4 research outputs found
Environmental Occurrence of Perfluoroalkyl Acids and Novel Fluorotelomer Surfactants in the Freshwater Fish <i>Catostomus commersonii</i> and Sediments Following Firefighting Foam Deployment at the Lac-MeĢgantic Railway Accident
On
July 6th 2013, an unmanned train laden with almost 8 million
liters of crude oil careened off the rails downtown Lac-MeĢgantic
(QueĢbec, Canada). In the aftermath of the derailment accident,
the emergency response entailed the deployment of 33āÆ000 L
of aqueous film forming foam (AFFF) concentrate that contained proprietary
fluorosurfactants. The present study examines the environmental occurrence
of perfluoroalkyl acids (PFAAs) and newly identified per and polyfluoroalkyl
substances (PFASs) in the benthic fish white sucker (<i>Catostomus
commersonii</i>) and sediments from Lake MeĢgantic and
ChaudieĢre River. In sediments, PFAAs displayed relatively low
concentrations (āPFAAs = 0.06ā0.5 ng g<sup>ā1</sup> dw) while the sum of fluorotelomer-based PFASs was in the range
< LODā6.2 ng g<sup>ā1</sup> dw. Notably, fluorotelomer
sulfonamide betaines (8:2-FTAB and 10:2-FTAB), fluorotelomer betaines
(9:3-FTB, 11:3-FTB and 9:1:2 FTB) and 6:2 fluorotelomer sulfonate
(6:2-FTSA) were ubiquitously identified in the sediment samples surveyed.
Levels of PFAAs remained moderate in fish muscle (e.g., PFOS: 0.28ā2.1
ng g<sup>ā1</sup> wet-weight), with little or no differences
when comparing 2013 or 2014 fish samples with 2011 archived samples.
In contrast, n:2-FTSAs emerged in the immediate weeks or months that
followed the accident, as did several betaine-based PFASs (8:2-FTAB,
10:2-FTAB, 9:3-FTB, 11:3-FTB, 7:1:2 FTB and 9:1:2 FTB), observed for
the first time in situ. Fluorotelomer thioether amido sulfonate (10:2-FTSAS)
and fluorotelomer sulfoxide amido sulfonate (10:2-FTSAS-sulfoxide)
were also occasionally reported after the AFFF spill. With time, levels
of betaine-based PFASs gradually decreased in fish, possibly indicating
attenuation by biodegradation of the fluorine-free moiety, supported
by the observation of likely metabolites such as n:3-fluorotelomer
carboxylates and n:2-fluorotelomer sulfonamides
Abnormal Ovarian DNA Methylation Programming during Gonad Maturation in Wild Contaminated Fish
There
is increasing evidence that pollutants may cause diseases
via epigenetic modifications. Epigenetic mechanisms such as DNA methylation
participate in the regulation of gene transcription. Surprisingly,
epigenetics research is still limited in ecotoxicology. In this study,
we investigated whether chronic exposure to contaminants experienced
by wild female fish (<i>Anguilla anguilla</i>) throughout
their juvenile phase can affect the DNA methylation status of their
oocytes during gonad maturation. Thus, fish were sampled in two locations
presenting a low or a high contamination level. Then, fish were transferred
to the laboratory and artificially matured. Before hormonal treatment,
the DNA methylation levels of the genes encoding for the aromatase
and the receptor of the follicle stimulating hormone were higher in
contaminated fish than in fish from the clean site. For the hormone
receptor, this hypermethylation was positively correlated with the
contamination level of fish and was associated with a decrease in
its transcription level. In addition, whereas gonad growth was associated
with an increase in DNA methylation in fish from the clean site, no
changes were observed in contaminated fish in response to hormonal
treatment. Finally, a higher gonad growth was observed in fish from
the reference site in comparison to contaminated fish
Wandering Albatrosses Document Latitudinal Variations in the Transfer of Persistent Organic Pollutants and Mercury to Southern Ocean Predators
Top
marine predators are effective tools to monitor bioaccumulative
contaminants in remote oceanic environments. Here, we used the wide-ranging
wandering albatross <i>Diomedea exulans</i> to investigate
potential geographical variations of contaminant transfer to predators
in the Southern Ocean. Blood concentrations of 19 persistent organic
pollutants and 14 trace elements were measured in a large number of
individuals (<i>N</i> = 180) of known age, sex and breeding
status from the subantarctic Crozet Islands. Wandering albatrosses
were exposed to a wide range of contaminants, with notably high blood
mercury concentrations. Contaminant burden was markedly influenced
by latitudinal foraging habitats (inferred from blood Ī“<sup>13</sup>C values), with individuals feeding in warmer subtropical
waters having lower concentrations of pesticides, but higher concentrations
of mercury, than those feeding in colder subantarctic waters. Sexual
differences in contaminant burden seemed to be driven by gender specialization
in feeding habitats, rather than physiological characteristics, with
females foraging further north than males. Other individual traits,
such as adult age and reproductive status, had little effect on blood
contaminant concentrations. Our study provides further evidence of
the critical role of global distillation on organic contaminant exposure
to Southern Ocean avian predators. In addition, we document an unexpected
high transfer of mercury to predators in subtropical waters, which
merits further investigation
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Environmental health impacts of equine estrogens derived from hormone replacement therapy
Many factors have been considered in evaluations of the risk-benefit balance of hormone replacement therapy (HRT), used for treating menopausal symptoms in women, but not its potential risks for the environment. We investigated the possible environmental health implications of conjugated equine estrogens (CEEs), the most common components of HRT, including their discharge into the environment, their uptake, potency, and ability to induce biological effects in wildlife. Influents and effluents from four UK sewage treatment works (STWs), and bile of effluent-exposed fish, were screened for six equine estrogens. In vitro estrogen receptor (ER) activation assays were applied in humans and fish to compare their potencies, followed by in vivo exposures of fish to equine estrogens and evaluation of bioaccumulation, estrogenic responses, and ER gene expression. The equine estrogen equilenin (Eqn), and its metabolite 17Ć-dihydroequilenin (17Ć-Eqn), were detected by tandem GC-MSMS in all STW influent samples and 83% of STW effluent samples analyzed, respectively, at low concentrations (0.07-2.6 ng/L) and were taken-up into effluent-exposed fish. As occurs in humans, these estrogens bound to and activated the fish ERs, with potencies at ERa 2.4-3490% of that for 17Ć-estradiol. Exposure of fish for 21 days to Eqn and 17Ć-Eqn induced estrogenic responses including hepatic growth and vitellogenin production at concentrations as low as 0.6-4.2 ng/L. Associated with these effects were inductions of hepatic ERa and ERĆ1 gene expression, suggesting ER-mediated mechanism(s) of action. These data provide evidence for the discharge of equine estrogens from HRT into the aquatic environment and highlight a strong likelihood that these compounds contribute to feminization in exposed wildlife