Biotransformation of the fungicide pentachloronitrobenzene by Tetrahymenathermophila

The protozoan, $\text{Tetrahymena}$$\text{thermophila}$, metabolizes pentachloronitrobenzene to several products, including nitrite, pentachlorothioanisole and pentachloroaniline. The latter two metabolites were identified by gas chromatographymass spectrometry. Pentachlorothioanisole may be produced via a glutathione-dependent pathway, and two key enzymes of this pathway, glutathione transferase and thiol S-methyltransferase, have been detected in crude extracts of this microorganism.     

Long term changes in polychlorodibenzo-p-dioxin concentrations in wood treated with technical pentachlorophenol

Wood samples treated with technical pentachlorophenol (PCP), technical sodium pentachlorophenoxide (NaPCP) and octachlorodibenzo-p-dioxin have been exposed outdoors for periods up to $\text{2}\text{1}\text{2}$ years. Analysis of extracts from the samples show that photolytic reductive dechlorination of highly chlorinated dibenzo-p-dioxins to less chlorinated isomers occurs. However there is no discernible increase in polychlorodibenzo-p-dioxin concentrations in the technical PCP treated wood presumably because further photolytic reactions and volatilisation compete effectively with the photolytic formation. There is no evidence for formation of octachlorodibenzo-p-dioxin (OCDD) in technical PCP treated wood in this study, probably because photolytic destruction and volatilisation compete effectively with formation reactions when the initial OCDD concentration is relatively high.     

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).     

Substitutes for phosphate containing washing products: Their toxicity and biodegradability in the aquatic environment

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 ($\text{Pseudomonas}$$\text{fluorescens}$), algae ($\text{Chlorella}$$\text{vulgaris}$ and $\text{Microcystis}$$\text{aeruginosa}$), crustaceans ($\text{Daphnia}$$\text{magna}$), insects ($\text{Aedes}$$\text{aegypti}$), fishes ($\text{Poecilia}$$\text{reticulata}$ and $\text{Oryzias}$$\text{latipes}$) and amphibians ($\text{Xenopus}$$\text{laevis}$). 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 $\text{Daphnia}$$\text{magna}$ and in case of LAS also with $\text{Poecilia}$$\text{reticulata}$) 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.     

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.     

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.     

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.     

Fate of 3,3′,4,4′-tetrachloroazobenzene in soybean plants grown in treated soils

Three soils of varying organic matter (OM) concentrations (0, 1.7 and 57%) were treated with 3,3′4,4′-tetrachlorazobenzene (TCAB) at the 25 ppm level. Germinated soybeans$\text{(Glycine}$$\text{max}$ (L.) Merr.) were planted in the treated soils, along with controls, and grown for 12 days. The shoots, roots and soil were air-dried and analyzed for TCAB and 3,3′,4,4′-tetrachloroazoxybenzene (TCAOB). TCAB appears to translocate from the treated soil into the plant shoots and roots. Residue levels varied with the percentage organic matter of each soil; levels as high as 58.4 ppm were identified in roots of soybeans grown in 1.7% OM soil and 0.620 ppm in the shoots from 0% OM soil. TCAOB was identified in soil and root extracts with the highest levels in soybean roots grown in 0% OM soil, 0.317 ppm. Residues of TCAB and TCAOB decreased in soil and root and shoot tissues as percentage OM increased. Bound residues of TCAB were released from roots grown in 0% OM soil by refluxing with boron trifluoride methanol (BF₃CH₃OH).     

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.     

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.     

Heavy metal pollution from a point source demonstrated by means of mussels, Mytilusedulis

Heavy metal pollution from a point source has been demonstrated by the levels of mercury in flesh of mussels, $\text{Mytilus}$$\text{edulis}$.     

Effect of fungicidal seed treatments on alfalfa growth and nodulation by Rhizobiummeliloti

A study of the effect of 5 fungicide seed treatments on alfalfa ($\text{Medicago}$$\text{sativa}$ L. var. Vernal) growth and nodulation by $\text{Rhizobium}$$\text{meliloti}$ 102F66 was conducted in a growth chamber. Captan, maneb and thiram exhibited greater toxicity to $\text{R}$. $\text{meliloti}$ and alfalfa plants than that of benomyl and zineb. Recovery of the inhibitory effect was rapid.     

PIXE trace element analysis of an aquatic plant as indicator of heavy metal pollution

A new way of detecting trace elements in water is developed by using charged $\text{P}$article $\text{I}$nduced $\text{X}$-ray $\text{E}$mission (PIXE) analysis of cell walls of $\text{Chara corallina}$, a fresh water alga.     

Measurement of vapour pressures of Fenitrothion and Matacil

Vapour pressures of Fenitrothion and Matacil were measured using a gas saturation method. Polyurethane foam was used to trap the volatilized materials from sand and glass surfaces, and Porapak Q for trapping materials volatilized from leaf surfaces. The vapour pressures (VP) were linearly related to the reciprocal temperature by the equation: $\text{Log (VP)}\text{= 6.3362 ? (}\text{3197.8}\text{T}\text{)}$ for a sand incorporated with Fenitrothion and $\text{Log (VP)}\text{= 8.8316 ? (}\text{4021.4}\text{T}\text{)}$ for a sand incorporated with Matacil. The greatest vapour loss rates were from sand incorporated with fenitrothion, followed by vapour loss rates from glass surfaces; the least vapour loss rate was from leaf surfaces.     

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.     

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 $\text{4}$.     

Interaction of higher marine fungi with the herbicide atrazine. III. Adsorption of atrazine to the marine fungus Dendryphiellasalina

The adsorption of the herbicide ¹⁴C-atrazine to the marine fungus $\text{Dendryphiella}$$\text{salina}$ was studied using sodium azide as an inhibitor of active uptake. Adsorption of atrazine (94 ppb) was found to reach equilibrium within six hours. Adsorption as a function of concentration (9.4 to 468 ppb) conformed to the empirically derived Freundlich equation giving a K value of 6.2. Atrazine on the fungal cell surface was easily desorbed by successive artificial seawater washes indicating a relatively loose binding. The ability of the marine fungus $\text{D.}$$\text{salina}$ to remove ¹⁴C-atrazine from an artificial seawater medium suggests an environmental role in the transport and redistribution of atrazine in estuaries.     

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.     

Enumeration of 2,4-D-degrading microorganisms in soils and crop plant rhizospheres using indicator media; high populations associated with sugarcane (Saccharum officinarum)

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 ($\text{Trifolium africanum}$ L.) soils, and $\text{46400}\text{178}$, $\text{156000}\text{1480}$ and $\text{40700}\text{6170}$ with sugarcane ($\text{Saccharum officinarum}$ 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.