Identification, characterization and quantitation of pyrogenic polycylic aromatic hydrocarbons and other organic compounds in tire fire products

On 15 August 2001, a tire fire took place at the Pneu Lavoie Facility in Gatineau, Quebec, in which 4000 to 6000 new and recycled tires were stored along with other potentially hazardous materials. Comprehensive gas chromatography-mass spectrometry (GC-MS) analyses were performed on the tire fire samples to facilitate detailed chemical composition characterization of toxic polycyclic aromatic hydrocarbons (PAHs) and other organic compounds in samples. It is found that significant amounts of PAHs, particularly the high-ring-number PAHs, were generated during the fire. In total, 165 PAH compounds including 13 isomers of molecular weight (MW) 302, 10 isomers of MW 278, 10 isomers of MW 276, 7 isomers of MW 252, 7 isomers of MW 228, and 8 isomers of MW 216 PAHs were positively identified in the tire fire wipe samples for the first time. Numerous S-, O-, and N-containing PAH compounds were also detected. The identification and characterization of the PAH isomers was mainly based on: (1) a positive match of mass spectral data of the PAH isomers with the NIST authentic mass spectra database; (2) a positive match of the GC retention indices (I) of PAHs with authentic standards and with those reported in the literature; (3) agreement of the PAH elution order with the NIST (US National Institute of Standards and Technology) Standard Reference Material 1597 for complex mixture of PAHs from coal tar; (4) a positive match of the distribution patterns of PAH isomers in the SIM mode between the tire fire samples and the NIST Standard Reference Materials and well-characterized reference oils. Quantitation of target PAHs was done on the GC-MS in the selected ion monitoring (SIM) mode using the internal standard method. The relative response factors (RRF) for target PAHs were obtained from analyses of authentic PAH standard compounds. Alkylated PAH homologues were quantitated using straight baseline integration of each level of alkylation.     

Polycyclic aromatic hydrocarbon analysis in different matrices of the marine environment

Polycyclic aromatic hydrocarbons (PAHs) were determined in marine samples of various types, i.e. seawater, sediment and mussel homogenate samples. The samples were spiked with standard PAH mixtures in both polar (acetonitrile) and non-polar (i-octane) solvents, then extracted. Extraction from seawater was performed by liquid/liquid extraction to hexane (LLE) and with solid phase extraction (SPE) discs. The water samples were filtered and unfiltered seawater, and redistilled water for comparison. The discs with PAHs adsorbed from water samples, and also the sediment and mussel homogenate samples, were extracted with acetonitrile by sonication. PAHs in the disc extracts and from the LLE were cleaned-up using TLC and next determined by GC/MS/IT (with ion-trap) and HPLC-DAD/UV. The analytical procedures were verified with deuterated PAH standard mixtures. The large differences in PAH recoveries (from 12 to 86% for sum, and from 3 to 135% for particular PAHs) do not depend solely on the type of matrix and analytical procedure applied (e.g. standard solvent, volume of evaporated sample), but also on the concentration and molecular structure of the analyte. Usually, only a fraction of each PAH content in the matrix is determined, depending on the particulate matter in seawater and the sorption properties of the solid matrix. The recoveries of deuterated PAHs are higher than those of non-deuterated compounds.     

Persistent organic pollutants (POPs) at Ross Sea (Antarctica)

The most significant findings on the presence of persistent organic pollutants (POPs) in the marine ecosystem at Ross Sea are presented. Seawater samples were collected in many sampling sites located in a large area of the Ross Sea during various Italian expeditions in Antarctica. Two classes of POPs were considered, namely polychlorobiphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). The results highlighted the presence of these compounds in seawater samples at a total concentration level of about 50 pg/l for PCBs, and 220 pg/l for PAHs. Moreover, seawater samples showed low to high molecular weight PAHs (LMW/HMW) and phenanthrene to anthracene (PHE/ANT) ratios higher than 1 and 5, respectively, which may suggest the predominance of a petrogenic source (i.e. petroleum product contamination). Results were also obtained on the POP depth profile in the water column at Cape Adere, where two water masses converge and mix, i.e. the Modified Circumpolar Deep Water (MCDW) and the High Salinity Shelf Water (HSSW). According to both the PAH and temperature profiles a two-fold higher PAH and PCB concentration was observed for MCDW samples with respect to HSSW. This result represents the first experimental evidence of the external input of pollutants in this area of the Ross Sea coming from the outer oceanic circulation.     

