Appendix B

STATE UNIVERSITY OF NEW YORK AT BINGHAMTON

(Department of Chemistry-Laboratory for Trace Methods and Environmental Analysis)

Recent analyses of foods for mercury-prepared January 1, 1971 (Spot checks on individua! samples, not brand averages) Commercial Foods for Human Consumption

Appendix C

RESULTS OF MERCURY ANALYSES ON DIET GROUP AND CONTROL GROUP

1 Average daily intake rate, from Hg in tuna unless otherwise noted, assuming all tuna at 0.25 p.p.m. Hg, all swordfish at 1 p.p.m. Hg, per 150 lb. body weight, adjusted for degree of exponential build-up if on diet less than 16 months.

2 Subsequent studies have shown that these results, while relatively correct, may be significantly lower than the actual values.

3 Diet contained large percentage of swordfish.

DIET INFORMATION FOR PERSONS IN MERCURY FOLLOW UP STUDY

(Keyed to Letters of Figure 2) (T=tuna; SF=swordfish

Subject A, male, age 52, 168 lbs. ; adj. daily intake 75 μg/day (1/6/71) 12 months prior to Jan. 1971; 56 oz/wk T; 8 oz/wk SF

Jan. to Mar. 1971: continued eating T; cut out SF

Mar. to Apr. 1971: cut down to 25 oz/wk T; 4 oz/wk Flounder

Subject B, female, age 42, 134 lbs. ; adj. daily intake 64 μg/day (1/6/71) 8-12 months prior to Jan. 1971: 25 oz/wk SF; no T

Jan. to Apr. 1971: cut out SF; subst. 8 oz/wk Halibut and 15-20 oz/wk Turbot

Subject C, female, age 54, 147 lbs; adj. daily intake 36 μg/day (1/6/71)

5-6 months prior to Jan. 1971: 42 oz/wk T; no SF; considerable amount of fresh (river) fish

Jan. to Mar. 1971: still eating some T

Mar. to Apr. 1971: 15 oz/wk Salmon and Halibut

Subject D, female, age 42, 124 lbs; adj. daily intake 15 μg/day (+Hg in Cod) (1/6/71)

28 months prior to Jan. 1971: 12 oz/wk T; no SF; 48 oz/wk Cod

Feb. to Mar. 1971: increased to 30 oz/wk T ; less Cod

Mar. to Apr. 1971: cut back down to 12 oz/wk T; 45 oz/wk Cod

Subject E, female, age 37, 115 lbs; adj. daily intake 68 μg/day (1/6/71)

7 months prior to Dec. 10, 1971: avg. 6 oz/wk T; 13 oz/wk SF; Stopped all fish on Dec. 10, 1971.

Senator HART. Now we shall hear from Dr. John Wood, associate professor of biochemistry at the University of Illinois. Ás I indi

cated in my opening statement, it was Dr. Wood who first established conclusively that organic mercury could come from methylhave I got that right?

STATEMENT OF DR. JOHN WOOD, ASSOCIATE PROFESSOR OF

BIOCHEMISTRY, UNIVERSITY OF ILLINOIS

Dr. Wood. First of all, I would like to thank you, Senator Hart, and your committee for giving me the opportunity to tell you about some of the recent research which we have been doing on this problem. I have been working fairly closely in the last 12 months with the government of Ontario looking at the Great Lakes system, so I can give you some more up to date information on some of the problems.

I would like to address myself to two specific elements this morning. I would like to continue the discussion with mercury, and I would like to tell you about the potential problem which would come from arsenic pollution.

I would like to point out to you exactly why we have the problem. I don't think this has been defined, why we have the problem. And after pointing this out I would like to tell you what might happen in the future, and furthermore, what we might do about it, what sort of analytical methods and what solutions there might be.

It has been known, of course, for centuries that both mercury and arsenic are poisoning elements. And first of all, I would like to show you how these compounds get into the environment as a result of industrialization: 26,000 tons of chlorine is manufactured daily in the United States, and 25 percent of this is manufactured by using mercury metal as an electrode. This gives ample opportunity to the chlorine industry for large losses of mercury metal and inorganic salts into lakes and rivers, in inland and coastal waterways.

I would like to give you two examples of this. The first significant example is in the St. Clair River system where one chemical company deposited 200,000 pounds of mercury into the St. Clair River system over a period of about 20 years.

A second example, which I think is more interesting from the scientific point of view because it gives us more information, is a chemical company which is situated in Saskatoon, Saskatchewan deposited 55,000 pounds of mercury into the Saskatchewan River system between 1963 and 1970.

Of course, in these two areas we find that these are the high places in North America. These are areas where methyl mercury concentrations in fish are exceedingly high.

In addition to the chlorine industry the plastics industry uses mercury as a catalyst, and, of course, it is the plastics industry which caused serious problems in Japan.

The electronics industry uses more and more mercury each year. In fact the long life alkaline batteries which you throw away contain 8 percent mercury, and these usually get combusted in municipal incinerators.

Powerplants are also responsible for significant losses.

Hospitals are responsible for significant losses because mercury salts are used in histology laboratories.

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And so, as you can see, there has been ample opportunity for literally hundreds of thousands of pounds of inorganic mercury to be spread around.

It turns out that microorganisms which live naturally in the sediment of lakes and rivers have the ability to convert inorganic mercury into two compounds principally. The first one is methyl mercury, and this is the compound which accumulates in fish. And the second compound is dimethyl mercury. This compound is volatile. It comes up through the water and into the atmosphere. Once it gets into the atmosphere it is oxidized, photolyzed by the sunlight, and comes back down again with the rainfall to pollute other

areas.

So one of the things that must be recognized is there is a mechanism for distribution of this particular problem through the atmosphere around local areas of pollution.

A third species of mercury which has not even been looked at in the United States carefully is methylmercury thiomethyl. This is a volatile mercury compound which is synthesized in shellfish. And shellfish, of course, were consumed in the Minamata disaster in Japan. Unfortunately, methylmercury thiomethyl is so volatile it would never be detected by the analytical methods which are currently being used in Government laboratories not only in the United States, but also in Europe. So this is a problem which we have to look at.

Now the mercury problem by definition is a problem which has been caused by two things. The first thing is the concentration of mercury which we put in sediments. And the second thing is the population of microorganisms which are present in sediments. You can't separate the two, you see, because the rate of formation of methylmercury in sediments is very much dependent on both the concentration of mercury and the population of microorganisms.

Well, over the years we have been feeding microorganisms extremely well. We have been giving them an adequate supply of carbon and nitrogen and phosphate which speeds up metabolism, and in this way we have increased the rate of formation of this deadly poisonous compound methylmercury so that it is far in excess of the rate of excretion of mercury in fish. This is why we have a problem.

I have been working very closely with the government of Ontario looking at the St. Clair River system, and I think that I can put this problem in the right perspective by telling you what we know about this system: Two hundred thousand pounds of mercury was deposited in that particular St. Clair River system by the Dow Chemical plant. Just up the river from Dow, sewage in various forms has been put into the river system, and a combination of feces and organic material which is swept down the St. Clair River system mixed together with the mercury has caused a particularly hazardous problem in that area. So it is the combination of these two things which causes the problem.

Extensive analyses have been done of sediments of the St. Clair River system. We can show very nicely that in sediments which are polluted from 0.3 of a part per million all the way up to