Photodecomposition of Isofenphos (O‐ethyl‐O(2‐isopropoxycarbonyl)‐phenyl)‐Isopropylphos‐Phoramidothioate)

Photodecomposition of the organophosphorus insecticide isofenphos (O‐ethyl‐O‐(2‐isopropoxy‐carbonyl)‐phenyl)‐N‐isopropylphosphoremidothioate) has been studied in solution, on glass and soil surfaces. Isofenphos underwent oxidation from P = S to the P = O group and deesterification on irradiation in hexane and methanol. Photoproducts were isolated and identified by spectroscopic methods.     

New O,O‐dimethyl (2,2,2‐trichloro‐1‐carbamoyloxy)‐ethyl phosphonates and their biological activity

A series of fifteen carbamoyl derivatives of O,O‐dimethyl (2,2,2‐trichloro‐l‐hydroxy) ethyl phosphonate (trichlorphon) was synthesized. A number of them showed higher insecticidal activity, having at the same time lower toxicity than the starting biologically active structure. A waste‐free technology for the production of the more promising representatives of this series could possibly be developed in the future.     

Biodegradation of plasticizer di‐n‐butyl phthalate (DBP) by immobilized microbial cells

Microorganisms capable of degrading di‐n‐butyl phthalate (DBP) were isolated by acclimated and enrichment technique. The adaptation of microorganism to DBP was investigated. The microbial cells were immobilized on ceramic particles. The results showed that the biomass adsorbed on ceramic particles can reach 85 mg dry weight/g carrier. The immobilized microbial cells were used for the treatment of wastewater containing DBP. The results demonstrated that the DBP concentration of the outlet reached the stationary‐state level of less than 1.0 mg/1 within 2 days at inlet DBP concentration of 100mg/l and 12h of hydraulic retention time.     

Toxicity of 3‐Amino‐1: 2: 4‐Triazole to Activated Sludge Biomass

3‐amino‐1: 2: 4‐triazole (AT), a potent weed killer, added to activated sludge, caused immediate and drastic reduction in oxygen uptake by biomass. AT, a known specific inhibitor of catalases of animal and plant sources, did not appreciably alter catalase of activated sludge biomass.     

Mutagenic activity of transition‐metal complexes: Relation structure‐mutagenic and antibacterial activity for some Pd(II), Pt(II) and Rh(I) complexes†

The inhibitory and mutagenic action of some Pd(II), Pt(II) and Rh(I) complexes towards various bacterial strains has been evaluated, and some correlations have been found between the chemical behaviour of the complexes and their selective biological activity: most of the complexes cause only a DNA damage repaired by the excision repair system. Particularly, the Rh(I) complexes used in this work show selective antibacterial effects on defective but no effect on wild‐type strains.     

Synthesis and antithyroid activity of 6‐n‐propyl‐5‐arylazo‐2‐thiouracils †

The synthesis of several 6‐n‐propyl‐5‐arylazo‐2‐thiouracil derivatives was achieved. The antithyroid activity of these derivatives has been determined using iodine‐125‐thiocyanate discharge technique in rats, and 6‐n‐propyl‐2‐thiouracil (PTU) as a standard. None of the 5‐arylazo‐2‐thiouracil analogs showed antithyroid activity as compared to PTU. The structure‐activity relationships (SAR) of position 5 in the PTU molecule and the requirements for better binding to the proposed receptor are discussed.     

Potentiometric studies of mixed complexes of cobalt(II) and copper(II) with l‐Asparagine and adenine

A potentiometric titration technique has been used to determine the stability constants for the various complexes of Co(II) and Cu(II) with L‐asparagine and from DNA base, e.g. adenine. Stability constants of ternary systems have been evaluated by the method suggested by Irwing‐Rossotti. In addition, the conditional constants were calculated as a function of pH. The maximum values of the conditional formation constants were found to be in accordance with the mixed‐ligand complex formation constants in a determined pH region. Furthermore, the molar fractions of different species from mixed complexes were calculated by means of formation constants. The values of stability constants of mixed‐ligand complexes at 25°C are as follows: log K= 5.25 for Co(II)‐L‐asparagine‐adenine; log K= 9.30 for Cu(II)‐L‐asparagine‐adenine. The ionic strength was kept constant at I = 0.20 with NaClO₄.     

