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1.
In the terrestrial environment, standardized protocols are available for measuring the exposure and effects of contaminants to invertebrates, but none currently exist for vertebrates. In an effort to address this, we proposed that developing lizard embryos may be used as a terrestrial vertebrate model. Lizard eggs may be particularly susceptible to soil contamination and in ovo exposure may affect hatchling size, mortality, as well as thyroid function. Toxicant-induced perturbations of thyroid function resulting from in ovo chemical exposure may result in toxicity during the critical perinatal period in reptiles. Fertilized Eastern fence lizard (Sceloporus undulatus) eggs were placed in cadmium (Cd)-spiked expanded perlite (0, 1.48, 14.8, 148, 1480, 14 800 μg Cd/g, nominal concentrations), artificially incubated at 28 °C, and examined daily for mortality. Whole lizard hatchlings as well as failed hatches were homogenized in ethanol and the homogenate was divided for Cd body residue analysis and thyroid hormone (triiodothyronine (T3) and thyroxine (T4)) analyses. Acute mortality was observed in the two highest doses (1480 and 14 800 μg Cd/g). Cadmium body residues showed a higher internal concentration with increasing exposure concentration indicating uptake of Cd. There was a decrease in T3:T4 ratio at the highest surviving dose (148 μg Cd/g), however, there were no differences observed in hatchling size measured as weight and snout-vent length, or in whole body thyroid hormone levels. In summary, this study has shown Cd amended to a solid phase representing soil (perlite) can traverse the thin, parchment-like shell membrane of the fence lizard egg and bioaccumulate in lizard embryos. We believe this study is a good first step in investigating and evaluating this species for use as a model.  相似文献   

2.
Aroclor 1254 (1860 mg/l) in alkaline 2-propanol and in the presence of acetone (4% v/v) was photodechlorinated to biphenyl at λ >300 nm with exceptionally high quantum yield (Φ= 18). Under similar conditions photodechlorination of extracts of Aroclor 1254 contaminated soil (730 mg/kg) proceeded with lower quantum yield Φ= 0.4. While oxygen severely quenched photolysis, dechlorination was accomplished under thermal conditions using di-t-butyl peroxide, t-BuOOBu-t, as free radical initiator. A free radical chain reaction is suggested in which acetone triplet, T1(n,π*), or t-BuO· radical abstracts H-atom from 2-propanol to give the ketyl radical, (CH3)2 OH, which after losing a proton to the alkaline medium gives the ketyl radical anion, (CH3)2CHO·−. The Aroclor in turn reacts with the latter species through an electron-transfer process giving unstable aryl radical anion, , which cleaves releasing the chloride anion, Cl and the aryl radical, A·  相似文献   

3.
Pang X  Wang DH  Xing XY  Peng A  Zhang FS  Li CJ 《Chemosphere》2002,47(10):1033-1039
In order to improve the plant ability to resist lead stress, effect of 0.05 mg/l La(NO3)3 on the activities of catalase (CAT), superoxide dismutase (SOD), the level of malondialdehyde (MDA) in wheat seedlings under lead stress was studied. The effect of La3+ on plant growth, chlorophyll content in wheat seedlings after adding 0, 50, 100 mg/l Pb(NO3)3 to the nutrient solution for 12 days was observed. The plants were grown in nutrient solution in a strictly controlled climate growth room. Effects of La3+ (with La treatment) compared with check groups was evidently observed. The activities of SOD and CAT in root were enhanced 0.45–1.69 times and 33.20–77.77% respectively and MDA content was reduced 11.05–27.49% in root after treatments from the second day till the end of the experiment. The activities of SOD and CAT was found to be increased slightly (P<0.05) and MDA content decreased in shoot and root of wheat seedlings by La3+ under lead stress within five days after treatments compared with Pb1 and Pb2 groups. It was assumed that antioxidant enzymes was found to be increased by La(NO3)3, the antioxidant potential of the wheat seedlings to resist lead stress enhanced. It is suggested that La3+ could be used to resist lead stress at the beginning under stress while the stress was not so serious.  相似文献   

