Only a few attempts have been made to compare the extraction/amalgamation/
spectrometry techniques and the nuclear methods, which perform on a ‘whole’
undigested sample, for the determination of particulate mercury. Keeler
et al
. (1995)
found excellent agreement (1.02
0.05 vs. 1.07
0.1) between NAA and the
extraction/amalgamation/CVAFS methodology for the determination of Hg con-
centration in a standard reference material (Urban Particulate, SRM1648, NIST).
Lamborg
et al
. (1994), however, found that the results of mercury in total sus-
pended particulate (TSP) obtained by NAA were higher than those obtained by
dual-amalgamation/CVAFS, but the concentrations of mercury in the fine mass
fraction as determined by NAA were virtually identical to those of Hg in TSP
collected on a glass-fiber filter and analyzed by CVAFS. They suggested the exis-
tence of ‘non-acid-extractable’ particulate mercury (PM) in the coarse fraction and
surmised that the content of ‘non-acid-extractable’ PM depends on the distance of
the sampling site from the PM source