About science; About lead in the atmosphere

This is about science produced by the California Institute of Technology and originally broadcast by station KPCC in Pasadena California. The programs are made available to the station by national educational radio. This program is about lead in the atmosphere with host Dr. Albert Hibbs and his guest Dr. Claire Patterson of Cal Tech's division of Geological Sciences. Here now is Dr. hymns. The element lead has a long history and human civilization because it's soft and melts at a low temperature. It's been worked and used steadily for most primitive days but it's also a poisonous element and lead poisoning is recognized as an occupational hazard in those industries which use lead such as the manufacture of batteries but lead is not restricted to the boundaries of any particular industry. It's present on the ground in lakes in rivers and in oceans and it's also present in the atmosphere. This means that every human being on earth comes in contact with lead eats it drinks it

and breathes it. The question is how much and is still more important question is how much more exposure is there today to lead poisoning. Because of the growing use of this element in such things as high premium gasoline. One man has made a recent and somewhat explosive study of this problem is with us now Dr. Claire Patterson of Caltex division of Geological Sciences. Going to start out with why don't we begin by giving some estimate about how much lead is handled in American industry today produced and refined zone electric halves. We produce in the United States today about 1 million tons of lead per year. This one million tonnes of lead is considerably larger than the amount of lead which exists naturally in various places

on the earth. The amount is released by nature and so natural processes I suppose are natural processes that release the lead volcanoes I imagine that some gaseous products with lead in them and so on. But the million tons a year how does that how does that compare or is there any way of comparing that with the amount that would be around if man was a mining mining and smelting lead. Well we have made geochemical investigations of lead in the oceans and in. Other in the in the atmosphere and it turns out that in the oceans themselves and all the oceans of the earth there are about ten thousand tons of lead each year which are being pursued potatoes on the bottoms of the oceans leaving the oceans and under natural conditions. There would be entering the oceans of this same amount from the rivers so this is

about an equilibrium rate that yes about 10000 earth or a bad one percent of the amount that we are producing in the United States today each year and is United States the biggest producer by the way of the year of lead it is the biggest consumer. It is a very large amount of lead is imported into the United States in the form of ores and metal. But it's then fabricated in the United States into different products which are used what are most of the products we use lead by the way the battery industry and led to traffic as in two major consumers of their autumn Azza goods and automotive products and primarily the U.S.'s large amounts are used for. Products that end up in the automobile Yes that's true. How much lead can a human bean stand without getting lead poisoning is a well-known number.

But now it's a very small number so must be rather hard to measure are there measurements of. Well here is the here is a matter over which there is been a controversy recently. The medical investigators who have been employed by that industries to and check their workers in these industries have certain criteria which they use to distinguish between a worker who is fit to carry out his duties and one who is not. And they they use the as AVIs criteria the concentration of lead in the blood and they say when it exceeds a certain value this worker will probably end up in the hospital with the lead poisoning. But if it stays below this level as far as are concerned he can perform his duties satisfactorily. Now of course this idea does not

involve a fundamental knowledge of the biochemistry of the of the. Chemistry of lead in the body and then sort of a yes no black or white right and it's at here. There must be some characteristic of lead in the body where if you have a certain amount it may not show up as chronic lead poisoning but you still can be sort of sick or really suffer a fact some of the old effect yes. If this is the point of view which I represent it does feel this way that there are subtle effects and not yet recognized involving interference with cell metabolisms and tissue dysfunction which may be actually pervasive in the United States today because.

The extent to which this industrially produced lead has leaked out into our environment has escaped into our environment is such that our estimates of what of how much lead should be in our bodies are very very small compared to what actually exists in the average American body today. How do you get an estimate of what it is as you say what should be in a human body. Well this is a again a a matter of contention. You see it's difficult to look at materials now that are not contaminated by lead. And so it one thing that we can do is to compare the abundance of other trace elements similar to lead both in mass and in chemical properties such as mercury or thousand or bismuth and to compare the abundance of these trace elements in man and in his environment and and

