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.
"It was the greatest crime that science has committed yet," he says now. "We burned 100,000 Japanese alive. Sometimes I go past the Rose Bowl and tell myself, 'Pat, you could fit all of them (the dead Japanese) in there, and you helped to burn them alive.' "
The notion of socially responsible science ultimately led to his lead research, beginning not long after he discovered in 1960 that lead was entering the ocean at a far greater rate than it had in prehistoric times.
There's a bewitching attraction to pure science, Patterson says. "For most, it remains an abstract, beautiful refuge within the mind, disconnected from the dirty world."
But for Patterson, the atomic bomb and lead pollution combined to tear down that "lovely edifice," he says.
"My science got entangled with social problems," he says. "It threatened the beauty of my scientific refuge. But there was no way out."
If lead is almost everywhere, one place you won't find it is in Patterson's laboratory on the third floor of Caltech's North Mudd Building. The little room is plastic-lined, with a pressurized atmosphere to keep that invisible snow from drifting in and contaminating specimens.
Patterson washes his hands with distilled water, dons a lab coat and surgical cap and prepares to enter the inner sanctum. "These are my lead-free shoes," he says, pulling on a pair of moth-eaten slippers.
He stands in the middle of the room, holding his gloved hands up, like a surgeon ready to operate. "People come from all over the world to see this room, and they're so disappointed at what it looks like," he says. "But it ain't how it looks that counts."
It's here, in the contamination-free air of the lab, that the geochemist and his assistants have analyzed 300-year-old snow from the Arctic Circle, examined fossils from deep in the ocean and determined the chemical composition of the bones of a 2,000-year-old Peruvian Indian.
The Indian "had about one-700th of the amount of lead in him that humans do today," Patterson says.
His next project will be to raise animals--rats, probably--in a lead-free environment. After centuries of smelting and gasoline-consuming, that's easier said than done.
The problem is devising lead-free food for the specimens. "All foods are contaminated," he says. "You can't just get a piece of lead-free steak. It's loaded with the lead that fell on the food the steer ate."
The restless geochemist probably could have retired 37 years ago and been assured of a niche in most histories of science. It was he who solved a problem that had stumped scientists for 300 years: How old is the Earth?
Until Patterson's discovery, the most recent estimates--admittedly imprecise ones--had set the Earth's age at about 3 billion.
Using the brand-new technology of radiometric dating, in which the rates of decay of elements such as uranium were used to establish the precise ages of rocks, Patterson announced that the Earth was 4.6 billion years old, give or take a few hundred thousand--a figure that has not been seriously challenged since he produced it in 1953.
Though Patterson has received little recognition for the discovery, it was a heady experience for a 31-year-old scientist. "Imagine--you're the the first person," he says, his face lighting up at the memory. "We know when this thing was born. It's not the number that's important. It's an electrifying awareness of the beauty of the human mind. That's an emotion that can't be communicated."
Patterson was born in Mitchellville, Iowa, a small town near the Skunk River. His parents were a rural mail carrier and "a repressed housewife," he says.
"I spent my days on the river bottom and taught myself chemistry in the basement. . . . I collected mushrooms and bones. If I found a dead animal, I'd collect the bones in a sack and reassemble them in the basement. It was a nutritive environment."
His high school was small--fewer than 100 students--and informal, and the instruction often circular, going from student to teacher as well as the other way around. "I explained to the science teacher, who was the football coach, that electricity was not a fluid," Patterson says.
He went on to Iowa's Grinnell College, where he met his wife, the former Lorna McCleary. She recently retired as a chemistry and physics teacher at La Canada High School. They have four grown children--two sons and two daughters.
After getting his master's degree from the University of Iowa, Patterson earned a Ph.D. from the University of Chicago. He joined the Caltech faculty in 1952.
Nowadays, Patterson lapses occasionally into diatribes against the scientific Establishment or ruminations on finding "new ways of thinking."
Science, as it's practiced in America, has lost the spark of imagination and creativity, he says. "The field is populated by data-gathering technicians."
He leads a quick excursion to the lawn outside North Mudd. "Forty years ago, that building wasn't there," he says, pointing scornfully at the Millikan Library, which towers over older, Spanish-style buildings. "There was a row of Italian cypresses and a smooth lawn here. It was something simple and beautiful. There was an integrity to it. But a rich guy gives an endowment, and what do you see? This is Alcatraz. This represents the degradation of science over the past 40 years."
Then he strolls back to the pristine environment of his own laboratory.