosis and can progress to leukemia, whereas pancytopenia may be reversible. Benzene-induced aplastic anemia is generally caused by chronic exposure at relatively high doses. Fatal aplastic anemia following benzene exposure was first reported in workers in the nineteenth century.

    • Benzene-induced leukemia has a usual latency period of 5 to 15 years and, in many cases, is preceded by aplastic anemia.

    Several agencies (e.g., the U.S. Department of Health and Human Services, the U.S. Environmental Protection Agency [EPA], and the International Agency for Research on Cancer) classify benzene as a confirmed human carcinogen. EPA estimates that a lifetime exposure to 4 ppb benzene in air will result in, at most, 1 additional case of leukemia in 10,000 people exposed. EPA has also estimated that lifetime exposure to a benzene concentration of 100 ppb in drinking water would correspond to, at most, 1 additional cancer case in 10,000 people exposed.



    • #3
      Re: Biomedical scientist concerned about effects of tar balls and orange sheen on human health

      People, including pregnant women, can be exposed to these chemicals by breathing them (air), by swallowing them (water, food), or by touching them (skin). If possible, everyone, including pregnant women, should avoid the oil and spill-affected areas. Generally, a pregnant woman will see or smell the chemicals in oil before those chemicals can hurt her or the baby. The EPA and CDC are working together to continue monitoring the levels of oil in the environment. If we begin to find levels that are more likely to be harmful, we will tell the public.