Regional sulfur isotopic end-member data (cdep ,δdep and δrock ) for the
Kola Peninsula and northern Sweden is summarized in Table 1. The Kola
Peninsula showed higher average annual cdepcompared to northern Sweden. It is likely the result of nearby smelter
emissions of sulfur dioxide (Forsius et al., 2010; Reimann et al.,
1997), while the also higher δdep has been
attributed to processing of high sulfide ores, which were transported
from the Norilsk mine in north central Russia to Kola smelters (de
Caritat et al., 1997). No
data was found on the specific δrock -value of
sulfide bedrock in Khibiny. We argue that since the Khibiny bedrock is
of magmatic origin (Kogarko, 2018) – as is the bedrock in the Imetjoki
catchment – sulfide minerals in Khibiny would most likely also haveδrock -values close to 0‰ justifying the use of
the isotopic dataset for Imetjoki also for the Khibiny catchments (Table
1). A reasonable range for the enrichment factor (ɛ) in shallow
groundwater and surface waters was assumed to be −33 to −1‰, considering
that most studies report values between −20‰ and −10‰ (Knöller et al.,
2004; Robertson and Schiff, 1994; Wu et al., 2011) while some estimates
reach as low as −33‰ (Massmann et al., 2003), and as high as −1‰ (Xia et
al., 2017).
Surface water measurements