Determination of polycyclic aromatic hydrocarbons in water by solid-phase microextraction and liquid chromatography.

This study describes the determination of polycyclic aromatic hydrocarbons (PAHs) in water using high-performance liquid chromatography (HPLC) coupled with fluorescence detection (FLD). Because individual PAHs are generally present in water only at trace levels, a sensitive and accurate determination technique is essential. The separation and detection of five PAHs were run completely within 25 min by the HPLC/FLD system with an analytical C18 column, a fluorescence detection, and acetonitrile-water gradient elution. Calibration graphs were linear with very good correlation coefficients (r > 0.9998), and the detection limits were in the range of 2-6 ng/l for five PAHs. Solid phase microextraction (SPME) was performed for sample pretreatment prior to HPLC-FLD determination, and the governing parameters were investigated. Compared to conventional methods, SPME has high recovery, saves considerable time, and reduces solvents waste. The extraction efficiencies of five PAHs were above 88% and the extraction times were 35 min in one pretreatment procedure. One particular discovery is that 1.5 M sodium monochloroactate (ClCH2COONa) can improve the extraction yield of PAH compounds more than other inorganic salts. The SPME-HPLC-FLD technique provides a relatively simple, convenient, practical procedure, which was here successfully applied to determine five PAHs in water from authentic water samples.     

Behaviour of polycyclic aromatic hydrocarbons in dissolved,colloidal, and particulate phases in sedimentary cores

Solid-phase microextraction (SPME) has been successfully used for extracting polycyclic aromatic hydrocarbons (PAHs) from porewater samples from the Mersey Estuary, UK. The majority of the PAHs in porewater samples are associated with colloids due to the high DOC concentrations. The truly dissolved PAH concentrations varied from 66 to 1050?ng?L^?1 in core 2 and from 95 to 740?ng?L^?1 in core 3, and were dominated by naphthalene, fluoranthene, and pyrene. Although absent in the dissolved phase, the high-molecular-mass compounds were found in the colloid-associated fraction of porewater. PAHs in sediments arose from a range of compounds with 4- and 5-ring PAHs dominating. The partitioning of PAHs between sediment and porewater shows that PAHs are enriched in the sediment phase. When the soot carbon content was considered, predictions of the partition behaviour were found to agree more closely with the observed distribution. The results reiterate the importance of evaluating the speciation of organic pollutants in both porewater and sediments in order to accurately predict their environmental fate and potential toxicity.     

Use of Ce(IV) oxidizing agent for the derivatization of polycyclic aromatic hydrocarbons for liquid chromatography-electrochemical detection.

Polycyclic aromatic hydrocarbons (PAHs) were oxidized with Ce(IV), and the resulting quinones were determined by reductive-mode liquid chromatography-electrochemical detection. This oxidation is a rapid, automatable step, involving of Ce(IV) reagent to the PAH sample and cleaning up the derivative with C18 solid-phase extraction. Using a C18 analytical column and a 2-propanol-phosphate buffer as the mobile phase, detection limits were in the ppb range for naphthalene, phenanthrene and anthracene, with linearity over 3-5 orders of magnitude. Method validation was performed by addition of the PAHs to tap water and determining the levels by reference to a calibration curve. The three PAHs can be simultaneously derivatized and determined under the same chromatographic conditions. Analysis of a motor-oil sample is also shown.     

Determination of polycyclic aromatic hydrocarbons in water by solid-phase microextraction-gas chromatography-mass spectrometry

A solid-phase microextraction (SPME)-gas chromatography (GC)-mass spectrometry (MS) analytical method for the simultaneous separation and determination of 16 polycyclic aromatic hydrocarbons (PAHs) from aqueous samples has been developed, based on the sorption of target analytes on a selectively sorptive fibre and subsequent desorption of analytes directly into GC-MS. The influence of various parameters on PAH extraction efficiency by SPME was thoroughly studied. Results show that the fibre exposure time and the use of agitation during exposure are critical in enhancing SPME performance. The presence of colloidal organic matter (as simulated by humic acid) in water samples is shown to significantly reduce the extraction efficiency, suggesting that SPME primarily extracts the truly dissolved compounds. This offers the significant advantage of allowing the differentiation between freely available dissolved compounds and those associated with humic material and potentially biologically unavailable. The method showed good linearity up to 10 μg/l. The reproducibility of the measurements expressed as relative standard deviation (R.S.D.) was generally <20%. The method developed was then applied to extract PAHs from sediment porewater samples collected from the Mersey Estuary, UK. Total PAH concentrations in porewater were found to vary between 95 and 742 ng/l with two to four ring PAHs predominating. Results suggest that SPME has the potential to accurately determine the dissolved concentrations of PAHs in sediment porewater.     