4.
Nguyen HT  Kim KH  Kim MY  Kang CH  Shim SG 《Chemosphere》2008,71(11):2017-2029
The concentrations of total gaseous mercury (TGM) and its relevant environmental parameters were measured at a highly industrialized area in the Ban Wall industrial complex (BWIC) in An San city, Korea from March to May 2005. The mean concentrations of Hg measured during the entire study period were computed to be 6.32 ± 8.56 ng m−3 (range of 2.32–181 ng m−3; N = 1160). Due to the effects of strong man-made activities, the significantly high Hg concentration levels (e.g., at or above 10 ng m−3) comprised about 7.5% of all data with the mean of 21.8 ± 26.3 ng m−3 (N = 87). By separating the data into daytime and nighttime periods, the Hg values exhibited a notable daytime enhancement possibly due to strong man-made activities during working hours. The results of the correlation analysis indicated the possible relationship between the Hg concentration and the temperature as well as several pollutant species (e.g., NO2 and NOx). Evaluation of the Hg data in relation with the air mass transport pattern confirms that the Hg concentration levels in this industrial area are affected most eminently by local, rather than distant, pollution sources.  相似文献   

5.
The present work focuses on the fate of two cancerostatic platinum compounds (CPC), cisplatin and carboplatin, as well as of two inorganic platinum compounds, [PtCl4]2− and [PtCl6]2− in biological wastewater treatment. Laboratory experiments modelling adsorption of these compounds onto activated sludge showed promising specific adsorption coefficients KD and KOC and Freundlich adsorption isotherms. However, the adsorption properties of the investigated substances were differing significantly. Adsorption decreased following the order cisplatin > [PtCl6]2− > [PtCl4]2− > carboplatin. Log KD-values were ranging from 2.5 to 4.3 , log KOC from 3.0 to 4.7.

A pilot membrane bioreactor system (MBR) was installed in a hospital in Vienna and fed with wastewater from the oncologic in-patient treatment ward to investigate CPC-adsorption in a sewage treatment plant. During three monitoring periods Pt-concentrations were measured in the influent (3–250 μg l−1 Pt) and the effluent (2–150 μg l−1 Pt) of the treatment plant using ICP-MS. The monitoring periods (duration 30 d) revealed elimination efficiencies between 51% and 63% based on averaged weekly input–output budgets. The derived log KD-values and log KOC-values ranged from 2.4 to 4.8 and from 2.8 to 5.3, respectively. Species analysis using HPLC-ICP-MS proofed that mainly carboplatin was present as intact drug in the influent and – due to low log KD – in the effluent of the MBR.  相似文献   


6.
The Ti02-mediated photomineralization of 8–1000 ppm of methanoic acid, of 6–100 ppm of ethanoic acid, of 6–180 ppm of propanoic acid, and of 6–90 ppm of n-decanoic acid in aqueous solutions was studied at 296± 2 K or 308 ± 2 K, with low and high pressure mercury arc lamps (radiant power in the absorption range 8 and 145 W respectively), using PHOTOPERM® CPP/313 membranes containing immobilized 30±3 wt.% Ti02, and, in parallel runs, 7 wt.% of a synergic mixture of tri(t-butyl)- and tri-(i-propyl) vanadate(V) as photocatalytic promoter. Stoichiometric H202 was used or, in some of the runs, 03, at saturation, as oxygen suppliers. Disappearance of total organic carbon (TOC) was followed as a function of time. To fit kinetic curves up to complete photomineralization, a kinetic model was employed, already used successfully in previous studies, which considers appearance and disappearance of all intermediates, as if they were represented by a hypothetical single molecule, mediating all of them. The photocatalytic activity of trialkyl vanadates was evaluated from quantum yields at “infinite” concentration, with respect to the maximum allowable efficiencies. When using O3, a dark catalysis effect clearly appeared towards intermediate species produced during the photocatalysed degradation.  相似文献   

