260 EISLER 



RECOMMENDATIONS 



On the basis of these studies, it appears that establishing marine 

 mercury-contamination standards requires abatement of existing 

 discharges, development of technologies to decontaminate polluted 

 waterways, monitoring criteria for protecting human health, and 

 research to modify existing standards, as well as to predict impending 

 mercury stress in marine ecosystems. Specific recommendations are 

 listed. 



1. Prohibit the sale, manufacture, and use of methyl mercury 

 compounds. All evidence presented to date implicates methyl 

 mercury as the most toxic chemical form of mercury. Its demon- 

 strated deleterious effects to mcirine biota and human health 

 mandate passage of legislation banning all environmental uses of 

 methyl mercury compounds. In the decade since Sweden prohibited 

 agricultural use of methyl mercury for seed coatings and pesticides, 

 bird populations have begun to recover and the amounts of mercury 

 in many types of food have decreased (Johnels and Westermark, 

 1969). 



2. Restrict use of other mercurials. Investigations are presently in 

 progress in several countries on the geochemistry and biogeo- 

 chemistry of mercury, but much remains to be learned about its 

 distribution, its conversion from one form to another, and its 

 transport on a global basis. It is well known, however, that inorganic 

 mercury compounds can be converted in nature to organomercury 

 compounds, which are more readily transported and accumulated in 

 tissues. Accordingly, legislation is needed which will curtail environ- 

 mental use of all mercury compounds, especially organomercurials. 



3. Develop alternative technologies. About 90% of the mercury 

 consumed annuEilly is used for industrial purposes. Mercury is used as 

 a catalyst in chlor— alkali plants, as a slimicide in pulp and paper 

 mills, as a chemical reagent in the plastics industry, in pharma- 

 ceuticals and paints, in power plants in special heat engines, in 

 metal-refinement operations by amalgamation, and in the manufac- 

 ture of electric switches, batteries, and lamps. Chlor— alkali plants 

 probably represent the greatest point-source hazard at this time; 

 typical plants contain more than 500,000 kg of liquid mercury and 

 discharge several kilograms daily to the environment. In the absence 

 of better controls, this loss could be averted by developing a new 

 technology that precludes mercury compounds. This technology is 

 urgently required and should be awarded the highest priority. 



4. Remove mercury from contaminated waterways. Thousands of 

 kilometers of our inland waterways and some coastal areas are 



