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At least 37 records · Page 2Linked to original sources
PubMed1976

Effect of dietary di-2-ethylhexyl phthalate on lipid biosynthesis in selected tissues from the rat, in vitro.

Di-2-ethylhexyl phthalate (DEHP), a plasticizer commonly used in the production of polyvinyl chloride plastics, has become an environmental pollutant. At the present time, the biological significance of phthalates in the environment is unknown. In the present studies, we observed that addition of DEHP to a stock diet of rats resulted in marked effects on incorporation of 14C-acetate into lipid by liver and kidney slices; other organs, such as heart, testes, and aorta, were unaffected. Incorporation of 14C-acetate into total lipid of liver (dpm/mg wet wt) from rats fed 0.5% or 1.0% DEHP for 10 or 18 days, respectively, was decreased to ca. 50% of control values. The decreased incorporation into liver lipid is not attributable to any one lipid fraction, inasmuch as incorporation into the phospholipid, sterol + diglyceride, free fatty acid, triglyceride, and sterol ester + hydrocarbon fractions was decreased 30-70% with respect to controls. In addition, the percent distribution of 14C-acetate among the individual phospholipids was ca. 25% lower in phosphatidyl choline of the DEHP-fed rats. In rats fed 0.5% DEHP, incorporation of 14C-acetate into total lipid of kidney was similar to control values, but incorporation into the triglyceride and sterol ester + hydrocarbon fraction was decreased 30-40%, whereas incorporation into the sterol + diglyceride fraction was increased 38%. Livers from DEHP-fed rats were ca. 20% larger than livers from control rats and, at the 0.5% level of DEHP feeding, testes wts were elevated; no significant changes were noted in wts of spleen, heart, aorta, kidney, or body wt gains in rats fed DEHP. These studies emphasize a subtle toxicity of phthalate esters not previously reported and emphasize the need for further biochemical studies to evaluate the effect of phthalates on biological systems.

Animals↗
PubMed1992

Fungal degradation of polyhydroxyalkanoates and a semiquantitative assay for screening their degradation by terrestrial fungi.

The current problems with decreasing fossile resources and increasing environmental pollution by petrochemical-based plastics have stimulated investigations to find biosynthetic materials which are also biodegradable. Bacterial reserve materials such as polyhydroxyalkanoates (PHA) have been discovered to possess thermoplastic properties and can be synthesized from renewable resources. Poly-beta-hydroxybutyric acid (PHB) is at present the most promising PHA; and BIOPOL, its copolymer with poly-beta-hydroxy-valerate (PHV), is already industrially produced (ICI, UK), and used as packaging material (WELLA, FRG). According to the literature, PHA degradation has so far mainly been observed in bacteria; only under certain environmental conditions has fungal degradation of PHAs been indicated. Since fungi constitute an important part of microbial populations participating in degradation processes, a simple screening method for fungal degradation of BIOPOL, a PHA-based plastic, was developed. Several media with about 150 fungal strains from different terrestrial environments and belonging to different systematic and ecological groups were used. PHA depolymerization was tested on three PHB-based media, each with 0.1% BIOPOL or PHB homopolymer causing turbidity of the medium. The media contained either a comparatively low or high content of organic carbon (beside PHA) or were based on mineral medium with PHA as the principal source of carbon. The degradation activity was detectable due to formation of a clear halo around the colony (Petri plates) or a clear zone under the colony (test tubes).(ABSTRACT TRUNCATED AT 250 WORDS)

Biodegradation, Environmental↗
PubMed1979

The assessment of sublethal effects of pollutants in the sea. Review of the problems.

Sublethal effects of pollution may be significant to survival of a stock of marine fish or even a species. Such effects sometimes lead to reproductive failure and have been identified so far only in freshwater systems. Atlantic salmon have disappeared from many streams in Europe and eastern North America, partly as a result of pollution in their freshwater spawning areas and in their estuarine nursing grounds. Reductions in populations of marine fishes due to pollution solely have not yet been demonstrated. However, Baltic Sea seals, where reproductive failure is apparently associated with high concentrations of DDT and polychlorinated biphenyl in the blubber, may have suffered a decline owing to the presence of these organochlorines. Sublethal effects of pollutants have been studied in the laboratory, essentially under four categories: (1) physiology (growth, swimming performance, respiration, circulation); (2) biochemistry/cell structure (blood chemistry, enzyme activity, endocrinology, histochemistry); (3) behaviour/neurophysiology; and (4) reproduction. Not all pollutants elicit meaningful responses in all categories, and a response is not always linear with pollutant concentration. For application to survival of populations the response has to be ultimately related to a healthy progression through a full life cycle, including successful reproduction. In recent time, physiological studies have moved into polluted marine environments with mobile laboratories having continuous sampling capability, to observe effects of pollutants in situ on marine organisms. The Controlled Ecosystem Pollution Experiment (Cepex) in Saanich Inlet, British Columbia, endeavours to investigate the effects of low concentrations of pollutants on marine organisms in large plastic silos having a slow replacement of water.

Animals↗
PubMed1986

The effect of aerosol on estimates of inhalation exposure to airborne styrene.

