Influence of collagen and natural casings on the polycyclic aromatic hydrocarbons in traditional dry fermented sausage (Petrovská klobása) from Serbia

The aim of this study was to determine the content of polycyclic aromatic hydrocarbons—PAHs (acenaphthylene, anthracene, fluorene, phenanthrene, pyrene, benz[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, chrysene, indeno[1,2,3-cd]pyrene, dibenz[a,h]anthracene, and benzo[ghi]perylene)—from Environmental Protection Agency list (United States Environmental Protection Agency) in traditional dry fermented sausage (Petrovská klobása) stuffed in collagen (C) and natural casings (N). Benzo[a]pyrene as well as PAH4 (benz[a]anthracene, benzo[b]fluoranthene, benzo[a]pyrene, and chrysene) were not detected in all examined samples. Results obtained in this study indicated that at the end of drying, as well as at the end of storage period, total content of 13 US-EPA PAH was significantly (P < 0.05) lower in sausages with collagen casing (56.2 and 73.6 μg/kg, respectively) than in sausages with natural casing (137.1 and 206.2 μg/kg, respectively).     

Determination of polycyclic aromatic hydrocarbons in cachaça by HPLC with fluorescence detection

Cachaça is a distilled alcoholic beverage obtained from sugar cane fermentation. In this study, 25 brands of cachaça commercially available in Brazil were analysed for the presence of 5 PAHs (benz[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene and dibenz[a,h]anthracene). The methodology involved liquid–liquid extraction with cyclohexane and dimethyilformamide–water (9:1, v/v), clean up on silica gel column and determination by high performance liquid chromatography using fluorescence detection. PAHs peak identity was confirmed by gas chromatography–mass spectrometry (GC–MS). Variable levels of summed PAHs were detected in the analysed samples, ranging from not detected to 1.94 μg/L. The results confirm the presence of PAHs in cachaça and suggest that contaminated sugar cane may be the source of PAHs in sugar cane spirits.     

Benzo[a]pyrene and total polycyclic aromatic hydrocarbons (PAHs) levels in vegetable oils and fats do not reflect the occurrence of the eight genotoxic PAHs

Concentrations of polycyclic aromatic hydrocarbons (PAHs) were determined in 115 samples of olive oil (extra virgin olive oil, virgin olive oil, olive oil, pomace olive oil and blended olive oil), cooking oil (corn oil, sunflower oil, sesame oil, palm olein oil, soya oil, canola oil, mustard oil, peanut oil and mixed vegetable oil) and fat (butter and table margarine) collected from retail stores in Kuwait. Carcinogenic benzo[a]pyrene (BaP) was detected in 43% of the samples analyzed. Benz[a]anthracene and chrysene were detected in 37 and 45% of the samples, respectively, that did not contain BaP. Of the individual non-carcinogenic PAHs, naphthalene showed the highest mean concentration (14 µg kg^?1), while for the carcinogenic PAHs, BaP (0.92 µg kg^?1) and chrysene (0.87 µg kg^?1) showed the highest mean values. Approximately 20% of the samples within the olive oil and cooking oil sub-categories exceeded the EU maximum tolerable limit for BaP, with the highest level of 6.77 and 11.1 µg kg^?1, respectively. For the fat sub-category, 9% of the samples exceeded the tolerance limit, with the highest level of 3.67 µg kg^?1. The Kuwaiti general population's dietary exposure to the genotoxic PAHs (PAH8: benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, dibenz[a,h]anthracene and benzo[ghi]perylene) was estimated to be 196 ng day^?1 (3.3 ng kg^?1 bw day^?1, assuming an average adult body weight of 60 kg). Results indicated that PAH8 and BaP_eq (total sum benzo[a]pyrene equivalents) are more reliable measures of the concentrations of other carcinogenic PAHs in oil and fat samples, while BaP and PAHs alone are not good indicators of the occurrence or degree of contamination by carcinogenic PAHs in these food products.     

