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@PHDTHESIS{Mller:787719,
author = {Müller, Anne-Katrin},
othercontributors = {Hollert, Henner and Schäffer, Andreas and Segner, Helmut},
title = {{B}ioavailability and impact of sediment-bound endocrine
disrupting chemicals on fish in context of flood events},
school = {RWTH Aachen University},
type = {Dissertation},
address = {Aachen},
reportid = {RWTH-2020-04225},
pages = {1 Online-Ressource (XIV, 178 Seiten) : Illustrationen,
Diagrame},
year = {2020},
note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
University; Dissertation, RWTH Aachen University, 2020},
abstract = {To date, numerous studies worldwide have demonstrated that
sediments function as a sink for a great variety of
environmental pollutants, among them are substances
interfering with the endocrine system, so called endocrine
disrupting chemicals (EDCs). Estrogenic activity evaluated
in sediment samples across Europe via in vitro bioassays
ranged from 0.02 up to 55 ng 17β-estradiol (E2)
equivalents/g sediment. This is of particular concern since
it is well documented that waterborne exposure to even low
ng/L concentrations of EDCs can impair the reproduction of
freshwater fish species. Feminization of male fish is one of
the most notable adverse impacts of exposure to EDCs and the
production of the female egg yolk protein vitellogenin (vtg)
has been observed to coincide with impairment of gonadal
development evident as intersex and, ultimately,
reproductive failure. In contrast, little is known about the
bioavailability and effects of sediment-associated EDCs on
fish. Particularly when sediments are perturbed, e.g.,
during flood events, sediment-bound substances may become
bioavailable. During the past decades, several extreme flood
events have occurred in central Europe, including Germany.
The likelihood and intensity of flood events have been
predicted to increase as a result of global climate change.
As consequence, the European Parliament established the
Directive 2007/60/EC on the assessment and management of
flood risk. In order to minimize adverse consequences of
flood events to humans and the environment part of such risk
assessment is the evaluation of potential sources of
environmental pollution as result of flooding. The main
objectives of the present thesis, as part of the
interdisciplinary Project House Water - a project supported
by the German Excellence initiative - , were to (i)
investigate the bioavailability of sediment-bound EDCs under
flood-like conditions when the sediment is subject to
suspension; (ii) evaluate the uptake of sediment-bound EDCs
during such a simulated flood event into fish and whether
this leads to endocrine responses in the fish and (iii)
assess the impact of sediment-bound EDCs to freshwater fish
species inhabiting a “hot-spot” of EDC contamination in
sediment under field conditions. In doing so, this thesis
aimed to provide implications for risk evaluation of
sediment associated contaminants with special emphasis on
flood events. In order to assess the bioavailability of
sediment-bound EDCs, the Luppe River previously described as
a “hotspot” for EDC accumulation in sediment was chosen
as a study site. The concentration of target EDCs and
estrogenic activity of sediments from the Luppe River were
investigated using chemical analysis (LC-MS/MS) in addition
to effect-based methods, such as a novel screening tool
(planar Yeast Estrogen Screen; p-YES) that utilizes high
performance thin-layer chromatography plates in combination
with an in vitro bioassay (YES). Estrone $(50\%,$ E1) and
nonylphenol $(35\%,$ NP) accounted for the majority of
estrogenic activity reported for sediment with up to 20 ±
2.4 ng 17β-estradiol equivalents (EEQ)/g dry weight in the
Luppe sediments. E2 accounted for approximately $14\%$ of
the estrogenic effect, whereas the estrogenic effect
attributed to 17α-ethynylestradiol (EE2), when present, was
negligible (approx. $1\%)$ from sediment across all Luppe
sampling sites. Two types of passive samplers (polar organic
chemical integrative sampler (POCIS) and Chemcatcher) were
used to investigate the bioavailability of EDCs from
suspended sediment under laboratory conditions. NP, E1, E2
and EE2 were remobilized from Luppe sediment when subjected
to turbulent conditions, such as in a flood event, and were
readily bioavailable at ecotoxicologically relevant
concentrations (NP 18 µg/L, E1 14 ng/L, E2 0.2 ng/L, EE2
0.5 ng/L). Both types of passive samplers were applicable in
a sediment-water suspension system, with the Chemcatcher
displaying higher sampling rates compared to the POCIS. A
laboratory exposure study with juvenile rainbow trout
(Oncorhynchus mykiss) was conducted to evaluate uptake and
ecotoxicological impact of remobilized sediment-bound EDCs
from the Luppe River. Therefore, rainbow trout were exposed
over 21 days to constantly suspended sediment in the
following treatments: i) a contaminated sediment from the
Luppe River ii) a control sediment (exhibiting only
background contamination), iii) a serial dilution of Luppe
sediment with the sediment control (1:8; 1:4; 1:2), and iv)
a water-only control. Measured estrogenic activity using in
vitro bioassays as well as target analysis of NP and E1 via
LC-MS/MS in sediment, water, fish plasma, as well as bile
samples, demonstrated that sediment-bound EDCs became
bioavailable during the simulated flood event. EDCs were
dissolved in the water phase, as indicated by passive
samplers, and were readily taken up by the exposed trout.
