PAH Exposure Research Articles

P3F149 - Biomarkers in relation to PAH exposure in aluminum smelter workers

P3F149 - Biomarkers in relation to PAH exposure in aluminum smelter workers

Bioavailability of PAH in effluent water from an aluminium works evaluated by transplant caging and biliary fluorescence measurements of Atlantic cod ( Gadus morhua L.)

Fixed wavelength fluorescence (FF) of bile was used as a biomarker for PAH exposure in fish caged adjacent to an aluminium works. After 30 days of caging, a 20–50 fold increase of pyrene fluorescence was found in groups caged adjacent to the works as compared to two control groups. The PAH uptake occurred mainly from suspended particles rather than from PAH contaminated sediments at the caging sites. Our results demonstrates the combined use of fish caging and bile-fluorescence measurements as a powerful field model for the monitoring of coastal waters subjected to PAH pollution.

Detection of 1-Hydroxypyrene as a Urine Biomarker of Human PAH Exposure Determined by Fluorescence and Solid-Matrix Luminescence Spectroscopy

A new solid-matrix luminescence method was developed for human biomonitoring that employs room-temperature fluorescence and phosphorescence for the detection and identification of 1-hydroxypyrene (1-OH-PY). Several high-performance liquid chromatography (HPLC) fractions from human urine samples were characterized by both solution fluorescence and solid-matrix luminescence. The solution fluorescence data and the solid-matrix luminescence data complemented each other. For example, in one of the fractions, the solution fluorescence showed the presence of tetrahydrotetrols of benzo[ a]pyrene. However, in this fraction, 1-OH-PY was readily detected by solid-matrix luminescence. In addition, solution fluorescence showed that 1-OH-PY was not in some of the fractions, but solid-matrix luminescence showed that 1-OH-PY was present. Solid-matrix phosphorescence was very effective in detecting 1-OH-PY in the fractions where solution fluorescence and solidmatrix fluorescence indicated that 1-OH-PY was not present. The limits of detection were in the pmol/mL range by solution fluorescence and in the subpicomole range with solid-matrix luminescence.

The use of a urine mutagenicity assay in the monitoring of environmental exposure to genotoxins

Urinary bacterial mutagenicity was used as a biomarker of exposure to ambient air pollution in a group of women working outdoors in the city of Teplice (TP; Northern Bohemia) with higher levels of air pollution than a similar group of women in the city of Prachatice (PT; Southern Bohemia). The Salmonella typhimurium plate incorporation assay with the TA98 and YG1041 strains and microsuspension assay with the YG1041 strain were used for testing the urinary mutagenicity. PAH and their metabolites were analyzed by HPLC and GC/MS methods. The significantly higher values of most PAHs/metabolites detected in a TP group confirmed the differences of PAH exposures between both groups. In the plate incorporation assay, the TA98 strain was not able to detect the increase in urinary mutagenicity, but, for the YG1041 strain, the urinary mutagenicity was clearly determined with a significant difference in number of YG1041+S9 revertants between the TP and PT groups. The microsuspension assay increased the mean response by about 10-fold over the standard plate test; however, no statistical difference between TP and PT groups was found due to high interindividual variability and small sample size. Comparing the urinary PAH/metabolites to urinary mutagenicity, significant correlations were observed between the plate incorporation mutagenicity results with the YG1041 revertants in the presence of metabolic activation and several of the urinary PAH/metabolites. On the contrary, in the microsuspension assay, several urinary PAH/metabolites correlated significantly with the YG1041 revertants only in the absence of metabolic activation. This may indicate the influence of different treatment conditions of assays on the urinary mutagenicity results. The results suggest the insufficient sensitivity of the TA98 tester strain to determinate low urinary level of mutagens. On the contrary, the use of the YG1041 tester strain increases the probability of detecting an effect of environmental exposure and seems to be applicable to biological monitoring. To definitely replace the standard plate incorporation assay with the microsuspension method is not possible without further comparative studies.