Polycyclic aromatic hydrocarbons in Italian preserved food products in oil

A method based on gas chromatography/ tandem mass spectrometry was used to assess levels of 16 EU priority polycyclic aromatic hydrocarbons (PAHs) in 48 preserved food products in oil including foods such as vegetables in oil, fish in oil and oil-based sauces obtained from the Italian market. The benzo[a]pyrene concentrations ranged from <0.04 to 0.40 µg kg^?1, and 72.9% of the samples showed detectable levels of this compound. The highest contamination level was observed for chrysene with three additional PAHs (benzo[a]anthracene, benzo[b]fluoranthene and benzo[c]fluorene) giving mean values higher than the mean value for benzo[a]pyrene. Chrysene was detected in all the samples at concentrations ranging from 0.07 to 1.80 µg kg^?1 (median 0.31 µg kg^?1). The contamination expressed as PAH4 (sum of benzo(a)pyrene, chrysene, benzo(a)anthracene and benzo(b)fluoranthene), for which the maximum tolerable limit has been set by Commission Regulation (EU) No. 835/2011, varied between 0.10 and 2.94 µg kg^?1.     

Assessment of the dietary habits and polycyclic aromatic hydrocarbon exposure in primary school children

Thirty Italian children, 7–9 year aged, living in Naples were investigated on their dietary habits and on polycyclic aromatic hydrocarbon (PAH) exposure by a food diary-questionnaire and one week duplicate diet sample analyses. Daily total food consumption mean value was 632 ± 215 g day^?1, median value 613 g day^?1. The daily energy intake and the diet composition meanly agreed with the official guidelines for the Italian children. Sixteen PAHs were simultaneously detected and, according to the European Food Safety Authority (EFSA) approach, benzo[a]pyrene; benzo[a]pyrene + chrysene (PAH2); PAH2 + benz[a]anthracene + benzo[b]fluoranthene (PAH4); PAH4 + benzo[k]fluoranthene + benzo[ghi]perylene + dibenz[a, h]anthracene + indeno[1,2,3-cd]pyrene (PAH8) were considered in evaluating the children's dietary exposure to PAHs. The benzo[a]pyrene (BaP) median concentrations in foods varied from 0.06 to 0.33 µg kg^?1. Only three samples of cooked foods (one fish and two meat samples) exceeded legal limits fixed by the European Union for BaP. Daily median intakes of benzo[a]pyrene, PAH2, PAH4, and PAH8 were 153; 318; 990; 1776 ng day^?1; their median exposure values were 5; 10; 28; 54 ng kg^?1 bw day^?1. The Margins of Exposure (MOEs) in median consumers agreed with the EFSA safety values except for PAH8.     

Effects of grilling and roasting on the levels of polycyclic aromatic hydrocarbons in beef and pork

The concentrations of seven polycyclic aromatic hydrocarbons (PAHs) viz. chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, benzo(g,h,i)perylene, and indeno(1,2,3-c,d)pyrene in 150 samples of commercial meat products were determined. The PAHs were extracted with hexane, purified with Sep-Pak Florisil cartridges and determined by high-performance liquid chromatography using a fluorescence detector. Levels of PAHs were dependent on the method of cooking and type of heat source used. Relatively high levels of PAHs, 10.2 μg/kg on average, were found in charcoal-grilled pork samples. Average PAH levels in beef did not exceed 0.80 μg/kg. Charcoal grilling of pork samples resulted in extremely high levels of benzo(a)pyrene (3.0 μg/kg), while the average benzo(a)pyrene levels in charcoal-grilled beef samples were 0.15 μg/kg. These data can be used to estimate the dietary exposure of consumers to PAHs and to assess any potential risk associated with the ingestion of these foods.     

Polycyclic aromatic hydrocarbons in traditionally smoked Slavonska kobasica

ABSTRACT

The traditional smoking procedure, which is the use of open fire, can lead to the formation of PAHs in sausages. The aim of this paper was to assess the types and concentrations of 16 PAHs in 30 samples of Slavonska kobasica, a traditional smoked sausage. In general, some samples showed high values of anthracene and acenaphthylene. In one sample, acenaphthylene reached the value of 1050 µg/kg and in another 1491 µg/kg anthracene was measured. Cancerogenic benzo(a)pyrene content was little above the maximum limit of 5 µg/kg in four samples, but mainly remained below the limit of quantification. PAH4 (i.c. benzo(a)anthracene, chrysene, benzo(b)fluoranthene and benzo(a)pyrene) were above the maximum limit of 30 µg/kg in three samples. Generally, it can be noted from the results that samples with high PAH4 and benzo(a)pyrene concentrations also have high PAH16 concentrations.     