7.
Three types of surfactants and related reference compounds containing sulfonate (-SO3Na), sulfate (-OSO3Na) or thioether carboxylate (-S-Cn-COOK) group were photodecomposed in an aqueous heterogeneous dispersion system. The photomineralization to SO42−ions was examined for the surfactants with different chemical structures. The photocatalytic activities of TiO2 and ZnO were compared for the sulfonates of dodecylbenzene sulfonate (DBS) and polystyrene sulfonate (PSS), the sulfates of sodium dodecyl sulfate (SDS), and the potassium salts of S-dodecylthioglycol acid (TGA), S-dodecylthiopropionic acid (TPA) and S-dodecylthiomalic acid (TMA). ZnO catalyst exhibited higher activity in the formation of SO42−ion than TiO2 catalyst.  相似文献   

8.
TiO2 powder-containing paper composites, called TiO2 paper, were prepared by a papermaking technique, and their photocatalytic efficiency was investigated. The TiO2 paper has a porous structure originating from the layered pulp fiber network, with TiO2 powders scattered on the fiber matrix. Under UV irradiation, the TiO2 paper decomposed gaseous acetaldehyde more effectively than powdery TiO2 and a pulp/TiO2 mixture not in paper form. Scanning electron microscopy and mercury intrusion analysis revealed that the TiO2 paper had characteristic unique voids ca. 10 μm in diameter, which might have contributed to the improved photocatalytic performance. TiO2 paper composites having different void structures were prepared by using beaten pulp fibers with different degrees of freeness and/or ceramic fibers. The photodecomposition efficiency was affected by the void structure of the photocatalyst paper, and the initial degradation rate of acetaldehyde increased with an increase in the total pore volume of TiO2 paper. The paper voids presumably provided suitable conditions for TiO2 catalysis, resulting in higher photocatalytic performance by TiO2 paper than by TiO2 powder and a pulp/TiO2 mixture not in paper form.  相似文献   

9.
Zhu R  Sun L 《Chemosphere》2005,59(11):1583-1593
Methane fluxes were measured from three exposed tundra sites and four snowpack sites on the Fildes Peninsula in the maritime Antarctic in the summertime of 2002. The average fluxes at two normal tundra sites were −15.3 μg m−2 h−1 and −14.3 μg m−2 h−1, respectively. The fluxes from tundra site with fresh penguin dropping addition showed positive values with the average of 36.1 μg m−2 h−1, suggesting that the deposition of fresh droppings greatly enhanced CH4 emissions from the poor Antarctic tundra during penguin breeding periods. The summertime variation in CH4 flux was correlated with surface ground temperature and the precipitation. The correlation between the flux and PT0, which is the product of the precipitation and surface ground temperature, was quite strong. The diurnal cycle of CH4 flux from the tundra soils was not obtained due to local fluky weather conditions. The fluxes through four snowpack sites were also obtained by the vertical CH4 concentration gradient and their average fluxes were −46.5 μg m−2 h−1, −28.2 μg m−2 h−1, −46.4 μg m−2 h−1 and −17.9 μg m−2 h−1, respectively, indicating that tundra soils under snowpack also consume atmospheric CH4 in the maritime Antarctic; therefore these fluxes could constitute an important part of the annual CH4 budget for Antarctic tundra ecosystem.  相似文献   

10.
采用紫外活化过硫酸盐(UV/PS)工艺降解典型磺胺类抗生素磺胺二甲氧嘧啶(SDM),比较单一紫外(UV)、单一过硫酸盐(PS)和UV/PS对SDM的去除效果,考察各因素对降解动力学的影响,并探究其降解机理,对SDM及其中间产物进行毒性测定和风险评价.结果显示,UV/PS可以加速SDM降解,反应速率常数分别是单一UV和单...  相似文献   

11.
Fenton''s type reaction and chemical pretreatment of PCBs   总被引:3,自引:0,他引:3  
This study evaluates the effects of Fenton's reagent (FR) on the rate and extent of the oxidative degradation of individual mono, di-, tri- and tetrachlorobiphenyls in the commercial mixture DELOR 103, equivalent to AROCLOR 1248. The oxidation effect of FR strongly increased with increasing the molar ratio of Fe2+/H2O2. The most effective oxidation of DELOR 103 (10 μg.ml−1) was achieved in a solution containing 1M H2O2 and 1 mM Fe2+. The FR elimination rate constants of PCB congeners decrease with increasing number of chlorine substituents in the biphenyl molecule and show a good correlation with the values of molecular weights of the PCB congeners and their 1-octanol/water partition coefficients.  相似文献   