The Importance of Long and Short-Term Air-Soil Exchanges of Organic Contaminants

Abstract

Retrospective analysis of archived soil samples collected and stored from long-term agricultural experiments in the UK has shown how soil organic chemical composition has changed over time. High molecular weight polycyclic aromatic hydrocarbons (e.g. benzo[a]pyrene) and polychlorinated dibenzo-p-dioxins and -furans have increased in concentration through this century as a result of cumulative atmospheric depositional inputs. Concentrations of polychlorinated biphenyls and low molecular weight hydrocarbons (e.g. phenanthrene) peaked in the late 1960s/early 1970s, but have declined subsequently. This reflects declining atmospheric inputs of these compounds and losses from surface soils by volatilisation back to the atmosphere and biodegradation. PCBs and low molecular weight PAHs exist predominantly in the vapour phase in air, whilst heavy PAHs and PCDD/Fs are predominantly particulate-bound. Outgassing from soils is probably the most important contemporary source of PCBs to the atmosphere in the UK. Future UK PCB air concentrations will presumably therefore be influenced (controlled) by the rate of desorption and outgassing, as soil and air concentrations move towards a condition of equilibrium partitioning. Archived soils collected and stored before the commercial manufacture of PCBs contain no PCBs indicating that there is no ‘natural production’ of these compounds. However, within a few hours of exposure to contemporary air these samples contain detectable quantities of PCBs. Short-term air-soil exchange, such as during soil drying in the laboratory, can lead to contamination of samples which contain low concentrations of PCBs and loss from samples which contain high concentrations.     

Determination of sixteen polycyclic aromatic hydrocarbons in aqueous and solid samples from an Italian wastewater treatment plant

A robust procedure for the determination of 16 US EPA PAHs in both aqueous (e.g. wastewaters, industrial discharges, treated effluents) and solid samples (e.g. suspended solids and sludge) from a wastewater treatment plant (WWTP) is presented. Recovery experiments using different percentages of organic modifier, sorbents and eluting solvent mixtures were carried out in Milli-Q water (1000 mL) spiked with a mixture of the PAH analytes (100 ng/L of each analyte). The solid phase extraction (SPE) procedures applied to spiked waste water samples (1000 mL; 100 ng/L spiking level) permitted simultaneous recovery of all the 16PAHs with yields >70% (6-13% RSD). SPE clean up procedures applied to sewage and stabilized sludge extracts, showed percent recoveries in the range 73-92% (7-13% RSD) and 71-89% (7-12% RSD), respectively. The methods were used for the determination of PAHs in aqueous and solid samples from the WWTP of Fusina (Venice, Italy). Mean concentrations, as the sum of the 16PAHs in aqueous and suspended solid samples, were found to be approx. in the 1.12-4.62 microg/L range. Sewage and stabilized sludge samples contained mean PAH concentrations, as sum of 16 compounds, in the concentration range of 1.44-1.26 mg/kg, respectively. Extraction and clean up procedures for sludge samples were validated using EPA certified reference material IRM-104 (CRM No. 912). Instrumental analyses were performed by coupling HPLC with UV-diode array detection (UV-DAD) and fluorescence detection (FLD).     

Rapid determination of PAHs in soil samples by HPLC with fluorimetric detection following sonication extraction

A rapid method for the determination of PAHs in soil samples based on their extraction with methylene chloride by sonication and subsequent separation by HPLC with fluorimetric detection is proposed. A Hypersil Green PAH column was used with a gradient of acetonitrile/water as the mobile phase, together with a program of nine excitation and emission wavelength pairs. Recoveries were in the range 70-98%, except for acenaphthene and naphthalene, at concentration levels 1.08-442 microg/kg with relative standard deviations in the range 2-15% (n = 4). Total PAHs found in soil samples were in the range 15-282 microg/kg. The results were compared with those obtained by applying the 3540 EPA method for two samples.     