Single-laboratory validation of a saponification method for the determination of four polycyclic aromatic hydrocarbons in edible oils by HPLC-fluorescence detection

An analytical method is reported for the determination of four polycyclic aromatic hydrocarbons (benzo[a]pyrene (BaP), benz[a]anthracene (BaA), benzo[b]fluoranthene (BbF) and chrysene (CHR)) in edible oils (sesame, maize, sunflower and olive oil) by high-performance liquid chromatography. Sample preparation is based on three steps including saponification, liquid–liquid partitioning and, finally, clean-up by solid phase extraction on 2 g of silica. Guidance on single-laboratory validation of the proposed analysis method was taken from the second edition of the Eurachem guide on method validation. The lower level of the working range of the method was determined by the limits of quantification of the individual analytes, and the upper level was equal to 5.0 µg kg^?1. The limits of detection and quantification of the four PAHs ranged from 0.06 to 0.12 µg kg^?1 and from 0.13 to 0.24 µg kg^?1. Recoveries of more than 84.8% were achieved for all four PAHs at two concentration levels (2.5 and 5.0 µg kg^?1), and expanded relative measurement uncertainties were below 20%. The performance of the validated method was in all aspects compliant with provisions set in European Union legislation for the performance of analytical methods employed in the official control of food. The applicability of the method to routine samples was evaluated based on a limited number of commercial edible oil samples.     

Evaluation of polycyclic aromatic hydrocarbon contents and risk assessment for fish and meat products in Korea

Contents and human exposure to polycyclic aromatic hydrocarbons (PAHs) in fish and meat products in Korea were analyzed. Liquid-liquid extraction and HPLC with fluorescence detection were used. The average concentrations of total PAHs were 0.21 μg/kg for fish and shellfish, 1.97 μg/kg for meat, and 0.32 μg/kg for smoked products. The benzo[a]pyrene (BaP) content was <5 μg/kg and contents of 4 PAHs (benzo[a]anthracene, chrysene, benzo[b]fluoranthene, and BaP) were lower than 30 μg/kg, which is the maximum tolerable limit. PAHs values were changed to BaP to conduct exposure assessments and risk characterization. Dietary exposure was 0.011-0.544 ng-TEQ_BaP/kg/day. The margin of exposure for all population groups assessed at the mean and 95^th percentile was 13,757–9,090,909, of low concern. PAHs were detected in fish and shellfish, meat, and smoked products, but their contribution to human PAH exposure was small.     

Rapid and sensitive method for the determination of four EU marker polycyclic aromatic hydrocarbons in cereal-based foods using isotope-dilution GC/MS

A rapid and sensitive method has been developed for the determination of the four European Union marker polycyclic aromatic hydrocarbons (PAHs; benz[a]anthracene, chrysene, benzo[b]fluoranthene and benzo[a]pyrene) in some cereal-based foods. The method is based on pressurised liquid extraction (PLE), solid-phase extraction clean-up (SPE) and isotope-dilution gas chromatography with mass-spectrometric detection (GC/MS). The developed method was calibrated for the content range of 0.05–12.5 µg kg^?1 (expressed on a product basis). Recoveries of PAH were monitored in each sample via the recovery of ¹³C-labelled PAHs. Recovery values were in the range between 86% and 91%, with relative standard deviations (RSDs) between 5% and 9%. The achieved limits of detection for all analytes were below 0.05 µg kg^?1. The applicability of the method for the analysis of routine samples was studied by the analysis of a set of commercial bread and breakfast cereal samples. In all analysed samples, benzo[a]pyrene (BAP) was the most prevalent PAH with the content between 0.09 and 0.30 µg kg^?1. On average, samples showed low levels of the sum of the four EU marker PAHs (ΣPAH4) that ranged between 0.11 and 0.22 µg kg^?1 for bread samples and between 0.23 and 0.87 µg kg^?1 for breakfast cereal samples. The developed method was found suitable for the determination of PAHs in cereal-based foods like cornflakes and breads with total relative fat contents below 3.5%.     

