With between 80,000 and 150,000 different synthetic chemicals manufactured regularly, it might be too much to expect that a small number of laboratory tests could be used to judge their effect on humans. But that is just what Mark Noble, a biologist at the University of Rochester Medical Center, reported in the February issue of the journal PLoS Biology.
His team tested three toxins –methylmercury, lead, and paraquat, which is an herbicide. Although each has a radically different chemical structure, they all increased the oxidation state of human cells. (In other words, they acted in the opposite manner to anti-oxidants in foods that are thought to ward off disease.) Normally, the cells Nobel used for the test would divide and give rise to a specialized type of cell in the central nervous system called an oligodendrocyte. But exposure to the chemicals blocked cell division, which could lead to neurological disabilities in babies if their cells are exposed at particular times during fetal development.
Not only were all the toxins acting in the same way on cells, but they did so even when small amounts, similar to amounts found in the environment, were used. “This is the level of mercury you have if you eat tuna three times a week,” says Nobel. “No one knows what fraction of synthetic chemicals are oxidizers but it could be a very very large fraction.” And the new test might just be the assay to tell us.