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A computational model to predict acute aquatic toxicity to the ciliate Tetrahymena pyriformis has been developed. A general prediction of toxicity can be based on three consecutive steps: 1. Identification of a potential reactive mechanism via structural alerts; 2. Confirmation and quantification of (bio)chemical reactivity; 3. Establishing a relationship between calculated reactivity and toxicity. The method described herein uses a combination of a reactive toxicity (RT) model, including computed kinetic rate constants for adduct formation (log k) via a Michael acceptor mechanism of action, and baseline toxicity (BT), modelled by hydrophobicity (octanol-water partition coefficient). The maximum of the RT and BT values defines acute toxicity for a particular compound. The reactive toxicity model is based on site-specific steric and quantum chemical ground state electronic properties. The performance of the model was examined in terms of predicting the toxicity of 106 potential Michael acceptor compounds covering several classes of compounds (aldehydes, ketones, esters, heterocycles). The advantages of the computational method are described. The method allows for a closer and more transparent mechanistic insight into the molecular initiating events of toxicological endpoints. 相似文献
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铜、镉对水螅的急性和联合毒性作用 总被引:17,自引:0,他引:17
试验研究重金属铜(Cu2 )、镉(Cd2 )对水螅的急性毒性和联合毒性作用,探索水螅(Hydra sp.)对Cu2 、Cd2 以及两者混合的毒性效应,为水产动物病害的防治中合理使用消毒、杀虫剂以及水体污染评价提供一些参考信息.结果表明,Cu2 对水螅的24 h半致死浓度(LC50)、48 hLC50、72 hLC50、96 hLC50分别为0.072、0.054、0.042、0.037 mg/L;Cd2 对水螅的24 hLC50、48hLC50、72 hLC50、96 hLC50分别为0.001 70、0.000 63、0.000 36、0.000 36 mg/L;Cu2 、Cd2 对水螅的安全浓度分别为3.7×10-4、3.6×10-6mg/L.水螅对两种重金属的毒性反应既快速又敏感,其中Cu2 对水螅的毒性较Cd2 快,但Cd2 的毒性比Cu2 的强.等毒性配比的两种重金属混合液对水螅的毒性大于单一毒性,为协同作用.两种重金属对水螅的LC50随试验时间的延长而减小,它们对水螅的安全浓度远低于渔业水质标准. 相似文献
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DNA damage and changes in enzyme activities were used as biomarkers to evaluate the genotoxicity and oxidative stress of tetracycline and chlortetracycline on the earthworm Eisenia fetida. The results showed that both antibiotics induced significant genotoxicity on earthworms in a dose-dependent manner (p < 0.01) with chlortetracycline having a stronger effect than tetracycline in the short term. The tests on the activities of superoxide dismutase (SOD) and catalase (CAT) enzymes further indicated biochemical stresses induced by the antibiotics. An N-shaped activity pattern was noted with the enzyme activities being stimulated first, then inhibited, and stimulated again with increasing concentration. The induced activity of SOD or CAT could scavenge oxygen free radicals and protect the organisms against oxidative stress by alleviating the corresponding DNA damage. Compared to enzyme activities, DNA damage as a biomarker was more sensitive and is thus more suitable for detecting low concentration exposure and diagnosing the genotoxicity of contaminants in terrestrial environment. 相似文献
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Neško K. Neškovid Vesela Karan Ibrahim Elezović Vesna Poleksić Milka Budimir 《Journal of environmental science and health. Part. B》2013,48(2):265-279
Abstract Acute and subacute 2,4‐D toxicity to carp (Cyprinus carpio L.) were investigated. Acute toxicity (LC‐ 50) was investigated in semi‐static test during a 24, 48, and 96‐ hours exposition. Subacute toxicity was investigated by exposing fish to different 2,4,‐D concentrations (150, 200, and 250 mg/L) for 14 days. Biochemical and morphological changes in certain organs and tissues were investigated. LC‐ 50 values at 24 hours exposure was 310.0 mg/L, 295.0 mg/L for 48 hours, and 270.0 mg/L for 96 hours exposure. Subacute toxicity tests show that 2,4‐D induce changes in the enzyme activities (AP, GOT, GPT) and morphological changes in the gills, liver and kidneys, but changes are of limited biological importance. 相似文献
