SIMPLE DIRECT METHOD FOR THE DETERMINATION OF TOTAL MERCURY LEVELS INBLOOD AND URINE AND NITRIC-ACID DIGESTS OF FISH BY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

A simple direct method was developed to determine Hg by ICP-MS in dilu ted urine, diluted blood and HNO3 digests of fish. Wash-out times of < 130 s for Hg concentrations less than or equal to 30 mu g l(-1) were achieved by complexing Hg with (NH4)(2)H(2)EDTA and the presence of am monia. A novel disinfection procedure for urine and blood utilised dil ution with a virucidal agent, Virkon, Virkon precipitated blood protei ns, requiring subsequent dissolution using tetramethylammonium hydroxi de. More than 85% of internal QC results were within +/- 1 mu g l(-1) of their target values for blood and > 80% within 5% for urine. There was successful participation in three QA schemes for urine and one for blood. NIST Albacore Tuna gave 95% recovery of the target, 0.95 mu g g(-1), and good precision, 0.90 +/- 0.01 mu g g(-1) (n = 3). The metho d did not discriminate between inorganic and organic Hg. Detection lim its for Hg, using 30 at or near the blank level, were 0.13 mu g l(-1) in blood, 0.27 mu g l(-1) in urine and 0,004 mu g g(-1) in fish, The d eveloped methods were used to analyse samples collected from four site s in the Tapajos Valley of Brazil in an EC funded study of exposure to Hg as a result of gold mining. All but one of the subjects (n = 106) had Hg levels in either blood or urine that exceeded the upper 95% lim its for nonexposed subjects, 55% had blood Hg levels above the 95% lim it in industrial workers (19 mu g l(-1)) and 17% exceeded the urine Hg limit at which industrial workers should be removed from exposure (50 mu g l(-1)). Subjects living in a fishing village, Jacareacanga, 100 km from mining activities, had significantly higher blood Hg levels (m ean 81 mu g l(-1)) than the other three groups (p < 0.004), presumed t o be related to fish consumption. Fish Hg levels n ere similar to thos e found in other polluted areas, mean 0.379 mg kg(-1) (n = 52), The EC study provided the strongest evidence to date in 1991 that Hg in fish in the Amazon basin posed much more of a general health problem than Hg vapour since it affected a larger proportion of the population than just the gold miners, ancillary workers and traders. The methods mere also used in the routine clinical analysis of blood and urine samples within the UK National Health Service. Investigations included a case of acute mercury poisoning in a 28-month-old boy who had swallowed a battery who had an initial blood Hg of 394 nmol l(-1) and urine Hg of 16 nmol mmol(-1) creatinine, He was successfully treated with the chel ating agent British Anti-Lewisite.