SSRN Electronic Journal,
Journal Year:
2022,
Volume and Issue:
unknown
Published: Jan. 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.
Estuarine
transition
zones
(ETZs)
are
biogeochemically
complex,
nutrient-rich
environments
supporting
diverse
and
productive
food
webs.
They
may
also
be
sites
of
microbial
production
methylmercury
(MeHg)
bioaccumulation
this
neurotoxicant
at
the
base
web.
However,
environmental
drivers
controlling
these
mechanisms
unclear.
We
studied
pattern
MeHg
in
zooplankton
along
200
km
ETZ
a
large
North
American
estuary,
St.
Lawrence
Estuary
(Québec,
Canada).
Our
approach
integrated
dynamic
variation
geochemistry,
focusing
on
speciation
change,
alongside
ecological
factors,
including
community
composition
stable
isotopic
tracers
diet
habitat.
decreased
with
distance
downstream
ETZ,
driven
by
salinity
gradient
traced
signature
sulfur
zooplankton.
modeling
suggested
that
complexation
to
dissolved
organic
matter
used
as
proxy
trophic
transfer
Further,
binding
was
reduced
presence
chloride,
thus
reducing
MeHg.
propose
conceptual
model
for
cycling
estuaries
hypothesizes
higher-level
consumers
turbid
upstream
regions
face
heightened
risks
toxicity
but
Hg
levels
diminish
drastically
increases.
Environmental Toxicology and Chemistry,
Journal Year:
2025,
Volume and Issue:
44(2), P. 335 - 343
Published: Jan. 6, 2025
Considerable
amounts
of
polyethylene
terephthalate
(PET)
microplastic
fibers
are
released
into
the
environment
by
laundering
polyester
clothing.
Microplastic
can
be
ingested
organisms
in
environment.
Therefore,
it
has
been
suggested
that
act
as
vectors
for
adsorbed
contaminants,
which
subsequently
desorbed
gut
organism.
We
undertook
sorption
isotherm
experiments
at
pH
6,
7,
and
8
to
quantify
methylmercury
(MeHg)
PET
fibers.
Sorption
isotherms
were
fit
Langmuir,
Freundlich,
Brunauer-Emmett-Teller
models.
decreased
with
increasing
pH,
explained
physisorption
on
negatively
charged
surfaces
greater
presence
neutral
or
MeHg
species
higher
pH.
used
parameters
obtained
model
fits
predict
likely
concentration
aquatic
ecosystems
environmentally
realistic
concentrations.
calculated
concentrations
four
orders
magnitude
lower
than
previously
observed
seston
(suspended
particles
comprising
algae
bacteria)
base
food
web.
The
results
indicate
do
not
elevate
exposure
ingest
Environmental Chemistry,
Journal Year:
2022,
Volume and Issue:
19(4), P. 104 - 115
Published: July 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