Gas phase equilibria for dibenzo‐p‐dioxin,dibenzo‐p‐furan and biphenyl in the C‐H‐O system

The gas phase equilibrium calculation for the C‐H‐O system at atmospheric pressure and temperature from 773 to 1773 K at intervals of 250 K was performed to understand the generation and decomposition behavior of dibenzo‐p‐dioxin (DD), dibenzo‐p‐furan (DF) and biphenyl (BP) in relation to the existing oxygen potential. It is possible to categorize these results into three regions from the viewpoint of this potential: region (A), region (B) and region (C) are that of the higher, modest and lower oxygen potential, respectively. In region (A), the equilibrium amounts of DD, DF and BP are nearly zero. In region (B), they increase once and then decrease with rise in temperature. In the most characteristic region (C), they increase uniformly with rise in temperature.     

Polychlorinated dibenzo‐p‐dioxins and dibenzofurans (PCDD/Fs) in dated environmental samples,and their connection to known sources

This article investigates available environmental data from measurements of the everywhere present contaminants polychlorinated dibenzo‐p‐dioxins and dibenzofurans (PCDD/F) in dated trends in sediment, soil and herbage from locales in Europe and North America. The PCDD/F data are examined in relation to potential major PCDD/F sources based on volume: wood and coal, example of natural combustion; pentachlorophenol (PnCP), example of chlorinated aro‐matics; and polyvinyl chloride (PVC) pyrolysis, example of chlorinated aliphatic. Collected PCDD/F data of congener sums and 2, 3, 7, 8‐substituted congener (PCDD/F profiles) have been investigated with multivariate methods: principal component analysis (PCA) and partial least squares projection to latent structures model (PLS). The results show that PCDD/F data from 12 locales can be separated in one to three independent profiles. Normally one profile is related to the PCDD/F found in PnCP and another to combustion. A subtype of the ‘PnCP’ and ‘combustion’ profiles indicates PCDD/F contributions from PVC‐related combustions. The environmental profiles exhibit some differences from the suggested sources. The relatively unprotected PCDD/F related to PnCP is suggested to have passed photolytic and/or thermal dechlorinations. Lower‐chlorinated congeners in environmental profiles related to combustion appear to have been influenced by environmental distribution processes. PCDD/F data before industrial production of chlorinated organics have only limited similarity to PCDD/F in technical PnCP profiles; an average 4.6% of the PCDD/F is related to PnCP. This suggests that PnCP similarity in recent deposition profiles cannot be a result of environmental transformation. The average proportion of PnCP‐related PCDD/F profile in recent depositions is 35% with North America high (average 57%) and Europe low (average 24%).     

Characterization studies of a semi‐automated separation method for analysis of non‐ortho substituted polychlorinated biphenyl (PCB) congeners in environmental samples

Non‐ortho substituted polychlorinated biphenyl (PCB) congeners can account for the majority of the dioxin‐like toxicity in environmental samples, yet analysis for these congeners is difficult because other PCB congeners co‐elute with them in most Chromatographic methods. An automated method was developed which incorporates a porous graphitic carbon (PGC) column which is commercially available. Non‐ortho substituted congeners were successfully separated from interfering PCB congeners. Recoveries of non‐ortho substituted congeners were consistently reproducible (CV < 9%) when chicken eggs were fortified with individual congeners.     

Antimutagenic and bacteriostatic activities of Schiff‐base compounds derived from aminoguanidine,semicarbazone and thiosemicarbazone and a copper(II)‐coordination complex

The Schiff‐base aminoguanidine compounds including a resorcylidene aminoguanidine copper(II) complex that were synthesized at our laboratory posses non‐mutagenic properties when tested with Ames test using Salmonella typhimurium TA97, TA100 and TA102 bacterial strains. These compounds were tested as possible pharmacological agents in preventing a wide array of illnesses. Additionally, some of these compounds exhibit strong antimutagenic and bacteriostatic activity. Nitrovin, a known mutagen, was used in the antimutagenicity tests as the inducer. A three‐dimensional projection of the copper(II) complex was derived by the semi‐empirical method ZINDO/1 to obtain additional information about its structure, and to help elucidate a possible mechanism of action.     

