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1.
The growth of was significantly inhibited by Cd2+ concentrations greater than 0.02 ppm (μg/ml) and completely inhibited at 0.06 ppm (Day 12). Cadmium had no significant effect upon the lag phase of growth or the culture doubling time, but caused the retardation phase to arrive sooner. One ppm Cd2+ significantly inhibited the rates of both photosynthesis and acetylene reduction, by . , with complete inhibition at 4 and 20 ppm respectively. Cell sensitivity increased directly with exposure time. Cadmium caused some cell lysis of . and induced an increase in filament length, heterocyst frequency, and a loss of cellular contents from filament apical cells. The cellular abnormalities observed and the fact that toxicity increased with longer exposure times, suggested that metal toxicity resulted from effects of Cd2+ taken up by cells rather than Cd2+ at the cell surface. 相似文献
2.
Weddell seal samples taken from the Antarctic have been found to be contaminated with chlordane compounds. ΣChlordane () was present in blubber of seals at the range of 12 - 62 ng/g fresh weight. The order of chlordane compound concentrations was . Relative aboundance of -chlordane in Σchlordane is higher than that in humans. A probable explanation for their occurrence in the Antarctic is an airborne transport. 相似文献
3.
The photolysis of methyl 2-benzimidazolecarbamate (Carbendazim, ) in methanol and in the presence of singlet oxygen, was studied. Dimethyl oxalate , 2-aminobenzimidazole , benzimidazole , N,N′-dicarbomethoxyguanidine , monocarbomethoxyguanidine , monocarbomethoxyurea , and 2-guanidinobenzimidazole , were isolated and identified in this reaction.A mechanism that accounts for the formation of the photoreaction products, is presented. 相似文献
4.
The kinetics of oxidation of methylhydrazine () and 1,1-dimethylhydrazine () by dissolved oxygen in water has been measured at various acidities as a function of catalyst (cupric ion) concentration. In dilute solutions the oxidation occurs through a cupric ion catalyzed process as well as by an uncatalyzed step. The extent of formation of nitrosodimethylamine () depends upon the initial concentration. In dilute solutions is not formed, but in more concentrated solutions, formation increases with increasing content, reaches a maximum at 60–80% (by volume) and then decreases. The yield appears to approximately parallel the viscosity of the medium, and it is speculated that the factors which control viscosity may also be responsible for governing formation. 相似文献
5.
C.M. Tu 《Chemosphere》1982,11(10):1027-1033
The relative toxicity of 23 pesticides, including 21 fungicides and two pyrethroid insecticides, on , four soybean pathogens, , , and , and germination of soybean seeds was compared with a highly toxic broad spectrum germicide, HgCl2 under laboratory conditions. 相似文献
6.
The acute toxicity of vanadium as sodium metavanadate to three benthic (, , and ) and three phytoplankton species (, and ) were studied. In general the phytoplankton were found to be more sensitive than the benthic organisms used in our experiments. Considering the results from LC50 (9 days) experiments, the organisms, can be classified in the following decreasing order of sensitivity: . (0.5 ppm), . (2 ppm), . (3 ppm), . (10 ppm), . (35 ppm), . (65 ppm). 相似文献
7.
A new way of detecting trace elements in water is developed by using charged article nduced -ray mission (PIXE) analysis of cell walls of , a fresh water alga. 相似文献
8.
The toxicity of nitrolotriacetic acid (NTA), citrex-S-5, sodium alluminium silicate (NAS), carboxymethyloxysuccinate (CMOS), linear alkylbenzene sulfonate (LAS) and soap was examined using bacteria (), algae ( and ), crustaceans (), insects (), fishes ( and ) and amphibians (). The biodegradability of NTA, citrex-S-5, CMOS and LAS was studied in the OECD-test.The acute toxicity of the compounds differed largely with the organisms tested (up to a factor 1,000). Based on the results of the short-term toxicity tests (with all test organisms) and the long-term toxicity tests (with and in case of LAS also with ) the following no-observed-effect concentrations (NOEC) could be derived: LAS 3.2 mg/1; NAS and soap 10 mg/1; CMOS 32 mg/1; NTA 100 mg/1 and citrex-S-5 320 mg/1. However, testing different samples of one test compound may result in marked differences in toxicity (e.g. NAS: a factor 32).All compounds tested showed to be biodegradable as the percentage DOC decreased more than 80% within four weeks. CMOS biodegraded quickly, whereas citrex-S-5 and LAS showed a somewhat slower rate of degradation. In contrast to the other compounds NTA required an adaptation period of 1 week. 相似文献
9.
