Short- and medium-chain chlorinated paraffins in commercial complementary baby food produced in different European countries: Occurrence, congener group profiles, portion-based dietary intake, and risk assessment.

This study was performed to evaluate the presence of chlorinated paraffins (CPs) in complementary baby food from different European countries, to assess portion-based dietary intake of CPs, and to characterize possible risks to children arising from CPs uptake. In total, 86 baby food samples from 22 countries were grouped into eight food-type categories considering the WHO classification. In six out of eight sample categories, predominance of medium-chain CPs (MCCPs) concentrations over short-chain CPs (SCCPs) was observed and, contrary to expectations, samples that contained ingredients of animal origin (e.g., meat or fish) did not display elevated CPs levels. The median ∑CPs concentrations for selected sample categories ranged from 0.8 ng g-1 for desert to 2.8 ng g-1 found in dry cereal and porridge subgroups, while the highest CPs concentration of 387 ng g-1 was observed in dry porridge. Among the selected groups of baby foods, portion-based intake of ∑CPs varied from 1.0 to 43.6 ng kg-1 body weight (b.w.) while exposure estimations indicated that portion-based dietary exposure through consumption of complementary baby food was the highest for infants aged 3-12 months due to the lower body weight. The risk characterization according to the European Food Safety Authority (EFSA) approach showed that the margin of exposure (MOE) figures higher than the critical value for ∑CPs, indicating that the dietary exposures through consumption of complementary baby food are unlikely to be of significant health concern for children. However, it should be pointed out that the performed risk assessment covered only SCCPs and MCCPs, while the occurrence of other groups from CPs and CPs related compounds (e.g., very short-chain CPs, chlorinated alkenes, or long-chain CPs (LCCPs)) was not addressed.

Polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDD), dechlorane-related compounds (DRCs), and emerging brominated flame retardants (EBFRs) in foods: The levels, profiles, and dietary intake in Latvia.

This study was performed to assess the Latvian population exposure to polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDD), dechlorane-related compounds (DRCs), and emerging brominated flame retardants (EBFRs). Food items including fish, fish products, meat, dairy products, cereals and bread, eggs, vegetable oils, and sweets were analyzed for the content of these contaminants, followed by per capita intake calculations and risk assessment. The highest dietary exposure for general population was observed in the case of HBCDD, .reaching an estimated daily intake (EDI) value of 2.92 ng kg-1 b.w. (or 3.35 ng kg-1 b.w. if an outlying data point is included), followed by PBDEs with EDI of 1.24 ng kg-1 b.w., including ~25% contribution of PBDE-209 to the overall EDI from PBDEs. DRCs and EBFRs were secondary contributors to the total intake of selected flame retardants (FRs), with the observed EDIs of 0.46 and 0.47 ng kg-1 b.w, respectively. The obtained occurrence data and risk characterization according to the European Food Safety Authority (EFSA) approach showed the calculated margin of exposure (MOE) values higher than the critical values for PBDE-47, -99 and -153as well as for HBCDD, indicating that the estimated dietary exposures are unlikely to be of significant health concern for the Latvian population. At the same time, it should be pointed out that the risk assessment was performed only for five out of the twenty-five selected halogenated flame retardants (HFRs), while cumulative effects due to the potential presence of other HFRs and their biodegradation products were not considered.

Polychlorinated naphthalenes (PCNs) in food products in Latvia: Congener-specific analysis, occurrence, and dietary exposure of the general population.

A study was performed to evaluate the dietary exposure of the Latvian population to polychlorinated naphthalenes (PCNs). Based on the toxicological characteristics, provisional levels of occurrence, congener patterns, and the availability of analytical standards, twenty-six congeners were included in the analysis. Considering the planar structure of PCNs, an analytical protocol on the basis of destructive clean-up and isolation of analytes on carbon was applied, while GC-HRMS and isotope dilution were used for the detection and quantification of analytes. Commonly consumed foods were analyzed for the content of PCNs, followed by per capita intake calculations. By applying the available in vitro relative potency (REP) factors, putative toxic equivalents (TEQ) were determined, in order to assess the "dioxin-like" effect arising from the presence of PCNs in food. The daily intake (EDI) for total PCNs (∑PCN) and PCN-TEQ for the general population were calculated to be 116 pg kg-1 body weight (b.w.) and 0.036 pg TEQ kg-1 b.w., respectively. Fish and fish products were found to provide the main contribution to the dietary "dioxin-like" burden of PCNs, constituting ∼60% of the total PCN-TEQ intake. For some fish samples, PCN-TEQ could additionally contribute up to ∼3% to the regulated PCDD/F-PCB-TEQ, while for other matrices this contribution could be lower by an order of magnitude. The obtained data indicated that the estimated dietary exposure to PCNs is likely to be of low concern, although PCN-TEQ could be recognized as a contributor to the overall "dioxin-like" TEQ loading that results from the exposure to halogenated aromatics.

Multi-analyte method for the analysis of legacy and alternative brominated and chlorinated flame retardants in food products of animal origin using gas chromatography - magnetic sector high resolution mass spectrometry.

