It's falling everywhere, like invisible snow. It clings to the leaves of plants, plunges into lakes and streams, settles in little drifts on city sidewalks. It accumulates on you and me, rising in clouds of microscopic particles when we comb our hair or brush our clothes.
"We're really all like that comic strip character--what's his name?--Pigpen," says geochemist Clair Patterson, standing at the door of his laboratory at Caltech. "Our bodies are all covered with lead."
Until Patterson started studying the ubiquitous element in the early 1960s, most scientists assumed that a measure of lead was just a natural, relatively benign, part of our environment. If you live in this world, you'll consume a bit of lead, they said. Not to worry.
But Patterson's pioneering studies showed that modern human beings are consuming hundreds of times as much lead as prehistoric people did. It combines with calcium, caking the bones and clogging the kidneys and circulatory system. It lodges in the skulls of children, snuffing out brain cells and shaving off IQ points.
Patterson pulls out an illustration of three almost-identical men drawn in outline. The first one displays a single dot on his chest. That's prehistoric man, Patterson says. The dot represents the comparative amount of lead that he consumed in his pre-industrial environment. The second looks as if he has measles, with dots covering his entire body. That's modern man.
"It's a polluted reservoir in your body," says Patterson, 68, a lanky, rubbery-faced man who walks around the Caltech campus with his hands at his sides like a gunfighter ready to draw. "It doesn't go away just because you reduce intake."
The third figure, with the dots coating the figure, could be "future man," with enough lead in him to kill him.
But there's good news from the lead front. Since Patterson seized on the issue almost 30 years ago, Northeastern cities have begun covering over tenement walls that were polluted with lead-based paints, and the canning industry has stopped sealing canned food with lead solder.
Most important, the Clean Air Act of 1970--passed largely because of pressure from environmentalists and scientists armed with Patterson's research--has drastically reduced lead emissions from cars burning leaded gasoline. The U.S. Environmental Protection Agency found last year that lead emissions had been cut by 96% since the law was enacted.
But there's still a lot of lead out there, fouling children's neurological systems and, in a few high-risk industries, ruining the health of American workers, says the cantankerous geochemist, who agrees to an interview only after checking what kinds of books are on the reporter's desk.
"The residues are still there," he says. "The costs of cleaning up the lead problem could be very large."
Despite his influence with environmentalists, the "lead man," as some call him on the Caltech campus, has not attracted the attention that some of the school's superstars have.
He was elected to the prestigious National Academy of Sciences, official science advisers to the U.S. government, only three years ago. "It seemed rather a delayed recognition, even for people who should have known about the importance of his work," says Stephen G. Brush, a science historian at the University of Maryland.
The lack of recognition may have had something to do with the way Patterson has challenged his colleagues, Stephen Budiansky wrote in "Environmental Science & Technology," a publication of the American Chemical Society.
"No one likes to be told that his analytic technique is off by a factor of 1,000," as Patterson has done, Budiansky said, "and Patterson hasn't balked at stepping on toes." He has alienated a few colleagues with remarks about ivory-tower scientists.
When Patterson was finally elected to the academy, geophysicist Barclay Kamb, a former Caltech provost, summed up a widespread impression of his colleague.
"His thinking and imagination are so far ahead of the times," Kamb said then, "that he has often gone misunderstood and unappreciated for years, until his colleagues finally caught up and realized he was right."
An energetic man with wide interests, Patterson has traveled to Greenland and Antarctica to retrieve ancient snow samples, tested for lead in the easterly trade winds in Samoa and set up a research project on a 10,000-foot peak in Yosemite National Park. He was the model for the disillusioned scientist Beech in Saul Bellow's novel "The Dean's December."
"Bellow helped me a lot in understanding the kinship between the artistic and scientific temperaments," says Patterson, who met Bellow in the early 1980s, when the novelist's mathematician wife taught at Caltech.
Some early experiences may have poisoned Patterson's attitude toward scientific research. During World War II, he worked on the atomic bomb project, in Chicago and in Oak Ridge, Tenn., where he helped to analyze the uranium isotopes that went into the bombs.