BLOOD BROMINE LEVELS 97 one source of dietary bromine, seaweed, is not normally a part of the Marshallese diet. Essential and nonessential trace elements are often distinguishable by normal and log-normal concentration distributions, respectively (9). A normaldistribution for bromine was found for both the New Yorkers and the Marshallese, in that the means of each of the three groups’ values were similar to their respective median values. Similar findings have been reported from Scotland (8). However, prolonged exposure to absorbed trace elements can result in elevated but stable tissue levels and a normal distribution (9). A strong correlation between serum and red cell Br levels (P < 0.01) was noted, a finding also reported by Stumpe7al. (5). This correlation was observed for the combined data from all 30 subjects, but was not found within any ofthe three subgroups (see Table 2). More than simple diffusion may be involved in bromine partition in vivo because the red cell to serum Br ratio of the Marshallese was more than twice that of the New Yorkers (Table 2). These data are not predicted by in vivo Br tracer studies. Gamble er al. (17) noted that, following the intravenousinjection of NH,®Br in man, equilibrium between plasma andredcell Br was reached within one hour. Thered cell to serum Br ratio they reported was 0.54, a value similar to that found in the Marshallese (Table 2). The low ratio found in the New Yorkers may therefore indicate a nonlinear relation between serum and red cell Br at lowerlevels. REFERENCES 1. Iyengar, G. V., Kollmer, W. E., and Bowen, H. J. M. (1978). ‘‘The Elemental Composition of Human Tissues and Body Fluids,’’ p. 22. Verlag Chemie, New York. 2. Bowen, H. J. M. (1959). The determination of chlorine, bromine, and iodine in biological material by activation analysis. Biochem. J. 73, 381-384. 3. Sky-Peck, H. H., and Joseph, B. J. (1981). Determination of trace elements in human serum by energy dispersive X-ray fluorescence. Clin. Biochem. 14, 126-131. 4. Rapaport. M. S., Mantel, M., and Shenberg, C. (1982). Determination of bromine in blood serum by '5I excited X-ray fluorescence. Med. Phys. 9, 194-198. 5. Stump, I. G., Carruthers, J., D'Auria, J. M., Applegarth, D. A., and Davidson, A. G. F. (1977). Quantitative analysis of trace elements in human blood and plasma by energy dispersive X-ray fluorescence. Clin. Biochem. 10, 127-132. 6. Alenius, G., Riedl, H., Rindby, A., Selin, E., and Standzenieks, P. (1977). Trace element analysis in thick organic specimens by photon excited X-ray fluorescence. Phys. Scr. 15, 220-224. 7. Mertz, W. (1981). The essential trace elements. Science 213, 1332-1338. 8. Cross, J. D., and Smith, H. (1978). Bromine in human tissue. Forensic Sci. 11, 147-153. 9. Liebscher, K., and Smith, H. (1968). Essential and nonessential trace elements. Arch. Environ. Health 17, 881-890. 10. Conard, R. A., Paglia, D. E., Larsen, P. R., Sutow, W. W., er al. (1980). *‘Review of Medical Findings in a Marshallese Population Twenty-Six Years after Accidental Exposure to Radioactive Fallout.’’ Brookhaven National Laboratory Report 51261. Upton, N.Y. 11. Lecomte, R., Paradis, P., Monaro, S., Barrette, M., Lamoureux, G., and Menard, H. A. (1979). Trace element contamination in blood-collecting devices. Int. J. Nucl. Med. Biol. 6, 207-211. 12. ‘‘Merck Index,’’ 9th ed. (1976). P. 179. 13. Wheatcraft, S. W., and Buddemeier, R. W. (1981). Atoll island hydrology. Groundwater 19, 311-320. 14. Naidu, J. R., Greenhouse, N. A., Knight, G., and Craighead, E. C. (1980). ‘Marshall Islands: A Study of Diet and Living Patterns." Brookhaven National Laboratory Report 51313. Upton, N.Y.