Organophosphate flame retardants are emerging environmental contaminants, although knowledge of their health risks is limited. Here, thyroid hormone homeostasis and neuronal development was studied ...in the progeny of adult zebrafish exposed to tris(1,3-dichloro-2-propyl) phosphate (TDCPP). Adult zebrafish were exposed to TDCPP (0, 4, 20, and 100 μg/L) for 3 months. Increased generation of reactive oxygen species and reduced survival rates was observed in exposed F1 larvae. We also observed a significant decrease in plasma thyroxine and 3,5,3′-triiodothyronine levels in F0 females and F1 eggs/larvae. The mRNA and protein expression of factors associated with neuronal development (e.g., α1-tubulin, myelin basic protein, and synapsin IIa) were significantly downregulated in exposed F1 larvae, as was the level of the neurotransmitters dopamine, serotonin, gamma amino butyric acid, and histamine. Larval locomotion was significantly decreased in exposed fish, but there was no effect on acetylcholinesterase activity. Bioconcentration of TDCPP was observed in F0 fish. TDCPP was also detected in F1 eggs following parental exposure, indicating maternal transfer of this compound. This study uniquely shows that TDCPP can be transferred to the offspring of exposed adults, causing thyroid endocrine disruption and developmental neurotoxicity.
•The acute and long-term exposure of TDCPP to zebrafish was investigated.•Uptake of TDCPP was observed in larvae but did not cause developing neurotoxicity.•Greater uptake of TDCPP was observed in ...female fish tissues including brain.•TDCPP could be metabolized to BDCPP in larvae and adult fish.•Long-term exposure of TDCPP resulted in gender-dependent neurotoxicity.
Organophosphate flame retardants are ubiquitous environmental contaminants; however, knowledge is limited regarding their environmental health risks and toxicity. Here, we investigated the effects of acute and long-term exposure to tris(1,3-dichloro-2-propyl) phosphate (TDCPP) to the nervous system of zebrafish. Zebrafish embryos (2h post-fertilization) were exposed to TDCPP (0–100μg/L) for 6 months up until sexual maturation. Concentrations of TDCPP and its metabolic product (bis(1,3-dichloro-2-propyl) phosphate, BDCPP) were measured in the tissues of 5 day post-fertilization (dpf) larvae. There was no effect on locomotion, acetylcholinesterase activity, levels of the neurotransmitters dopamine and serotonin, and expression of mRNAs and proteins related to central nervous system development (e.g., myelin basic protein, α1-tubulin) in any exposure group. However, in adult fish, reductions of dopamine and serotonin levels were detected in the brains of females but not males. Downregulation of nervous system development genes was observed in both the male and female brain tissues. TDCPP concentrations were measured in adult fish tissues including the brain, and greater levels were detected in females. Our results showed that females are more sensitive to TDCPP stress than males in terms of TDCPP-induced neurotoxicity. We demonstrate that long-term exposure to lower concentrations of TDCPP in fish can lead to neurotoxicity.
A strategy to construct multivariate biomarkers for exposure to algal neurotoxins via correlating changes to the profiles of a series of neurotransmitters and their metabolites in the central nervous ...system (CNS) of exposed test organism is reported. 3-Month-old marine medaka (Oryzais melastigma) were exposed to waterborne brevetoxin PbTx-1 at two sub-lethal dose levels (0.5 and 2.5 μg-PbTx-1 L−1) for a duration of 12 h before quantification of 43 selected neurotransmitters and metabolites in their CNS were measured via dansyl chloride derivatization and LC-MS/MS determination. The profiling data were analyzed by multivariate statistical analyses, including principle component analysis (PCA), projection on latent structure-discriminate analysis (PLS-DA) and orthogonal projection on latent structure-discriminate analysis (OPLS-DA). Neurotransmitters and metabolites related to activation of voltage-gated sodium channels (VGSCs), N-methyl-D-aspartic acid receptors (NMDARs) and cholinergic neurotransmission were found to contribute significantly to class separation in the corresponding OPLS-DA models. Those models obtained from different exposure dosages were correlated by the Shared and Unique Structures Plot (SUS-plot) to identify appropriate variables for the construction of exposure biomarkers in the form of multivariate predictive scores. The established biomarkers for male and female medaka fish were able to predict acute sub-lethal exposure to PbTx-1 with good sensitivity and specificity (male fish: sensitivity 94.7%, specificity 80.0%; female fish: sensitivity 91.4%, specificity 83.3%). Neurotransmitter profiles in the CNS of medaka fish that should have recovered from exposure to PbTx-1 have also been determined to reveal long-term impacts to the CNS of the affected organism even after the exposure has been interrupted.
