Co-Exposure of Phenanthrene and the cyp-Inducer 3-Methylchrysene Leads to Altered Biotransformation and Increased Toxicity in Fish Egg and Larvae.

Polycyclic aromatic hydrocarbons (PAHs) have frequently been suspected of governing crude oil toxicity because of similar morphological defects in fish. However, PAH concentrations are often not high enough to explain the observed crude oil toxicity. We hypothesize that one PAH can enhance the metabolism and toxicity of another PAH when administered as a mixture. Early life stage Atlantic haddock (Melanogrammus aeglefinus) were in this study exposed to phenanthrene in the presence and absence of 3-methylchrysene that is known to induce the metabolic enzyme cytochrome P450 1A via cyp1a gene expression. Uptake, metabolism, and multiple toxicity endpoints were then measured in a time-course study up to 3 days post-hatching. Passive dosing provided aqueous concentrations ≈180 µg/L for phenanthrene and ≈0.6 µg/L for 3-methylchrysene, which resulted in tissue concentrations ≈60 µg/g ww for phenanthrene and ≈0.15 µg/g ww for 3-methylchrysene. The low concentration of 3-methylchrysene led to the elevated expression of cyp1a but no toxicity. Levels of phenanthrene metabolites were 5-fold higher, and morphological defects and cardiotoxicity were consistently greater when co-exposed to both compounds relative to phenanthrene alone. This work highlights the metabolic activation of PAH toxicity by a co-occurring PAH, which can lead to excess toxicity, synergistic effects, and the overproportional contribution of PAHs to crude oil toxicity.

Lethal, behavioral, growth and developmental toxicities of alkyl-PAHs and non-alkyl PAHs to early-life stage of brine shrimp, Artemia parthenogenetica.

Alkyl-PAHs are the predominant form of PAHs in crude oils which are supposed to demonstrate different toxicities compared to non-alkyl PAHs. Little information is available about the toxicity of alkyl-PAHs on marine Artemia. This study addressed and compared the lethal, behavioral, growth and developmental toxicities of three alkyl-PAHs, namely 3-methyl phenanthrene (3-mPhe), retene (Ret) and 2-methyl anthracene (2-mAnt), to their non-alkyl forms, phenanthrene (Phe) and anthracene (Ant) using Artemia parthenogenetica (nauplii, <24 h) as test organism following a 48 h and a 7 d of exposure, respectively. Benzo-a-pyrene (Bap) was selected as a reference toxicant for the comparison with the above alkyl-PAHs and non-alkyl PAHs. Results showed that for all tested endpoints, A. parthenogenetica nauplii had the highest sensitivity to Bap while Ant had no significant effect on nauplii survival or development within given concentrations. Considering the aqueous freely dissolved PAH concentrations, the 48 h-LC50 (survival), 48 h-EC50 (immobility) and 7 d-LC10 (survival) of Bap were calculated as 0.321, 0.285 and 0.027 µg/L, respectively, which were twofold to fivefold lower than those of Phe, 3-mPhe, Ret, Ant and 2-mAnt. A higher acute toxicity of alkyl-PAHs (3-mPhe and 2-mAnt) than their non-alkyl forms (Phe and Ant) was observed. Not limited to Phe, the common non-polar narcotic mode of action was also observed for Bap, 3-mPhe, Ret and 2-mAnt, which was evident by the inhibited mobility of nauplii. The decreased body lengths were found for all PAH treatments compared to the solvent control, whereas instar retardations were only found in nauplii exposed to Bap, Phe and Ret. Our findings emphasized the sensitivity differences of A. parthenogenetica nauplii to selected alkyl PAHs and non-alkyl PAHs and confirmed the application of lethal, behavioral and growth indicators in the toxicity evaluation of selected PAHs other than Ant. However, the distinct toxicities of these PAHs suggested other toxic modes of action may play more important roles apart from narcotic mode of action and need to be elucidated in future studies. In addition, a strong correlation between the body length and the instar of A. parthenogenetica nauplii was observed for each PAH exposure, suggesting that body length can be representative for both growth and developmental indicators during biological monitoring of PAH pollution in marine environment.

Histological, oxidative and immune changes in response to 9,10-phenanthrenequione, retene and phenanthrene in Takifugu obscurus liver.