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Sea salts (seven brands from six commercially-available sources) were dissolved in water to develop 30 g/l solutions, and selected water quality characteristics were then monitored for 96 h. One or more water quality characteristics changed significantly during the 96 h period in six of the reconstituted sea salts. Measured characteristics of sea water diluted to 30 g/l demonstrated no changes during the observation period. The sea salts from different sources also demonstrated differences in absolute concentrations of some characteristics measured. Application of the Biotic Ligand Model to predict copper toxicity to the bivalve Mytilus edulis in solutions of the salts tested yielded 96-h median-lethal concentrations that ranged from 2 to 13 μg/l. Since water quality affects toxicity of many environmental pollutants, the source of the sea salt and equilibration time should be considered when planning toxicity tests. 相似文献
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Assessing the chemical and biological accessibility of the herbicide isoproturon in soil amended with biochar 总被引:2,自引:0,他引:2
Decamethylcyclopentasiloxane (D5) is a cyclic volatile methyl siloxane (cVMS) commonly found in commercially available products. D5 is expected to enter the terrestrial environment through the deposit of biosolids from sewage treatment plants onto agricultural fields for nutrient enrichment. Little to no information currently exists as to the risks of D5 to the terrestrial environment. In order to evaluate the potential risk to terrestrial organisms, the toxicity of a D5 contaminated biosolid in an agricultural soil was assessed with a battery of standardized soil toxicity tests.D5 was spiked into a surrogate biosolid and then mixed with a sandy loam soil to create test concentrations ranging from 0 to 4074 mg kg−1. Plant (Hordeum vulgare (barley) and Trifolium pratense (red clover)) and soil invertebrates (Eisenia andrei (earthworm) and Folsomia candida (springtail)) toxicity tests were completed to assess for lethal and sub-lethal effects. Plant testing evaluated the effects on seedling emergence, shoot and root length, and shoot and root dry mass. Invertebrate test endpoints included adult lethality, juvenile production, and individual juvenile dry mass (earthworms only). Soil samples were collected over time to confirm test concentrations and evaluate the loss of chemical over the duration of a test. The toxicity of the D5 was species and endpoint dependent, such that no significant adverse effects were observed for T. pratense or E. andrei test endpoints, however, toxicity was observed for H. vulgare plant growth and F. candida survival and reproduction. Chemical losses of up to 50% were observed throughout the tests, most significantly at high concentrations. 相似文献
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Cadmium selenium (CdSe) quantum dots (QDs) are semiconductor nanocrystals that hold wide range of applications and substantial production volumes. Due to unique composition and nanoscale properties, their potential toxicity to aquatic organisms has increasingly gained a great amount of interest. However, the impact of CdSe QDs exposure on zebrafish embryo and larvae remains almost unknown. Therefore, the lab study was performed to determine the developmental and behavioral toxicities to zebrafish under continuous exposure to low level CdSe QDs (0.05-31.25 mg L−1) coated with mercaptopropionic acid (MPA). The results showed MPA-CdSe exposure from embryo to larvae stage affected overall fitness. Our findings for the first time revealed that: (1) The 120 h LC50 of MPA-CdSe for zebrafish was 1.98 mg L−1; (2) embryos exposed to MPA-CdSe resulted in malformations incidence and lower hatch rate; (3) abnormal vascular of FLI-1 transgenic zebrafish larvae appeared after exposure to MPA-CdSe including vascular junction, bifurcation, crossing and particle appearance; (4) larvae behavior assessment showed during MPA-CdSe exposure a rapid transition from light-to-dark elicited a similar, brief burst and a higher basal swimming rate; (5) MPA-CdSe induced embryos cell apoptosis in the head and tail region. Results of the observations provide a basic understanding of MPA-CdSe toxicity to aquatic organisms and suggest the need for additional research to identify the toxicological mechanism. 相似文献