Crystallization and X‐ray structure of 3,3’,4‐trichlorobiphenyl (PCB 35)∗

A method for the preparation of single crystals of PCB 35 suitable for single crystal X‐ray structure determination was developed. This method has already been proven suitable for 2,4'‐dichlorobiphenyl and may prove useful for other PCBs or related compounds. The crystals of PCB 35 are orthorhombic, spacegroup P2₁22₁ (a= 10.665(8), 6 = 3.825(3), c= 14.086(9) Å) and the structure was refined to R = 0.094 for 156 unique observed reflections and 43 parameters. Although the crystals were of poor quality, the structure determination unequivocally confirmed the substitution pattern of the biphenyl moiety by Cl atoms inferred previously from spectroscopic methods. The dihedral angle between the planes of the two phenyl rings is 33(2)°.     

Quantitative structure‐activity relationships of hydrophobic organic chemicals 1

Quantitative structure‐activity relationships of hydrophobic organic chemicals were studied based on equations we established. Results showed that observed toxicity of hydrophobic organic chemicals were correlated to two physical‐chemical parameters: reaction equilibrium constant of target molecule‐organic chemical; octanol/water partition coefficient. Regression results showed that the molecular connectivity index of first‐order was an ideal parameter instead of the equilibrium constant. Good relationships between toxicity data and the two parameters were found for three aquatic organisms with a wide range of chemicals.     

Formation of polychlorinated biphenyls and chlorinated benzenes by heating of bis(2,4‐dichlorobenzoyl) peroxide

The formation of di‐, tri‐, and tetrachlorobenzenes, and di‐ to hexachlorobiphenyls was demonstrated after thermal degradation of bis(2,4‐dichlorobenzoyl) peroxide alone or in various solvents at 250 °C with yields of up to several percent. Possible radical reactions between solvents and the solute are suggested. PCB congeners are also present in silicone rubber crosslinked by this peroxide.     

Concentrations of polychlorinated dibenzo‐p‐dioxins and dibenzofurans in outdoor air of North‐Rhine‐Westphalia,Germany

Measurements of polychlorinated dibenzo‐p‐dioxins (PCDD) and dibenzofurans (PCDF) in outdoor air of North‐Rhine‐Westphalia were carried out. Fifty‐six samples were taken at different sites in areas of different land use and emission structures. A special filter system allowed analysis of the gas and particle phases separately. It was found that higher chlorinated PCDD/PCDF (7 or 8 chlorine atoms) are collected on glass fiber filter and lower chlorinated PCDD/PCDF (tetra‐ and penta‐CDD/CDF) are absorbed on polyurethane foam. The following isomers were determined: OCDD, OCDF and 11 isomers with chlorine substitution in 2,3,7,8‐position as well as the sum of TCDD, PeCDD, HxCDD, HpCDD, TCDF, PeCDF, HxCDF, HpCDF and the sum of PCDD (4–8) and PCDF (4–8). No 2,3,7,8‐TCDD could be detected but 2,3,7,8‐TCDF was found at 15 sites. Mean concentration in the Rhine‐Ruhr‐District for the sum of PCDD (4–8) and PCDF (4–8) was 3.2pg/m³ and 5.5pg/m³ respectively. Detection limit for TCDD and PCDD/PCDF (5–8) was 0.1–0.2 pg/m³ and 0.005–0.015 pg/m³ respectively. There is no significant indication that 2,3,7,8‐chlorinated isomers of PCDD/PCDF are predominantly decomposed by photochemical reactions in outdoor air.     

Evaluation of linear alkylbenzenesulfonate (LAS) biodegradability in sediment by solid‐phase extraction and HPLC analysis

The linear alkylbenzenesulfonate (LAS) sorption on environmental sediments has been known long ago. Their high concentrations reflect the massive input of these chemicals from household and industrial uses. However few attempts were made to identify biodegradation metabolites of LAS in sediment. In this report, a method for the determination of these compounds in sediment samples by high‐performance liquid chromatography (HPLC) is described. The first step of our work was performed by solid‐phase extraction with octadecyl‐bonded silica (C18) mini‐columns and provided a suitable recovery of LAS (90 ± 5%) and most metabolites. Furthermore, laboratory investigations led to study the behaviour of LAS in sediment. The environmental samples used for this purpose were collected from a pond (named étang de Bolmon) located in the French Mediterranean coast. Our results were in agreement with an aerobic biodegradation process of LAS that occurred only with high values of sediment redox potential and needed the samples to be vigorously shaken to ensure adequate mixing and suspension of particulate material. In a stagnant sediment or under anaerobic conditions, LAS is not degraded. p‐Sulfophenylacetic acid and p‐sulfocinnamic acid were evidenced as predominant metabolites and were found not to be persistent.     