Time- and dose-dependent biom arker responses in flounder (Platichthys flesus L.) exposed to benzo[a]pyrene, 2,3,3′,4,4′, 5-hexachlorobiphenyl (PCB-156) and cadmium

Responses in flounder (Platichthys flesus) towards benzo [a]pyrene (BaP), 2,3,3′,4,4′,5-hexachlorobiphenyl (PCB-156), and cadmium (Cd) were investigated in time-course and dose-response studies of selected biomarkers. Measurements of biliary fluorescent BaP metabolites and hepatic concentrations of PCB-156 and cadmium showed that the injected toxicants were rapidly m obilized from the muscle to the liver, but a depot effect was indicated in the highest dose groups of BaP and PCB-156 (12 mg kg-1 bodyweight). Clearest biomarker responses were found in the induction of hepatic cytochrome P450 1A (CYP1A) enzymes as a response towards BaP and PCB-156 exposure. Maximum induction of CYP1A dependent 7-ethoxyresorufin O-deethylase (EROD) activity was observed after 2 and 8 days in BaP and PCB-156-treated flounder, respectively. Positive dose-effect relationships were observed towards both compounds, but the CYP1A induction was more persistent with PCB exposure than with BaP exposure. In Cd-exposed fish, the hepatic level of metallothionein responded more slowly with highest levels observed after 16 days in the time-study. In the combined BaP + Cd treatment, the CYP1A induction was only slightly suppressed. Aspartate aminotransferase in serum appeared to be responsive towards BaP, but also towards the acetone vehicle in controls in the first part of the exposure period. Hematocrit as well as hepatic activities of aldrin epoxidase, glutathione S-transferase, and UDP-glucuronyl transferase were not responsive to any treatm ent in the present study. In general, the results demonstrate that selected biom arkers in flounder are responsive to PAH, PCB, and heavy metal pollutant exposure, indicating the applicability of this species in future environmental pollution monitoring programmes.

The effect of inorganic and organic supplements on the microbial degradation of phenanthrene and pyrene in soils.

The effects of several bioremediation stimulants, including potential metabolism pathway inducers, inorganic/organic nutrients, and surfactants on the metabolism of phenanthrene and pyrene, as well as the population dynamics of PAH degrading microorganisms was examined in five soils with differing background PAH concentrations, exposure histories and physical properties. Most of the supplements either had no significant effect or decreased the mineralization of [14C]-phenanthrene and [14C]-pyrene in soil slurry microcosms. The effect of a particular supplement, however, was often not uniform within or across soils. Decreased mineralization of [14C]-phenanthrene and [14C]-pyrene was usually due to either preferential use of the supplement as carbon source and/or stimulation of non-PAH degrading microorganisms. Many of the supplements increased populations of heterotrophic microorganisms, as measured by plate counts, but did not increase populations of phenanthrene degrading microorganisms, as measured by the [14C]-PAH mineralization MPN analysis or cellular incorporation of [14C]-PAH. These results suggest that the PAH degrading community at each site may be unique in their response to materials added in an attempt to stimulate PAH degradation. The characteristics of the site, including exposure history, soil type, and temporal variation may all influence their response.

Nereis virens (Annelida: Polychaeta) is not an adequate sentinel species to assess the genotoxic risk (comet assay) of PAH exposure to the environment.

