Application of solid-phase microextraction method to determine bioavailable fraction of PAH in hazardous waste.

The solid-phase microextraction (SPME) method was developed to determine PAH free dissolved concentration (C(free)) in field leachates from hazardous waste disposal. SPME technique, involving a 100-µm polydimethylsiloxane (PDMS) fiber coupled to GC-MS was optimized for determination of C(free). The following PAH were found in bioavailable form: acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, with C(free) varying between 2.38 and 62.35 ng/L. Conventional solvent extraction was used for measurement of total concentration (C(total)) in the same samples, and ranging from 1.26 to 77.56 µg/L. Determining C(free) of the hydrophobic toxic pollutants could give useful information for risk assessment of the hazardous waste.

Sorption of polycyclic aromatic compounds to humic and fulvic acid HPLC column materials.

Two different humic acids (HA) and a fulvic acid (FA) were chemically immobilized to a high performance liquid chromatography (HPLC) silica column material. The immobilization was performed by binding amino groups in HA/FA to the free aldehyde group in glutardialdehyde attached to the silica gel. The HPLC column materials were compared with a blank column material made by applying the same procedure but without immobilizing HA or FA. Also, a column was made by binding carbonyl groups in HA to amino groups attached to the silica gel. The humic substances were selected to secure appropriate variation of their structural features. The retention factors of 45 polycyclic aromatic compounds (PAC) to the four columns were determined by HPLC. The advantage of the technique is a large number of compounds can easily be studied. The binding procedure does not appear to cause a drastic selection between the HA molecules. The k' values obtained for the two Aldrich HA columns agree in general reasonably. The retention or sorption of the compounds increased with the size of the PAC and the number of lipophilic substituents, but decreased when polar substituents were present. The PAC retention was much stronger to the two HA columns than to the FA and blank column, both for hydrophobic polycyclic aromatic hydrocarbons (PAH) and the polar PAC. Other factors impacting the PAC binding may be specific interactions with HA and the ionic strength of the aqueous phase. The technique has been applied to do direct determinations of Koc.

Role of algae in fate of carcinogenic polycyclic aromatic hydrocarbons in the aquatic environment.

Polycyclic aromatic hydrocarbons (PAHs) represent an ecotoxicologically relevant, combustion-related substance group. The bioconcentration and transformation of a priority PAH, benzo[a]pyrene (BaP), by brown (Fucus vesiculosus and Chorda filum), red (Furcellaria lumbricalis), green (Enteromorpha intestinalis, and Cladophora glomerata), and chara (Chara aspera) algae have been studied. A flux budget was made of the amounts of BaP that are accumulated and metabolized by different algae during an estimated time. The results indicated that of all the BaP consumed, 89-99% was found in the biomass of Fucus, an insignificant part was in the solution, and the remainder (up to 4%) was not recovered, i.e., was considered to have been metabolized. For green and chara algae the proportion of transformed PAHs was more essential, 42-49%. The transformation of BaP in marine and freshwater algae is species specific and depends on the presence and activity of enzymes localized in the plant cells. The most important enzyme systems for detoxification of BaP are o-diphenol oxidase, cytochrome P450, and peroxidase. The data obtained indicate the important role of marine and freshwater algae in the fate of carcinogenic PAHs in the environment.

Application of HPLC capacity coefficients to characterize the sorption of polycyclic aromatic compounds to humic acid.

The sorption coefficients to humic acid of 46 PAC having a wide range in polarity were compared with the capacity coefficients of the PAC to a non-polar HPLC column material (ODS) and a polar one (Diol). It is shown that polar interactions contribute to the sorption of polar PAC in addition to the non-polar interactions. The results also suggest that humic acid may contain different hydrophilic adsorption sites. The non-polar column material was only the best model substrate, if the test materials were limited to the hydrophobic unsubstituted PAC, PAH+O,S-PAC.

Environmental health and monitoring in Estonia.

An assessment of environmental health and monitoring in Estonia after the dissolution of the Soviet Union has shown that the country suffered from neglect during the "cold war" after World War II, and efforts to improve the status quo have been slow since independence was gained in 1991. Conditions in Estonia are affected by the fifty-year long occupation. Industrial, military and agricultural activities have left a legacy of pollution and obsolete installations. The regulatory framework and life style attitudes from the Soviet era interfere with reform efforts. The current transition period holds risks that derive from a run-down infrastructure, a weak economy, and disruptions, inherent in the reorganization itself. Over the past few years a recession has further complicated the situation and the public health status has worsened. International assistance programmes as well as efforts by Estonians have led to some change and progress in environmental management since 1991, and lately ambitious environmental and public health sector programmes have been initiated by the government. Much work, however, still needs to be done. An examination of the recent history of this small country provides examples of environmental neglect and consequences, as well as recommended corrective measures.

