They laughed five years ago when the National Bureau of Standards started its liver bank.

Today, they either want to start their own liver banks or use the one at NBS.

The liver bank is a freezer in which scientists from the bureau keep specimens of human livers, removed during autopsies from people in many walks of life and various parts of the country.

The long-range goal is to have a collection of preserved human tissues spanning a period of time in which environmental conditions may have changed. Because livers tend to retain many pollutants and other substances that humans eat and breathe, they make good indicators of a person's toxicological history.

Fist-sized portions of the livers are removed at death using special equipment, such as titanium knives and Teflon bags, that minimize contamination. The samples are quickly frozen in liquid nitrogen and kept at about 250 degrees below zero Fahrenheit.

Whenever someone wants to study the specimens, only a tiny fragment need be removed, leaving enough tissue to last for many decades. Freezing at such extreme temperatures should protect the specimens from almost all deterioration.

Although the NBS liver bank now has specimens covering only five years, preliminary analysis of the livers has revealed that the amount of lead in people's bodies seems to be declining. This is thought to reflect the diminishing use of leaded gasoline.

"The bank is especially valuable for determining pollutants present in the environment at a given place and time," says Stephen A. Wise, manager of the bank that is officially called the Pilot National Environmental Specimen Bank and was started in collaboration with the Environmental Protection Agency.

Although human tissues have been examined at death many times before and then discarded, the bureau's bank of frozen assets makes it possible to examine specimens for years. Thus, if some new environmental hazard is perceived, it will be possible to go back to the old livers and see whether the hazard was present all along. The bank will also preserve old specimens for analysis by more accurate or more sensitive methods that are likely to be invented years hence.

Stored with each specimen is basic information about the person from whom it came -- such as sex, age at death, occupation and place of residence.

The occupational information has already produced one surprising finding: When a researcher examined 30 livers for evidence of pesticides, he found that all contained measurable amounts of eight widely used chemicals, including DDT.

"We initially thought we'd find high levels of pesticides for our study in an older farmer who might have been exposed to them over a number of years when his crops were sprayed," Wise said. "But we looked at a farmer's liver, and his levels really weren't that high. So we suspect that the reason all the livers have some degree of exposure is that the pesticides were absorbed through the food chain."

Wise said that although some of the pesticides were banned in this country, they showed up in American livers, probably because foods treated with the chemicals are imported into the United States.

In addition to livers, the bank is collecting and storing marine mussels from Rhode Island's Narragansett Bay. Mussels take up and store many pollutants from water and are considered good indicators of environmental conditions.

The bank is also designed to store other natural indicators of environmental quality such as milk and grain, which store food contaminants, and mosses and lichens, which take up air pollutants. Such samples have not yet been collected. But to carry out a program of banking and analyzing foods, the NBS has cooperative agreements with the Department of Agriculture, the Food and Drug Administration and the International Atomic Energy Agency.

The goal is to collect samples of typical meals from around the United States and 11 other countries and analyze them for nutritional value. "A typical day's meal," says project coordinator Rolf Zeisler, an NBS chemist, "including, for example, a breakfast consisting of bacon, eggs, toast and coffee will be blended together -- homogenized -- and then analyzed for chemical makeup." Researchers will measure the levels of 20 nutrients and several environmental pollutants that may have entered the food chain.

Other specimen banks, including a large one in West Germany, are adopting some NBS methods, and the number of research proposals for the bank is growing. -- Boyce Rensberger