Polychaetes, because of their bioturbation capacity, play an important role in the distribution of anthropogenic contaminants (including polycyclic aromatic hydrocarbons [PAHs]) throughout the sediments. In this work the use of Nereis virens (Annelida: Polychaeta) as a bioindicator to assess the genotoxic risk of PAH exposure for the environment was evaluated. For this purpose the alkaline single cell gel electrophoresis [comet] assay was applied on the coelomocytes of in vivo exposed Nereis virens. Benzo[a]pyrene (B[a]P) was chosen because it is classified by the IARC (International Agency for Research on Cancer) as "probably carcinogenic to humans" and because its mechanisms of action are well-known. Nereis virens was exposed to B[a]P in concentrations of 0.3, 0.6, 10, 20, 35 and 45 mg/ml by an intracoelomic injection of B[a]P (20 microliters) dissolved in dimethyl sulphoxide (DMSO). A solvent control with DMSO, a positive control with ethyl methane sulphonate (EMS) (12.1 mg/ml) and a negative control were included in each experiment. For each treatment four animals were analysed. After 1 hr treatment coelomocytes were harvested by puncturing the coelomic cavity with a sharpened Pasteur pipette, mixed with 0.5% low melting point agarose and sandwiched between two other gel layers. Ethidium bromide stained nuclei were analysed for tail length and tail moment. 12.1 mg/ml EMS, pure DMSO (98.9%) and B[a]P in all tested concentrations induced a statistically significant increase of DNA single strand breaks in the comet assay. The effect of B[a]P, however, was only at the highest concentration (45 mg/ml) significantly stronger than the effect of DMSO alone. Although a relatively large heterogeneity in the results could be observed, these experiments clearly showed that Nereis virens is not suited as a sentinel species for the assessment of the genotoxic risk of PAH exposure because this species seems to be very resistant to benzo[a]pyrene.

Nereis virens (Annelida: Polychaeta) is not an adequate sentinel species to assess the genotoxic risk (comet assay) of PAH exposure to the environment

Polychaetes, because of their bioturbation capacity, play an important role in the distribution of anthropogenic contaminants (including polycyclic aromatic hydrocarbons [PAHs]) throughout the sediments. In this work the use of Nereis virens (Annelida: Polychaeta) as a bioindicator to assess the genotoxic risk of PAH exposure for the environment was evaluated. For this purpose the alkaline single cell gel electrophoresis [comet] assay was applied on the coelomocytes of in vivo exposed Nereis virens. Benzo[a]pyrene (B[a]P) was chosen because it is classified by the IARC (International Agency for Research on Cancer) as "probably carcinogenic to humans" and because its mechanisms of action are well-known. Nereis virens was exposed to B[a]P in concentrations of 0.3, 0.6, 10, 20, 35 and 45 mg/ml by an intracoelomic injection of B[a]P (20 microliters) dissolved in dimethyl sulphoxide (DMSO). A solvent control with DMSO, a positive control with ethyl methane sulphonate (EMS) (12.1 mg/ml) and a negative control were included in each experiment. For each treatment four animals were analysed. After 1 hr treatment coelomocytes were harvested by puncturing the coelomic cavity with a sharpened Pasteur pipette, mixed with 0.5% low melting point agarose and sandwiched between two other gel layers. Ethidium bromide stained nuclei were analysed for tail length and tail moment. 12.1 mg/ml EMS, pure DMSO (98.9%) and B[a]P in all tested concentrations induced a statistically significant increase of DNA single strand breaks in the comet assay. The effect of B[a]P, however, was only at the highest concentration (45 mg/ml) significantly stronger than the effect of DMSO alone. Although a relatively large heterogeneity in the results could be observed, these experiments clearly showed that Nereis virens is not suited as a sentinel species for the assessment of the genotoxic risk of PAH exposure because this species seems to be very resistant to benzo[a]pyrene.

Biomonitoring of aquatic pollution with feral eel ( Anguilla anguilla) II. Biomarkers: pollution-induced biochemical responses