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•Exposure to PbTx-1 perturbs neurotransmitter profile in the CNS of marine medaka•Multivariate biomarkers for PbTx-1 exposure via targeted neurometabolomics•Long-term impact to the CNS even after ceasation of PbTx-1 exposure revealed
Sewage discharge could be a major source of polycyclic aromatic hydrocarbons （PAHs） in the coastal waters. Stonecutters Island and Shatin Sewage Treatment Works （SCISTW and STSTW） in Hong Kong, ...adopted chemically enhanced primary treatment and biological treatment, respectively. This study aimed at （1） determining the removal efficiencies of PAHs, （2） comparing the capabilities in removing PAHs, and （3） characterizing the profile of each individual PAHs, in the two sewage treatment plants （STPs）. Quantification of 16 PAHs was conducted by a Gas Chromatography. The concentrations of total PAHs decreased gradually along the treatment processes （from 301 ± 255 and 307 ± 217 ns/L to 14.9 ± 12.1 and 63.3 ± 54.1 ng/L in STSTW and SCISTW, respectively）. It was noted that STSTW was more capable in removing total PAHs than SCISTW with average total removal effidency 94.4% ± 4.12% us. 79.2% ± 7.48% （p 〈 0.05）. The removal of PAHs was probably due to sorption in particular matter, confirmed by the higher distribution coefficient of individual and total PAHs in solid samples （dewatered sludge contained 92.5% and 74.7% of total PAHs in SCISTW and STSTW, respectively） than liquid samples （final efffluent-total contained 7.53% and 25.3% of total PAHs in STSTW and SCISTW, respectively）. Despite the impressive capability of STSTW and SCISTW in removing PAHs, there was still a considerable amount of total PAHs （1.85 and 39.3 ks/year, respectively for the two STPs） being discharged into Hone Kon coastal waters, which would be an environmental concern.
To determine whether and how probiotic supplement can alter gut microbiota dysbiosis and lipid metabolism disorders caused by perfluorobutanesulfonate (PFBS), the present study exposed adult ...zebrafish to 0, 10, and 100 μg/L PFBS for 28 days, with or without dietary administration of probiotic Lactobacillus rhamnosus. Regarding intestinal health and gut microbiota, probiotic supplement altered the innate toxicities of PFBS, depending on exposure concentration and the sex of the fish. Lactobacillus genus correlated positively (P <0.001; r >0.5) with other beneficial bacteria in the gut microbiota, thereby indirectly regulating host metabolic activities. In female fish, the PFBS and probiotic combination enhanced fatty acid synthesis and β-oxidation, but mitigated the accumulation of cholesterol in the blood compared with PFBS single exposure, highlighting the benefits of the probiotic to host health. In male zebrafish, probiotic administration antagonized the PFBS-induced disturbances of bile acid metabolism, presumably via farnesoid X receptor signaling. However, coexposure to PFBS and probiotic caused significant accumulation of triglyceride in male livers (2.6-fold relative to the control), implying the induction of hepatic steatosis. Overall, the present study underlined the potential of probiotics to modulate gut microbial dysbiosis and lipid metabolism disorders caused by PFBS exposure, which could provide implications to the application of probiotics in aquaculture.
► Fish samples were collected from two islands in the Republic of Kiribati. ► The mouse neuroblastoma assay indicated that most of the fish were toxic. ► Pacific ciguatoxin-1 equivalent toxicity was ...species- and location-dependent. ► Carnivorous species, especially groupers and moray eels, were the most toxic.
Ciguatera is food poisoning caused by human consumption of reef fish contaminated with ciguatoxins (CTXs). The expanding international trade of tropical fish species from ciguatera-endemic regions has resulted in increased global incidence of ciguatera, and more than 50000 people are estimated to suffer from ciguatera each year worldwide. The Republic of Kiribati is located in the Pacific Ocean; two of its islands, Marakei and Tarawa, have been suggested as high-risk areas for ciguatera. The toxicities of coral reef fish collected from these islands, including herbivorous, omnivorous and carnivorous fish (24% n=41, 8% n=13 and 68% n=117, respectively), were analyzed using the mouse neuroblastoma assay (MNA) after CTX extraction. The MNA results indicated that 156 fish specimens, or 91% of the fish samples, were ciguatoxic (CTX levels >0.01ngg−1). Groupers and moray eels were generally more toxic by an order of magnitude than other fish species. All of the collected individuals of eight species (n=3–19) were toxic. Toxicity varied within species and among locations by up to 10000-fold. Cephalapholis argus and Gymnothorax spp. collected from Tarawa Island were significantly less toxic than those from Marakei Island, although all individuals were toxic based on the 0.01ngg−1 threshold. CTX concentrations in the livers of individuals of two moray eel species (Gymnothorax spp., n=6) were nine times greater than those in muscle, and toxicity in liver and muscle showed a strong positive correlation with body weight. The present study provides quantitative information on the ciguatoxicity and distribution of toxicity in fish for use in fisheries management and public health.
Applications of lead isotope ratio measurements Yip, Yiu-chung; Lam, James Chung-wah; Tong, Wai-fong
TrAC, Trends in analytical chemistry (Regular ed.),
05/2008, Letnik:
27, Številka:
5
Journal Article
Recenzirano
Lead isotope ratio measurements (Pb-IRM) have been widely used for identification purposes for several decades. This article reviews current analytical techniques available for Pb-IRM, including:
(
...i)
thermal ionization mass spectrometry (TIMS);
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ii)
quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS);
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iii)
inductively coupled plasma sector field mass spectrometry (ICP-SMS);
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iv)
multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS); and,
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v)
inductively coupled plasma time-of-flight mass spectrometry (ICP-TOF-MS).