Results of an European inter-laboratory comparison study on the determination of the 15 + 1 EU priority polycyclic aromatic hydrocarbons (PAHs) in liquid smoke condensates

A collaborative study on the determination of the 15 + 1 EU priority PAHs in Primary Smoke Condensate (PSC) investigating the performance profile of EU Member States’ laboratories and supporting the work carried out by the European Food Safety Authority on smoke flavourings was organised. Two spiked liquid smoke condensate materials were employed in this study. The results of 25 laboratories from across the European Union, using either high performance liquid chromatography with fluorescence detection or gas chromatography with mass selective detection, were evaluated by application of robust statistics. The assessment of the data indicated broadened Gaussian distributions for all analytes. For benzo[a]pyrene (BaP), benzo[a]anthracene (BaA), chrysene and 5-methylchrysene more than 80% of the respective reported values gave rise to a satisfactory score of |z| ? 2. For benzo[b]fluoranthene, benzo[k]fluoranthene, and dibenzo[a,l]pyrene 70–80%, for the remaining analytes less than 70%, and for dibenzo[a,i]pyrene 52% of the scores were satisfactory. No systematic differences could be detected between values reported by laboratories using methods based on HPLC and the values related to methods based on GC for most of the analytes, except for benzo[k]fluoranthene and benzo[c]fluorene. In both cases laboratories using GC based methods reported about 50% higher values than laboratories using HPLC based methods. The overview on all z-scores sorted by laboratory revealed broad distributions and/or laboratory biases for several laboratories. An assessment of the reported method performance parameters revealed that for the two regulated compounds, BaP and BaA, only two thirds of the reported data were in compliance with Regulation (EC) 627/2006. Overall the methods used in the participating laboratories were – with ample room for improvement – well on the way to comply with European legislation.     

Polycyclic aromatic hydrocarbon levels and risk assessment for food from service facilities in Korea

ABSTRACT

In this study, levels of benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene (BaP), dibenzo[a,h]anthracene, benzo[g,h,i]perylene and indeno[1,2,3-c,d]pyrene in 412 food items collected from food service facilities in Korea were analysed. The concentrations of the eight polycyclic aromatic hydrocarbons (PAHs) ranged 0.13–0.48 μg/kg. The concentrations of benzo[a]pyrene in all food samples were <1 μg/kg, which is the lowest maximum limit in foods regulated by European Union legislation. PAH contents were employed to conduct exposure and risk assessment. The chronic daily intake of PAHs from 412 food samples was 5.48 × 10^–6-4.70 ×x 10^–4 µg-TEQ_BaP/kg/day with margins of exposure of 1.04 × 10⁹-1.16 × 10¹¹.     

Polycyclic aromatic hydrocarbons (PAHs) in yerba mate (Ilex paraguariensis) from the Argentinean market

Polycyclic aromatic hydrocarbons (PAHs) occurrence in 50 samples marketed in the main supermarkets from Argentina was surveyed. A high performance liquid chromatography (HPLC) method was applied with fluorescence detection (FLD) and UV—VIS diodes array detector (DAD) for the analysis of 16 PAHs in “yerba mate” (Ilex paraguariensis), with recoveries higher than 89% and limits of detection and quantification lower than that found by other methodologies in previous studies. Contamination expressed as the sum of 16 analysed PAHs ranged between 224.6 and 4449.5 μg kg^?1 on dry mass. The contamination expressed as PAH4 (sum of benzo(a)pyrene, chrysene, benzo(a)anthracene and benzo(b)fluoranthene) varied between 8.3 and 512.4 μg kg^?1. The correlation coefficient for PAH2 (sum of benzo(a)pyrene and chrysene) and PAH4 groups was 0.99, for PAH2 and PAH8 (sum of benzo(a)pyrene, chrysene, benzo(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(g,h,i)perylene, dibenzo(a,h)anthracene and indeno(1,2,3cd) pyrene) 0.97 and for PAH4 and PAH8 0.98.     

Assessment of contamination source and quality control approach for polycyclic aromatic hydrocarbons in wood-pressed rapeseed oil

