Изображения страниц
PDF
EPUB

Actually the Baltimore City Health Department did go back to four different houses in which this family had lived to look for other affected children. This is one of the ways of identifying affected children before serious illness occurs.

I think the other point is the need for special screening tests, because it is the only way of identifying affected children before this sort of thing happens.

Senator HUGHES. Doctor, it seems in the instance of these two cases the local physicians had difficulty diagnosing what was wrong. I do not know whether that is the result of further deterioration or what. To what extent are physicians alerted to look for the symptoms?

Dr. CHISOLM. I think this is quite variable. One of the big problems is that most of the hospitals in high-risk lead poisoning areas are staffed largely by young doctors just starting into medicine who have a lot of things to learn about beside lead poisoning.

The second thing is that lead poisoning does not show up on the usual sorts of laboratory tests. If you go to a hospital and have the usual chest X-ray or usual blood count or urine specimen tests, lead poisoning may not show on the usual examinations.

I think this is where the real diagnostic problem lies. You have to do special sorts of tests.

Senator HUGHES. What are the symptoms of lead-based paint poisoning?

Dr. CHISOLM. The early symptoms are change in behavior. The child becomes irritable and fussy. He may vomit from time to time, and these are the sort of things that are often passed off as a cold, as these mothers have mentioned.

They are passed off as being inconsequential, and then you have, as both of these represent, very chronic cases. For example, Mrs. Haskin's child stopped talking, and this was called a behavior disorder because there was nothing in the clinical and routine laboratory examination of the child pointing specifically to a diagnosis of lead poisoning. The other problem I think is the limited availability of laboratory diagnostic facilities.

Senator HUGHES. What do you do to treat them?

Dr. CHISOLM. We administer drugs that reduce the amount of lead that is in the soft tissues. We really cannot get much out of the bone once it is there. Prompt treatment will limit the risk, because the toxic effects of lead are related to the levels of lead in the nonbony tissues. We can reduce soft tissue lead levels with drugs, but we cannot reverse damage to brain cells once it has occurred.

Senator HUGHES. It seems that the proponents of the .06 percent indicate the way to fight the problem basically is to teach the parents and to post the sign in the rooms, to point out to children that they may be harmed in chewing and eating, and this sort of thing. Could you give us your opinion of that?

Dr. CHISOLM. I would ask whether a mother who has three or four children under 5 years of age is going to be able to do this in addition to all of her other duties.

There are some mothers who seem to be able to bring pica under control. For example, Mrs. Haskins told me on the way over that her younger child actually was spanked for eating paint when she was

about a year or so of age, and that this particular child never had this tendency of putting things in her mouth.

So it was not so much a problem for Mrs. Haskins with the younger child, but, with the affected boy, she could not stop this habit in him. This is one point of my original testimony. Physicians really do not know how to tell people to control pica. There seems to be too great an urge in some children to eat paint, paper, and so forth. Some parents can control it and others cannot.

Senator HUGHES. What does it cost to run a test for a high lead level in children?

Dr. CHISOLM. A blood level test by the most exact method of analysis costs about $15 or so per test. With regard to the newer atomic absorption techniques I think the question would be better directed to the director of laboratories, New York City Health Department. I think the cost is down around $2 there. They do 500 tests or more each day. This is with atomic absorption techniques.

Senator HUGHES. Is it possible to bring a testing program into a school system to test school children?

Dr. CHISOLM. That is a little bit late, sir. The real high risk age range is 1 to 3 years of age. It is even too young for the causat

program.

Senator HUGHES. Before any entrance really into the school system? Dr. CHISOLM. Yes.

Senator HUGHES. Do you have any recommendations? Part of the problem is calculating the financial costs.

You come out strongly in support of State laboratories, early diagnosis, training, teaching not only parents but physicians, and so on. When I ask you how many children might be so affected in the country you cannot supply us with an estimate.

Dr. CHILSOLM. I do not think there are any hard figures on that. Senator HUGHES. What can we base our estimates on, do you think? How can we figure the cost of identification and treatment programs?

Dr. CHISOLM. I think really the best estimates could be made on the experience of the New York City and Chicago health departments. They are the ones who have been doing this for the greatest length of time and have tested the largest numbers of children.