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以上海地区7处典型污水处理厂产生的污水污泥为研究对象,利用体外生物测试工具,检测了污水污泥有机提取液的基线毒性、遗传毒性、雌激素效应和芳香烃受体效应水平,并结合化学分析对某些能引起毒性效应的有机污染物进行确认。结果表明,污水污泥有机提取液的基线毒性强度为133~3 401 mg·kg-1;遗传毒性强度从未检出到25 mg·kg-1;雌激素效应当量均低于0.02 ng·kg-1;芳香烃受体效应强度为73~6 838 ng·kg-1。与国内外相关研究比较发现,基线毒性、遗传毒性、雌激素效应水平均较低,仅芳香烃受体效应水平接近于国内外污水污泥中芳香烃受体效应的水平。在对芳香烃受体效应水平的检测中发现:S1点检出的化学物质可以解释污水污泥70%的类二恶英效应,其中多环芳烃(PAHs)尤其是PAHs的单体BkF占主导地位,而其余样点则不到10%的效应可以被解释,因此有待进一步对其余样点的化学污染物进行分析和确认。 相似文献
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Peter B. Key Elizabeth Simonik Nicole Kish Katy W. Chung Michael H. Fulton 《Journal of environmental science and health. Part. B》2013,48(11):967-973
This study assessed the in vitro and in vivo effects of an acetylcholinesterase enzyme inhibitor (chlorpyrifos) in two estuarine crustaceans: grass shrimp (Palaemonetes pugio) and mysid (Americamysis bahia). The differences in response were quantified after lethal and sublethal exposures to chlorpyrifos and in vitro assays with chlorpyrifos-oxon. Results from the in vitro experiments indicated that the target enzyme, acetylcholinesterase (AChE), in the two species was similar in sensitivity to chlorpyrifos inhibition with IC50s of 0.98 nM and 0.89 nM for grass shrimp and mysids, respectively. In vivo experiments showed that mysids were significantly more sensitive to chlorpyrifos-induced AChE inhibition after 24 h of exposure. The in vivo EC50s for AChE inhibition were 1.23 μg L?1 for grass shrimp and 0.027 μg L?1 for mysids. Median lethal concentrations (24h LC50 values) were 1.06 μg L?1 for grass shrimp and 0.068 μg L?1 for mysids. The results suggest that differences in the response of these two crustaceans are likely related to differences in uptake and metabolism rather than target site sensitivity. 相似文献
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A novel method dependent only on the mixture information (MIM) for evaluating the toxicity of mixture 总被引:2,自引:0,他引:2
Zhang J Liu SS Liu HL Zhu XW Mi XJ 《Environmental pollution (Barking, Essex : 1987)》2011,159(7):1941-1947
Compound contamination and toxicity interaction necessitate the development of models that have an insight into the combined toxicity of chemicals. In this paper, a novel and simple model dependent only on the mixture information (MIM), was developed. Firstly, the concentration-response data of seven groups of binary and multi-component (pseudo-binary) mixtures with different mixture ratios to Vibrio qinghaiensis sp.-Q67 were determined using the microplate toxicity analysis. Then, a desirable non-linear function was selected to fit the data. It was found that there are good linear correlations between the location parameter (α) and mixture ratio (p) of a component and between the steepness (β) and p. Based on the correlations, a mixture toxicity model independent of pure component toxicity profiles was built. The model can be used to accurately estimate the toxicities of the seven groups of mixtures, which greatly simplified the predictive procedure of the combined toxicity. 相似文献
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D. Moir R. Poon A. Yagminas G. Park A. Viau V.E. Valli 《Journal of environmental science and health. Part. B》2013,48(4):545-564
