EFFECTS OF REGULATORY GUIDELINES ON THE INTAKE OF 

 MERCURY FROM FISH— THE MECCA' PROJECT 



Roland Finch^ 



ABSTRACT 



The MECCA program applies a survey of the fish consumption habits of a sample of 

 over 4,500 individuals, representative of the U.S. population, to build a computer model, 

 which uses known levels of microconstituents in 52 kinds of fish to predict the distribution 

 of the daily intakes of the microconstituents from fish among the survey participants. 

 The model was applied to mercury levels in fish to estimate the effects of guidelines 

 (maximum permitted levels) for fish in protecting the population against excessive intake. 

 The study indicated that, for the sample population, intakes of mercury from fish would 

 remain safe if the guideline for mercury in fish were raised from the present level of 

 0.5 ppm to 1.5 ppm. The effect of such an increase would be of benefit to both the 

 consumer and the fishing industry. This model can be used to predict the distribution 

 of consumer intakes from fish of any constituent present in the fish, whether nutritious 

 or potentially hazardous, for which the levels in the edible portion of the 52 kinds of 

 fish used in the model are known. 



Following incidents of methyl mercury poison- 

 ing reported from Japan and Sweden, the U.S. 

 Food and Drug Administration (FDA) in 1970 

 established an interim guideline permitting a 

 maximum level of 0.5 part per million (ppm) 

 for methylmercury in fish, determined in prac- 

 tice through total mercury. This level was 

 based on a careful review of the limited infor- 

 mation available to the FDA at that time, but 

 it was noted that this was an interim action 

 and the level would be subject to amendment 

 if subsequent information indicated this should 

 be done. The level was based on the following 

 assumptions: 



1. Fish is the sole significant contributor of 

 methylmercury in the U.S. food supply. 

 Traces of mercury are sometimes found 

 in other foods but are present in the sub- 

 stantially less toxic inorganic form. 



2. Almost all of the mercury present in 

 marine fish, which compose most of the 



' MECCA is an acronym for Model for the Estimation 

 of the Consumption of Contaminants from Aquatic Foods. 



^ Fishery Products Research and Inspection Division, 

 National Marine Fisheries Service, NOAA, Washington, 

 DC 20235. 



U.S. supply, is present in the form of 

 methylmercury. 



3. Man can safely consume up to 30 fig 

 methylmercury daily (see Peterson. 

 Klawe, and Sharp, 1973). 



Continued consumption of larger average 

 intakes increases his body burden and can 

 result in harmful effects. 



4. An average high consumption level of fish 

 in the United States does not normally 

 exceed 60 g (just over 2 oz) daily. This 

 figure can be compared with the calculated 

 national average of approximately 14 g 

 daily. 



5. Limiting the methylmercury level of fish 

 to 0.5 ppm would limit the intake pro- 

 vided by 60 g fish to 30 jLig/day. 



It was pointed out at the time that the 

 greater part of the fish supply in the United 

 States contains considerably less than 0.5 ppm 

 mercury and suggested that it would be more 

 realistic to use a weighted average of the 

 mercury levels of all species consumed in cal- 

 culating a guideline. This average, calculated 

 to be below 0.20 ppm, would give a guideline 

 of 1.2 ppm or higher. Such an approach was 

 not regarded as acceptable by the FDA, since 



Manuscript accepted Februarv 1973. 

 FISHERY BULLETIN: VOL. 71, NO. .V 197.1. 



615 



