10 research outputs found

    Effects of Bisphenol S Exposure on Endocrine Functions and Reproduction of Zebrafish

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    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

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    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

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    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

    Identification of Mid-Polar and Polar AhR Agonists in Cetaceans from Korean Coastal Waters: Application of Effect-Directed Analysis with Full-Scan Screening

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    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

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    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

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    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
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