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Biomedical subjects

G Dura

Publications and source records attributed to G Dura.

7 recordsLinked to original sources
PubMed2000

The impacts of exposure to organic compounds occurrence of natural origin in thermal water on health in Békés, Hungary.

Deep thermal well (75 degrees C) in Békés county, South East Hungary has been studied. The chemical measurements showed that the thermal water coming from deep geological layers (> 800 m) contains up to 117.2, 35.2, 30.2 and 26 micrograms/l of benzene, toluene, ethylbenzene, and xylenes, respectively. The objectives of this study are: to measure these naturally occurring compounds; estimating to potential risk and hazard index for the population who are using this well mainly for swimming and health baths; assessing the relationship between exposure to environmental chemical and human health; and to stimulate thinking about possible broader uses of risk assessment in identifying and solving public health problems. This paper is not intended as a complete study concerning the four measured compounds. A particular emphasis on benzene which is highly toxic and carcinogenic has been paid. The exposure assessment of benzene based on Risk Assistant model was done. The results showed that the Hazard Quotient (H.Q.) for benzene is more than 1 (requiring actions) and the probability of getting cancer from this exposure is 8E-5 exhibiting high risk for exposed population.

Benzene↗
PubMed2000

Human health risk assessment and management in hazardous waste site contaminated by polychlorinated benzenes.

The improper management of large quantity of chemical waste of a chemical plant caused considerable soil contamination on a temporary hazardous waste disposal site. Initial and action-oriented exposure and health risk assessment was carried out in early 90's. The dominant contaminants were tetrachlorobenzenes (TeCBs), pentachlorobenzene and hexachlorobenzene (HCB). Concentration of TeCBs in top soil layer and vadoze zone exceeded several g/kg. After taking appropriate technical measures quantitative health risk assessment was performed for the target population living in the surrounding settlements. Health risk estimates to HCB ingested or inhaled with suspended dust and soil particulates showed that carcinogenic risk values lower than 10(-6) i.e. below the acceptable risk. For other chlorobenzenes that cause non-cancer toxic effects risk quotients showed marked health hazard inside the dump and small potential risk in vicinity. However, this assessment is based on limited monitoring data, additional information is needed to substantiate this conclusion.

Benzene Derivatives↗
PubMed2000

Sensitivity analysis of risk assessment programs to various input parameters.

HESP 2.b risk assessment program was studied in detail concerning the effect of changing different input parameters for the output ADI values calculated by the program. We used the standard Netherlands 1.0 scenario offered by the program. With this we fixed a lot of input parameters which define the area, human and animal recipient parameters etc. The remaining 31 unfixed parameters were fixed at first to "BASE" input values and the BASE output values were calculated by HESP. Later we chose only one parameter at a time and changed it to an another value. The calculated ADI values were then compared to BASE output values. Seven parameters (soil type, soil usage, site length, soil pH, groundwater fraction in drinking water, basement floor type and Qev) were studied. We found, that changing soil pH or Qev have not any influence on the output ADI values in case of any contaminant. Soil type change has not any effect on the output ADI value in case of Pb or Cd but it seems to play important role in all cases of the four organic material we investigated. Changing soil usage have influence on the output ADI value almost in every case. It seems to be linear relation between the maximal concentration of contaminant and calculated ADI. Changing the site length and basement floor type gave in some cases different ADI values compared to BASE values. If we alter the groundwater fraction in drinking water we got usually different ADI values. With Risc Human risk assessment program we got similar results: nor the changes in soil type, site diameter or soil pH gave any changes in output ADI values. Our results hint that using HESP and Risc Human requires enhanced caution.

Adult↗
PubMed1985

Prediction of toxicity using quantitative structure-activity relationships.

The relationships between toxicity and physicochemical indices of derivates of four chemical groups: of phenol, benzene, aniline and aliphatic amine were studied. Using the Hansch model the feasibility of using the octanol/water partition coefficient, electronic and steric constants was estimated. The acute lethal doses and no effect levels for rats were found not to be predictable using these parameters. The molecular connectivity indices, which describe the topology of the molecular structure have shown a closer relationship to toxicity, than the physicochemical parameters. The application of both physicochemical and molecular connectivity indices provided the best correlations and has been recommended for prediction of toxicological parameters.

Amines↗
PubMed1977

Testing of pesticide toxicity in tissue culture.

The effect of pesticides on cell growth and on the cell layer was examined. The pesticides under study had a similar toxicity for the cell suspension and for the cell layer. Vital staining of the cells allowed a more sensitive determination of the cytotoxic concentrations than did the studies on cell morphology without staining. No correlation was found between the cytotoxic concentrations and LD50 values of mammals. The results were compared with those of earlier experiments on rats in which methods of general toxicology and neurotoxicology were applied. Of the eight compounds tested, in six the tissue culture method proved even more sensitive than did the functional neurotoxicological tests. It is suggested that the in vitro method with cultured cells should be used to complement in vivo functional toxicological procedures.

Animals↗
PubMedDate not supplied

Toxicity of malathion to mammals, aquatic organisms and tissue culture cells.

The effect of malathion on rats (75 and 38 mg/kg bwt), aquatic organisms (100 to 0.001 mg/L), and cells in tissue culture (1000 to 1 ppm) was studied. The conventional toxicological tests conducted for 90 days on rats yielded negative results. ChE activity was determined in plasma, liver, brain and erythrocyte samples. It was significantly reduced in the erythrocytes of animals treated with the larger dose for 21 days and in the cerebral cortex of rats fed either of the doses. ChE activity of rats consuming malathion for 90 days did not differ significantly from that of the controls. In contrast, the psychophysiological examinations utilized in the experiments indicated abnormalities within 21 days. Alterations were observed in the EEG and EMG records after 90 days of feeding. Malathion had a definitely harmful effect on phylogenetically and ontogenetically young aquatic organisms, as well as on the cells of monkey kidney culture. The latter finding suggests that the preparation has a direct destructive effect on cells. Although it is not suggested that malathion should be regarded a toxic agent thus requiring limitation of application, attention is directed to the fact that inconsiderate use of the preparation may involve potential dangers for man and his environment.

Animals↗