An analytical method was developed and validated for the analysis of 32 halogenated flame retardants (HFRs), including 13 polybrominated diphenyl ethers (PBDEs), 9 dechlorane-related compounds (DRCs) and 10 of the so-called alternative BFRs in food samples of animal origin. Gas chromatography (GC) coupled with magnetic sector high resolution mass spectrometry (HRMS) was used for the instrumental analysis. Intralaboratory validation of the developed method was performed in terms of recovery, repeatability, linear calibration ranges, instrumental and method limits of quantitation (i-LOQ and m-LOQ). Where possible, trueness was verified by the analysis of reference materials (RMs). For analytes with available isotopically labeled surrogates, recoveries in the range of 70-120% and repeatability rates below 20% were observed, while for compounds quantitated using absolute calibration the values of recovery ranged from 59 to 153% and the repeatability in terms of RSDs was in the range of 1-26%. The values measured for the four analyzed RMs agreed with the provided consensus values, revealing that the recovery of reference concentrations for compounds with assigned consensus values was in 72-119% range. The elaborated method met the sensitivity criteria according to the Commission Recommendation, 2014/118/EU on the monitoring of BFRs in food products. The developed method was successfully applied for the analysis of numerous food samples. The analyses revealed ubiquitous presence of PBDEs and the majority of DRCs in the analyzed samples, while alternative BFRs were detected only occasionally.

Evaluation of analytical performance of gas chromatography coupled with atmospheric pressure chemical ionization Fourier transform ion cyclotron resonance mass spectrometry (GC-APCI-FT-ICR-MS) in the target and non-targeted analysis of brominated and chlorinated flame retardants in food.

A new analytical method was established and validated for the analysis of eighteen halogenated flame retardants (HFRs)in food products. Gas chromatography (GC) coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) employing atmospheric pressure chemical ionization (APCI) was used for the identification and quantitation of contaminants. Intra-laboratory validation of the method was performed with respect to recovery, repeatability, linear calibration ranges, instrumental and method limits of quantitation (i-LOQ and m-LOQ), and trueness was verified where possible by analysis of reference materials (RMs). The validation results indicated recoveries of analytes between 59 and 115%, the repeatability in terms of relative standard deviations (RSDs) in the range of 5-15% and linearity with correlation coefficients of ≥0.99 between the i-LOQ and 250 pg injected on-column. The method i-LOQs ranged from ∼1 pg to ∼5 pg injected on-column, while m-LOQs were in the range of 0.002-0.04 ng g-1 sample. The measured values for RMs agreed with the provided values, giving the accuracy of obtained concentrations in the range of 92-133% with RSD range of 2-15% and were in agreement with the results obtained with the reference method based on magnetic sector GC-HRMS. For the majority of the compounds, the method met a limit of quantification criterion stated in the Commission Recommendation, 2014/118/EU on monitoring BFRs in food. The developed method was demonstrated to be suitable for qualitative screening of suspect target contaminants presented in the samples by the post-run treatment of raw data and confirmation by isotope cluster analysis.

Emerging brominated flame retardants and dechlorane-related compounds in European eels (Anguilla anguilla) from Latvian lakes.

Fifteen halogenated flame retardants (HFRs) including seven emerging brominated flame retardants (EBFRs) and eight dechlorane-related compounds (DRCs) were analyzed in eels (Anguilla anguilla) sampled from five Latvian lakes. Out of the seven EBFRs, hexabromocyclododecane (HBCD) and decabromodiphenyl ethane (DBDPE) were found in eels in quantifiable concentrations, up to 6.58 and 33.0 ng g-1 lipid weight (l.w.), respectively. The mean total concentration of DRCs (∑DRC) in the samples was 0.62 ng g-1 l.w. and the geographical distribution of DRC contamination was nearly uniform among the selected lakes. Dechlorane 602 (Dec 602) was the predominant component, whereas the composition of mixture containing syn- and anti-Dechlorane Plus (DP) stereoisomers showed a pronounced enrichment of the anti-DP isomer and was close to the composition of OxyChem® DP commercial product. The determined concentrations of HFRs were lower than in other studies of aquatic biota from Europe and Asia, and the obtained results reflect the acceptable environmental status of Latvian lakes with regard to the total content of HBCD (∑HBCD), considering the environmental quality standards (EQS) stated in the Directive 2013/39/EU. The highest ∑HBCD levels were observed in eels from lakes corresponding to the industrialization of those areas, while the results of principal component analysis (PCA) showed that the concentration of HBCD depended on the particular sampling lake, reflecting non-uniform contamination of the Latvian environment with this EBFR.

Brominated flame retardants and toxic elements in the meat and liver of red deer (Cervus elaphus), wild boar (Sus scrofa), and moose (Alces alces) from Latvian wildlife.

