10 research outputs found
Effects of Bisphenol S Exposure on Endocrine Functions and Reproduction of Zebrafish
While bisphenol S (BPS) has been
frequently detected both in environment
and biota, limited information is available on their effects of endocrine
system. In the present study, adult zebrafish pairs were exposed to
0.5, 5, and 50 μg/L of BPS for 21 d, and the effects on reproduction,
sex steroid hormones, and transcription of the genes belonging to
the hypothalamic-pituitary-gonad (HPG) axis were investigated. The
adverse effects on performances of F1 generation were further examined
with or without subsequent exposure to BPS. Egg production and the
gonadosomatic index in female fish were significantly decreased at
≥0.5 μg/L BPS. Plasma concentrations of 17β-estradiol
were significantly increased in both male and female fish. In male
fish, however, significant decreases of testosterone concentration
were observed along with up-regulation of cyp19a and
down-regulation of cyp17 and 17βhsd transcripts. Parental exposure to BPS resulted in delayed and lesser
rates of hatching even when they were hatched in clean water. Continuous
BPS exposure in the F1 embryos resulted in worse hatchability and
increased malformation rates compared to those without BPS exposure.
Our observations showed that exposure to low level BPS could affect
the feedback regulatory circuits of HPG axis and impair the development
of offspring
Effect-Directed Analysis Combined with Nontarget Screening to Identify Unmonitored Toxic Substances in the Environment
Effect-directed analysis (EDA) combined with nontarget
screening
(NTS) has established a valuable tool for the identification of unmonitored
toxic substances in environmental samples. It consists of three main
steps: (1) highly potent fraction identification, (2) toxicant candidate
selection, and (3) major toxicant identification. Here, we discuss
the methodology, current status, limitations, and future challenges
of EDA combined with NTS. This method has been applied successfully
to various environmental samples, such as sediments, wastewater treatment
plant effluents, and biota. We present several case studies and highlight
key results. EDA has undergone significant technological advancements
in the past 20 years, with the establishment of its key components:
target chemical analysis, bioassays, fractionation, NTS, and data
processing. However, it has not been incorporated widely into environmental
monitoring programs. We provide suggestions for the application of
EDA combined with NTS in environmental monitoring programs and management,
with the identification of further research needs
Naphthenic Acids in Coastal Sediments after the <i>Hebei Spirit</i> Oil Spill: A Potential Indicator for Oil Contamination
Naphthenic acids (NAs) as toxic components
in most petroleum sources
are suspected to be one of the major pollutants in the aquatic environment
following oil spills, and the polarity and persistence of NAs make
it a potential indicator for oil contamination. However, the contamination
and potential effects of pollutants in oil spill affected areas remain
unknown. To investigate NAs in oil spill affected areas, a sensitive
method was first established for analysis of NAs, together with oxy-NAs
in sediment samples by UPLC-QTOF-MS. Then the method was applied to
determine the NA mixtures in crude oil, weathered oil, and sediments
from the spilled sites after the Hebei Spirit oil
spill, Taean, South Korea (Dec. 2007). Concentrations of NAs, O3–NAs, and O4–NAs were found to be
7.8–130, 3.6–44, and 0.8–20 mg kg–1 dw in sediments from the Taean area, respectively, which were much
greater than those measured in the reference sites of Manlipo and
Anmyundo beaches. Concentrations of NAs were 50–100 times greater
than those (0.077–2.5 mg kg–1 dw) of PAHs
in the same sediment samples, thus the ecological risk of NAs in oil
spill affected areas deserves more attention. The sedimentary profiles
of oil-derived NAs and background NAs centered around compounds with
21–35 and 12–21 carbons, respectively, indicating that
the crude-derived NA mixtures originating from the 2007 oil spill
were persistent. Acyclic NAsn=5–20 were easily degraded compared to cyclic NAsn=21–41 during the oil weathering processes, and the
ratio of oxy-NAsn=21–41 relative
to NAsn=21–41 could be a novel
index to estimate the degree of oil weathering in sediments. Altogether,
the persistent oil-derived NAsn=21–41 could be used as a potential indicator for oil-specific contamination,
as such compounds would not be much affected by the properties of
coastal sediments possibly due to the high sorption of the negatively
charged compounds (NAs) in sediment
Supplementary document for Entangling three identical particles via spatial overlap - 5975237.pdf
Detailed calculation, experimental setup, etc
Supplementary document for Error-mitigated photonic variational quantum eigensolver using a single-photon ququart - 5521038.pdf
