Genotoxicity of chromium in vitro on yeast: Interaction with DNA†

The genotoxicity of chromium chloride was investigated in cells of D₇ strain of Saccharomyces cerevisiae harvested either from logarithmic or stationary growth phase.

A weak induction of mifotic gene conversion and point reverse mutation was obtained when the incubations were performed using phosphate buffer. No genetic effect was observed when the incubations were performed using Tris‐HCl buffer.

The experiments with ⁵¹Cr radiotracer demonstrated that Cr³⁺ ion enters the yeast cells and binds to DNA even if the incubation mixture was performed with Tris HCl buffer. This behaviour could be due to the highest concentration of CrCl₃ that cause some damages to cytoplasmatic membrane.     

Sea water quality monitoring in Rhodes and Cos (Greece)

During the years 1983–1986, a program aiming at monitoring water quality of the most crowded beaches, as well as assessing and minimizing pollution from certain land based sources was carried out in Rhodes and Cos. The program was directed towards inspections of treatment plants as well as laboratory analyses of treated effluents from large hotels. As a result, almost one in four hotels was obliged to construct a new treatment plant. In order to help personnel to improve plant efficiency through day‐to‐day maintenance a three day seminar was held in June 1985. Sea water quality parameters (total coliforms and E. coli) were found to be well below the limits set by E.E.C. directives.     

Hazardous halogenated substances formed during combustion processes

The results of the emissions from combustion processes and/or from fire accidents show the risk to man and his environment and thus the need for strict legislation and critical analysis of unwanted compounds. These substances or their thermolysis products are often due to incomplete combustion or may result from the interaction of various substances.

In the following we report the formation of octachlorostyrene (OCS) and of high‐toxic substances such as polybrominated dioxins (PBrDD's), dibenzofurans (PBrDF's) by the combustion.

In order to determine a possible source of the non‐manufactured compound OCS, we conducted several model experiments in a combustion chamber at various temperatures from 400 °C to 800 °C. The thermolysis of chlorinated solvents like chloroform or of chlorinated aromatice like pentachlorobenzene produced—among other chlorinated substances—OCS as one of the major products.

Analogous combustion experiments with polyester plastics containing decabromodiphenylether as flame retardant and antimony trioxide as Synergist led to PBrDD's and PBrDF's. Here antimony trioxide seems to play an important role because in absence of this oxide, PBrDD's and PBrDF's were not found in our experimental conditions.     

Occupational exposure to airborne aromatic amines in rubber manufacturing: Determination by gas chromatography‐mass spectrometry

Aromatic amines (AAs) are used in a variety of chemical industries and consequently they are the object of great attention in occupational hygiene owing to the carcinogenic effects that many of them have shown. This work outlines a procedure for the determination of occupational exposure to airborne AAs in the rubber industry and the application of this method in a tyre manufacturing plant using p‐phenylenediamines as antiozonants. Samples were collected on a glass fibre filter followed by a silica gel tube and analyzed by GC‐MS/SIM using a capillary column coated with methyl silicone. p‐Phenylendiamines and other AAs probably formed as thermodegradation products were found in concentrations of up to 10 μg/m³ during rubber vulcanization.     

Statistical interpolation model for the description of ground pollution due to the TCDD produced in the 1976 chemical accident at seveso in the heavily contaminated zone “A”;

The influence of NTA on chromium genetic activity was studied in the D7 strain of Saccharomyces cerevisiae. At low dose (subgenotoxic) of sodium chromate (CrVI) (5mM), NTA increased the point mutation while at higher dose (25 mM) of chromate in the presence of NTA a decrease of point reverse mutation was observed. Probably NTA affected either the uptake of Cr(VI) favouring the intracellular reduction to Cr(III), or the recombinational repair of DNA breaks induced by chromate oxiding activity.

An increase of point (reverse) mutation was obtained in the experiments with NTA and chromium chloride, suggesting the hypothesis that NTA might interact with Cr(III) forming NTA‐Cr(III) complexes able to permeate cellular membranes and bind to DNA. In addition NTA genetic inactivity was confirmed.     

Effects of the level of dietary protein on the toxicity of hexachlorocyclohexane in rats

Male albino rats were fed for 28 days from weaning on diets containing 5% (group 1), 10% (group 2) and 21% (group 3, normal protein) protein as casein. At the end of dietary period, HCH was administered daily for 30 days to investigate the interaction between protein deficiency and pesticide toxicity. The results indicated that rats fed a lower protein diet and HCH had a higher mortality, lower rate of growth, increased liver weight and deposition of the pesticide in blood and tissues in larger amounts. Blood pressure (systolic and diastolic) was significantly increased and the heart rate showed tachycardia in low protein exposed animals. A significant increase of total lipids, cholesterol, triglycirides, free fatty acids in serum and tissues of animals exposed to low protein was observed. A close correlation existed between lipid accumulation and storage of HCH in tissues and dietary protein seemed to play an important role in detoxification.     

Hydrolysis of a model surfactant as measured using ACYL coenzyme a synthetase

Hydrolysis of a model nonionic surfactant, [1‐¹⁴C]methyl palmitate, was compared between porcine esterase and lipase using a new hydrolase assay. The assay incorporates acyl coenzyme A (CoA) synthetase to convert the hydrolytic product of methyl palmitate, palmitic acid, to its acyl CoA derivative; palmitoyl CoA is separated from unreacted substrate for quantitation by a highly efficient extraction. The assay achieves quantitative separation between product and substrate due to the high water solubility of the acyl CoA derivative, eliminating the need for time‐consuming chromatographic separations. After 60 min under optimal conditions, only 20 U/mL porcine hepatic esterase hydrolyzed 93.6+0.9% of 20μM methyl palmitate, while 100U/mL porcine pancreatic lipase was required to hydrolyze only 82.3 ±0.7% of the same substrate. While both enzymes detoxified the surfactant, esterase was more efficient, possibly indicating preferential specificity for simple monoesters; generally selective for endogenous triacylglycerols, lipase may be less specific for surfactants. However, together both enzymes may enable mammals to hydrolyze ingested nonionic surfactants from oil spill dispersants, reducing their toxicity.     

Characterization of airborne particulate matter in thessaloniki,Greece

TSP samples, collected at two stations in the area of Thessaloniki during the period July 1987‐June 1988, were analysed for heavy metals (Fe, Pb, Zn, Cu, Mn, Cr, Co, Ni and V). Flame and flameless atomic absorption spectrophotometry was used for metal determinations. Metals determined were characterized with respect to their origin from natural or man‐made emission sources. Source identification was attempted by relation of metal concentrations to wind direction, and interelement correlations.

Results obtained showed that Pb, Zn and Cu are emitted from man‐made sources (traffic, domestic heating, industry), V, Ni and Co are derived partially from natural and man‐made sources, while Cr is mainly soil‐derived.     

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.     

Sorption‐desorption kinetics of some organochlorine insecticides in silt‐water suspensions

Kinetic (batch) sorption and desorption experiments for some organochlorine insecticides in silt‐water suspensions are described. The effect of possible experimental artifacts on the results is examined. The influence of the silt/water ratio on the linear sorption coefficient and on the “nonextractable”; solute fraction is determined. The sorption process is described in terms of some kinetic models.