C.M. Tu 《Chemosphere》1981,10(1):127-134
A study of the effect of 5 fungicide seed treatments on alfalfa ( L. var. Vernal) growth and nodulation by 102F66 was conducted in a growth chamber. Captan, maneb and thiram exhibited greater toxicity to . and alfalfa plants than that of benomyl and zineb. Recovery of the inhibitory effect was rapid. 相似文献
10.
A mixture of ten metals (As, Cd, Cr, Cu, Fe, Pb, Hg, Ni, Se and Zn) at the Great Lakes Water Quality Objective levels was found to reduce the primary productivity of four cultured freshwater algae (, , and ) as well as natural phytoplankton from Lake Ontario water. The metal mixture also caused a reduction in the reproduction and transport of an amino acid analogue (α-aminoisobutyric acid) by . The depuration and exchange of the amino acid analogue were not affected by the metal mixture. The nitrogenase activity of was, however, reduced in the presence of the metal mixture. 相似文献
11.
For the determination of the quantum yields of 1,2,3,4,7-pentachlorodibenzo--dioxin () and 1,2,3,4,7,8-hexachlorodibenzo--dioxin (), ten Pyrex glass photochemical cells were constructed and their correction factors determined. Quantum yields at 313 nm for and in aqueous acetonitrile (4:6 v/v) were (9.781 ± 2.376) 10?5 and (1.096 ± 0.020) × 10?4, respectively. These quantum yields and the measured absorption spectra were used to estimate the environmental phototransformation first-order rate constants and photochemical half-lives of and in water under conditions of variable sunlight intensity during various seasons from solar intensity data available in the literature. In summer, typical half-lives for the phototransformation of and , respectively, near the surface of water bodies at 40° north latitude would be 364 ± 88 and 151 ± 3 h; whilst such values in winter would be 1257 ± 309 and 518 ± 10 h. 相似文献
12.
Photolysis (254 nm, 72h) of 1-nitro-2-phenylnaphthalene in methanol gave 2-phenyl-1,4-naphthoquinone-4-monoxime , 2,2′-diphenyl-4,4′-binaphth-1,1′-diol and 2,2′-diphenyl-4,4′-binaphth-1,1′-dione . Straightforward reactions available to the environment account for the formation of the products: (a) isomerisation of the nitro compound into a nitrite ester followed by either (a) migration of the nitroso group and isomerisation into the oxime or (b) oxidative coupling and solvolysis into the binaphthol and followed by oxidation into the binaphthone . 相似文献
13.
Daniel Barug 《Chemosphere》1981,10(10):1145-1154
The degradation of the biocide bis (tributyltin) oxide by pur cultures of microorganisms has been studied. Attempts to isolate microorganisms able to utilize bis (tributyltin) oxide as sole carbon source, were unsuccessful. Of many bacterial species investigated and degraded sublethal amounts of bis (tributyltin) oxide during aerobic growth in the presence of suitable carbon sources. converted bis (tributyltin) oxide into monobutyltin and small amounts of dibutyltin derivatives. Similar results were obtained with growing mycelium of , and . Microbial conversion of monobutyltin trichloride was not observed. Dibutyltin dichloride was converted into monobutyltin derivatives under certain sterile conditions. 相似文献
14.