then infer what should the concentrations of lead be. Now when we do this. And using a gradation relationships and the out on Earth series of calcium strontium bearing and its relationship to it we look at these elements in man and his environment. We find that there should be for example only about two milligrams of lead in a 70 kilogram man. Now actually the average American contains about 200 milligrams. But 100 times more than your calculations would that already should. Was there any way of checking this against people who are not exposed to lead Haven't there been a set at some attempts to measure the lead concentration in people who live in remote areas of the earth. Not really in one thousand thirty two the FAA corporation had investigators examined some

people in a Indian tribe in Mexico and they found that the their data showed of course that these people had less lead in them than people in United States. But the methods that they used and the and their results show that these people also were contaminated with lead they ate their their food was prepared in dishes in which it were crudely glazed with high concentrations of lead. They had their own lead into they had their own lead in. And now these data showed that of course that these people did contain lead in their food and in their bodies. No serious study has been made to really by investigators who are aware that the stance even as in the pervasiveness of this lead contamination problem. To really try to ascertain what are the natural concentrations of lead

in man in his environment I suppose that this would be very difficult to do even find a tribe or some remote area where first of all they didn't use lead because it is certainly clear that lead is a common metal for humans to use and he's even going to get it. It's convenient it's been used for thousands of years and all over the earth so I know the man has contaminated quite a bit of the earth aside some of our studies show in acar in studying the atmospheric pollution problem with lead. Now this lead of course enters the atmosphere from the exhaust of automobiles burning their gasoline. We have found lead in the in the snows of the North Pole. Can which are excessive and should our non-natural should not be there. But you see this pervasive distribution of lead contamination is makes it renders it very difficult to to try you measure natural concentrations

and to choose tribes that have not used bullets that are have not eaten off of dishes that contain lead glazes have never been in contact with man never driven automobiles. It is very very difficult and but we are. There are indications now that this kind of research may be carried out as the the this controversy has has brought this problem to the to the attention of those government agencies that are responsible for granting money for research in these areas and it appears that a considerable amount of effort made on what kind of research could be carried out to establish a limit. A natural is that the right word to use by the way the natural level of lead in man. Yes I have a phrase which I coined which I might say has meaning. You see the difficulty here is that.

This particular point was never brought out before in all in the past decades of the so-called examination of the problem the toxicity problems that as a matter of fact the lead industries have tried to confuse the this issue in such a way that it would be is to make it appear that it is that that there is little distinction between natural concentrations of lead in typical concentration of lead which include of course the kind of contamination is from industrial sources so we have an educational problem here and try to be good responsible people aware of this distinction and first of all and then to try to conceive of ways that we can objectively measure these these differ so the picture is that even though we're now today in the world and particularly in America. Blood levels of lead perhaps rather high.

The natural level you would relate to the level of yes in a man. When you let humans later and how serious I think this situation is in the average person United States today the concentration of late in the blood is a bad a quarter of a part per million that is point to 5 parts per million. The level of lead in the blood which the industrial medical representatives claimed will yield will cause lead poisoning classical lead poisoning is varies between point five parts per million and point eight parts per million. So you see you're within the factors of two or three of us level. Now geochemical estimates of what the concentration of late in our blood should be are one one hundredth of a point to find it without any led industry. Yes without a lead contamination from industry. And it is so this is a point which has never been thought of until just the very recently. So we're 200

times or were about a hundred times higher than what the natural level might be but only and within the factor of only 2 was a level which I clearly toxic levels toxic levels which will put you in the hospital. So we're close to the edge. That's right and now when you combine this with the fact that there are no we have no knowledge today of the biochemistry of lead in the body where there is none. We do not understand how the body handles it by the chemical process by how lead travels through the body. And if we don't understand the chemistry of how it lead does poison a cause is classical lead poisoning these. Factors suggest that we may be suffering today from a from chronic exposure which is not good for us in a very serious way because one of

the things that lead does in in the end when you suffer lead poisoning severe lead poisoning it affects the function of the central nervous system. And now the effect of these of these toxic metals is not an either or proposition at least from our point of view. It is not. You have a great ational effect so consequently since our society depends upon the way in which our minds function. It's quite possible that here we are. Being exposed is a very high concentration of A if that is it may be affecting our the way we think and the way we react. And it could be the cause of many forms or might be the root cause of many forms of our social aberrations. I mean this is a distinct possibility I think it should be seriously considered because lead does have an effect on the brain this way.