Abstract The subchronic toxicity of acridine was investigated in rats following dietary exposure at 0, 1, 10, 100 and 500 ppm for 13 weeks. The growth rate and food consumption were not affected by treatment and no clinical signs of toxicity were observed. There was a slight but significant decrease in spleen weight, both in absolute terms and as a percent of body weight, in the 500 ppm males and a slight increase in absolute thymus weight in the females of the same dose group. Both hepatic ethoxyresorufin O‐deethylase (EROD) and pentoxyresorufin O‐dealkylase (PROD) activities were slightly, but significantly, elevated in females in the 500 ppm dose group. No haematological or other biochemical changes were observed. Females also displayed dose‐related increases in inorganic phosphate and uric acid levels. Treatment‐related histopathological changes were seen in the thyroid, liver and kidney and included hepatic anisokaryosis and vesiculation of nuclei and glomerular adhesions, reticulin sclerosis and nuclear pyknosis in the kidney. Residue data showed a dose‐dependent accumulation of acridine in liver, kidney and adipose with the highest concentration being found in the fat of the 500 ppm dose group. Based on these data, the no observable adverse effect level of acridine was judged to be 100 ppm or 12 mg/kg bw/day. 相似文献
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Eva Petrovova David Sedmera Frantisek Lesnik Lenka Luptakova 《Journal of environmental science and health. Part. B》2013,48(4):383-388
The aim of the study was to investigate toxicity of bendiocarb (2, 3-isopropyledene-dioxyphenyl methylcarbamate) to organs of chicken embryo. The toxic action of bendiocarb was observed on liver and central nervous system (CNS). Bendiocarb was administered to chicken embryos at embryonic day (ED) 3 in a dose 500 μ g/egg and 10 ED (800 μ g/egg). The observations showed no macroscopic or microscopic changes in the liver and CNS with either dose or day of incubation when the bendiocarb was administered. The liver and CNS were also investigated for caspase activity in relation to application of bendiocarb and no differences in the number of cells with caspase immunopositivity were observed in comparison with the control. The results obtained indicate that bendiocarb administered in the respective doses showed no toxicity to investigated organs. Furthermore, both at the early (3 ED) and the later (10 ED) stages of development no increase in numbers of apoptotic cells in chicken embryos was observed. 相似文献
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对乙醛生产废水进行碱解预处理,研究碱投加量、反应温度、反应时间对脱毒效果的影响。结果表明,乙醛生产废水经碱解预处理后,废水中有毒物质降解明显,且厌氧生物毒性和好氧活性污泥毒性显著下降。碱投加量、反应温度和反应时间是影响乙醛生产废水碱解预处理效果的重要因素,在反应时间为0.5 h,碱投加量为1.2 g/L,反应温度为30℃,好氧活性污泥毒性即可有大幅下降;产甲烷抑制率在反应时间为3 h以上,反应温度为60℃、碱投加量为2 g/L以上,有大幅下降。 相似文献
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Marta Batoryna Marcin Lis Grzegorz Formicki 《Journal of environmental science and health. Part. B》2017,52(8):600-606
This study was undertaken to determine the redox balance in the developing brain after exposure to acrylamide (ACR), a potent neurotoxin. The studies were performed using an in ovo chick embryo model. The antioxidant enzymes SOD, GPx, CAT, and reduced glutathione (GSH) were used as indicators of the redox balance. Eggs were injected with ACR doses of 40 mg kg?1 egg mass (2.4 mg egg?1) on embryonic day 17 (E17). The activity of the antioxidant enzymes and the concentration of GSH were measured at E17, E18, and E19 in the medulla oblongata, cerebrum, cerebellum, and optic lobe. The results indicated a significant decrease in the GSH concentrations in the optic lobe (E19, E20) and cerebrum (E20) of embryos exposed to ACR. The activities of SOD and GPx were significantly increased in the majority of the examined structures after injection of ACR. CAT activity was completely inhibited in the brains of the embryos exposed to ACR compared to that in the brains of the control embryos. Thus, we concluded that ACR exerts a significant influence on the redox balance in the developing brain by impacting the activity of antioxidant enzymes and the levels of GSH. 相似文献