Interestingly, similar patterns of EDCs were observed in the
water and fish blood and bile, suggesting that EDCs
partitioned from sediment into the water and subsequently
absorbed by the fish, indicating that freely dissolved
aqueous concentrations of EDCs might be a major route for
uptake of EDCs in fish. An estrogenic response of fish to
Luppe sediment was indicated by increased abundance of
transcripts of typical estrogen responsive genes, i.e.
vitelline envelope protein α, in the liver and vitellogenin
induction in the skin mucus. Hepatic gene expression
profiles by RNA-sequencing were altered in Luppe exposed
fish compared to controls, whereas the repression of a great
number of genes involved in cell cycle in combination with
induction of apoptotic markers suggest a broader response.
However, similar downregulation of cell cycle genes was
observed with the sediment control. Together with
histological alterations, i.e. local areas of cell lysis,
infiltration of immune cells and degenerative nuclear
alterations, observed in the liver of fish throughout all
treatments, indicates that exposure to suspended particles
might elicit stress at the cellular level. Moreover, tench
(Tinca tinca) and roach (Rutilus rutilus) as a benthic and
pelagic living fish species, respectively, were sampled at
the Luppe River. A field reference site, the Laucha River,
in addition to fish from a commercial fish farm as a
reference were studied. Blackworms (Lumbriculus variegatus),
which are a source of prey for fish, were exposed to
sediment of the Luppe River and estrogenic activity of worm
tissue was investigated using in vitro bioassays. A 153-fold
greater estrogenic activity was measured using in vitro
bioassays in sediment of the Luppe River compared the Laucha
River. Estrogenic activity of Luppe exposed worm tissue (14
ng EEQ/mg) indicated that food might act as secondary source
to EDCs. While there were no differences in concentrations
of NP in plasma of tench from the Luppe and Laucha, vtg as
biomarker for exposure to EDCs was induced in male tench and
roach from the Luppe River compared to both the Laucha and
commercially cultured fish by a factor of 264 and 90,
respectively. However, no histological alterations in testis
of these Luppe exposed fish were observed. Our findings
suggest that sediments substantially contribute to the
overall EDC exposure of both benthic and pelagic fish in the
field but that the exposure did not translated to adverse
effects on the gonad level and, thus, might not be of
relevance for the reproductive success of these populations
in the wild. The present thesis demonstrated that sediments
not only function as a sink for EDCs but can turn into a
significant source of pollution when sediments are
resuspended. The results demonstrated that sediment-bound
EDCs were readily bioavailable for fish under conditions
similar to those of a flood event. Partitioning of EDCs into
the water phase might be a major route for uptake of
remobilized sediment-bound EDCs into the fish. Passive
sampling was a useful tool to assess the bioavailability of
sediment-bound EDCs and could be a good indicator of
sediment toxicity in a regulatory context. Overall, the work
described in this thesis greatly contribute to the
assessment of sediment-bound EDCs in the context of flood
risk.},
cin = {162710 / 160000},
ddc = {570},
cid = {$I:(DE-82)162710_20140620$ / $I:(DE-82)160000_20140620$},
typ = {PUB:(DE-HGF)11},
doi = {10.18154/RWTH-2020-04225},
url = {https://publications.rwth-aachen.de/record/787719},
}
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