Yes it does but but as you point out the metabolism of this whole led process in the body isn't well known is it. I assume that lead like other heavy metals is stored in the body. It doesn't all get better and that's that is a true eat it or thrown out the average person as I said has about 200 milligrams of lead in his body. And his daily the daily amount of lead which enters his systemic blood the main blood that flows through his soft tissues and is then excrete in the kidneys. Of all is on the order of 30 micrograms a day some somewhere in that range that's a point 0 3 milligrams compared to 200 milligrams he has stored his body. Now this is a on amount of lead which is built up slowly over the years. Thank you.

So he has some reservoir which of lead in his body. There's always a little bit coming in each day a little bit leaving yet almost an equal amount leaving a little bit. The difference is that which is accumulated and stored. And now this this this man which is stored as a as a mood and other mood problems. Well that relates back to the metabolism itself of how much of what passes through the body is stored in it and that yes comes down to the process by which that that's correct. And now of course the medical investigators for LED industries have. Attached great significance too to this this problem of lead entering and leaving the body. And what they have tried to do is to imply that the amount that says Lead is a toxic metal and you don't like to have it stored in the body and so therefore if you can show that as much as much lead leave the body as enters the body why then

under presentation when you have anything you have little to worry about. Right. So they have in the past decades this has been one of their main contributions to this area has been to study this matter of material balance how how they come out on. Well they have showed. That indeed was almost a very large amount of The Lead which enters the body does leave the body. But for decades they have maintained that there is the body is in perfect equilibrium and it is only recently that people like myself have examined these experiments and have shown that these these claims of complete equilibrium in the body are fallacious and erroneous. Oh how what kind of data could they get to show complete equilibrium that have to have extremely sensitive measurements of in taken out flow.

That's Well yes and there their data is and their methods are hard. Are borderline in showing this but this is not where their fallacy lies a fallacy Hamdoon to lie in the fact that the investigators measured the amount of lead leaving the body in the feces of the year and they measured the amount of lead entering the body by food and they discovered that the. The subjects were extreme more lead than they were they could measure entering the body. So then they assumed that the lead this extra little bit of lead which they found leaving originated from the air because they had been making measurements of land here and they knew that there was lead in the air which came from automobile exhaust and they said well they're bringing us in from the look in their lungs and absorbing their blood and their excreta get as what remains we mean they assumed it was exactly the right amount this is a fallacy they assume that the amount of lead they observe extra lead they observed coming

from in the urine was exactly equal to the amount of lead entering from the lungs Now they didn't measure the amount of lead that was entering from the lungs so this just assumes that soon the answer they assume that there was an equilibrium you say but all it would take is just a fraction of this lead entering the lungs to be absorbed by the body each day to account for the amount of lead and that is stored in the bones. Now this kind of. This kind of attitude of course is not basic science it doesn't contribute to our our knowledge of the biochemistry of metabolism which we can't lead which can provide a basis for the proper understanding of just how much lead is safe for us to be exposed to and to to contain our body. But what happens when some of the research that you were involved in reached reached the press and was distributed in the journals what kind of response did you get back from Hollis.

Well I published a study on the this very thing and the reaction of course was quite quite explosive. The lead industries reacted violently they took away my doctors and revoked my Ph D such things but now the high. Call attention to the fact that the United States Public Health Service and other regulatory agencies had been participating in the past with lead industries in deciding whether or not led industries were committing sins you see in this matter of contemp Aleutian. And I had criticized some of their most recent reports which hit which clearly whitewashed the lead industries in this

regard and were not in a proper He did not represent the proper interpretations which the easy regulatory government agencies were obliged to do provide to us actually or time they really hadn't been doing their job properly I don't imagine they respond out with complete enthusiasm to that. Well they call a national meeting in in one thousand sixty five in the December 1065 to. As a consequence of my study and invited many people from all over the United States to this meeting. And as a as a result of this meeting and the United States Public Health Service has changed their attitude and they are now for the main For the most part sympathetic to the one which I have proposed. And my feeling is that they are going to push

research in this area as best they can. Furthermore a Senate subcommittee headed by Sen. Muskie from Maine on air pollution. He reopened the air pollution hearings when he heard about this he had closed the hearings because he said the way he was he was astounded that no one had mentioned lead in all the discussions of lead to air pollution. And when this matter came up he reopened hearings and in those hearings on many factors concerning this problem were brought to public attention and this whole matter he has now I think receiving attention that it should be see. Well you appeared at those hearings into yes I recall you were one of the witnesses. Yes. Did you have an opportunity to bring out some of the points you've been talking about tonight. Yes.