Exposure to volatile organic contaminants usually is attributed to vapors alone; samples are collected on charcoal tubes or by passive dosimeters. This study demonstrated that aerosols, generated during the spraying of polyester resin solution, can contribute significantly to the exposure to volatile organic contaminants. Four spraying experiments were performed during which 64 samples were collected and analyzed to determine the styrene air concentrations. The results from the four spraying experiments showed that aerosols represented 30% +/- 3% of the total air concentration of styrene. The contribution of aerosols to inhalation exposure needs to be considered in other industrial situations where spray processes are used.

Aerosols↗
PubMed1978

[Radiolytic decontamination of Di-n-butyl phthalate from water (author's transl)].

Recently, a considerable amount of phthalic acid esters (PAE), the most widely utilized plasticizer, has been released into and polluted the environment. Since their toxicity and teratogenicity, although fairly low, to experimental animals have recently been shown, the removal of them from the environment, especially from the drinking water, is desirable. As an attempt for the removal, the radiolytic degradation of 7-14C-di-n-butyl phthalate (14C-DBP) in water was investigated at several pHs. Approximately 50% of 14C-DBP (1 ppm aqueous solution) was decomposed by 60Co gamma-irradiation to a dose of 3 X 10(4) rad at pH 7 and the main product was mono-n-butyl phthalate (MBP). At pHs 3 and 11 14C-DBP was more easily radiolyzed and converted to ether-soluble compounds other than MBP or phthalic acid (PA). By irradiation to 10(6) rad 14C-DBP as well as 14C-MBP and 14C-PA, at pH value tested, was almost completely decomposed to volatile or water-soluble substances of possibly low molecular weight. These findings suggest that the gamma-irradiation is effective to make the PAE-polluted water clean.

Chemical Phenomena↗
PubMed1990

Toxicity tests of soil contaminated by recycling of scrap plastics.

The present investigation studied the toxicity of soil contaminated by untreated discharge from a factory that recycles used plastics. The nearby agricultural areas and freshwater fish ponds were polluted with high concentrations of Cu, Ni, and Mn. Water extracts from the contaminated soil retarded root growth of Brassica chinensis (Chinese white cabbage) and Cynodon dactylon (Bermuda grass) where their seeds were obtained commercially. The contaminated populations of C. dactylon, Panicum repen (panic grass), and Imperata cylindrica (wooly grass) were able to withstand higher concentrations of Cu, Ni, and Mn, especially C. dactylon, when compared with their uncontaminated counterparts.

Environmental Monitoring↗
PubMedDate not supplied

[Air pollution in the vicinity of streets].

Air samples were collected in plastic bags simultaneously at various measuring points in the close range of streets. When examining the various bag materials, Teflon bags showed the smallest deviations in direct analyses and in analyses of up to two hours after the drawing of samples. The following methods were used for the analysis of the air samples collected in the bags: coulometry for CO and SO2, chemiluminescence for NO/NO2, chromotrophic acid for CH2O and flame ionization for hydrocarbons. The various components were measured close to a highway and near streets in residential and business areas. The simultaneously drawn samples showed a marked dependence on traffic frequency, type of built-up area along the streets as well as meteorological conditions. An opinion survey among adjacent residents on annoyance caused by air pollution and noise resulted in distinct differences between the sections with different traffic intensity.

Air Pollutants↗
PubMed1987

Diethylhexylphthalate as an environmental contaminant--a review.

Di(2-ethylhexyl)phthalate (DEHP) is a priority pollutant in several countries; annual production amounts to 3-4 million tonnes. Approximately 95% is used as a plasticizer in polyvinylchloride (PVC). DEHP is emitted to the environment during the production of plastics and plastic products, during their use and after disposal. In the environment, physico-chemical degradation of DEHP is practically non-existent. Biodegradation occurs readily under aerobic conditions (t1/2 = 2-4 weeks), but not under anaerobic conditions. The acute toxicity of DEHP to mammals is low. Many subchronic and chronic effects have, however, been identified. The most important of these are: influence on the liver and energy metabolism, teratogenicity, adverse effects on male reproductive organs, carcinogenicity and influence on the immune system. On the basis of figures concerning human exposure, most of these effects are not likely to occur. With respect to carcinogenicity the situation is uncertain, especially for some risk groups. The ecotoxicology of DEHP is especially relevant for aquatic communities where data are contradictory: several authors have found adverse effects on Daphnia and fish species after exposure to the present environmental concentrations; others, however, produced less alarming results. Emissions of DEHP can be reduced by the biological treatment of wastewater and waste gas, the use of alternative plasticizers in PVC or the substitution of other plastics for PVC.

Abnormalities, Drug-Induced↗
PubMed1991

Toxicology and occupational hazards of new materials and processes in metal surface treatment, powder metallurgy, technical ceramics, and fiber-reinforced plastics.

Many new materials and processes are about to find their way from the research laboratory into industry. The present paper describes some of these processes and provides an overview of possible occupational hazards and a list of chemicals used or produced in the processes. The technological areas that are considered are metal surface treatment (ion implantation, physical and chemical vapor deposition, plasma spraying), powder metallurgy, advanced technical ceramics, and fiber-reinforced plastics.

Air Pollutants, Occupational↗