Comparative fluorometric study of benzo(a)pyrene and aza-aromatic hydrocarbon penetration and metabolism kinetics in the skin of hairless mice.

The kinetics of penetration and metabolism of BaP, BACs, DB(a,h)ACs and DB(c,g)Cs in the skin of hairless mice was studied. The relative fluorescence intensities were measured during three hours after applying 10 nmoles of the compound to the interscapular region of the mice. By using a kinetical model which combines a non-steady diffusion of a hydrocarbon through the stratum corneum and the metabolic oxidation by epidermal cells, the rate constants for the two processes were calculated. It has been shown that B(a)AC, B(c)AC and 12-MB(a)AC penetrate into the skin and are oxidized by epidermal cells more efficiently than BaP. In contrast, alkyl-DB(a,h)ACs (except 14-MDB(a,h)AC) show a great stability in the mouse skin. The carcinogenic BaP, 7-MB(c)AC and DB(a,h)AC have average rates of elimination from the skin.

Fluorescence method for the measurement of penetration and metabolism of carcinogens in mouse skin.

The present study aims at elucidating by fluorescence measurements the possibilities of the mathematical description of the processes of penetration and metabolism of carcinogenic polynuclear arenes in mouse skin. The fluorescence intensities of the topically applied benzo(a)pyrene (BaP), 10-60 nmoles of BaP in 100 microliters of acetone, were measured in the interscapular region of hairless mice during three hours. A kinetic model combining a non-steady diffusion of BaP through the stratum corneum and BaP metabolic oxidation by epidermal cells was elaborated. Both the processes were described by first-order kinetic equations. Four parameters, viz. BaP flux rate constant into the stratum corneum, BaP metabolism rate constant, BaP flux at zero time and relative fluorescence intensity at zero time, can be calculated from experimental data (fluorescence intensity-time) using the kinetic model. The above method makes it possible to study the effect of other compounds, e.g., phenolic antioxidants, on BaP metabolism rates in the in vivo system.

[Effect of antioxidants on the carcinogenic and mutagenic activity of benzo[a]pyrene]. / Vliianie antioksidantov na kantserogennuiu i mutagennuiu aktivnost' benz[a]pyrena.

The changes in toxic, mutagenic and carcinogenic activities of benzo(a)pyrene (BP) in combination with two new phenolic antioxidants, phenosan-acid and -ester, were studied. Although both phenols investigated were characterized by marked toxic and mutagenic activity, their combination with BP appeared to protect mammalian cells against the action of the carcinogenic substance. A distinct correlation between inhibition of the mutagenic and toxic activities of BP and the dose of antioxidants was observed. The effect of phenosans on skin carcinogenesis induced by BP depended to a larger degree on the conditions of application of test substances. When combined applications of BP and antioxidants to the skin of mice were used, phenosans suppressed carcinogenesis, thus prolonging the latent period of tumor induction. When two-stage scheme of carcinogenesis was applied, a tendency for development predominantly benign skin tumors under the influence of antioxidants was noted. The use of the new phenolic antioxidants--phenosan-acid and -ester--seems to offer advantage in reducing mutagenicity and carcinogenicity of polycyclic aromatic hydrocarbons.

[Is benzo(a)pyrene an indicator of carcinogenic pollution?]. / Iavliaetsia li benz(a)piren indikatorom kantserogennogo zagriazneniia?

High-pressure liquid chromatography was used in the measurement of level of polycyclic aromatic hydrocarbons (PAH) in 60 environmental specimens (water, bottom sediments and soil in fresh- and sea-water basins, solid wastes of fuel combustion). Concentrations of benzo(a)pyrene considered to be an indicator of carcinogenic PAH, varied significantly: 0.05-13.0% of the total hydrocarbon level and 0.8-100.0% of carcinogenic PAH in water; 2.7-8.1 and 4.0-36.8 in bottom sediments, and 0.4-6.0 and 9.9-45.1 in solid wastes of fuel combustion, respectively. Since PAH, other than benzo(a)pyrene, e. g. benzofluoranthenes and dibenzopyrenes, sometimes predominated, it is suggested that benzo(a)pyrene cannot be used as indicator of environmental pollution, unless a full-scale test for other PAH is completed. Benzo(a)pyrene level may be used for monitoring carcinogenic pollution after relevant hygienic and cancer control tests are carried out.