The aim of this study was to develop a method for the
determination of low CH3Hg+ concentrations in non-filtered
humic-rich natural water samples collected from ditches and
stump holes in peatland forest catchments. The method is used to
monitor low CH3Hg+ concentrations in stream waters to investigate
the potential consequences of forest harvesting practices on
biogeochemical cycles and leaching of mercury to surface waters.
In this study, a purge and trap preconcentration with ethylation
and GC-ICP-MS was used to determine CH3Hg+ in water matrix.
Prior to the instrumental determination, CH3Hg+ was separated
from the organic-rich sample matrix using N2-assisted distillation
in order to achieve low enough detection limits. Quantitative results
were obtained by using a SSID technique in which an isotopically
enriched spike of methyl mercury was added to samples prior to
the distillation step. The potential methylation of inorganic mercury
during the distillation stepwas also investigated. The performance of
the method was estimated by determining method detection limit,
precision and accuracy. In addition to the CH3Hg+ samples were
analyzed for total mercury (THg) and dissolved organic carbon
(DOC).