I would make another comment about overall cost. Not every child who has a slightly elevated blood level is going to be put in the hos pital. From those we identify in screening programs I am sure we will find relatively few who really have to be hospitalized.

I would estimate that 2 percent of 1- to 3-year-olds in a moderate sized city might require brief hospitalization during the first year of testing. During succeeding years this would decrease to less than 1 percent who require hospitalization and prolonged treatment.

Senator HUGHES. Could you tell us briefly what your experience has been with lead paint poisoning in children in Baltimore?

Dr. CHISOLM. Well, our experience has been that proper diagnosis is made fairly readily at the large hospitals where the problems are recognized. It is not diagnosed so well at the smaller hospitals.

The overall experience has been a steady decline over the past 20 years or so in the incidence of obvious clinical lead poisoning cases.

However, the number of cases of what is called increased lead absorption-these are children without symptoms of illness-has not declined until recently so the total numbers for lead poisoning and increased lead absorption cases stayed at a relatively constant level from about 1954 to 1965 or shortly thereafter.

Since that time ithas decreased with the exception of one year. During this one year a small pilot screening project was carried out. In this project the incidence of increased lead absorption was the same as it had been 15 years earlier in another study.

Senator HUGHES. Could you give us any recommendations for trying to eliminate the problem in the big city?

Dr. CHISOLM. I think it would take a long hard effort. I think that you cannot effectively educate mothers by traditional means. Some education combined with the testing of children would eventually bring the problem under control.

The testing really should be concentrated in the 1- to 3-year-old age range for greatest benefit and impact.

In terms of housing, some of the houses that I have been in really are not worth rehabilitating. I think the choice in housing is to determine what is worth rehabilitating.

I do not think that answers your question really directly. It is a very difficult problem.

Senator HUGHES. In the past the attitude has been that if the house cannot be rehabilitated the family is put out with no place to go. This. has also happened when highways are run through a neighborhood.

If the house is not worth rehabilitating I think we still have an obligation to provide housing that is decent for these people to live in. Senator Schweiker.

Senator SCHWEIKER. Thank you, Mr. Chairman.

Dr. Chisolm, I would just like to briefly go back again as to how 0.06 was arrived at, since that seems to be the only matter of controversy in the bill. Would you just review briefly again.

Dr. CHISOLM. The medical?

Senator SCHWEIKER. In layman's terms, can you tell us how that 0.06 percent was arrived at? Was it through your association or through a study the Public Health Service made?

Dr. CHISOLM. The Academy's position was drawn up on the basis of evaluations of data in a document I mentioned before prepared by the National Research Council, and the report of an ad hoc committee of the Public Health Service which evaluated the question of a safe daily permissible intake of lead for young children.

Did you want me to go over the medical part of it, or how we got from the DPI of 300 micrograms per day to the 0.06 limit in paint? Senator SCHWEIKER. From repeating your testimony that 300 micrograms per day is the key, and you take it and build on how much is likely to show up in a chip of paint that has had as many coats on it

as 10.

Dr. CHISOLM. Yes.

Senator SCHWEIKER. So it really relates to the 300 microgram standard based on the assumption that a child would eat a small chip a day with possibly as much as 10 layers of that paint on it.

Is that really what we are saying?

Dr. CHISOLM. Yes. The 300 microgram total includes about 150 micrograms of lead on the average from food and water, so it allows for an additional 150 micrograms of lead that the child might eat from walls, dirt, and so forth, without harm.

The key to it then is the total of 300 micrograms, but we are allowing from extraneous sources only 150, since half of the 300 micrograms is taken up in food and water.

We then calculate the lead content that might be in 10 layers of paint containing various amounts of lead. This is in the table at the end of my written statement. For example, if each layer contained 10 percent of lead then 10 layers of such paint would weigh 65 milligrams and would contain 650 micrograms of lead per square centimeter of exposed surface.

That 650 micrograms should be equated against the 150 micrograms within the daily permissible intake that we have allocated for nonfood substances.

If we take it back to six layers of paint by the same calculation then six layers weighing 40 milligrams per square centimeter would contain 400 micrograms of lead per square centimeter if all layers of paint contained 1 percent lead.

