Physiological and biochemical responses of several freshwater algae to a mixture of metals

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 ($\text{Scenedesmus}$, $\text{Chlorella}$, $\text{Anabaena}$ and $\text{Navicula}$) 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 $\text{Ankistrodesmus}$. The depuration and exchange of the amino acid analogue were not affected by the metal mixture. The nitrogenase activity of $\text{Anabaena}$ was, however, reduced in the presence of the metal mixture.     

Photochemistry of pesticides, 3: Photolysis of methyl 2-benzimidazolecarbamate (Carbendazim) in the presence of singlet oxygen

The photolysis of methyl 2-benzimidazolecarbamate (Carbendazim, $\text{1}$) in methanol and in the presence of singlet oxygen, was studied. Dimethyl oxalate $\text{4}$, 2-aminobenzimidazole $\text{7}$, benzimidazole $\text{9}$, N,N′-dicarbomethoxyguanidine $\text{13}$, monocarbomethoxyguanidine $\text{14}$, monocarbomethoxyurea $\text{15}$, and 2-guanidinobenzimidazole $\text{17}$, were isolated and identified in this reaction.A mechanism that accounts for the formation of the photoreaction products, is presented.     

Studies on the acute toxicity of fluoride ion to stickleback,fathead minnow,and rainbow trout

We have studied the acute toxicity of fluoride ion to $\text{Gasterosteus aculeatus}$, $\text{Pimephales promelas}$, and juvenile $\text{Salmo gairdneri}$. 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 $\text{Salmo gairdneri}$.     

The effect of cadmium ion on the growth,photosynthesis, and nitrogenase activity of Anabaenainaequalis

The growth of $\text{Anabaena}$$\text{inaequalis}$ 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 $\text{A}$. $\text{inaequalis}$, with complete inhibition at 4 and 20 ppm respectively. Cell sensitivity increased directly with exposure time. Cadmium caused some cell lysis of $\text{A}$. $\text{inaequalis}$ 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.     

Metabolism of 3-hydroxybenzo (a) pyrene in rat,isolated hepatocytes and kidney

After intravenous injection of 3-hydroxybenzo (a) pyrene into rat, benzo (a) pyrene-diols were detected in urine, and $\text{in vitro}$ experiment using isolated hepatocytes and sliced kidney also indicated the metabolism of 3-hydroxybenzo (a) pyrene to diol derivatives. THese results suggested the presence of unknown metabolic pathway of benzo (a) pyrene-phenols such as 3-hydroxybenzo (a) pyrene to diol derivatives both $\text{in vivo}$ and $\text{in vitro}$.     

Photoreaktionen von Stickstoffdioxid mit Indan in Lösung

Photochemical reactions of nitrogendioxide and indane $\text{1}$ were investigated in homogeneous phase with wavelengths above 290 nm. Nitro- and hydroxyindanes were isolated as the principal transformation products. The resulting photoproducts $\text{2}$ - $\text{9}$ could be identified by spectroscopical methods such as ¹H-NMR, UV, IR and MS.     

Kinetics of oxidation of methylhydrazines in water. Factors controlling the formation of 1,1-dimethylnitrosamine

The kinetics of oxidation of methylhydrazine ($\text{MMH}$) and 1,1-dimethylhydrazine ($\text{UDMH}$) 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 ($\text{NDMA}$) depends upon the initial $\text{UDMH}$ concentration. In dilute solutions $\text{NDMA}$ is not formed, but in more concentrated solutions, $\text{NDMA}$ formation increases with increasing $\text{UDMH}$ content, reaches a maximum at 60–80% $\text{UDMH}$ (by volume) and then decreases. The $\text{NDMA}$ 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 $\text{NDMA}$ formation.     

