Photoreduction of parathion ethyl †

Photodegradation of parathion ethyl in presence of unsaturated biomolecules takes place by sufficient reduction of the phenyl nitro group. Main products are N,0‐dialkenyl hydroxylamino, cis/trans azo, and azoxy derivatives of parathion.     

Aliphatic and aromatic halocarbons as potential mutagens in drinking water

Chlorinated phenols are either products of industrial chemical processes or the result of chlorination of drinking water. Often, the formation of chlorinated phenols is based upon naturally occurring phenol. The following chlorinated phenols have been selected for testing in the Ames‐test for their mutagenic activity: 3‐chlorophenol, 4‐chlorophenol, 2,3,6‐, 2,4,5‐, 2,4,6‐trichlorophenol, 4‐chloro‐2‐methylphenol and 4‐chloro‐3‐methylchlorophenol. The tester strains TA97, TA98, TA100 and TA104 were employed. All tested compounds produced mutagenic activity at least in one tester strain. The highest numbers of revertants were detected for 2,3,6‐ and 2,4,6‐trichlorophenol. But in contrast to the other substances, these two induced only frameshift mutations in presence of a metabolizing system. The evidence of their presence in drinking water and of their mutagenic activity makes them to a potential health hazard.     

Synthesis of 2,5‐diaryl‐2,4‐pentadienenitriles and their spectral,fluorescence and mutagenic properties

The condensation of substituted cinnamaldehydes and arylacetonitriles using sodium ethoxide in ethanol at room temperature afforded 2,5‐diaryl‐2,4‐pentadienenitriles in good yield. The structure of the reaction products was established on the basis of their infrared, nuclear magnetic resonance and elemental analysis data. Two representative compounds were studied for their mutagenic activity. One of them showed a weak mutagenicity while the second showed a high mutagenic activity in TA97a Salmonella strain. Both were negative in TA100. Some of these pentadienenitriles showed fluorescence in solutions.     

A model for approving and controlling sea water pollution for recreational activity

A model for assessing approval of a beach for recreational water activity was proposed. The model is based upon a sanitary survey together with intensive microbiological monitoring three times a day, five times a week for a month. In highly populated areas, continuous surveys once a day, five days a week are needed in order to assure the cleanliness and safety of these beaches.

Due to our intensive monitoring system, we can assure that Tel‐Aviv has one of the cleanest beaches near a metropolitan area in the Mediterranean Sea.     

Regression models for octanol‐water partition coefficients,and for bioconcentration in fish

Octanol‐water partition coefficients (P) of a number of organochlorine insecticides (OCs) are presented. The merits of log‐log regressions between experimental ? values and calculated estimates of P, solute activity coefficients in water, solute molecular surface area data, and reversed‐phase liquid‐chromatographic net retention data, are critically evaluated for several classes of pollutants: polycyclic aromatic hydrocarbons (PAHs), chlorinated benzenes, chlorinated biphenyls and OCs. Special attention is paid to the predictive accuracy of such semi‐empirical regressions in connection with possible effects of solute molecular shape and polarity.

Finally, bioconcentration and ‐accumulation of hydrophobic pollutants in fish are briefly discussed.     

Cleanup by solid‐phase extraction and HPLC of organochlorine insecticides and PCBS in various nonfatty and fatty samples

An accurate, simple and cheap extraction and cleanup procedure for capillary GC analysis of organo‐chlorine insecticides (OCs) in vegetables (cabbage and carrots) at the ng/g level, and for soil at the μg/g level is presented. The cleanup is carried out on solid‐phase extraction (SPE) cartridges, filled with 500 mg silica, 1 g of deactivated Florisil (10% w/w water), and 100 mg of anhydrous sodium sulphate. Recoveries >90% are obtained. The cleanup of OCs in fatty samples on an HPLC LiChrosorb Si 100 column is evaluated for subsequent capillary GC analysis. Fractionation of OCs and Aroclor 1254 and 1260 on an HPLC Nucleosil 100 column appears to be satisfactory.     

Diazinon leaching through a sandy soil amended with different humic materials

The water leaching of diazinon (O,O‐diethyl‐O‐2‐isopropyl‐6‐methylpyrirnidin‐4‐yl phosphoroth‐ioate) through soil columns, was studied after column amendments with two well characterized humic acids (HA), in both liquid and solid state, and with the original raw organic materials, an oxidized coal and a leonardite, from which the HA were extracted. The percolation curves and the pesticide distribution over the soil columns showed that the addition of the raw organic materials and the solid HAs reduced significantly the mobility of the pesticide along the soil column. The oxidized coal was more effective than the leonardite original material; the different origin of the two carbon‐rich materials had an influence on the diazinon movement along the soil columns and such difference was enhanced with increasing addition rates. Moreover, incubation at field capacity for two months of the soil columns treated with raw oxidized coal and leonardite, largely enhanced the described effects on pesticide behaviour. A complete adsorption of diazinon on columns and a practical absence of leaching was observed when the HA from both materials were added in dissolved form. These results were explained with the swelling of the humic micelles in water and the enhanced availability of inner hydrophobic surfaces for the strong adsorption of diazinon. The water diffusion into the solid humic materials after two months incubation, also explains their high pesticide retention capacity. This work indicates the usefulness of either solid o dissolved humic substances, with the proper hydrophobic character, in preventing the vertical leaching of non‐polar organic pesticides in soils.     

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.     

Determination and QSPR analysis of log Kow and log Koc for fluorine containing benzene derivatives

Octanol‐water partition coefficients (Kow) and soil organic carbon sorption coefficients (Koc) were determined for 14 fluorinated benzene derivatives. Quantitative structure‐property relationships were developed using molecular connectivity indices and quantum chemical parameters to analyze the most significant factors influencing these physico‐chemical properties of the compounds. The substitution by F in benzene derivatives has greater influence on Koc than on Kow.     

Removal of pesticides from water samples by adsorption with fatty acids supported on barium sulphate

Oleic or linoleic acid supported on barium sulphate was used to remove atrazine and terbuthylazine in the range of 0.1–2.0 μg/L using spiked water samples. The sorption of atrazine depends on the stirring time and the best value is 150 min. Terbuthylazine is removed well with a stirring time of 60 min and its adsorption is about 90%. Detection of the residual pesticide in treated waters, after solid phase extraction (SPE), was carried out by GC‐MS operating in selected ion monitoring (SIM) using a calibration curve by direct injection of standard solutions of herbicide.