The Daily Item, Sunbury, PA

Technology

March 20, 2013

Slate: In Toms River, N.J., Cancer Cluster or Chance?

(Continued)

Many chemicals, natural and synthetic, can damage DNA and increase the background mutation rate. But most cancers require several genetic hits — whether they are spontaneous, inherited, or induced from outside. Cancer clusters have been verified among workers who are exposed for years to high levels of carcinogens such as asbestos. The hits just keep on coming. But even occupational clusters are rare. One study after another has concluded that the relatively dilute exposures received by the public are probably not causing much cancer, even in places near toxic waste dumps, like Love Canal.

Toms River, like Woburn, appeared to be an exception. But was the difference caused by two federal Superfund sites that had been polluting the area for years? Or was it a statistical anomaly? Years earlier, the epidemiologist Seymour Grufferman coined the term "Texas sharpshooter effect." Stand way back and blast the side of a barn with a shotgun and then find some holes that are crowded together. Draw a circle around them and you have what looks like a bull's-eye.

When New Jersey officials concluded that there was probably nothing to worry about in Toms River, angry residents stormed the county health department. As the pressure continued, the state joined federal epidemiologists in a full-blown investigation. Interviews were conducted. Birth records were studied. Computer models were made of the water system and of the paths toxic emissions might have followed through the air. DNA was tested, and effluents were analyzed.

As epidemiologists worked through the data, they were struck by a pattern of evidence that appeared to implicate one of the town's polluted well fields. But given the small number of cases, the uncertainty was overwhelming. In the end, two correlations seemed to rise above the rest — but only when boys were excluded from the statistics. That left eight girls whose mothers had drunk most often from the well field. Five of the girls had leukemia, a cancer of the blood, and three did not. The boys were apparently unaffected. A similar association was suggested for leukemia in girls with prenatal exposure to polluted air. For the other types of cancer a link to environmental contaminants couldn't be established.

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