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High lead levels in food cans may be a hazard

When geochemist Clair Patterson suggested I take a critical look at the food cans in my cupboard, I laughingly humored him. Like most people, I've been more interested in the contents than in the containers. But the laugh soon faded. On can after can, as he predicted, were the lead-soldered seams that he now believes are one of the most widespread, and unrecognized, forms of poisonous pollution.

Through studies made by his research unit at the California Institute of Technology, Dr. Patterson has found that lead is leaching out of those seams into the food contents to an alarming degree. This is not a question of food packaging exceeding safety standards, or of there being no attempt to set lead level standards. It is, rather, a matter of present standards being set by false assumptions about "natural" levels of lead in the environment and of monitoring through measurements that, although it was not known, have been in serious error.

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Reviewing these findings recently in the journal Science, Dr. Patterson and his colleague Dorothy M. Settle explained that, as a pollutant, lead has been accumulating in the environment for centuries, rather than just decades, as in the case of most industrial contaminants. Thus, regulatory agencies have been fooled into thinking that natural levels of lead in food -- levels to which humans have adapted over hundreds of thousands of years -- to have been much higher than they actually were.

Second, the two scientists note, industrial lead is so unsuspectedly pervasive now that laboratories cannot make accurate lead level tests without elaborate precautions -- precautions that had not been thought necessary.Repeating measurements by government laboratories, Drs. Patterson and Settle say they found these in error by factors as large as 1,000.

The result of all this is that regulators are misled into thinking that lead-soldered cans elevate lead levels in food only a few times the natural background -- well within safe limits. In fact, the scientists report, their measurements indicate lead contamination thousands of times the natural background that prevailed in prehistoric times (in the case of canned tuna, a 10 ,000-fold contamination).

In short, the two scientists warn that present standards for maximum permissible levels of lead in air, food, and water are 500 to 40,000 times the natural lead concentrations to which humans are adapted. They say that United States consumers, especially, have average lead intakes hundreds of times that of prehistoric peoples, and only a few times below levels that would produce lead poisoning symptoms.

They believe lead-soldered food cans to be a major, and ultimately unnecessary, contributor to this lead intake. They urge discontinuing the use of such cans.

Here is a serious warning of an unsuspected pollution hazard. The Food and Drug Administration should look into it without delay. Happily, there are now alternatives to lead solder and, with new plastic containers, even to metal food cans themselves.


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