Editors' Column Trace Metals, Indians, and Urban Man A recent N a t i o n a l Science F o u n d a tion report tells t h a t scientists, s t u d y i n g primitive tribes in r e m o t e areas of S o u t h A m e r i c a , have determined that chromosome damage and m e r c u r y levels in blood s e r u m in some isolated I n d i a n t r i b e s exceed those n o r m a l l y found in u r b a n m a n . T h i s discovery c a m e a b o u t from a s t u d y s t a r t e d eight years ago. Working w i t h t h e I n d i a n s in the A m a z o n jungles, t h e scientists were seeking to distinguish tribal genetic s t r u c t u r e s a n d g a t h e r biomedical d a t a to serve as base line m e a s u r e m e n t s to p e r m i t t h e m to gauge t h e n a t u r e a n d t e m p o of m o d e r n m a n ' s evolution. T h e y w a n t e d to learn more a b o u t the biological a d a p t a t i o n s of m a n as he progressed from a primitive h u n t e r to an u r b a n worker. T h e findings are surprising because c h r o m o s o m e d a m a g e and m e r c u r y levels are considered t h e price m a n pays for b e c o m i n g civilized. T h e s t u d y also found, besides the u n u s u a l l y high m e r c u r y levels, unusually low levels of c a d m i u m and lead. Dr. Lawrence Hecker of the University of M i c h i g a n ' s School of Public H e a l t h , who headed t h e research portion of the s t u d y t h a t was concerned with mercury and other trace m e t a l s said, " M e r c u r y has been present in low levels in our environment for years with no a p p a r e n t ill effect. At high levels in some areas, mercury is known to h a v e ill effects on m a n . S o m e of t h e Y a n o m a m a (a tribe in Venezuela a n d n o r t h e r n Brazil) villages have m u c h higher levels t h a n people in cities in t h e United S t a t e s , but it's having no a p p a r e n t adverse effect on t h e m . Fish, a common source of m e r c u r y , is not a major part of the Y a n o m a m a d i e t . " T h e mercury levels were expected to be m u c h lower a m o n g these tribes because m i n e s a n d factories t h a t cont r i b u t e to mercury in the environment do not exist in t h e area i n h a b i t ed by the I n d i a n s . T h e low lead levels, a m o n g the lowest ever recorded in the world, could not be a c c o u n t e d for by just the a b s e n c e of gasoline b u r n i n g vehicles which m a y c o n t r i b ute to higher levels in t h e civilized world. According to Dr. J a m e s Neel from
the University of M i c h i g a n ' s School of M e d i c i n e a n d t h e project's h e a d , " T h e s e d a t a imply two possibilities— m o d e r n m a n is not as badly off as he s o m e t i m e s supposes, a n d genetic a n d biological d a m a g e has been with h i m a long t i m e , probably t h r o u g h all stages of his d e v e l o p m e n t . " A l t h o u g h the group of scientists were able to hypothesize t h a t the c h r o m o s o m e d a m a g e m a y have been c a u s e d by a n a t u r a l agent such as a virus, they could not explain t h e high incidence of m e r c u r y or the low levels of c a d m i u m a n d lead e n c o u n t e r e d . U n f o r t u n a t e l y , Dr. Neel's c o m m e n t t h a t " m o d e r n m a n is not as badly off as he s o m e t i m e s s u p p o s e s . " if t a k e n out of context, could lend credence to the a r g u m e n t s of some t h a t pollution is not as great a problem as was recently t h o u g h t . T h i s b e c o m e s especially i m p o r t a n t in this t i m e of energy crisis when second t h o u g h t s are being h a d about emission controls on a u t o m o b i l e s and t h e b u r n i n g of sulfur-containing coal. His conclusion is based on a n i n c o m p l e t e s t u d y , although to be fair, one must r e m e m b e r t h a t the mercury, c a d m i u m , a n d lead d a t a were a c t u a l l y b y - p r o d u c t s of a different s t u d y . T h e reasons why t h e mercury levels are so high a n d the c a d m i u m a n d lead levels so low m u s t first be a s c e r t a i n e d before one can conclude t h a t m o d e r n m a n m a y be all right with regard to these trace metals. T h e detection limits for these trace metals are c o n s t a n t l y being lowered, a n d t h e d e t e r m i n a t i o n of these metals is now being done in more a n d varied s a m p l e s . E'erhaps t h e t i m e has come to e m p h a s i z e the correlation of levels d e t e c t e d in e n v i r o n m e n t a l s a m p l e s or in m a n with specific problems e n c o u n t e r e d by m a n because of these metal.s. How m a n y t i m e s should we be told t h a t a certain element can be d e t e r m i n e d in a specific s a m p l e by a specific analytical t e c h n i q u e down to what m a y be an insignificant level? S h o u l d n ' t it be t i m e to e m p h a size finding out if a certain level is significant or not a n d why—possibly s t a r t i n g with the I n d i a n s a n d working u p to u r b a n m a n ? A. A.
Husovsky
ANALYTICAL CHEMISTRY. VOL. 46, NO. 2. FEBRUARY
1974 • 233 A
