SSRN Electronic Journal,
Год журнала:
2022,
Номер
unknown
Опубликована: Янв. 1, 2022
As
the
first
step
of
methylmercury
(MeHg)
entry
into
aquatic
food
web,
phytoplankton
uptake
MeHg
is
crucial
in
determining
final
human
exposure
risks.
availability
to
plankton
regulated
by
dissolved
organic
matter
(DOM)
water,
while
these
impacts
could
vary
largely
among
different
DOM
sources.
In
this
study,
we
investigate
sources
bioconcentration
three
freshwater
algae
(
S.
quadricauda,
Chlorella
and
Microcystis
)
a
microcosm
system.
We
found
that
algae-derived
prohibit
cellular
percentage
up
77‒93%,
yet
soil-derived
didn't
display
similar
inhibition
effects.
characterization
excitation‒emission
matrices,
fourier
transform
infrared
spectrum,
ultra‒high
performance
liquid
chromatography‒tandem
quadrupole
time
flight
mass
spectrometry
indicated
molecular
size
S-containing
compounds
rather
than
thiol
concentrations
had
played
roles
regulating
algal
uptakes.
Climate
change
increasing
nutrient
loadings
from
activities
may
affect
growth
freshwater,
ultimately
changing
qualities
DOM.
Potential
changes
on
together
with
other
fields
should
be
integrated
when
exploring
Hg
cycling
accessing
their
risks
beings
or
wild
life.
Environmental Chemistry,
Год журнала:
2022,
Номер
19(4), С. 104 - 115
Опубликована: Июль 8, 2022
Environmental
context
Understanding
mercury
transformations
in
the
aquatic
environment
is
of
utmost
importance
for
improvement
biogeochemical
modelling
and
sound
environmental
risk
assessment.
In
such
a
context,
we
discuss
critically
advancement
knowledge
on
role
phytoplankton
(algae
cyanobacteria)
cycling
environment.
Important
research
advances
revealed
that
different
microalgal
species
cyanobacteria
contribute:
to
biotic
reduction
inorganic
elemental
mercury;
demethylation
methylmercury
transformation
into
metacinnabar;
production
biomolecules
which
can
contribute
abiotic
reduction.
Abstract
Phytoplankton
may
directly
influence
(Hg)
through
accumulated
metal
via
methylation/demethylation
reduction/oxidation,
indirectly,
excretion
low
high
molecular
weight
ligands,
likely
triggering
or
influencing
pathways
as
well
carried
out
by
bacteria.
However,
unlike
extensive
work
already
done
bacteria
Hg
transformations,
current
about
processes
still
limited.
Critical
evaluation
existing
topic
(iHg
HgII)
(Hg0),
monomethylmercury
(MeHg)
iHg
metacinnabar.
The
released
complex
Despite
these
advances,
underlying
mechanisms
their
are
be
explored
detailed.
development
novel
molecular,
stable
isotope-based
multi-omics
approaches
would
provide
further
impetus
understanding
key
interactions
between
phytoplankton.
Such
will
modelling,
mitigation
strategies
rational
assessment
changing
Water,
Год журнала:
2023,
Номер
15(8), С. 1494 - 1494
Опубликована: Апрель 11, 2023
The
contents
of
total
mercury
(THg)
and
methylmercury
(MMHg)
were
measured
in
Nansi
Lake
its
inflow
river
estuaries
to
investigate
their
spatial
distribution
characteristics
the
geochemical
relationships
between
THg,
MMHg,
methylation
rate
(%MMHg)
with
mineral
phases
sediment.
%MMHg
lake
sediment
lower
than
those
estuary
Inputting
rivers
was
primary
source
THg
MMHg
Lake.
decreased
from
upper
lake,
while
indicated
opposite
trends
variations.
significantly
positively
correlated
estuarine
but
has
a
significant
negative
correlation
Total
organic
carbon
(TOC),
acid
volatile
sulfide
(AVS),
clay
have
great
influence
on
Methylmercury
AVS,
TOC,
clay,
these
not
revealed
Cluster
principal
component
analysis
results
showed
that
TOC
derived
same
sources
It
implied
for
improving
water
environmental
quality
lakes,
management
entering
should
be
strengthened.
