13 research outputs found
Trophic Transfer of Contaminants in a Changing Arctic Marine Food Web: Cumberland Sound, Nunavut, Canada
Contaminant dynamics in arctic marine food webs may be
impacted
by current climate-induced food web changes including increases in
transient/subarctic species. We quantified food web organochlorine
transfer in the Cumberland Sound (Nunavut, Canada) arctic marine food
web in the presence of transient species using species-specific biomagnification
factors (BMFs), trophic magnification factors (TMFs), and a multifactor
model that included δ<sup>15</sup>N-derived trophic position
and species habitat range (transient versus resident), and also considered
δ<sup>13</sup>C-derived carbon source, thermoregulatory group,
and season. Transient/subarctic species relative to residents had
higher prey-to-predator BMFs of biomagnifying contaminants (1.4 to
62 for harp seal, Greenland shark, and narwhal versus 1.1 to 20 for
ringed seal, arctic skate, and beluga whale, respectively). For contaminants
that biomagnified in a transient-and-resident food web and a resident-only
food web scenario, TMFs were higher in the former (2.3 to 10.1) versus
the latter (1.7 to 4.0). Transient/subarctic species have higher tissue
contaminant levels and greater BMFs likely due to higher energetic
requirements associated with long-distance movements or consumption
of more contaminated prey in regions outside of Cumberland Sound.
These results demonstrate that, in addition to climate change-related
long-range transport/deposition/revolatilization changes, increasing
numbers of transient/subarctic animals may alter food web contaminant
dynamics
Manufacturing Origin of Perfluorooctanoate (PFOA) in Atlantic and Canadian Arctic Seawater
The extent to which different manufacturing sources and
long-range
transport pathways contribute to perfluorooctanoate (PFOA) in the
world’s oceans, particularly in remote locations, is widely
debated. Here, the relative contribution of historic (i.e., electrochemically
fluorinated) and contemporary (i.e., telomer) manufacturing sources
was assessed for PFOA in various seawater samples by an established
isomer profiling technique. The ratios of individual branched PFOA
isomers were indistinguishable from those in authentic historic standards
in 93% of the samples examined, indicating that marine processes had
little influence on isomer profiles, and that isomer profiling is
a valid source apportionment tool for seawater. Eastern Atlantic PFOA
was largely (83–98%) of historic origin, but this decreased
to only 33% close to the Eastern U.S. seaboard. Similarly, PFOA in
the Norwegian Sea was near exclusively historic, but the relative
contribution decreased to ∼50% near the Baltic Sea. Such observations
of contemporary PFOA in coastal source regions coincided with elevated
concentrations, suggesting that the continued production and use of
PFOA is currently adding to the marine burden of this contaminant.
In the Arctic, a spatial trend was observed whereby PFOA in seawater
originating from the Atlantic was predominantly historic (up to 99%),
whereas water in the Archipelago (i.e., from the Pacific) was predominantly
of contemporary origin (as little as 17% historic). These data help
to explain reported temporal and spatial trends from Arctic wildlife
biomonitoring, and suggest that the dominant PFOA sourceÂ(s) to the
Pacific and Canadian Arctic Archipelago are either (a) from direct
emissions of contemporary PFOA via manufacturing or use in Asia, or
(b) from atmospheric transport and oxidation of contemporary PFOA-precursors
Validated quantitative cannabis profiling for Canadian regulatory compliance - Cannabinoids, aflatoxins, and terpenes
In response to the Canadian federal government's Cannabis Tracking and Licensing System compliance standards, a quantitative method was created for cannabis analysis, and validated using Eurachem V.2 (2014) guidelines. Cannabinol, cannabidiol, cannabigerol, canna
Temporal trends of persistent organic pollutants in Arctic marine and freshwater biota
More than 1000 time-series of persistent organic pollutants (POPs) in Arctic biota from marine and freshwater ecosystems some extending back to the beginning of 1980s were analyzed using a robust statistical method. The Arctic area encompassed extended from Alaska, USA in the west to northern Scandinavian in the east, with data gaps for Arctic Russia and Arctic Finland. The aim was to investigate whether temporal trends for different animal groups and matrices were consistent across a larger geographical area. In general, legacy POPs showed decreasing concentrations over the last two to three decades, which were most pronounced for α-HCH and least pronounced for HCB and β-HCH. Few time-series of legacy POPs showed increasing trends and only at sites suspected to be influenced by local source. The brominated flame retardant congener B