Contamination sources of polycyclic aromatic hydrocarbons (PAHs) in the raw material, oil production and storage processes of wood-pressed rapeseed oil were investigated in this study. The results showed that benzo[a]pyrene (BaP) and PAH4 (sum of BaP, benzo[a]fluoranthene, benzo[b]fluoranthene and chrysene) were unevenly distributed in the kernel (0.56–0.98 and 2.84–8.64 μg/kg, respectively) and hull (1.53–3.17 and 13.49–22.31 μg/kg, respectively) of the rapeseed raw materials. The contents of BaP and PAH4 continuously increased during the process of wood-pressed rapeseed oil, ranging from 2.21 to 10.93 and 9.36 to 40.03 μg/kg, thus demonstrating that a wide range of pollution sources of PAHs existed for the test wood-pressed rapeseed oils. The initial temperature and time of roasting should be controlled at <210°C and <60 min, due to the generation of PAHs in rapeseed by over-roasting. In addition, contact tools and substance such as lubricating oil (from the mill), heat-transfer oil (from roasting machine), rubber gaskets and straws should be properly screened. The BaP and PAH4 of rapeseed placed in the roasting area increased from 0.5 to 2.24 and from 2.08 to 9.03 μg/kg, respectively. Therefore, roasting fume control and treatment systems are necessary and the roasting section should be strictly isolated from the other stages. Storage can slightly lower the PAHs amounts in the rapeseed oil, which made the contents of BaP and PAH4 decrease from 27.00 to 24.70 and from 138.63 to 117.58 μg/kg, respectively. Quality control measures of PAHs in wood-pressed rapeseed oil were proposed and implemented, and the final oil products’ BaP and PAH4 were kept below 2 and 10 μg/kg, respectively, which meets the European Commission Regulation No. 835/2011.     

Survey of polycyclic aromatic hydrocarbons in canned bivalves and investigation of their potential sources

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants in the marine environment derived from uncontrolled petroleum spills, marine transports, discharges from ships, and urban runoff. The NW coast of Spain (Galicia) has a characteristic hydrography, defined by a continuous suite of estuarine systems called “Rías Gallegas”. Some of these estuaries support important industrial and urban centres while others are preserved from human influence. The PAH contents in invertebrate organisms, such as bivalves, have been widely investigated because they are good bioindicators of pollution due to their ability to filter the water. 12 PAHs were determined in canned mussels (Mytilus galloprovincialis), clams (Venerupis pullastra), cockles (Cerastoderma edule) and knives (Ensis ensis) from the Galician “Rías Gallegas” to perform a possible risk assessment on these contaminants. Pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene were detected in all the selected samples by liquid chromatography coupled with fluorescence spectroscopy. With regard to benzo[a]pyrene, which represents the most potentially carcinogenic PAHs, European Regulation 1881/2006/EC fixed at 10 μg/kg of wet weight the MRL (maximum residual level) in bivalve molluscs. None of these marine invertebrates showed values higher than the MRL and therefore, they do not suppose risk for human health. Mussels hydrocarbon body burden levels were highest than exhibited by others bivalves. Some factors may determine this feature, as lipid content or habitat. Lower PAH levels of five and six benzene rings were detected in canned mussels in pickle sauce (vegetable oil, vinegar, paprika, salt and other spices) than in mussels in natural sauce (water, salt and other spices). PAHs migration from mussels to the vegetable oil in pickle sauce was verified to be the reason.     

Polycyclic aromatic hydrocarbons (PAHs) in different types of smoked meat products from Serbia

The contents of the16 EU priority PAHs in six different meat products from Serbia (beef ham, pork ham, bacon without skin, bacon with skin, cajna sausage and sremska sausage) were examined during the process of smoking. All these meat products from meat industry Zlatiborac, Mačkat, Serbia presented in this study, have not previously been analysed concerning to their contents of PAH compounds. Determination and quantification of PAHs in meat products were performed by a Fast GC/HRMS method. The maximum level for benzo[a]pyrene (BaP) of 5 μg/kg in smoked meat products was not exceeded in any samples. BaP comprises in general 4.6% of the total sum of the 16 EU priority PAHs and 15.2% of the total sum of the 12 IARC PAH compounds. The suitability of BaP as a marker both for 16 EU priority PAHs and 12 IARC probably and possibly carcinogenic PAHs was checked by applying correlation analysis.     

Polycyclic aromatic hydrocarbons in fresh and cold-smoked Atlantic salmon fillets

The occurrence of polycyclic aromatic hydrocarbons (PAHs) in smoked fish as a consequence of cold smoking was studied. Raw fillets of Salmo salar from Norway or the Irish Sea were sampled in a modern smokehouse and examined for PAH content. The same fillets, labeled with an identification number, were sampled immediately after the smoking process and analyzed. Among the investigated compounds, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, and benzo[ghi]perylene were detected in both raw and smoked fillets. No significant difference (P < 0.01) was observed between raw and smoked samples in the concentrations of six PAHs, but significant differences were found for fluorene, anthracene, fluoranthene, benz[a]anthracene, and benzo[ghi]perylene. Results confirm that PAHs concentrations in smoked fish are the product of both sea pollution and the smoking process. A modern smoking plant with an external smoke generator and a mild treatment as described here will not add significantly to the concentration of PAHs, except for some compounds.     