12.
Fang GC  Wu YS  Lin JB  Lin CK  Rau JY  Huang SH 《Chemosphere》2006,63(11):1912-1923
Air aerosol samples for TSP (total suspended particulate), coarse particulate (particle matter with aerodynamical diameter 2.5–10 μm, PM2.5–10), fine particulate (particle matter with aerodynamical diameter <2.5 μm, PM2.5) and metallic elements were collected during March 2004 to January 2005 at TH (Taichung Harbor) in central Taiwan. The seasonal variation average concentration of TSP (total suspended particulate), coarse particulate (particle matter with aerodynamical diameter 2.5–10 μm, PM2.5–10) and fine particulate (particle matter with aerodynamical diameter <2.5 μm, PM2.5) were in the range 132–171.1 μg m−3 and 43–49.5 μg m−3, respectively. Seasonal variation of metallic elements Cu, Mn, Zn and Fe in the TSP (total suspended particulate) shows that higher concentration was observed during spring. Seasonal variation of metallic elements Pb, Cr and Mg in the TSP (total suspended particulate) shows that higher concentration was observed during winter. The average metallic element TSP (total suspended particulate) concentration order was Fe > Zn > Mg > Cu > Cr > Mn > Pb in spring. In addition, at the TH sampling site, the average concentration variation of TSP (total suspended particulate) displayed the following order: spring > winter > autumn > summer. However, the average concentration variation of coarse particulate (particle matter with aerodynamical diameter 2.5–10 μm, PM2.5–10) displayed the following order: spring > winter > summer > autumn. Finally, the average concentration variations of fine particulate (particle matter with aerodynamical diameter <2.5 μm, PM2.5) were in the following order: winter > spring > summer > autumn at the TH sample site.  相似文献   

13.
Exposure to environmental contaminants has been shown to alter normal thyroid function in various wildlife species, including the American alligator (Alligator mississippiensis). Abnormalities in circulating levels of the thyroid hormone thyroxine (T4) have been reported in juvenile alligators from several contaminated lakes in Florida. To further elucidate these functional thyroid abnormalities, this study examines the structure of thyroids and circulating T4 concentrations from juvenile alligators collected from three sites of varying contamination on Lake Okeechobee, Florida. The following variables were used to characterize thyroid morphology: epithelial cell height, width and area, percent colloid, and follicle area. These variables were compared among study sites and between genders. No difference was detected in epithelial cell height, epithelial cell area, or follicle area among the sites, whereas significant differences in epithelial cell width (p=0.02) and percent colloid (p=0.008) were found. Animals from the most contaminated site (Belle Glade) had significantly greater epithelial cell widths and significantly less colloid present in their follicles compared to animals from the reference site (West). Gender did not have a significant interaction with site for any variable measured. Thyroxine (T4) concentrations were elevated in the intermediately contaminated site (Conservation Area 3A) compared to the other sites (p<0.0001). It is proposed that the disruptions seen in Lake Okeechobee alligators are due to disruptions at both the thyroid and extra-thyroidal tissues.  相似文献   

14.
Zhang JB  Song CC  Yang WY 《Chemosphere》2005,59(11):1703-1705
Cold season (winter and thaw) CH4, CO2 and N2O fluxes from freshwater marshes (47°35′N, 133°31′E, Northeast China) were measured, using the static chamber method. The mean CH4 and CO2 fluxes from Carex lasiocarpa (Cl) were 0.5 ± 0.19 and 6.23 ± 1.36 mg C m−2 h−1, respectively, and those from Deyeuxia angustifoli (Da) were 0.18 ± 0.15 and 5.22 ± 2.48 mg C m−2 h−1, respectively in winter. There was no significant difference between Cl and Da (p > 0.05). The contributions of winter CH4 fluxes were about 5.5% and 3% in the Cl and Da, respectively. Marshes are an important potential N2O sink in winter season in northeast China. During thaw, the CH4 and CO2 emissions rapidly increased, 4.5–6 times of winter emissions. Wetland became a source of N2O. Cold season gases flux from northern wetlands play an important role in the seasonal gas exchange.  相似文献   