Polycyclic aromatic hydrocarbons (PAHs) are typical pollutants and may be alkylated and oxygenated to form alkyl-PAHs and oxygenated-PAHs (oxy-PAHs), respectively. Takifugu obscurus is an important anadromous fish species and displays a high risk of being exposed to PAHs-contaminated areas. In the present study, the effects of acute exposure to 44.29 µg L-1 9,10-phenanthrenequione (9,10-PQ), retene and phenanthrene (Phe) on T. obscurus liver histology, antioxidant enzymes and immune indices were compared. After exposure to these three compounds, histological sections showed damages of hepatocyte, and the activities of alanine and aspartate aminotransferase increased in plasma, indicating direct hepatic toxicity. Hepatic malondialdehyde (MDA) content increased, but superoxide dismutase (SOD) and catalase (CAT) activities decreased in response to treatments with Phe, retene and 9,10-PQ. These results revealed peroxidative effects on T. obscurus hepatocytes. In addition, total immunoglobulin content and lysozyme activity in plasma increased in treatments with Phe, retene and 9,10-PQ, which might be resulted from the damaged liver cells and the subsequently hepatic inflammation. Besides, the changes were more severe in treatment with 9,10-PQ than those with Phe and retene, demonstrating higher toxicity of 9,10-PQ than the other two compounds. Overall, the present study posed a high environmental risk of PAH derivatives to aquatic ecosystems.

Source characterisation and distribution of selected PCBs, PAHs and alkyl PAHs in sediments from the Klip and Jukskei Rivers, South Africa.

A study of the distribution of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) utilising 16 priority PAHs, benzo(e)pyrene, perylene, 19 alkylated PAHs and 31 ortho substituted PCBs in South Africa is presented. It was aimed to (a) deduce characteristic contamination patterns for both PCBs and PAHs and (b) provide the first comprehensive dataset for establishment of source characterisation of PCBs and PAHs. This is in line with new South African legislation on mandatory monitoring of PCB and PAH emissions. Bar charts, principal component analysis (PCA) and biplots were utilised to identify signature contamination patterns and distribution of PCBs and PAHs within the Jukskei and Klip Rivers. Sediments from the Jukskei and Klip River catchments both showed distinct contamination signatures for hexa to nonachlorinated PCBs, characteristic of contamination by Aroclor 1254 and 1260 technical mixtures. PCB signature patterns in order of abundance were 138 > 180 > 206 > 153 > 187 > 149 and 138 > 153 > 180 > 149 > 187 > 110 > 170 for the Jukskei and Klip River sediments, respectively. The upstream Alberton point had the highest Σ31 PCB and Σ (parent+alkyl) PAH concentrations in the Klip River of 61 and 6000 µg kg-1 dry weight (dw), respectively. In the Jukskei River, the upstream Marlboro point had the highest Σ31 PCB concentration of 19 µg kg-1 dw and the N14 site recorded the highest Σ (parent+alkyl) PAH concentration of 2750 µg kg-1 dw. PAH concentrations in both the Jukskei and Klip Rivers were significantly higher than the PCB concentrations. Fluoranthene, phenanthrene and pyrene were found in the highest concentrations in both the Jukskei and Klip River sediments. Both the Jukskei and Klip River sediments showed trends of a mixed pyrogenic-petrogenic PAH source contamination.

Polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs in the coastal seawater, surface sediment and oyster from Dalian, Northeast China.

A total of 46 polycyclic aromatic hydrocarbons (PAHs, 21 parent and 25 alkylated) were determined in seawater, surface sediment and oyster from coastal area of Dalian, North China. The concentration of Σ46PAHs in seawater, sediment, and oyster were 136-621 ng/L, 172-4700 ng/g dry weight (dw) and 60.0-129 ng/g wet weight (ww) in winter, and 65.0-1130 ng/L, 71.1-1090 ng/g dw and 72.8-216 ng/g ww in summer, respectively. High PAH levels were found in industrial area both in winter and summer. Selected PAH levels in sediments were compared with Sediments Quality Guidelines (ERM-ERL, TEL-PEL indexes) for evaluation probable toxic effects on marine organism and the results indicate that surface sediment from all sampling sites have a low to medium ecotoxicological risk. Daily intake of PAHs via oyster as seafood by humans were estimated and the results indicated that oyster intake would not pose a health risk to humans even 30 days after a oil spill accident near by. Water-sediment exchange analysis showed that, both in winter and summer, the fluxes for most high molecular weight PAHs were from seawater to sediment, while for low molecular weight PAHs, an equilibrium was reached between seawater and sediment.