We summarize recent applications of Pb-IRM in four major areas, including:
(
i)
tracing Pb sources and monitoring historical and environmental changes;
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ii)
determination of Pb by isotope-dilution mass spectrometry;
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iii)
forensic examination and authentication; and,
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iv)
U-Pb and U-Th-Pb dating of zircon.
In addition, we briefly describe new trends in direct Pb-IRM for solid and liquid samples.
The Consultative Committee for Amount of Substance – Metrology in Chemistry (Comité Consultatif pour la Quantité de Matière, CCQM) has the task of organizing international key comparisons. The main ...purpose is to establish a technical basis for mutual recognition of measurement capabilities among national measurement institutes (NMIs) in the field of chemical measurement. More importantly, key comparison results provide an effective means of assessing the degree of equivalence of measurement standards used at different NMIs. Since 1998, the Inorganic Analysis Working Group of CCQM has been identifying and organizing key comparisons for the determination of analytes, such as elements, inorganic compounds and organo-metallic compounds in various matrices.
Methodologies, including inorganic mass spectrometry e.g., isotope dilution mass spectrometry (IDMS) and species-specific IDMS, inductively coupled plasma atomic emission spectrometry, neutron activation analysis, ion chromatography, high performance liquid chromatography, X-ray fluorescence spectrometry, flame atomic absorption spectrometry (AAS) and graphite furnace AAS, have provided satisfactory results in terms of accuracy and precision.
Complex sample matrices examined so far include inorganic solutions and water (e.g., calibration solutions and natural water), metal and metal alloys (e.g., steel and aluminum alloy), biological fluids, materials and food (e.g., serum, rice, wine, shellfish, salmon fish, tomato and bovine liver), fuels (e.g., diesel), sediments and soils (e.g., sediments and sewage sludge). The use of IDMS for elemental analysis has attracted considerable attention.
In this review, we focus on commonly used methodologies for inorganic analysis in CCQM key comparisons between 1998 and 2007, and we suggest potential areas for strategic research and development.
A method for the determination of Pb in Chinese herbs based on “approximate matching” isotope dilution inductively coupled plasma mass spectrometry was developed. The method was validated using NIST ...SRM 1547 (Peach Leaves). Satisfactory analytical figures of merit were achieved, including good sample recovery (∼99%) and low relative expanded uncertainty (less than ±2%). The validated method was applied to the analysis of a herbal sample for the international comparison CCQM-P97. Measurement uncertainty was evaluated according to three approaches, namely Kragten’s spreadsheet approach, GUM Workbench and Monte Carlo method (MCM). A practical way was established for the evaluation of measurement uncertainty based on the propagation of distributions using MCM. The validated method was also employed for the provision of SI-traceable mass fraction of Pb in an in-house herbal reference material and the assignment of a reference value to a proficiency testing programme.
Sea turtles are globally endangered and face daily anthropogenic threats, including pollution. However, there is a lack of ecotoxicological information on sea turtles, especially in the Asia-Pacific ...region. This study aims to determine pollutant levels of foraging green turtles (Chelonia mydas) in South China, including Hong Kong, Guangdong and Taiwan, as a basis for their conservation. Scute, liver and muscle tissues of stranded green turtles were analysed for levels of 17 trace elements and methylmercury (MeHg) (n = 86 for scute and n = 14 for liver) and polybrominated diphenyl ethers (PBDEs) (n = 11 for muscle and n = 13 for liver). Ten-fold higher levels of Pb, Ba, V and Tl and 40-fold greater Cd levels were measured in green turtle livers in South China relative to other studies conducted over 10 years ago. Measured PBDE levels were also 27-fold and 50-fold greater than those reported in Australia and Japan. These results warrant further investigation of potential toxicological risks to green turtles in South China and their source rookeries in Malaysia, Micronesia, Indonesia, Marshall Islands, Japan and Taiwan. Research should target monitoring pollutant levels in sea turtles within the West Pacific/Southeast Asia regional management unit spanning East Asia to Southeast Asia to fill in knowledge gaps, in particular in areas such as Thailand, Vietnam, Indonesia, Malaysia and the Philippines where less or no data is available and where foraging grounds of sea turtles have been identified.
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●First report of baseline levels of PBDE and MeHg in green turtles from South China.●Higher PBDE levels (50-fold) in green turtle livers compared to previous studies.●Higher Pb, Ba, V and Tl (10-fold), Cd (40-fold) levels were also found.●There is potential risk of toxicity to foraging green turtles in South China.●Source rookeries in the Pacific may be affected and warrant conservation concern.
High loadings of pollutants (e.g. Pb, Ba, V., Tl and PBDEs) measured in green turtles in South China suggest potential risks to Pacific populations that warrant giving them higher priority for conservation and research.