The primary aim of this study was to select a set of relevant biomarkers in feral eel for the biological assessment of inland water pollution. A suite of biochemical parameters in eel (hepatic biotransformation enzymes and cofactors, antioxidant enzymes, PAH metabolites, DNA adducts, serum transaminases) was measured in order to determine their response to xenobiotic compounds in the environment. The results of the analyses of organic trace pollutants in sediments and eel from six Amsterdam freshwater sites with different pollution levels have been discussed in the first part of this paper (Van der Oost, R., Opperhuizen, A., Satumalay, K., Heida, H. and Vermeulen, N.P.E., 1996a. Biomonitoring aquatic pollution with feral eel ( Anguilla anguilla): I. Bioaccumulation: biota-sediment ratios of PCBs, OCPs, PCDDs and PCDFs. Aquat. Toxicol., 35: 21–46). The main conclusions drawn from the trends found for the levels and activities of biochemical parameters in eel were the following: the phase I biotransformation enzymes in eel liver appeared to be the most sensitive to environmental xenobiotics. Cytochrome b 5 (Cyt b 5), cytochrome P450 1A (CYP1A), ethoxyresurofin- O-deethylase (EROD) and EROD turnover (EROD/P450) in eel liver showed significant responses to contamination, and can therefore be used as biomarkers. Levels of a CYP3A-like protein were significantly elevated in eel from three moderately polluted sites, but since this protein was not induced in eel from the most polluted site its relevance as a biomarker remains unclear. Phase II enzymes and cofactors in eel liver were less susceptible to pollutants than phase I enzymes. The activity of UDP glucuronyl transferase (UDPGT) in eel may, however, be a useful biomarker, while glutathione S-transferase (GST) activity and levels of oxidized glutathione (GSSG) were less sensitive. The reduced glutathione (GSH) cofactor levels in eel liver are most probably not reliable as biomarkers. Hepatic activities of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT) and GSH-peroxidase (GPOX)) in eel did not show any response to pollution and are therefore not feasible as biomarkers. The level of 1-hydroxypyrene (1-OH pyrene) in eel bile might be a useful biomarker to determine short-term PAH exposure. The hepatic level of DNA adducts in eel liver seems to be a sensitive biomarker for exposure to (and possible effects of) mutagenic and carcinogenic xenobiotics. In feral eel, serum transaminases are not usable as biomarkers of chronic intoxication. The proposed set of the most relevant biomarkers for the assessment of inland water pollution with feral eel thus consists of the following six parameters: cyt b 5, CYP1A, EROD, EROD/P450, UDPGT and DNA adducts.

Formation of pyrene metabolites by the terrestrial isopod Porcellio scaber

The formation of pyrene metabolites by the temestrial isopod Porcellio scaber (Latr.) was studied following exposure for 13 days to 100 μg/g pyrene in its food. An alkaline hydrolysis method with subsequent liquid-liquid extraction was developed to determine the metabolite content, especially 1-hydroxypyrene. Synchronous Fluorescence Spectroscopy (SFS) was explored as a fast screening method and HPLC was applied as a complementary method for confirmation of the SFS results. In Porcelho scaber the amount of 1-hydroxypyrene exceeded that of pyrene, which indicates that pyrene is being metabolized extensively. SFS and HPLC demonstrated that Porcellio scaber also forms a number of other fluorescent metabolites. These metabolites exhibit fluorescence at the same excitation wavelength as 1-hydroxypyrene, possibly indicating a similar fluorophore structure. Determination of 1-hydroxypyrene is considered as a first step towards an improved environmental risk assessment of PAH exposure, as pyrene is a predominant member of this class of environmental contaminants and 1-hydroxypyrene is its major metabolite.

Long‐term toxicity of five polycyclic aromatic hydrocarbons for the terrestrial isopodsOniscus AsellusandPorcellio Scaber

AbstractPolycyclic aromatic hydrocarbons (PAH) are a common component of soil pollution, yet little is known of the ecotoxicological risks these compounds may pose to life in soil. This article reports the ecotoxicity of five PAHs for two terrestrial isopod species. Isopods were exposed to food contaminated with four different concentrations of either fluorene, phenanthrene, fluoranthene (up to 4 μmol/g), benz[a]anthracene, or benzo[a]pyrene (up to 1.25 μmol/g). Exposure ofPorcellio scaberlasted 16 weeks, and no adverse effects on survival, growth, or total protein (only females tested) were observed in any of the treatments. A small but significant reduction in growth ofOniscus aselluswas observed at 47 weeks of exposure to 0.125 μmol benz[a]anthraceneṁg−1dry weight and 1.25 μmol fluoreneṁg−1dry weight and higher concentrations. A significant stimulation of the reproduction ofO. aselluswas observed in some of the phenanthrene, fluoranthene, benz[a]anthracene, and benzo[a]pyrene treatments; a larger proportion of the females were gravid, which resulted in a higher number of juveniles per female. Exposure did not significantly affect brood size, weight of the mother after release of the juveniles, or the survival of the juveniles upon starvation. Total protein content of females was significantly reduced at 0.4 μmol fluorene g−1dry weight and higher concentrations. Growth and protein content of isopods is likely to be affected by PAH exposure only at highly contaminated sites. The ecological consequences of stimulated reproduction and possible DNA damage are poorly understood and require further attention because soil invertebrates may be exposed to PAHs over many generations.