Rapid and sensitive method for the simultaneous determination of PAHs and alkyl-PAHs in scrubber water using HS-SPME-GC-MS/MS.

Scrubber water, a waste stream generated by ships exhaust gas cleaning systems, may pose a threat when released into the marine environment due to potential contamination with polycyclic aromatic hydrocarbons (PAHs) and their alkyl derivatives (alkyl-PAHs). This study aims to develop a reliable analytical procedure combining headspace solid-phase microextraction (HS-SPME) with gas chromatography coupled to triple quadrupole tandem mass spectrometry (GC-MS/MS) to simultaneously separate and determine target compounds in aqueous samples. Method validation demonstrated good linearity up to 200 ng L-1 (r2> 0.996) and low limits of detection (0.33 to 1.67 ng L-1, except for naphthalene at 3.3 ng L-1). The method shows good precision (RSD<20%) and satisfactory analytical recoveries. The methodology was successfully applied to scrubber water samples collected from a container ship and the results highlight the prevalence of naphthalene, phenanthrene, and their alkyl derivatives.•Rapid and reproducible HS-SPME-GC-MS/MS method for the analysis of PAHs and alkyl-PAHs in scrubber water.•The capacity of SPME to analyze both filtered and unfiltered samples was assessed, showing that the more hydrophobic PAHs may be lost during filtration.

Discovery of polycyclic aromatic acid metabolites in fish exposed to the petroleum compounds 1-methylphenanthrene and 1,4-dimethylphenanthrene.

Most of the polycyclic aromatic hydrocarbons (PAHs) in petroleum are alkylated (alkyl PAHs), still the metabolism of these alkyl PAHs to the expected acid products (polycyclic aromatic acids; PAAs) has yet to be demonstrated in oil-exposed fish. Should these compounds be discovered in fish as they have in ragworm, rodents, and humans, they could present an indicative biomarker for assessing oil pollution. In this study, the ability to biotransform alkyl PAHs to PAAs was examined on Atlantic haddock (Melanogrammus aeglefinus). Exposure to phenanthrene, 1-methyphenanthrene or 1,4-dimethylphenanthrene was performed via intraperitoneal injection. An Ion Mobility Quadrupole Time-Of-Flight Mass Spectrometer (IMS-Q-TOF MS) was used in exploratory analysis of extracted bile samples. Acquisition of four-dimensional information by coupling liquid chromatography with the IMS-Q-TOF MS and in-silico prediction for feature prioritization in the data processing workflow allowed several tentative identifications with high degree of confidence. This work presents the first detection of PAAs in fish and suggests the importance of investigating alkyl PAHs in ecotoxicological studies of oil-polluted fish environments.

Characterization of scrubber water discharges from ships using comprehensive suspect screening strategies based on GC-APCI-HRMS.

An extended suspect screening approach for the comprehensive chemical characterization of scrubber discharge waters from exhaust gas cleaning systems (EGCSs), used to reduce atmospheric shipping emissions of sulphur oxides, was developed. The suspect screening was based on gas chromatography coupled with high-resolution mass spectrometry (GC-HRMS) and focused on the identification of polycyclic aromatic hydrocarbons (PAHs) and their alkylated derivatives (alkyl-PAHs), which are among the most frequent and potentially toxic organic contaminants detected in these matrices. Although alkyl-PAHs can be even more abundant than parent compounds, information regarding their occurrence in scrubber waters is scarce. For compound identification, an in-house compound database was built, with 26 suspect groups, including 25 parent PAHs and 23 alkyl-PAH homologues. With this approach, 7 PAHs and 12 clusters of alkyl-PAHs were tentatively identified, whose occurrence was finally confirmed by target analysis using GC coupled with tandem mass spectrometry (GC-MS/MS). Finally, a retrospective analysis was performed to identify other relevant (poly)cyclic aromatic compounds (PACs) of potential concern in scrubber waters. According to it, 18 suspect groups were tentatively identified, including biphenyls, dibenzofurans, dibenzothiophenes and oxygenated PAHs derivatives. All these compounds could be used as relevant markers of scrubber water contamination in heavy traffic marine areas and be considered as potential stressors when evaluating scrubber water toxicity.

