the wisconsin division of health investigated mercury exposure in a 40-year - old man , his 42-year - old wife , and their 2.5-year - old son . at the time of our investigation , these individuals had blood mercury levels ranging from 37 to 58 micrograms / l ( normal < 5 micrograms / l ) and hair samples from the adults contained 10 - 12 micrograms mercury / g dry weight . a personal interview and home inspection failed to identify any occupational or household sources of mercury exposure . 
 the family 's diet included three to four fish meals per week . 
 the fish was purchased from a local market and included lake superior whitefish , lake superior trout , farm - raised trout and salmon , and imported seabass . 
 analysis of these fish found that only one species , the imported seabass , contained significant mercury levels . 
 two samples of the seabass obtained from the vendor on different days contained mercury concentrations of 0.5 and 0.7 mg / kg . 
 based on consumption estimates , the average daily mercury intakes for these individuals ranged from 0.5 to 0.8 micrograms / kg body weight . 
 six months after the family stopped consuming the seabass , blood mercury levels in this man and woman were 5 and 3 micrograms / l , respectively . 
 analysis of sequential blood samples confirmed that mercury elimination followed first - order kinetics with a half - life of approximately 60 days.imagesfigure 1 .