Fully automated trace level determination of parent and alkylated PAHs in environmental waters by online SPE-LC-APPI-MS/MS

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous compounds that enter the environment from natural and anthropogenic sources, often used as markers to determine the extent, fate, and potential effects on natural resources after a crude oil accidental release. Gas chromatography-mass spectrometry (GC-MS) after liquid–liquid extraction (LLE+GC-MS) has been extensively used to isolate and quantify both parent and alkylated PAHs. However, it requires labor-intensive extraction and cleanup steps and generates large amounts of toxic solvent waste. Therefore, there is a clear need for greener, faster techniques with enough reproducibility and sensitivity to quantify many PAHs in large numbers of water samples in a short period of time. This study combines online solid-phase extraction followed by liquid chromatography (LC) separation with dopant-assisted atmospheric pressure photoionization (APPI) and tandem MS detection, to provide a one-step protocol that detects PAHs at low nanograms per liter with almost no sample preparation and with a significantly lower consumption of toxic halogenated solvents. Water samples were amended with methanol, fortified with isotopically labeled PAHs, and loaded onto an online SPE column, using a large-volume sample loop with an auxiliary LC pump for sample preconcentration and salt removal. The loaded SPE column was connected to an UPLC pump and analytes were backflushed to a Thermo Hypersil Green PAH analytical column where a 20-min gradient separation was performed at a variable flow rate. Detection was performed by a triple-quadrupole MS equipped with a gas-phase dopant delivery system, using 1.50 mL of chlorobenzene dopant per run. In contrast, LLE+GC-MS typically use 150 mL of organic solvents per sample, and methylene chloride is preferred because of its low boiling point. However, this solvent has a higher environmental persistence than chlorobenzene and is considered a carcinogen. The automated system is capable of performing injection, online SPE, inorganic species removal, LC separation, and MS/MS detection in 28 min. Selective reaction monitoring was used to detect 28 parent PAHs and 15 families of alkylated PAHs. The methodology is comparable to traditional GC-MS and was tested with surface seawater, rainwater runoff, and a wastewater treatment plant effluent. Positive detections above reporting limits are described. The virtual absence of sample preparation could be particularly advantageous for real-time monitoring of discharge events that introduce PAHs into environmental compartments, such as accidental releases of petroleum derivates and other human-related events. This work covers optimization of APPI detection and SPE extraction efficiency, a comparison with LLE+GC-MS in terms of sensitivity and chromatographic resolution, and examples of environmental applications.     

Analysis of organic compounds in environmental samples by headspace solid phase microextraction

The analysis of samples contaminated by organic compounds is an important aspect of environmental monitoring. Because of the complex nature of these samples, isolating target organic compounds from their matrices is a major challenge. A new isolation technique, solid phase microextraction, or SPME, has recently been developed in our laboratory. This technique combines the extraction and concentration processes into one step; a fused silica fiber coated with a polymer is used to extract analytes and transfer them into a GC injector for thermal desorption and analysis. It is simple, rapid, inexpensive, completely solvent-free, and easily automated. To minimize matrix interferences in environmental samples, SPME can be used to extract analytes from the headspace above the sample. The combination of headspace sampling with SPME separates volatile and semi-volatile analytes from non-volatile compounds, thus greatly reducing the interferences from non-target compounds. This paper reports the use of headspace SPME to isolate volatile organic compounds from various matrices such as water, sand, clay, and sludge. By use of the technique, benzene, toluene, ethyl-benzene, and xylene isomers (commonly known as BTEX), and volatile chlorinated compounds can be efficiently isolated from various matrices with good precision and low limits of detection. This study has found that the sensitivity of the method can be greatly improved by the addition of salt to water samples, water to soil samples, or by heating. Headspace SPME can also be used to sample semi-volatile compounds, such as PAHs, from complex matrices.     

Monitoring of carcinogenic PAHs in air under mild–warm ambient temperatures: relative importance of vapour- and particulate-phase analyses in assessing exposure and risk

Atmospheric polycyclic aromatic hydrocarbons (PAHs) are often determined by collecting only the particulate phase. The aim of this study was to ascertain in the field to what extent not collecting the vapour phase may affect the exposure assessment and the risk assessment for carcinogenic PAHs, under ambient temperatures typical of Southern Europe. PM₁₀ 24-h samples were collected in Rome every two months throughout one year on a filter backed by two polyurethane foam sections. Daily mean temperatures during sampling reached 31°C, with hourly maximum values up to 36°C. While four-ring PAHs were found in the vapour phase to a large extent, the calculated annual means of five-ring PAHs, including benzo[a]pyrene, were not affected significantly by the amounts collected as vapour phase. By using the “toxicity equivalence factor” approach, the carcinogenic risk overall attributable to particle-bound PAHs accounted for at least 97% of the risk attributable to total (particulate + vapour phase) PAHs.     