Distributions and potential sources of polychlorinated biphenyls and polycyclic aromatic hydrocarbons in the glacimarine sediments of Arctic Svalbard.

Distribution and sources of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in the glacimarine sediments (35 sites) of Svalbard were investigated. PCBs (32 congeners), traditional PAHs (15 homologs), emerging PAHs (11 homologs), and alkylated PAHs (16 homologs) were widely distributed in the Svalbard sediments (ranges: below method detection limit to 20, 21 to 3600, 1.0 to 1400, and 31 to 15,000 ng g-1 dry weight, respectively). Compositional analysis indicated that PCBs mainly originated from combustion sources, with PAHs being strongly influenced by local sources. Positive matrix factorization analysis showed that PAHs were associated with vehicle and petroleum combustion, coal, and coal combustion. Coal-derived PAHs contributed significantly to the sediments of Van Mijenfjorden. Remnants of coal mining activity trapped in the permafrost appear to enter the coastal environments as ground ice melts. Consequently, PAHs are currently emerging as the most significant contributors to potential risks in the Svalbard ecosystems.

Examination of aryl hydrocarbon receptor (AhR), estrogenic and anti-androgenic activities, and levels of polyaromatic compounds (PACs) in tire granulates using in vitro bioassays and chemical analysis.

Tire granulates recovered from end-of-life tires contain a complex mixture of chemicals, amongst them polyaromatic compounds (PACs), of which many are recognized to be toxic and persistent in the environment. Only a few of these PACs are regularly monitored. In this study a combined approach of chemical analysis and a battery of CALUX® in vitro bioassays was used to determine PAC concentrations and estrogenic, (anti)-androgenic and aryl hydrocarbon receptor (AhR) activities in tire granulates. Tire granulates from a recycling company was analyzed for PAHs, alkyl-PAHs, oxy-PAHs and heterocyclic PACs (NSO-PACs), in total 85 PACs. The concentrations of PACs were between 42 and 144 mg/kg, with major contribution from PAHs (74-88%) followed by alkyl-PAHs (6.6-20%) and NSO-PACs (1.8-7.0%). The sum of eight priority PAHs were between 2.3 and 8.6 mg/kg, contributing with 4.7-8.2% of ∑PACs. Bioassay analysis showed presence of AhR agonists, estrogen receptor (ERα) agonists, and androgen receptor (AR) antagonists in the tire granulate samples. Only 0.8-2.4% of AhR-mediated activities could be explained by the chemical analysis. Benzo[k+j]fluoranthenes, benzo[b]fluoranthene, indeno[1,2,3-cd]pyrene, 2-methylchrysene, and 3-methylchrysene were the major contributors to the AhR-mediated activities. The high contribution (98-99%) of unknown bioactive compounds to the bioassay effects in this study raises concerns and urges for further investigations of toxicants identification and source apportionment.

Concentrations and source identification of PAHs, alkyl-PAHs and other organic contaminants in sediments from a contaminated harbor in the Laurentian Great Lakes.

As a result of historical industrial activity, the sediments in the inner harbor of Owen Sound Bay in the northeastern part of Lake Huron in Ontario, Canada are contaminated with organic compounds. The present study showed that the concentrations of Æ© PAH16-EPA in all sediments in the inner harbor were above the sediment quality guidelines for the province of Ontario, Canada, with mean Æ© PAH16-EPA concentrations at the most contaminated site of 46,000 µg/kg dry weight. The concentrations of polychlorinated biphenyls, brominated diphenyl ethers, and organochlorine compounds were all below sediment quality guidelines. The patterns of PAH and alkyl-PAH compounds in sediment cores indicated that contamination is from mixed sources, with a strong indication of pyrogenic contamination from industries that used to operate in the area, including a coal gasification plant. Other areas of the bay are impacted by petrogenic contamination, potentially from spills of fuel. The even distribution of PAH and alkyl-PAH compounds throughout core profiles at depths up to 25 cm indicates that this is a dynamic system and contaminated sediments are not being covered by deposition of less contaminated sediments. This study illustrates the value of determining the patterns of both PAH and alkyl-PAH compounds in sediments for regulatory purposes and also for forensic source tracking.

Chemical characterization of particulate organic matter from commercial restaurants: Alkyl PAHs as new tracers for cooking.

