Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: THURSDAY, March 24, 1994 TAG: 9403240035
SECTION: NATIONAL/INTERNATIONAL PAGE: A7 EDITION: METRO
SOURCE: Associated Press
DATELINE: NEW YORK LENGTH: Medium
Researchers examined layers of sediment from 19 lakes in Sweden. They found that lead, a byproduct of silver refining, began settling on Europe's lakes and soils 2,600 years ago, when Greeks began refining silver for coins.
Lead emissions rose to a pre-industrial peak 600 years later, under the Romans, but then declined again as the Romans exhausted their mines, the sediments showed.
Lead pollution soared with the arrival of the Industrial Revolution in the 19th century. But the total amount of lead released before then is at least as large as what has since been released, the study found.
The study by biologist Ingemar Renberg and colleagues at the University of Umea in Sweden is being published today in Nature, a British scientific journal.
Sulphur and other toxic metals probably were injected into the atmosphere along with the lead, Renberg said. Studies are under way to measure those other pollutants, he said.
The toxic metals released in the pre-industrial era remain a threat to health, he said. "Metals are metals and can't be destroyed, and they must be somewhere in the soils or the systems," Renberg said in a telephone interview.
The Swedish study provides the most complete historical record of lead emissions, said Claire Patterson, an emeritus professor of geochemistry at the California Institute of Technology in Pasadena.
"This is quite new," Patterson said.
Patterson said he has looked for evidence of lead pollution in Greenland ice cores, which also provide a historical record of the atmosphere. But the new study "shows details for the Roman and Greek periods that we did not have in the ice cores," he said.
The silver ores mined in pre-industrial times often contained 200 to 300 times as much lead as silver, Patterson said.
Lead poisoning is a chronic condition that can lead to kidney disease in adults and to retardation or seizures in children.
Common sources of exposure to lead include paint chips eaten by children, foods and beverages stored in some lead-glazed ceramics and leaded gasoline. People also can be exposed through contaminated dust and soil.
by CNB