95/06574 Occupational PAH exposure: Urinary 1-hydroxypyrene levels of coke oven workers, aluminum smelter pot-room workers, road pavers, and occupationally non-exposed persons in Sweden

95/06574 Occupational PAH exposure: Urinary 1-hydroxypyrene levels of coke oven workers, aluminum smelter pot-room workers, road pavers, and occupationally non-exposed persons in Sweden

Estimation of reference values for urinary 1-hydroxypyrene and α-naphthol in Danish workers

In order to assess environmentally and occupationally related exposures to PAH compounds it is essential to have reference or normal values in human body fluids. The establishment of reliable reference intervals is an absolute pre-requisite in determining relationships between internal PAH exposure in humans and health effects in occupationally exposed workers. In this context the estimation of the biological level of PAH metabolites in urine from reference populations has become increasingly important in the field of environmental and occupational toxicology. The present study describes the calculation of tentative reference values for urinary 1-hydroxypyrene on the basis of two reference populations and for urinary α-naphthol on the basis of one reference population in accordance with IFCC recommendations. The study subjects were 115 healthy male workers occupationally exposed to PAH at low levels and 121 reference subjects non-occupationally exposed to PAH. Tentative reference values for urinary 1-hydroxypyrene were estimated. In addition, 236 healthy male workers were used to estimate tentative reference values for urinary α-naphthol. The reference populations were described by distribution free one-sided tolerance intervals. The 95% one-sided tolerance limit calculated for 1-hydroxypyrene in urine was 0.053 μmol/mol creatinine for non-occupationally exposed individuals and 0.169 μmol/mol creatinine for low level PAH exposed workers, with the coverage interval (95 ± 4.5) percent at a probability of 0.95. Thus, the probability was 0.975 that the tolerance interval included at least 90.5% of the distribution. In addition, the probability was 0.025 that the tolerance interval included > 99.5% of the population. The tolerance interval for α-naphthol in urine was 5.665 μmol/mol creatinine with the coverage interval (95 ± 4.5) percent at a probability of 0.95.

Comparison of SO 2 capture capacities of limestones and dolomites under pressure

Urinary bacterial mutagenicity was used as a biomarker of exposure to ambient air pollution in a group of women working outdoors in the city of Teplice (TP; Northern Bohemia) with higher levels of air pollution than a similar group of women in the city of Prachatice (PT; Southern Bohemia). The Salmonella typhimurium plate incorporation assay with the TA98 and YG1041 strains and microsuspension assay with the YG1041 strain were used for testing the urinary mutagenicity. PAH and their metabolites were analyzed by HPLC and GC/MS methods. The significantly higher values of most PAHs/metabolites detected in a TP group confirmed the differences of PAH exposures between both groups. In the plate incorporation assay, the TA98 strain was not able to detect the increase in urinary mutagenicity, but, for the YG1041 strain, the urinary mutagenicity was clearly determined with a significant difference in number of YG1041+S9 revertants between the TP and PT groups. The microsuspension assay increased the mean response by about 10-fold over the standard plate test; however, no statistical difference between TP and PT groups was found due to high interindividual variability and small sample size. Comparing the urinary PAH/metabolites to urinary mutagenicity, significant correlations were observed between the plate incorporation mutagenicity results with the YG1041 revertants in the presence of metabolic activation and several of the urinary PAH/metabolites. On the contrary, in the microsuspension assay, several urinary PAH/metabolites correlated significantly with the YG1041 revertants only in the absence of metabolic activation. This may indicate the influence of different treatment conditions of assays on the urinary mutagenicity results. The results suggest the insufficient sensitivity of the TA98 tester strain to determinate low urinary level of mutagens. On the contrary, the use of the YG1041 tester strain increases the probability of detecting an effect of environmental exposure and seems to be applicable to biological monitoring. To definitely replace the standard plate incorporation assay with the microsuspension method is not possible without further comparative studies.