15.
To elucidate mechanisms of Cr3+ sorption onto the unaltered solid natural organic matter, the comparative studies of this ion binding from a solution at pH 4.0 onto three selected particle size fractions: 2000–1000 μm, 630–200 μm and 63–20 μm of markedly different HS content and structure, separated by a wet sieving from an overall sample of peat (Brushwood Peat Humus) were carried out. Comparable patterns of COOH groups and CECt confirmed that for cation exchange capacity were responsible mainly cations connected with COO functional groups. It was though found that aliphatic acids in the solid state did not take part in Cr3+ binding, thus the finest studied fraction 63–20 μm of the highest contents of functional groups showed the lowest sorption capacity for Cr3+, while similar patterns of sorbed Cr3+, soluble HS content and base CEC0 indicated that these parameters were directly interrelated. The base ion exchange processes determined by CEC0 (with Ca2+ as a predominant exchangeable cation) appeared to be not the major mechanisms responsible for Cr3+ sorption. For this metal, strong binding to insoluble large molecular weight organic pool two- to threefold prevailed over the ion exchange processes. Very low acid desorption indicated generally low mobility of Cr3+-organic compounds.  相似文献   

16.
The temporal variability and bioaccumulation dynamics of C12–25 n-alkanes, isoprenoids and unresolved aliphatic hydrocarbons (UCM) were studied in a detritivorous fish (Sábalo: Prochilodus lineatus) collected from 1999 to 2005 in the sewage impacted Buenos Aires coastal area. Fish muscles contain huge amounts of n-C12–25 (165 ± 93, 70 ± 48 or 280 ± 134 μg g−1, dry, fresh and lipid weight, respectively) and UCM (931 ± 560, 399 ± 288 and 1567 ± 802 μg g−1) reflecting the chronic bioaccumulation of fossil fuels from sewage particulates. On a temporal basis, lipid normalized aliphatic concentrations peaked by the end of 2001–2002 during the rainiest period over the last four decades (1750 vs. 1083 ± 4.6 mm in 1999, 2004 and 2005), reflecting an enhanced exposition due to massive anthropogenic fluxes from Metropolitan Buenos Aires in wet years. The hydrocarbon composition in fish muscles is enriched in n-C15–17 and isoprenoids relative to a fresh crude oil and settling particulates, with fresher signatures during the 2001–2002 maxima. Fish/settling material bioaccumulation factors (BAFs: 0.4–6.4 dry weight or 0.07–0.94 lipid-organic carbon) plotted against Kow showed a parabolic pattern maximizing at n-C14–18 and isoprenoids. The optimal bioaccumulation window corresponds to highly hydrophobic (log Kow: 7.2–9.9), intermediate-size C14–18 n-alkanes and C15–20 isoprenoids (MW: 198–282; length: 17.9 to 25.4 Å) with melting points ranging from −19.8 to 28 °C. The uptake efficiency is inversely correlated to melting points and increased from 75% for n-C25 to above 90% for n-C14–15 and isoprenoids.  相似文献   

17.
18.
The Ah or 2,3,7,8-TCDD receptor protein plays an important role in mediating the biologic, toxic and genotoxic effects of aryl and halogenated aryl hydrocarbons. An assessment of the physicochemical parameters which facilitate ligand: receptor interactions was determined by multiple parameter linear regression analysis of the relative receptor binding affinities of a series of 7-substituted-2,3-dichlorodibenzo-p-dixoins (Eq 1), 8-substituted-2,3-di (Eq. 2) and 2,3,4-trichlorodibenzofurans (Eq 3). The results demonstrate that substituent lipophilicity (π) and molecular volumes were
(Eq.1)
log (I/EC50) = 1.24 π + 6.10
(Eq.2)
log (I/EC50) = 1.10 π + 5.19
(Eq.3)
log (I/EC50) = 1.09 π + 5.77

the major determinant factors governing interactions between the rat hepatic cytosolic receptor protein and the diverse substituted ligands. It has been shown that there are marked differences in species sensitivity to 2,3,7,8-TCDD (i.e. guinea pig > rat maice > hamster) although hepatic receptor levels in these species are comparable. QSAR analysis of the receptor binding EC50 data for the 7-substituted-2,3-dichlorodibenzo-p-dioxins using rat (Eq. 1), mouse (Eq. 4), guinea pig (Eq. 5) and hamster (Eq. 6) hepatic cytosol demonstrated that there were significant differences in these equations. However it was also noted that