Leverett R. Smith Thomas M. Holsen Noel C. Ibay Ronald M. Block Anthony B. De Leon 《Chemosphere》1985,14(9):1383-1389
We have studied the acute toxicity of fluoride ion to , , and juvenile . LC50 values varied with species and (due to precipitation) initial water hardness. Exposure to elevated fluoride levels in water resulted in increased blood fluoride levels in . 相似文献
15.
Population of microorganisms able to degrade 2,4-D (2,4-dichlorophenoxyacetate) were estimated in 4 non-rhizosphere and 5 rhizosphere soils in Natal by a most probable number (MPN) method using 2,4-D-bromocresol purple media to show 2,4-D degradation with the formation of HC1. Confirmation of herbicide degradation in acid 2,4-D tubes was required by subculturing into fresh 2,4-D-and control indicator media. The MPN estimates of 2,4-D-degrading organisms per g of corresponding rhizosphere/control soils were 6100/212 with African clover ( L.) soils, and , and with sugarcane ( L.) soils. The high, stimulated populations of 2,4-D-degrading microorganisms in the sugarcane rhizospheres suggest the possibility of rapid degradaton in the rhizosphere as an additional mechanism for the protection of certain plants against soil-applied herbicides. 相似文献
16.
-Phenyl--naphthylamine, a widely used rubber antioxidant and antiozonant, was biotransformed into -naphthylamine, a potent carcinogen, in a laboratory sewage sludge system. -Naphthylamine appeared to accumulate in the aqueous phase of the system while the undegraded parent compound appeared to be associated with the sludge solids. 相似文献
17.
Uptake, clearance and extent of metabolism of 14C-labelled t-butylphenyldiphenyl phosphate (t-BPDP), tri-m-cresyl phosphate (mTCP), tri-p-cresyl phosphate (pTCP) and triphenyl phosphate (TPP) were studied in rainbow trout () and fathead minnows () using short-term static exposures (50 and 5 μmg/L). Bioconcentration factors for pTCP, mTCP, TPP and tBPDP calculated by use of total radioactivity in whole fish were 1420, 784, 573 and 1096 respectively, for rainbow trout and 928, 596, 561 and 1010 respectively, for fathead minnows. Differences in rates of clearance and biotransformation among the four compounds were more closely related to their ease of hydrolysis than to hydrophobicity. 相似文献
18.
Killifish () were exposed in the laboratory to pentachlorophenol (PCP) at concentrations of 57 to 610 μg PCP/L. Bioaccumulation reached a plateau value of about 53 by 168 hrs and remained at this level for at least 72 hrs. One-half the plateau value was reached in about 25 hrs. Following exposure, fish placed in PCP-free aquaria lost PCP rather slowly (). The depuration data were suggestive of a pool of PCP which was lost more rapidly (). The results of this study are compared to similar studies in other species. The bioaccumulation factors measured in this study agree relatively well with those in other marine species, but are lower than reported for fresh water species. Possible reasons for this difference are discussed. 相似文献
19.
The adsorption of the herbicide 14C-atrazine to the marine fungus was studied using sodium azide as an inhibitor of active uptake. Adsorption of atrazine (94 ppb) was found to reach equilibrium within six hours. Adsorption as a function of concentration (9.4 to 468 ppb) conformed to the empirically derived Freundlich equation giving a K value of 6.2. Atrazine on the fungal cell surface was easily desorbed by successive artificial seawater washes indicating a relatively loose binding. The ability of the marine fungus to remove 14C-atrazine from an artificial seawater medium suggests an environmental role in the transport and redistribution of atrazine in estuaries. 相似文献
20.
This study described an experiment on biotransformation of 2,6-DIPN in carp hepatopancreas. It has already been revealed by the previous studies to be metabolized with enzymatic oxidation in the liver and been postulated a metabolic pathway. These results were confirmed by means of incubation with 2,6-DIPN in carp hepatic microsome preparation with NADPH, and G-6-P as co-factor. It was suggested that DIPN may be mainly metabolized in the hepatic cytochrome P-450 in the microsomes system. The kinetic parameters i.e. apparent Michaelis constant (Km) and maximum velocity (Vmax), in the metabolites formation were also calculated. 相似文献