Chlordane compounds residues in Weddell seals (Leptonychotesweddelli) from the Antarctic

Weddell seal samples taken from the Antarctic have been found to be contaminated with chlordane compounds. ΣChlordane ($\text{cis}\text{-chlordane}\text{+}\text{cis}\text{-nonachlor}\text{+}\text{trans}\text{-nonachlor}\text{+}\text{oxychlordane}$) was present in blubber of seals at the range of 12 - 62 ng/g fresh weight. The order of chlordane compound concentrations was $\text{trans}\text{-nonachlor}\text{>}\text{oxychlordane}\text{>}\text{cis}\text{-nonachlor}\text{>}\text{cis}\text{-chlordane}$. Relative aboundance of $\text{cis}$-chlordane in Σchlordane is higher than that in humans. A probable explanation for their occurrence in the Antarctic is an airborne transport.     

Synthesis of anti-12-hydroxyendrin and 12-ketoendrin,the two major mammalian metabolites of endrin

The first synthesis of $\text{syn}$ and $\text{anti}$ 12-hydroxylated derivatives of endrin (and thence 12-ketoendrin) has been accomplished in three steps starting from hexachlorocyclopentadiene and 7-benzoyloxy [2.2.1]hepta-2,5-diene.     

Environmental photochemistry of PCDDs. Part I. Kinetics and quantum yields of the photodegration of 1,2,3,4,7-penta- and 1,2,3,4,7,8-hexachlorodibenzo-p-dixin in aqueous acetontrile

For the determination of the quantum yields of 1,2,3,4,7-pentachlorodibenzo-$\text{p}$-dioxin ($\text{1}$) and 1,2,3,4,7,8-hexachlorodibenzo-$\text{p}$-dioxin ($\text{2}$), ten Pyrex glass photochemical cells were constructed and their correction factors determined. Quantum yields at 313 nm for $\text{1}$ and $\text{2}$ 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 $\text{1}$ and $\text{2}$ 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 $\text{1}$ and $\text{2}$, 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.     

Photochemistry of 1-nitro-2-phenylnaphthalene available to the environment

Photolysis (254 nm, 72h) of 1-nitro-2-phenylnaphthalene $\text{1}$ in methanol gave 2-phenyl-1,4-naphthoquinone-4-monoxime $\text{2}$, 2,2′-diphenyl-4,4′-binaphth-1,1′-diol $\text{3}$ and 2,2′-diphenyl-4,4′-binaphth-1,1′-dione $\text{4}$. 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 $\text{2}$ or (b) oxidative coupling and solvolysis into the binaphthol $\text{3}$ and followed by oxidation into the binaphthone $\text{4}$.     

Toxicite aigue du vanadium vis-a-vis de quelques especes benthiques et phytoplanctoniques marines

$\text{Acute toxicity of vanadium to some marine benthic and phytoplanktonic species}$The acute toxicity of vanadium as sodium metavanadate to three benthic ($\text{Carcinus}$$\text{maenas}$, $\text{Mytilus}$$\text{galloprovincialis}$, and $\text{Nereis}$$\text{diversicolor}$) and three phytoplankton species ($\text{Dunaliella}$$\text{marina}$, $\text{Prorocentrum}$$\text{micans}$ and $\text{Asterionella}$$\text{japonica}$) 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: $\text{D}$. $\text{marina}$ (0.5 ppm), $\text{A}$. $\text{japonica}$ (2 ppm), $\text{P}$. $\text{micans}$ (3 ppm), $\text{N}$. $\text{diversicolor}$ (10 ppm), $\text{C}$. $\text{maenas}$ (35 ppm), $\text{M}$. $\text{galloprovincialis}$ (65 ppm).     

Effects of some pesticides on Rhizobiomjaponicum and on the seed germination and pathogens of soybean

The relative toxicity of 23 pesticides, including 21 fungicides and two pyrethroid insecticides, on $\text{Rhizobium}$$\text{japonicum}$, four soybean pathogens, $\text{Fusarium}$$\text{oxysporum}$, $\text{Phytophthora}$$\text{megasperma}$, $\text{Phytophthora}$$\text{parasitica}$ and $\text{Pythium}$$\text{ultimum}$, and germination of soybean seeds was compared with a highly toxic broad spectrum germicide, HgCl₂ under laboratory conditions.