Cooking is one of the primary sources of particulate organic matter (POM) in urban environments. Numerous experiments have been performed to investigate the composition of POM generated during cooking. However, there still remain substantial uncertainties in our knowledge regarding the emission characteristics of alkyl polycyclic aromatic hydrocarbons (PAHs) from cooking. In addition, previous studies have selected several tracers for Chinese cooking; however, these results were acquired based on observations in the Pearl River Delta region of China, and only four of the eight Chinese cooking styles were tested. Therefore, the organic compositions of the PM2.5 emitted from four Chinese cooking restaurants in different cities are examined to investigate the emission characteristics of alkyl PAH and to verify whether the selected tracers vary with geographical location and cooking styles. In this study, C1- and C2-phenanthrenes/anthracenes, and C1-pyrenes were detected in the PM2.5 from the four tested restaurants, but the concentrations of these PAH alkyl homologues were all at low levels, and also much lower than the corresponding parent PAHs. However, the distribution pattern of the alkyl PAHs in the cooking fumes was significantly different from that in the PM from other emission sources. Additionally, some candidate tracers for cooking such as levoglucosan were less influenced by cooking styles or geographical location. Thus, these alkyl PAHs in conjunction with other specific tracers for cooking were utilized to estimate the contribution of cooking to ambient organic carbon. The results showed that the estimates from the chemical mass balance model that includes alkyl PAHs will be higher than the model that does not, and in the case of high alkyl PAHs ambient concentrations, the model that includes alkyl PAHs will provide more reasonable results.

Similar polycyclic aromatic hydrocarbon and genotoxicity profiles of atmospheric particulate matter from cities on three different continents.

The extractable organic material (EOM) from atmospheric total suspended particles (TSP) contains several organic compounds including non-substituted polycyclic aromatic hydrocarbons (PAHs), alkyl-PAHs, and nitro-PAHs. These chemicals seem to be among the key drivers of TSP genotoxicity. We have shown previously that the mutagenic potencies of the EOM from Limeira, Stockholm, and Kyoto, cities with markedly different meteorological conditions and pollution sources are similar. Here we compare the profiles of non-substituted PAHs (27 congeners), alkyl-PAHs (15 congeners), and nitro-PAHs (7 congeners) from the same EOM samples from these cities. We also compared the genotoxicity profiles using comet and micronucleus assays in human bronchial epithelial cells. The profiles of PAHs, as well as the cytotoxic and genotoxic potencies when expressed in EOM, were quite similar among the studied cities. It seems that despite the differences in meteorological conditions and pollution sources of the cities, removal, mixing, and different atmospheric transformation processes may be contributing to the similarity of the PAHs composition and genotoxicity profiles. More studies are required to verify if this would be a general rule applicable to other cities. Although these profiles were similar for all three cities, the EOM concentration in the atmospheres is markedly different. Thus, the population of Limeira (∼10-fold more EOM/m3 than Stockholm and ∼6-fold more than Kyoto) is exposed to higher concentrations of genotoxic pollutants, and Kyoto's population is 1.5-fold more exposed than Stockholm's. Therefore, to reduce the risk of human exposure to TSP genotoxins, the volume of emissions needs to be reduced.

Occurrence and leachability of polycyclic aromatic compounds in contaminated soils: Chemical and bioanalytical characterization.

An important concern regarding sites contaminated with polycyclic aromatic compounds (PACs) is the risk of groundwater contamination by release of the compounds from soils. The goal of this study was to investigate the occurrence and leachability of 77 PACs including polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic compounds (NSO-PACs) among total aryl hydrocarbon receptor (AhR) agonists in soils from historical contaminated sites. A novel approach combining chemical and bioanalytical methods in combination with characterization of leachability by use of a column leaching test was used. Similar profiles of relative concentrations of PACs were observed in all soils, with parent PAHs accounting for 71 to 90% of total concentrations in soils. Contribution of oxy-PAHs, alkyl-PAHs and N-PACs ranged from 2 to 9%, 3 to 9% and 1 to 14%, respectively. Although the contributions of groups of PACs were small, some compounds were found in similar or greater concentrations than parent PAHs. Leachable fractions of 77 PACs from soils were small and ranged from 0.002 to 0.54%. Polar PACs were shown to be more leachable than parent PAHs. The contribution of analyzed PACS to overall AhR-mediated activities in soils and leachates suggests presence of other AhR agonists in soils, and a potential risk. Only a small fraction of AhR agonists was available in soils, indicating an overestimation of the risk if only total initial concentrations in soils would be considered in risk assessment. The results of the study strongly support that focus on 16US EPA PAHs may result in inadequate assessment of risk and hazard of PACs in complex environmental samples.