Biomarkers of PAH exposure in oyster toadfish ( Opsanis tau) from the Elizabeth River, Virginia

Biomarkers of PAH exposure in oyster toadfish ( Opsanis tau) from the Elizabeth River, Virginia

Determination of coal tar pitch volatile materials on sampling filters. Comparison of gravimetric and spectroscopic methods

Urinary bacterial mutagenicity was used as a biomarker of exposure to ambient air pollution in a group of women working outdoors in the city of Teplice (TP; Northern Bohemia) with higher levels of air pollution than a similar group of women in the city of Prachatice (PT; Southern Bohemia). The Salmonella typhimurium plate incorporation assay with the TA98 and YG1041 strains and microsuspension assay with the YG1041 strain were used for testing the urinary mutagenicity. PAH and their metabolites were analyzed by HPLC and GC/MS methods. The significantly higher values of most PAHs/metabolites detected in a TP group confirmed the differences of PAH exposures between both groups. In the plate incorporation assay, the TA98 strain was not able to detect the increase in urinary mutagenicity, but, for the YG1041 strain, the urinary mutagenicity was clearly determined with a significant difference in number of YG1041+S9 revertants between the TP and PT groups. The microsuspension assay increased the mean response by about 10-fold over the standard plate test; however, no statistical difference between TP and PT groups was found due to high interindividual variability and small sample size. Comparing the urinary PAH/metabolites to urinary mutagenicity, significant correlations were observed between the plate incorporation mutagenicity results with the YG1041 revertants in the presence of metabolic activation and several of the urinary PAH/metabolites. On the contrary, in the microsuspension assay, several urinary PAH/metabolites correlated significantly with the YG1041 revertants only in the absence of metabolic activation. This may indicate the influence of different treatment conditions of assays on the urinary mutagenicity results. The results suggest the insufficient sensitivity of the TA98 tester strain to determinate low urinary level of mutagens. On the contrary, the use of the YG1041 tester strain increases the probability of detecting an effect of environmental exposure and seems to be applicable to biological monitoring. To definitely replace the standard plate incorporation assay with the microsuspension method is not possible without further comparative studies.

EXPOSURE TO POLYCYCLIC AROMATIC HYDROCARBONS (PAHs) IN TWO DIFFERENT SILICON CARBIDE PLANTS

Silicon carbide is produced in Acheson ovens by heating a mixture of petroleum coke and silica sand at a temperature of 2000°C. A total of 38 personal and stationary samples were taken in the working atmosphere in two plants to determine the concentrations of 20 unsubstituted PAHs by gas chromatography-mass spectrometry. These included benzo(a)anthracene, chrysene, benzo(a)pyrene, benzo(j+b+k)fluoranthene, dibenzo(ah)anthracene and indeno(1.2.3-cd)pyrene, all of which are carcinogenic. In plant A, the total PAH concentrations in the personal samples varied from 0.28 to 2.67 μg m−3 (mean value 1.13 μg m−3)with a mean BaP concentrations of 0.05 μg m−3 for all worksites. In plant B, the total PAH varied from 2.93 to 50.03 μg m−3 (mean value 10.50 μg m with a mean BaP concentration of 0.13 μg m−3. The differences in job-specific PAH exposure in both plants could be explained by different working conditions. Compared to the exposure to carcinogenic PAHs in coke and aluminium plants, the measured concentrations in both silicon carbide plants were low.

