A new study has found that Israeli naval commando divers who trained in the heavily polluted Kishon River had significantly higher incidence of many kinds of cancers than would otherwise be expected. The study, conducted by researchers at Hebrew University-Hadassah in Jerusalem, was published today in the science journal "Environmental Health Perspectives".
The study evaluated trends in exposures to contaminants and risks for cancer among 682 Israeli naval commando divers between 1948 and 2000, compared to rates among Israeli-born males in general. The authors analyzed data from water samples taken over this period and compared them to data on the health of both marine life and divers. They calculated the estimated daily dose intake of toxicants absorbed by the divers via skin and ingestion per kilogram of body weight.
The average diver in the study spent 2,500 hours in underwater training over 19 years, with over 2,000 of those hours coming in their first four years of service. The Kishon River, its estuaries, and the port of Haifa, where the river flows into the Mediterranean Sea, were increasingly contaminated over the years studied, primarily by discharge from an oil refinery, petrochemical and fertilizer plants, and a sewage treatment plant. As the exposure to pollutants increased, the rates of cancer incidence rose, and marine life was more severely damaged.
"Increased risks for cancer were associated with organ sites having the highest contact with the water or in tissues with the known affinities of many of the reported toxics in the water," the authors conclude. Routes of exposure and associated cancers included direct exposure via the skin (melanoma) and gastrointestinal tract (stomach, bowel, and salivary gland cancers), inhalation of heavy metals and volatile chemicals (lung), and absorption and deposition of carcinogens in fat-soluble target tissues (blood-forming organs and central nervous system).
The cancer risk increased dramatically with the time spent in the water. The authors calculate that, averaged over the entire time studied, the risk from one hour of diving in the heavily polluted river was equal to that from smoking two packs of cigarettes a day.
Published by Globes [online] - www.globes.co.il - on October 31, 2002