Water Resources Research,
Год журнала:
2023,
Номер
59(11)
Опубликована: Окт. 30, 2023
Abstract
Climate
change
and
permafrost
thaw
may
impact
the
mobilization
of
terrestrial
dissolved
organic
carbon
(DOC),
mercury
(Hg),
neurotoxic
methylmercury
(MeHg)
into
aquatic
ecosystems;
thus,
understanding
processes
that
control
analyte
export
in
northern
catchments
is
needed.
We
monitored
water
chemistry
for
3
years
(2019–2021)
at
a
peatland
catchment
(Scotty
Creek)
mixed
(Smith
Dehcho
(Northwest
Territories),
within
discontinuous
zone
boreal
western
Canada.
The
had
higher
DOC
MeHg,
but
lower
total
Hg
concentrations
(mean
±
standard
deviation;
19
2.6
mg
L
−1
;
0.08
0.04
ng
DMeHg
1.1
0.3
THg
)
than
(12
4.4
0.05
0.01
3.1
2.2
).
Analyte
increased
with
discharge
catchment,
suggesting
transport
limitation
flushing
near‐surface,
organic‐rich
flow
paths
during
wet
periods.
In
contrast,
were
not
primarily
associated
discharge.
MeHg
concentrations,
MeHg:THg,
MeHg:DOC
temperature,
enhanced
methylation
warmer
Mean
open
season
yields
greater
more
variable
from
(1.1–6.6
vs.
1.4–2.4
g
m
−2
5.2–36
6.1–10
Crucial
storage
thresholds
controlling
runoff
generation
likely
drove
inter‐annual
variability
catchment.
Our
results
suggest
climate
influence
production
boreal‐Arctic
as
temperatures
increase,
peatlands
thaw,
altered.
Hydrology,
Год журнала:
2024,
Номер
11(2), С. 26 - 26
Опубликована: Фев. 13, 2024
Mercury
(Hg)
is
a
toxic
contaminant
that
bioaccumulates
in
trophic
chains
its
organic
form—methylmercury
(MeHg).
Hg
methylation
driven
by
microorganisms
favourable
conditions,
stagnant
water
pools
being
among
potential
hotspots.
In
the
present
study,
we
estimated
total
and
MeHg
concentrations
sediments
of
water-filled
management-induced
terrain
depressions
(ruts,
mounding
pits
partly
functional
drainage
ditch)
nearby
undisturbed
soil
six
hemiboreal
forest
sites
with
organic-matter-rich
soils
Latvia.
Environmental
samples
were
taken
spring,
summer
autumn
2022.
Furthermore,
evaluated
risks
element
leaching
from
using
high-resolution
digital
models
(DTM)
meteorological
data.
The
results
suggested
possible
past
as
THg
significantly
lower
than
surrounding
soil.
higher
%MeHg
found
identifying
Spatial
analysis
DTMs
pointed
to
very
likely
periodical
elements
during
high
precipitation
episodes
well
snowmelts.
Moreover,
it
was
observed
ruts
left
heavy
machinery
often
channel
surface
runoff.
ACS ES&T Water,
Год журнала:
2023,
Номер
3(4), С. 934 - 942
Опубликована: Март 16, 2023
Reservoirs
are
reported
to
stimulate
mercury
(Hg)
methylation
and
thereby
affect
methylmercury
(MeHg)
dynamics
in
rivers
by
trapping
sediment
increasing
the
hydraulic
residence
time
(HRT).
However,
whether
there
similarities
%MeHg
(MeHg/Hg)
relation
reservoir
properties
for
different
their
associated
mechanisms
remain
unknown.
Here,
we
investigated
MeHg
two
heavily
dammed
one
naturally
flowing
river
same
region.
We
found
that
damming
results
accumulation
of
Hg
OC
a
higher
abundance
hgcAB,
thus
elevating
%MeHg.
Sediment
showed
positive
correlation
with
HRT,
acts
as
threshold
value
determine
impact
on
had
either
or
negative
age
rivers,
effect
depends
stock
substances
has
dominance
internal
consumption
is
external
supply.
These
findings
provide
an
important
reference
further
research
biogeochemical
cycling
risk
management
rivers.