Lack of Change of Hepatic Catalase and Superoxide Dismutase Activities in Flounder,Platichthys Flesus, with Short-term Exposure to Benzo[a]pyrene or Long-Term Exposure to Contaminated Sediment

Abstract In two experiments the responses of the antioxidant enzymes catalase and superoxide dismutase (SOD) were measured in liver of flounder with exposure to PAH and other pollutants as an indicator of contaminant-enhanced oxyradical generation. In a short-term experiment flounder were injected i.p. with 10 mg benzo[a]pyrene (BaP) per kg body weight, and samples taken after 0, 1, 2, 3, 4 and 7 days. In a mesocosm experiment flounder were exposed for 6 months to heavily contaminated harbor sludge containing PAH. Hepatic catalase and SOD activities were indicated to increase slightly with exposure to harbor sludge, but the differences were not statistically significant (P>0.05). No changes were detected in either activity with i.p. injection of BaP. As a comparison, induction of cytochrome P4501A, by means of hepatic 7-ethoxyresorufin O-deethylase (EROD) activity, and excretion of PAH metabolites in the bile were also measured as well-established biomarkers for PAH exposure. In the short-term experiment a marked increase occurred in EROD activity and enhanced 3-OH-BaP levels were detected in the bile after injection. In the mesocosm experiment high levels of 1-OH-pyrene were detected in the bile after exposure. The results of both experiments suggest that long-term rather than short-term exposure, plus possibly the presence of a mixture of contaminants, is necessary to invoke a response in antioxidant enzymes. This combined with the fact that oxyradical generation can also be increased by factors other than pollution alone e.g. oxygen tension, indicates a limited application for such measurements as a biomarker for PAH contamination per se.

Exposure to particle-bound polyaromatic hydrocarbons in the Al-Mansoria residential area during the Kuwait oil fires: A qualitative appraisal of the adsorption role

High ambient levels of inhalable particulate matter (PM 10) were detected in residential areas during the oil well burning in Kuwait (February–November 1991). Because inhalation exposures to PM 10 were significant (data on PAH quantification are scarce), it became possible to describe the exposure to PM 10-associated PAHs of alternative courses of events, such as PAH-particle interaction mechanisms. Depending on particle adsorption characteristics (affinity and site availability), it is concluded that, contrary to what is currently believed, low levels of ambient PM 10 levels did not indicate low PAH exposures in Al-Mansoria residential area during May 10–31, 1991. Due to the frequent presence of dust particles in the ambient air caused by the heavy dust fallout in Al-Mansoria (average > 65 tons/km 2) during May, 1991, the predicted patterns can be explained by two hypothesized mechanisms. The first is a two-step process: loss of PAHs from low affinity sites and reabsorption onto stronger affinity ones leading to low surface coverage at high PM 10 concentrations. The second involves dilution of PAH-containing soot with aeolian particles. Both events can lead to low ambient PAHs at high PM 10 levels or high ambient PAHs at low PM 10 levels.

Sensitivity of different bacterial assays in detecting mutagens in urine of humans exposed to polycyclic aromatic hydrocarbons

The urine mutagenicity and excretion of 1-hydroxypyrene (1-OH PYR) in non-smoking psoriatic patients treated topically with coal-tar-based ointments were analysed in order to find the most appropriate procedure for monitoring occupational PAH exposure. The bacterial mutagenicity assays used were the plate incorporation, macro-scale fluctuation and microsuspension tests, all on Salmonella typhimurium strain TA98 in the presence of S9 mix and β-glucuronidase. The sensitivities of the three assays in detecting mutagenic urinary PAH metabolites were compared. The efficiencies of XAD-2 and C18 resins for concentrating PAH urinary mutagens were evaluated in the microsuspension assay. The plate and fluctuation tests on XAD-2 urine extracts were shown to be insufficiently sensitive to detect low urinary levels of mutagens, being positive on urine samples with very high PAH metabolite content, estimated as more than 30 μg/g of creatinine of 1-OH PYR. The microsuspension assay on XAD-2 or, even better, on C18 urine extracts was very sensitive in detecting up to 5 μg/g of creatinine of 1-OH PYR. It therefore seems to be applicable to the biological monitoring of most occupational low exposures to coal tar.