closely. Mercury levels in the billfishes ranged from 

 0.35 to 14 ppm. Of the total mercury, organic (methyl) 

 mercury constituted a small percentage (up to 10%). 

 One example, a 155-pound (70.3-kg) fish, contained 

 4.1 ppm total mercury and of this 0.54 ppm was 

 organic mercury. A regression analysis of all samples 

 tested showed an asymptotic level of 1.55 ppm organic 

 mercury. Ms. Shultz noted that their studies in- 

 dicated an upper level to the amount of organic mer- 

 cury accumulated and theorized that any amount 

 over and above this level was transformed into in- 

 organic mercury and excreted. She also theorized that 

 mercury in billfishes originates from natural con- 

 tamination, possibly of a volcanic origin; however, 

 much more work needs to be done in this area. This 

 paper authored by J. B. Rivers, J. E. Pearson, and C. 

 D. Shultz has been published in the Bulletin of En- 

 vironmental Contamination and Toxicology 8(5):257- 

 266, 1972. 



Albert C.Kolbye, Jr. 



"Potential Health Hazards 



of Mercury in Fish" 



The full text of this presentation appears as Annex 



8 of this volume. 



Richard E. Marland 

 "Status of Mercury Studies in Hawaii" 



The full text of this presentation appears as Annex 



9 of this volume. 



Discussion. — The following includes some of the 

 more significant questions asked of the panel by the 

 audience, and the panel's answers. 5 



George Parker (Kailua-Kona, Hawaii): 



Ms. Shultz referred to fish tolerating a certain 

 amount of methylmercury and then possibly convert- 

 ing it to another form of mercury which is excreted. 

 Might this follow with humans? 



Ms. Shultz: 



We don't know the answer. Our data merely in- 

 dicate that biotransformation may be taking place. 



Captain Parker: 

 Does methylmercury keep being accumulated? 



Dr. Kolbye: 



The biological half-life of methylmercury is 70 days; 

 to stay below the safe blood level the intake of 

 methylmercury should not exceed 30 micrograms per 

 day. 



James Delohery (Australia): 



Would you comment on selenium detoxification? 



'For purposes of brevity, the question and answer section has 

 been abbreviated and in some cases paraphrased. 



Mr. Beckett: 



There was some work that suggested that selenium 

 may reduce toxicity of mercury; however, more work 

 is needed. 



William F. Royce (NMFS, Wash., D.C.): 



Why did FDA impose a prohibition on the sale of 

 fish with mercury levels over 0.5 ppm rather than 

 merely warn the public such as is done with other 

 products containing poison? 



Dr. Kolbye: 



The public has a varying understanding, a varying 

 consumption rate and therefore FDA determined that 

 a guideline was necessary in the interest of protecting 

 the public. With respect to swordfish, 95% of the 

 samples exceed the guideline. There are also FDA 

 guidelines for other food items and toxicants. 



Witek Klawe (IATTC, La Jolla, Calif.): 



Would you comment on various articles criticizing 

 the mercury guideline? 



Dr. Kolbye: 



FDA is prepared to defend the guideline. 



Dudley C. Lewis (Honolulu): 



Why were there no public hearings held before the 

 guideline was set? Were any of the deliberations made 

 public? Was the guideline politically motivated? 



Dr. Kolbye: 



Many guidelines do not require hearings. The 

 guideline was reviewed extensively within FDA and 

 by a panel of 12 experts. Testimony was given before 

 the U.S. Senate. Scientific documentation was 

 presented in the Journal of Environmental Health. I 

 don't know if this is considered making it public. The 

 question as to whether the guideline was politically 

 motivated is ridiculous. 



Richard F. MacMillan (Honolulu): 



People have been eating marlin in Kona for 

 generations with no ill effects. Therefore, I question 

 Dr. Marland's statement that years and years of work 

 is needed to come up with an answer. What is your 

 reaction to the situation in Kona? 



Dr. Marland: 



There is no evidence of damage from eating marlin 

 in the United States. However, there has been no 

 systematic search for subclinical symptoms. Studies 

 by trained medical doctors to look for subtle symp- 

 toms would be highly desirable; however, it cannot be 

 done quickly or cheaply. 



Richard H. Stroud (Sport Fishing Institute, Wash., 

 D.C.): 



Is the 0.5 ppm guideline for total mercury? In view 

 of recent findings regarding methylmercury not con- 

 stituting 100% of the mercury present, shouldn't the 

 standard be for methylmercury? 