So in going down from a half to a tenth to <0.06 percent we have calculated that if you have 10 layers of paint containing 0.05 percent lead, that 1 square centimeter would contain only 32 micrograms of lead which would be well within the limits of the DPI.

Even if a child ate 1 square inch of <0.06 percent lead paint, the amount of lead eaten would still be just about within the allowance for non food lead in the DPI.

Senator SCHWEIKER. This is 0.5 percent.

Dr. CHISOLM. 0.05.

Senator SCHWEIKER. Oh, I am sorry. That is what I did not understand; 0.05.

Dr. CHISOLM. Yes.

Senator SCHWEIKER. You would end up with the 32 micrograms on a 10-layer chip of paint of 1 square centimeter.

Dr. CHISOLM. That is right.

Senator SCHWEIKER. So you are talking about a factor of 5 or 6 in there as the margin of safety. Is that what you are saying, Doctor?

Dr. CHISOLM. Yes; this is right. In other words, if a child were to eat say a square inch of 0.05 percent lead paint 10 layers thick daily, the amount of lead would be six times 32, or about 150 micrograms of lead.

If a child ate a square inch even of this 0.05 percent paint, and he had no other sources, it really would not take him much above what we call the daily permissible intake.

The big assumption is that he would eat a square inch of paint. We feel there is quite an allowance in there.

Senator SCHWEIKER. How likely is the 10-layer chip? I am not familiar with how many layers you find in these old dwellings.

Dr. CHISOLM. There was a study in Philadelphia. They went around to old existing houses and attempted to peel off chips of paint and determine the number of layers in the chip. They estimated that there were about 10 layers, on the average.

Senator SCHWEIKER. Was the study in Philadelphia based on the 10 layers of paint?

Dr. CHISOLM. That is right. They seized and weighed these old chips, and then in the laboratory the Public Health Service deliberately painted layer on layer of paint, and the weight of the 10 layers of paint that the Public Health Service applied to surfaces in the laboratory were equivalent to the average weight of old chips that were picked off the houses in Philadelphia.

In other words, they did it two ways: they made an estimate of the number of layers in the chips they got off the old houses, and then they painted layer on layer, and the weights for 10 layers of chips of paint from freshly painted boards, 1 square centimeter in size, were about the same as the chips they got off the old houses. So this I think is a reasonable estimate of weight.

Senator SCHWEIKER. Using the same calculations, if you took a 0.05 percent standard now, one-half of 1 percent-you have a figure in front of you-how many micrograms does that bring out?

Dr. CHISOLM. That would be half of the 1 percent. The amount of lead would be half of the 1-percent calculation, which is at the top of the table or 325 micrograms per square centimeters.

Senator SCHWEIKER. I guess it would be just 10 times your 0.05 figure, 320 micrograms?

Dr. CHISOLM. Yes.

Senator SCHWEIKER. And because you are already allowing 150 micrograms from natural sources-you allow 150-it would be about 170 micrograms over the level?

Dr. CHISOLM. Yes.

We also have to make some allowance for lead-laden dirt and dust. Senator SCHWEIKER. As a scientist and physician, along with the assumption there is a safety factor here, how strongly do you feel about 0.06? Is this something that in your judgment the committee should look at with some flexibility; or how do you personally feel ? How do you feel personally?

Dr. CHISOLM. I would say first this is calculated for what we think is perfect protection of health and, second, with assumption as to how much a child eats-obviously, assumptions.

I think there is a little flexibility in it with respect to timing, but not a great deal. One to three layers of 0.5-percent paint does not pose a risk, but 10 layers in old houses 30 years from now will.

Senator SCHWEIKER. On the one-chip-a-day assumption, I assume here your calculations are based on a chip a day; right? Dr. CHISOLM. That is right.

Senator SCHWEIKER. HOW realistic or scientific is that? What does that mean in terms of someone who has pica?

Dr. CHISOLM. If we take abdominal X-rays of someone who has pica, we often see the tremendous amounts of foreign material in the abdomen.

Senator SCHWEIKER. In other words, one chip would be a lot for someone who has pica.

Dr. CHISOLM. Yes.

Senator SCHWEIKER. Assuming the chips were there, the pica child would ingest far more.

Dr. CHISOLM. Yes.

« ПредыдущаяПродолжить »