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There is the need to integrate existing toxicity data in a coherent framework for extending their domain of applicability as well as their extrapolation potential. This integration would also reduce time and cost-consuming aspects of these tests and reduce animal usage. In this work, based on data extracted from literature, we have assessed the advantages that a dynamic biology-toxicant fate coupled model for Daphnia magna could provide when assessing toxicity data, in particular, the possibility to obtain from short-term (acute) toxicity test long-term (chronic) toxicity values taking into account the inherent variability of D. magna populations and the multiple sources of data. The results show that this approach overcomes some of the limitations of existing toxicity tests and that the prediction errors are considerably reduced when compared with the factor from 2 to 5 obtained using acute-to-chronic ratios. 相似文献
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Svecevicius G Syvokiene J Stasiŭnaite P Mickeniene L 《Environmental science and pollution research international》2005,12(5):302-305
Goal, Scope and Background Chlorite (ClO2ˉ) is a primary decomposition product when chlorine dioxide (ClO2) is added during water treatment; therefore
the toxic effects of both compounds on aquatic organisms are possible. Limited data are available concerning their toxicity
to fish. The aim of this study was to investigate sensitivity of rainbow trout to acute and chronic toxicity of chlorine dioxide
and chlorite, and to estimate the Maximum-Acceptable-Toxicant-Concentration (MATC) of those compounds in fish.
Methods The acute and chronic toxicity of chlorine dioxide and chlorite to larval and adult rainbow trout was investigated in 96-hour
to 20-day laboratory exposures evaluating the wide range spectrum of biological indices under semi-static conditions.
Results and Discussion Median lethal concentration (96-hour LC50) values derived from the tests were: 2.2 mg/l for larvae; 8.3 mg/l for adult fish
and 20-day LC50 for larvae was 1.6 mg/l of chlorine dioxide, respectively. Chlorite was found to be from 48 to 18 times less
acutely toxic to larvae and adult fish, correspondingly. Both chemical compounds induced similar toxic effects in rainbow
trout larvae during chronic tests (they affected cardio-respiratory and growth parameters), but chlorine dioxide had a higher
toxic potency than chlorite. A significant decrease in the heart rate and respiration frequency of larvae was established.
However, within an increase in exposure duration recovery of cardio-respiratory responses was seen to have occurred in larvae
exposed to chlorite. Meanwhile, in larvae exposed to chlorine dioxide, a significant decrease in cardio-respiratory responses
remained during all 20-day chronic bioassays. Chlorine dioxide also more strongly affected growth parameters of rainbow trout
larvae at much lower test concentrations. Decreased rate of yolk-sack resorption occurred only in the tests with chlorine
dioxide.
Conclusions Maximum-Acceptable-Toxicant-Concentration (MATC) of 0.21 mg/l for chlorine dioxide and of 3.3 mg/l for chlorite to fish was
derived from chronic tests based on the most sensitive parameter of rainbow trout larvae (growth rate). According to substance
toxicity classification accepted for Lithuanian inland waters, chlorine dioxide and chlorite can be referred to substances
of \moderate\ toxicity to fish.
Recommendations and Outlook Due to its very reactive nature, chlorine dioxide is rapidly (in a few hours) reduced to chlorite, which is persistent also
as a biocide but 16 times less toxic to fish, according to MATC. Therefore, it is much more likely that fish will be exposed
to chlorite than to chlorine dioxide in natural waters. Presently accepted, the Maximum-Permitted-Concentration of total residual
chlorine (TRC) in waste-water discharging into receiving waters is 0.6 mg/l. If this requirement will not be exceeded, it
is unlikely that fish would be exposed to lethal or even to sublethal concentrations of chlorine dioxide or chlorite. Furthermore,
chlorine dioxide does not generate toxic nitrogenous (chloramines) or carcinogenic organic residuals (trihalomethanes). All
these properties make chlorine dioxide a more promising biocide than chlorine. 相似文献