Supplemental document
Identification of Mid-Polar and Polar AhR Agonists in Cetaceans from Korean Coastal Waters: Application of Effect-Directed Analysis with Full-Scan Screening
Major aryl hydrocarbon
receptor (AhR) agonists were identified
in extracts of blubber, liver, and muscle from six long-beaked common
dolphins (Delphinus capensis) and one fin whale (Balaenoptera physalus) collected from Korean coastal waters
using effect-directed analysis. Results of the H4IIE-luc bioassay indicated that the polar fractions of blubber and liver
extracts from the fin whale exhibited relatively high AhR-mediated
potencies. Based on full-scan screening with high-resolution mass
spectrometry, 37 AhR agonist candidates, spanning four use categories:
pharmaceuticals, pesticides, cosmetics, and natural products, were
selected. Among these, five polar AhR agonists were newly identified
through toxicological confirmation. Concentrations of polar AhR agonists
in cetaceans were tissue-specific, with extracts of blubber and liver
containing greater concentrations than muscle extracts. Polar AhR
agonists with great log KOA values (>5)
were found to biomagnify in the marine food chain potentially. Polar
AhR agonists contributed 8.9% of the observed AhR-mediated potencies
in blubber and 49% in liver. Rutaecarpine and alantolactone contributed
significantly to the total AhR-mediated potencies of blubber, whereas
hydrocortisone was a major AhR contributor in the liver of the fin
whale. This study is the first to identify the tissue-specific accumulation
of polar AhR agonists in blubber and liver extracts of cetaceans
Genotoxicity and Endocrine-Disruption Potentials of Sediment near an Oil Spill Site: Two Years after the <i>Hebei Spirit</i> Oil Spill
The Hebei Spirit oil spill episode (December 7, 2007) has affected the western coastal area of South Korea; however, there is limited information on the potential toxicity of the oil spill to the ecosystem or humans. The potential toxicity of sediments collected from the affected area (n = 22) 2 years after the spill was evaluated. Acute lethal toxicity tests using Vibrio fischeri and Moina macrocopa and tests for genotoxicity and alteration of steroidogenesis using chicken DT40 cells and H295R cells, respectively, were conducted. Both crude and weathered oil extracts were evaluated in order to link the observed toxicity in the sediment extracts to the oil spill. Whereas toxicity to bacteria and daphnids was observed in only two elutriate samples, 10 of the 22 sediment extracts showed genotoxic potential in DT40 cells. The mechanisms of genotoxicity involved nucleotide excision repair (XPA–/), homologous recombination (RAD54–/–), and translesion synthesis pathways (REV3–/–). In addition, nine sediment extracts caused significantly greater production of E2 in H295R cells, and significant up-regulation of CYP19, CYP11B2, and 3βHSD2 by sediment extracts was observed. The pattern of toxicities observed in both crude and weathered oil samples was similar to that observed in the sediment extracts. The genotoxicicity and endocrine-disruption potential of the sediment extracts suggest a need for long-term followup for such toxicity in humans and wildlife in this area
Two Years after the <i>Hebei Spirit</i> Oil Spill: Residual Crude-Derived Hydrocarbons and Potential AhR-Mediated Activities in Coastal Sediments
The <i>Hebei Spirit</i> oil spill occurred
in December
2007 approximately 10 km off the coast of Taean, South Korea, on the
Yellow Sea. However, the exposure and potential effects remain largely
unknown. A total of 50 surface and subsurface sediment samples were
collected from 22 sampling locations at the spill site in order to
determine the concentration, distribution, composition of residual
crudes, and to evaluate the potential ecological risk after two years
of oil exposure. Samples were extracted and analyzed for 16 polycyclic
aromatic hydrocarbons (PAHs), 20 alkyl-PAHs, 15 aliphatic hydrocarbons,
and total petroleum hydrocarbons using GC-MSD. AhR-mediated activity
associated with organic sediment extracts was screened using the H4IIE-<i>luc</i> cell bioassay. The response of the benthic invertebrate
community was assessed by mapping the macrobenthic fauna. Elevated
concentrations of residual crudes from the oil spill were primarily
found in muddy bottoms, particularly in subsurface layers. In general,
the bioassay results were consistent with the chemistry data in a
dose-dependent manner, although the mass-balance was incomplete. More
weathered samples containing greater fractions of alkylated PAHs exhibited
greater AhR activity, due to the occurrence of recalcitrant AhR agonists
present in residual oils. The macrobenthic population distribution
exhibits signs of species-specific tolerances and/or recolonization
of certain species such as <i>Batillaria</i> during weathering
periods. Although the <i>Hebei Spirit</i> oil spill was
a severe oil exposure, it appears the site is recovering two years
later