Characterization of AhR agonist compounds in roadside snow

Aryl hydrocarbon receptor (AhR) agonistic contaminants were identified in roadside snow samples. Snow was collected in Oslo, Norway, and compared to a background sample collected from a mountain area. The water and particulate fractions were analysed for AhR agonists using a dioxin-responsive, chemically activated luciferase expression (CALUX) cell assay and by gas chromatography coupled to high-resolution time-of-flight mass spectrometry with targeted analysis for polycyclic aromatic hydrocarbons (PAHs) and broad-spectrum non-target analysis. The AhR agonist levels in the dissolved fractions in the roadside samples were between 15 and 387 pg/L CALUX toxic equivalents (TEQ(CALUX)). An elevated AhR activity of 221 pg TEQ(CALUX) per litre was detected in the mountain sample. In the particle-bound fractions, the TEQ(CALUX) was between 1,350 and 7,390 pg/L. One possible explanation for the elevated levels in the dissolved fraction of the mountain sample could be the presence of black carbon in the roadside samples, potentially adsorbing dioxin-like compounds and rendering them unavailable for AhR interaction. No polychlorinated dibenzodioxins and dibenzofurans or polychlorinated biphenyls were detected in the samples; the occurrence of PAHs, however, explained up to 9 % of the AhR agonist activity in the samples, whilst comprehensive two-dimensional gas chromatography coupled to mass spectrometry GCxGC-ToF-Ms identified PAH derivatives such as polycyclic aromatic ketones and alkylated, nitrogen sulphur and oxygen PAHs in the particle fractions. The (large) discrepancy between the total and explained activity highlights the fact that there are other as yet unidentified AhR agonists present in the environment.     

PAH metabolism in the earthworm Eisenia fetida – identification of phase II metabolites of phenanthrene and pyrene

Polycyclic aromatic hydrocarbons (PAHs) are soil contaminants. Because of their high lipophilicity, PAHs are associated with the organic matter in the soil. Transformation of PAHs generates polar metabolites and the interaction with organic matter in the soil changes. The polar PAH metabolites are persistent, highly water-soluble and potentially leachable from the soil; the understanding of transformation of PAHs to polar metabolites in the responsible organisms is of great importance. Here, we present a study of transformation of the PAHs pyrene and phenanthrene, by the common earthworm Eisenia fetida. The study showed that E. fetida in hydroponic culture was able to transform PAHs to conjugated phase II metabolites. We detected phenanthrene and pyrene metabolites with single- and multiple-phase II-conjugated groups. Sulphate conjugates were excreted to experiment water, and glucuronide and glucoside conjugates and metabolites with several hydroxylations and multiple conjugations were detected in worm tissue. The results demonstrate that earthworms are able to transform PAHs to water-soluble phase II metabolites, which can be excreted to the surrounding environment.     

用固相萃取技术富集水中多环芳烃

系统地研究了淋洗剂强度、用量和有机改性剂的加入对固相萃取水中多环芳烃回收率的影响。研究表明,二氯甲烷和苯的洗脱效果较好,回收率为８７％～１０２％;当淋洗剂的用量超过１．５ｍＬ时,对多环芳烃的回收率没有明显的影响;向自来水样中加入２０％有机改性剂可明显改善多环芳烃的回收效果,使回收率达到８９％～１０８％。     

Determination of trace PAHs in seawater and sediment pore-water by solid-phase microextraction (SPME) coupled with GC/MS