Heavy metal contents of the sperm whale physeter macrocephalus and the bottle‐nosed dolphin tursiops truncatus beached on Languedoc‐Roussillon seaside (Mediterranean,France)

The contamination of Sperm Whale Physeter macrocephalus and bottle‐nosed dolphin Tursiops truncatus by lead is less than detection limit, insignificant by cadmium and nickel, not very high by copper and quite high by zinc. On the other hand, the concentration of mercury, very low for Sperm Whale, is very high for bottle‐nosed dolphin.

The pollution of Physeter macrocephalus is significantly lower than that of dolphin Stenella coeruleoalba and probably that of other species of cetaceans living near the coast; this might be due to its pelagic life and its diet.

The mercury pollution of Tursiops truncatus (especially that of one of the two subjects analyzed) is quite similar to that of Stenella coeruleoalba. This might be due to the fact that Tursiops truncatus can live in the open sea just as well as close to the seashore.     

PCB and PCT levels in cultivated and free‐living mussels of galicia (North west Spain)

PCB and PCT residues were measured in free‐living (FM) and cultivated mussels (CM) from ten sites in Galicia by gas chromatography with electron capture detector and capillary column. The level of PCB₁₂₆₀ and PCT₅₄₆₀ in FMs increases going from Muros‐Noya to Vigo estuarine bay. There was a trend of increase from north to south.     

Recovery efficiency of the hydrofluorocarbon (HFC‐134a) by activated carbons of different physicochemical properties

The adsorption characteristics of 1,1,1,2‐tetrafluoroethane (HFC‐134a) on activated carbon were investigated to evaluate the recovery efficiency of HFC‐134a by six activated carbons (two granular activated carbons (GAC1 and GAC2), one high‐surface area activated carbon (HAC), and three activated carbon fibers (ACF10, ACF15, and ACF20)). HFC‐134a adsorption on the activated carbons increased with increase in the specific surface area and pore volume of the activated carbon. The differential heat of the HFC‐134a adsorption decreased with increase in the percentage of the micropore volume to the total pore volume. The adsorption model of HFC‐134a on the activated carbon could be based on the Langmuir model. The constant a of the Langmuir plot of HAC and ACF20 is smaller than GAC1 or GAC2 and ACF10 or ACF15, respectively. The constant W_s of HAC has the largest value. The constant a was correlated to the heat of adsorption. It is concluded that the largest amount of HFC‐134a was adsorbed on HAC, and the least amount of interaction occurred between HFC‐134a and the HAC. The amount of HFC‐134a adsorbed on the activated carbons over time was applied to the Sameshima equation. The adsorption rate constant of HFC‐134a on HAC was the largest. The HAC could be suitable for the recovery of HFC‐134a.     

Mass spectral studies of 6‐n‐propyl‐2‐thiouracil,its oxygen,selenium and fluorinated congeners∗

The electron ionization mass spectra of the clinically used antithyroid agent 6‐n‐propyl‐2‐thiouracil (la), its minor metabolite, 6‐n‐propyluracil (lb) and their synthetic selenium and fluorinated analogs (1c and d) have been examined. The fragmentation pattern of these thiouracil and selenouracil studied bear strong similarities with those previously derived from a study of uracil analogs. Thus, the first step in the fragmentation is a retro Diel‐Alder decomposition with the loss of HCNX (X=O, S or Se) and the production of an ion radical which undergoes further fragmentation pathways which are discussed. 6‐n‐Propyl‐2‐selenouracil (1c) did show more complicated spectra due to the six natural isotopic abundance exhibited by the selenium atom. While the fluorinated analogs (1d) did substantiate the fact that the fragmentation pattern of these derivatives proceed through fragmentation between C₂ and N₃ bond since this produces the more resonance stabilized ion.