FATE OF MERCURY IN THE ARCTIC Michael Evan ... - COGCI

134 F. Roos-Barraclough et al. / The Science of the Total Environment 292 (2002) 129–139
Fig.1.Hg concentrations measured in both unfertilised and artificially fertilised peat dried at RT, 30, 60, 90 and 105 8C for up to
2 weeks.
at RT and would therefore account for an increase
y1
of only 0.9 ng g , or 2%, during 14 h of air
drying.It is therefore likely that most of the
observed increase stems from error in the bulk
density determination, which was high in this case
due to the presence of ice in the peat.
3.4. Effect of grinding samples
Grinding promotes homogenisation of the sample
by reducing particle size and by mixing.It
also allows a greater mass of sample to be analysed
at one time, as more material can be placed into
each sample vessel.Therefore grinding allows a
more representative value to be obtained.
The average Hg concentration for unground
y1
samples was 47.9"1. 2 ng g (ns5) and the
average for ground samples was 45.2"1.2 ng
y1 g (ns5).It is therefore possible that a slight
loss of Hg occurs on grinding, possibly due to
elevated temperature, coupled with smaller particle