(Eq.4)
log (I/EC50) = 0.95 + 0.93 Es + 5.28
(Eq.5)
log (I/EC50) = 0.94 + 0.579 σp + 6.13
(Eq.6)
log (I/EC50) = 0.70 + 1.227 σp + 6.38

physicochemical factors which are important for ligand-receptor interactions were identical for the most sensitive (guinea pig) and least sensitive (hamster) species. These results indicate that events which follow the initial ligand-receptor interaction must be the major factors which determine species sensitivity to 2,3,7,8-TCDD.  相似文献   


19.
An increasing percentage of agricultural land in Germany is used for oil seed plants. Hence, rape has become an important agricultural plant (in Saxony 1998: 12% of the farmland) in the recent years. During flowering of rape along with intensive radiation and high temperatures, a higher production and emission of biogenic VOC was observed. The emissions of terpenes were determined and more importantly, high concentrations of organic carbonyl compounds were observed during this field experiment. All measurements of interest have been carried out during two selected days with optimal weather conditions. It is found that the origin or the mechanism of formation of different group of compounds had strong influence on the day to day variation of their concentrations. The emission flux of terpenes from flowering rape plants was determined to be 16–32 μg h−1 m−2 (30–60 ng h−1 per g dry plant––540–1080 ng h−1 per plant), in total. Limonene, -thujene and sabinene were the most important compounds (about 60% of total terpenes). For limonene and sabinene reference emission rates (MS) and temperature coefficients were determined: βlimonene=0.108 K−1 and MS=14.57 μg h−1 m−2; βsabinene=0.095 K−1 and MS=5.39 μg h−1 m−2.

The detected carbonyl compound concentrations were unexpectedly high (maximum formaldehyde concentration was 18.1 ppbv and 3.4 ppbv for butyraldehyde) for an open field. Possible reasons for these concentrations are the combination of primary emission from the plants induced by high temperature and high ozone stress, the secondary formation from biogenically and advected anthropogenically emitted VOC at high radiation intensities and furthered by the low wind speeds at this time.  相似文献   


20.
The influence of intact (FLT) and photomodified (phFLT) fluoranthene (0.05, 0.5 and 5 μmol l−1) and herbicide Basagran (5, 20, 35 and 50 nmol l−1) on the germination, growth of seedlings and photosynthetic processes in pea plants (Pisum sativum L., cv. Garde) was investigated. The germination was significantly inhibited already by the lowest concentration (0.05 μmol l−1) of FLT and phFLT, while Basagran caused inhibition only in higher concentrations (35 and 50 nmol l−1). The growth of roots was significantly inhibited by higher concentration 5 μmol l−1 of both FLT and phFLT and the shoot of seedlings was significantly influenced only by photomodified form. The length of root and shoot was inhibited already by concentration 5 nmol l−1 of Basagran. Organic compounds applied on chloroplasts suspension influenced primary photochemical processes of photosynthesis. In chlorophyll fluorescence parameters, the significant increase of F0 values and the decrease of FV/FM and ΦII values by application of FLT (0.5 and 5 μmol l−1) and phFLT (0.05, 0.5 and 5 μmol l−1) was recorded. The maximum capacity of PSII (FV/FM) was influenced by the highest (50 nmol l−1) and the effective quantum yield of PSII (ΦII) already by the lowest (5 nmol l−1) concentration of Basagran. Hill reaction activity decreased and was significantly inhibited by higher concentration (0.5 and 5 μmol l−1) of FLT and phFLT and already by the lowest concentration (5 nmol l−1) of Basagran.  相似文献   

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