Modified ion source triple quadrupole mass spectrometer gas chromatograph for polycyclic aromatic hydrocarbon analyses.

We describe modified gas chromatography electron-impact/triple-quadrupole mass spectrometry (GC-EI/MS/MS) utilizing a newly developed hydrogen-injected self-cleaning ion source and modified 9mm extractor lens. This instrument, with optimized parameters, achieves quantitative separation of 62 polycyclic aromatic hydrocarbons (PAHs). Existing methods historically limited rigorous identification and quantification to a small subset, such as the 16 PAHs the US EPA has defined as priority pollutants. Without the critical source and extractor lens modifications, the off-the-shelf GC-EI/MS/MS system was unsuitable for complex PAH analysis. Separations were enhanced by increased gas flow, a complex GC temperature profile incorporating multiple isothermal periods, specific ramp rates, and a PAH-optimized column. Typical determinations with our refined GC-EI/MS/MS have a large linear range of 1-10,000pgµl(-1) and detection limits of <2pgµl(-1). Included in the 62 PAHs, multiple-reaction-monitoring (MRM) mode enabled GC-EI/MS/MS identification and quantitation of several constituents of the MW 302 PAH isomers. Using calibration standards, values determined were within 5% of true values over many months. Standard curve r(2) values were typically >0.998, exceptional for compounds which are archetypally difficult. With this method benzo[a]fluorene, benzo[b]fluorene, benzo[c]fluorene were fully separated as was benzo[b]fluoranthene, benzo[k]fluoranthene, and benzo[j]fluoranthene. Chrysene and triphenylene, were sufficiently separated to allow accurate quantitation. Mean limits of detection (LODs) across all PAHs were 1.02±0.84pgµl(-1) with indeno[1,2,3-c,d] pyrene having the lowest LOD at 0.26pgµl(-1) and only two analytes above 2.0pgµl(-1); acenaphthalene (2.33pgµl(-1)) and dibenzo[a,e]pyrene (6.44pgµl(-1)).

Comparative embryotoxicity of phenanthrene and alkyl-phenanthrene to marine medaka (Oryzias melastigma).

Alkylated polycyclic aromatic hydrocarbons (alkyl-PAHs) are the predominant form of PAHs in oil, comprising 85-95% of total PAHs. However, little attention has been paid to these chemicals in ecological risk assessment of marine oil spill. A comparative study of the toxic effects of phenanthrene and retene (7-isopropyl-1-methylphenanthrene, an alkyl-phenanthrene) on the early life stage of marine medaka (Oryzias melastigma) was conducted. Results showed that retene was significantly more toxic than phenanthrene, and marine medaka could be more sensitive to retene than some freshwater fishes. Retene had a higher excretion rate than phenanthrene during the larvae stage. Both of compounds resulted in developmental malformation of marine medaka embryos, with phenanthrene affecting on peripheral vascular system and yolk sac, while retene affecting on cardiac tissues. The toxicity of phenanthrene might be mainly related to its anesthetic effects, and that of retene might be related to the CYP1A-mediated toxicity of its metabolites.

Localized enrichment of polycyclic aromatic hydrocarbons in soil, spruce needles, and lake sediments linked to in-situ bitumen extraction near Cold Lake, Alberta.

The extraction of bitumen from the Alberta oil sands using in-situ technologies is expanding at a rapid rate; however, investigations into the environmental impacts of oil sands development have focused on surface mining in the Athabasca region. We measured polycyclic aromatic hydrocarbons (PAH) in soils, spruce needles, and lake sediment cores in the Cold Lake oil sands region to provide a historical and spatial perspective on PAH contamination related to in-situ extraction activities. A pronounced increase in PAH concentrations was recorded in one of two study lakes (Hilda Lake) corresponding to the onset of commercial bitumen production in ~1985. Distance from extraction rigs was not an important predictor of PAH concentrations in soils, although two samples located near installations were elevated in alkyl PAHs. Evidence of localized PAH contamination in Hilda Lake and two soil samples suggests that continued environmental monitoring is justified to assess PAH contamination as development intensifies.