Improperly Taken Samples Can Throw Off Tests

When the tiny Church of God of Prophecy outside Leeds, Ala., needed a parking lot in the early 1980s, a neighbor agreed to help.

The Interstate Lead Co., a recycler of used automobile batteries, had a slag pile that it said a church member could use to fill in a small ravine. Since laboratory tests showed the slag was safe, Interstate provided it to other places around Leeds.

But the laboratory tests were wrong.

The slag contained heavy concentrations of lead--hazardous enough to turn the church and seven other locations into federal Superfund sites.

The Church of God’s misfortune was a consequence of unrepresentative sampling, which environmental regulators say causes far more unreliable data than testing problems in laboratories.

Improperly taken samples that are not typical of the slag, soil, water or other substance that is to be tested will produce misinformation, no matter how good the testing lab.

“I’d say better than three-quarters of (data) errors are traceable to sampling handling and design,” said Nancy Wentworth, director of the Environmental Protection Agency’s quality assurance management staff.

In a 1989 report, the U.S. Geological Survey found that about 85% of the data that was supposed to be representative of water quality in Colorado streams in the mid-1980s apparently was not. Poor sampling procedures were to blame.

There are no national standards or requirements for training people to take proper samples in the field, Wentworth said. Anyone can take samples. And just about anyone does.

“At a waste-water treatment facility, it could be anyone ranging from a truck driver to a chemist,” Wentworth said. “. . . Somebody says, ‘Go get this bucket and fill it up. . . .’

“At a Superfund site, it could be, ‘This stuff smells bad. You go do it.’ ”

At Interstate, EPA officials suspected that the company deliberately took samples that would not show the severity of pollution.

Interstate denied cooking its test results. But a federal judge ruled that improper sampling had been used and fined Interstate more than $4 million--including $800,000 to repay the government for cleaning up the Church of God site. Interstate declared bankruptcy and went out of business.