And how did the Senate seem to react Elisa's their general understanding did you feel in the part of musky and his colleagues or yes I felt that Senator Muskie showed a very very proper attitude a very perceptive understanding of the problems involved. And and I was greatly encouraged by it by this by the so what do you think should be done now that as you say the public health service is a little bit more aware that of it and concerned about it. What. What can I do. Well as we mentioned this study of what we might do to to investigate what are the natural levels of the lead of lead. And now I might say that in this regard what can we do. Lead is a is an example of a case of a situation which is general. I mean this is a this is not the contamination power of these pollution problems of course are generally involve many

things. But now we would like to know. The kind of the natural concentrations of many trace elements in the earth and man his environment because it provides it can provide a proper understanding of nutrition and mineral metabolism so it's the basis for this and consequently we don't want to study just they had to make these natural studies for LET we want to study many other trace elements as well. And this will be a and extensive and expensive and complicated program but I hope that we can get started and then much work will be done so that is one very representative example. Now other things you can do you can do developmental well and you can do research on lead itself in. You can make great subacute and studies of the effects of chronic

exposures of lead on on organisms by properly designing these experiments experiments have not been performed or designed in the past now there are some in Europe very small single laboratory that has been performing some of these experiments. Is this because the quantities involved are so tiny that no he doesn't the attitude no want first of all. No no research basic research people have been interested in this problem and second there's been no official encouragement on the part of a governor or government agencies now that this problem has arisen perhaps and the interest is there. Careful investigations of the sub acute chronic exposures of these toxic elements lead bismuth Allium and so on will be made and will begin to get acquire some information their epidemic will epidemic logical studies of of disorders in people from can present data which present exist a correlation with with exposures to lead and so on. I'm sure are going to be

made. This is another area. But but really they are the main work that has to be done. We must acquire a basic understanding of the biochemistry of lead metabolism and this will not be done wholly solely by direct it by direct study of lead it will be. It will be accomplished by the broad increase of our general biochemical knowledge of the metabolism of many metals in the body. We don't understand clearly the metabolism of calcium and iron. These these fundamentally important macro elements and you suspect there's something similar to lead. All well of course they're related and all these things are related and so that we can get at this by a roundabout way but varied in a very long it's going to take decades of careful study to do this and what I'm trying to point out. Encouraged is a more conservative attitude toward lead pollution. Now

until we acquire this this kind of information. But the accusation of the information is of course something that has to start immediately. It should yes it would. So it's very the change of attitude of the Public Health Service has really been a very important step. You know yes in the back of this is how it is a necessary step. Is there any possibility that a substitute can be found for tetraethyl lead in cars. Oh yes there is a I don't know there's a possibility or not but I suspect it is. And there are investigations in there along this line have been continuously carried out by the oil people for decades. They now have several that are possible substitutes. But in this case we're not going to repeat the story. The Public Health Service has already issued notices that they will they will examine the problem differently than they did 30 years ago in the case of

ledes. So something definitely has happened either manganese and nickel additives that they're considering. Oh I see. Maybe the problem will be repeat. I had kind of a void that Dr. Patterson thank you very much for joining us tonight and talking with us about a letter in the atmosphere. This was about science with host Dr. Albert hims and his guest Dr. Claire Patterson of the division of Geological Sciences at the California Institute of Technology. Join us again for our next program when two more members of the Cal Tech faculty will discuss a subject of interest about science is produced by the California Institute of Technology and is originally broadcast by station KPCC in Pasadena California. The programs are made available to this station by national educational radio. This is the national educational radio network.