Polycyclic aromatic hydrocarbons in food samples collected in Barcelona, Spain

This study reports on the concentrations of eight polycyclic aromatic hydrocarbons (PAHs) in food samples collected in the city of Barcelona (Catalonia, Spain) from 2003 to 2004. Food samples included meat products, fish (fresh and smoked), other seafood (cephalopods, crustaceans, and bivalves), vegetable oil, and tea. Concentrations of benz[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[g,h,i]perylene, benzo[alpha]pyrene, benzo[e]pyrene, dibenz[a,h]anthracene, and indeno[1,2,3-c,d]pyrene were determined by reversed-phase high-performance liquid chromatography with fluorescence detection. PAHs were detected in most tea samples (94%), which had the highest concentration of total PAHs (mean concentration of 59 microg/kg). Other food groups with a high presence of PAHs were bivalves (present in 34% of the samples; mean value of 2.7 microg/kg) and meat products (present in 13% of the samples; mean value of 1.7 microg/kg). The PAHs detected most frequently were benzo[e]pyrene and benzo[b]fluoranthene. No sample had levels above current regulation standards. Nevertheless, the frequent presence of PAHs in bivalves, tea samples, and meat products, together with the fact that dietary sources are the main exposure to these carcinogenic compounds, suggests the need for some monitoring scheme to follow up on these trends.     

Multi-Walled Carbon Nanotubes as Effective Sorbents for Rapid Analysis of Polycyclic Aromatic Hydrocarbons in Edible Oils Using Dispersive Solid-Phase Extraction (d-SPE) and Gas Chromatography—Tandem Mass Spectrometry (GC-MS/MS)

A method was developed for the analysis of four polycyclic aromatic hydrocarbons regulated in the European Union, namely, benzo[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo[a]pyrene in edible oils. Multi-walled carbon nanotubes were applied for dispersive solid-phase extraction of analytes from the oils after dilution with n-hexane followed by elution of analytes with toluene under reflux conditions. Gas chromatography coupled to tandem mass spectrometry was used for quantitative determination of the analytes. The efficiency of four nanotube-based sorbents was evaluated. The performance characteristics of the method permitted reliable measurement of four regulated polycyclic aromatic hydrocarbons in oil samples according to the criteria stated in the Commission Regulation No. 836/2011 and considering the maximum levels (MLs) stated in the Commission Regulation (EU) No. 835/2011. The concentrations of the selected analytes in real-world samples determined by our developed method and by previously validated gel permeation chromatography method were found to be in a good agreement.     

Trophic dilution of polycyclic aromatic hydrocarbons (PAHs) in a marine food web from Bohai Bay, north China

Trophic transfer of polycyclic aromatic hydrocarbons (PAHs) in aquatic ecosystems is an important criterion for assessing their ecological risk. This study analyzed 18 PAHs in phytoplankton/seston, zooplankton, five invertebrate species, five fish species, and one seabird species collected from Bohai Bay, and trophic transfer of the PAHs was determined in the food web, of which the length was approximately 4 on the basis of stable nitrogen isotope values. The concentrations of PAHs (2-64.5 ng/g wet weight) in the marine ecosystem were moderate compared with other marine organisms worldwide, and the PAH compositions exhibited species-specific profiles that were related to trophic levels in some organisms. Significant negative relationships were also found between trophic levels and lipid-normalized concentrations for 10 PAH compounds (acenaphthylene, anthracene, fluoranthene, pyrene, chrysene, benz[a]anthracene, benzo[b]fluoranthene + benzo[k]fluoranthene, benzo[e]pyrene, benzo[a]pyrene, and perylene), and their trophic magnification factors (TMFs) ranged from 0.11 for fluoranthene to 0.45 for acenaphthylene. These results confirm that PAHs undergo trophic dilution in the marine food web, which is likely to be the combined results of low assimilation efficiencies and efficient metabolic transformation at higher trophic levels.