A fast and reliable method for the determination of trace PAHs (polynuclear aromatic hydrocarbons) in seawater by solid-phase microextraction (SPME) followed by gas chromatographic (GC) analysis has been developed. The SPME operational parameters have been optimized, and the effects of salinity and dissolved organic matter (DOM) on PAHs recoveries have been investigated. SPME measures only the portion of PAHs which are water soluble, and can be used to quantify PAH partition coefficient between water and DOM phases. The detection limits of the overall method for the measurement of sixteen PAHs range from 0.1 to 3.5 ng/g, and the precisions of individual PAH measurements range from 4% to 23% RSD. The average recovery for PAHs is 88.2±20.4%. The method has been applied to the determination of PAHs in seawater and sediment porewater samples collected in Jiaozhou Bay and Laizhou Bay in Shandong Peninsula, China. The overall levels of PAHs in these samples reflect moderate pollution compared to seawater samples reported elsewhere. The PAH distribution pattern shows that the soluble PAHs in seawater and porewater samples are dominated by naphthalenes and 3 ring PAHs. This is in direct contrast to those of the sediment samples reported earlier, in which both light and heavy PAHs are present at comparable concentrations. The absence of heavy PAHs in soluble forms (<0.1-3.5 ng/L) is indicative of the strong binding of these PAHs to the dissolved or solid matters and their low seawater solubility.     

Solid-phase extraction clean-up procedure for the analysis of PAHs in lichens

A clean-up procedure based on a solid-phase extraction column was optimized for determination of polycyclic aromatic hydrocarbons (PAHs) in lichen extracts to remove co-extracted compounds from the matrix in the final extract. Several kinds of solid phases were evaluated: normal phase (-NH₂ and alumina), strong anion exchange and reversed phase. The -NH₂ columns were the most effective by using a packed solid bed of 500?mg. The lichen raw extract was loaded on the column previously conditioned with dichloromethane and hexane. Hexane (0.5?mL) was used as rinsing solvent, and PAHs were quantitatively eluted (80–97%) using 2?mL of hexane–dichloromethane (65–35) as eluting solvent. In these conditions, even the heaviest PAHs were quantitatively eluted. The optimized SPE method provides a short time and low-solvent-consumption sample clean-up compared with other conventional methods based on column chromatography. The analytical procedure, dynamic sonication-assisted extraction, followed by the optimized solid-phase extraction clean-up, was used to determine the 16 EPA priority PAHs from native lichens collected from the Aragon valley in central Pyrenees. The PAH concentrations in lichen samples ranged from 352 to 1654?ng?g^?1, and the minimum concentration value was established as the regional reference PAH levels in the area.     

Initial applications of phospholipid-coated mercury electrodes to the determination of polynuclear aromatic hydrocarbons and other organic micropollutants in aqueous systems

Mercury electrodes coated with di-oleoyl lecithin are described for the determination of polynuclear aromatic hydrocarbons (PAHs) and other micropollutants in aqueous solutions. The coated electrodes give a characteristic response in the capacitance/voltage curve to three-, four- and five- ring PAHs. The extent of the negative potential shift in the reversible capacitance peaks (and thus sensitivity) is related to the number of aromatic rings and substituents on the PAH. The capacitance/voltage curves were recorded by phase-sensitive a.c. voltammetry. The response is quantitatively related to the concentration of PAH in solution. Detection limits are about 0.4 μg l^?1 and the reproducibility (RSD) for separate samples is 7%. Intercalibration of the method with fluorescence spectrophotometry of pyrene-spiked sea-water samples, showed recoveries of 80%. The analytical system is useful for sea water and tap water. Bovine serum albumin (1 mg l^?1) enhances the sensitivity to pyrene. The monolayer is sensitive to oil-contaminated waters ( > 40 μg l^?1). The capacitance peaks respond selectively to other groups of compounds and to individual compounds within a group. The monolayer appears highly sensitive to the solution behaviour of PAHs because only soluble unbound PAHs penetrate the monolayer. Humic acid added to the solution decreases the response to PAH presumably by binding a fraction of PAH in the solution.     

Rapid determination of PAHs in soil samples by HPLC with fluorimetric detection following sonication extraction

A rapid method for the determination of PAHs in soil samples based on their extraction with methylene chloride by sonication and subsequent separation by HPLC with fluorimetric detection is proposed. A Hypersil Green PAH column was used with a gradient of acetonitrile/water as the mobile phase, together with a program of nine excitation and emission wavelength pairs. Recoveries were in the range 70–98%, except for acenaphthene and naphthalene, at concentration levels 1.08–442 μg/kg with relative standard deviations in the range 2–15% (n = 4). Total PAHs found in soil samples were in the range 15–282 μg/kg. The results were compared with those obtained by applying the 3540 EPA method for two samples. Received: 9 May 2000 / Revised: 17 June 2000 / Accepted: 23 June 2000