In order to evaluate the contamination status of terrestrial biota in Latvia, muscle and liver tissues of red deer (Cervus elaphus), wild boar (Sus scrofa), and moose (Alces alces) were analyzed for the content of polybrominated diphenyl ethers (PBDE), hexabromocyclododecane (HBCD), tetrabromobisphenol A (TBBPA), as well as cadmium and lead. The highest mean concentrations of PBDEs (46.6pgg-1 wet weight (w.w.)), cadmium (0.95mgkg-1 w.w.), and lead (0.22mgkg-1 w.w.) were observed in the tissues of moose, while the wild boar samples contained the highest levels of HBCD, with the mean concentration equal to 264pgg-1 w.w. in muscle tissues. Generally low mean concentrations of TBBPA from 0.52 to 4.54pgg-1 w.w. were observed. The liver tissue of all analyzed specimens was found to contain higher concentrations of contaminants, compared to muscle tissue. The congener profile of PBDEs in the analyzed tissues indicated that the recently used "penta-BDE" formulation was a probable source, while components of HBCD, "octa-BDE", and "deca-BDE" technical mixtures are likely to undergo congener-specific or diastereomer-specific bioaccumulation or metabolic degradation. Considering the reports from other regions, it can be concluded that the terrestrial biota in Latvia is less affected by the studied contaminants.

Determination of steroidal oestrogens in tap water samples using solid-phase extraction on a molecularly imprinted polymer sorbent and quantification with gas chromatography-mass spectrometry (GC-MS).

An analytical method was established and validated for the analysis of steroidal oestrogens in tap water samples. Gas chromatography coupled to high-resolution mass spectrometry (GC-HRMS) and gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) were used for the identification/quantification of selected compounds and the analytical performance of these techniques was evaluated. Liquid-liquid extraction (LLE) and solid-phase extraction (SPE) with a molecularly imprinted polymer (MIP) stationary phase that was highly selective for oestrogens were used for the extraction of 100-mL aliquots of water samples. The recoveries of analytes with the described methods ranged from 92 to 114 %, while the repeatability in terms of relative standard deviations (RSDs) was in the range from 2.1 to 15.2 % (n = 5). It was concluded that SPE with MIP that was highly selective for oestrogens in combination with GC-HRMS detection is more preferable for the analysis of oestrogens in tap water samples. The typical oestrogen, 17ß-estradiol (17ß-E2), was detected above the method limit of quantification (m-LOQ) in 5 of 14 analysed tap water samples at concentrations from 0.09 to 0.15 ng L(-1). Despite that 17α-ethynylestradiol (17α-EE2) was not quantified in this study above m-LOQ, the presence of this chemical was qualitatively confirmed in some of the analysed samples.

Trace determination of perfluorooctane sulfonate and perfluorooctanoic acid in environmental samples (surface water, wastewater, biota, sediments, and sewage sludge) using liquid chromatography - Orbitrap mass spectrometry.

An analytical method was established and validated for the analysis of the most frequently monitored representatives among the group of perfluorinated compounds (PFAS), namely, perfluorooctanoic acid (PFOA) and prefluorooctane sulfonate (PFOS) in environmental samples (surface water, wastewater, sediments, sewage sludge, and biota). High performance liquid chromatography (HPLC) coupled to Orbitrap mass spectrometry (Orbitrap-MS) employing a heated electrospray ionization (HESI) interface operated in negative mode was used for the quantitative determination of these contaminants. HPLC separation of analytes was achieved using a reversed phase C18 (RP-C18) analytical column. The efficiency of various solid phase extraction (SPE) columns for the pre-concentration and clean-up as well as the performance of different ionization sources and detection modes for the instrumental determination were evaluated. The validation results indicate recoveries of analytes between 88 and 116%, while the intra-day and inter-day precision parameters in terms of relative standard deviations (RSDs) were in the range of 1.0-5.9% and 1.5-7.3%, respectively. The measured values for certified reference material (CRM) agreed with the provided reference values, revealing the accuracy of obtained concentrations in the range of 107-108%. The trueness of the method was verified by a successful participation in a proficiency testing (PT) program. These performance characteristics of the method permit reliable monitoring of PFOS and its derivatives in environmental samples according to the environmental quality standard (EQS) criteria regarding the maximum allowable concentrations and taking into account the annual average concentrations stated in Directive 2013/39/EU. The elaborated method was applied for the routine analysis of selected PFAS in environmental samples from the Baltic region.

Analytical capabilities of high performance liquid chromatography - Atmospheric pressure photoionization - Orbitrap mass spectrometry (HPLC-APPI-Orbitrap-MS) for the trace determination of novel and emerging flame retardants in fish.

A new analytical method was established and validated for the analysis of 27 brominated flame retardants (BFRs), including so called "emerging" and "novel" BFRs (EBFRs and NBFRs) in fish samples. High performance liquid chromatography (HPLC) coupled to Orbitrap mass spectrometry (Orbitrap-MS) employing atmospheric pressure photoionization (APPI) interface operated in negative mode was used for the identification/quantitation of contaminants. HPLC-Orbitrap-MS analysis provided a fast separation of selected analytes within 14 min, thus demonstrating a high throughput processing of samples. The developed methodology was tested by intralaboratory validation in terms of recovery, repeatability, linear calibration ranges, instrumental and method limits of quantitation (i-LOQ and m-LOQ), and where possible, trueness was verified by analysis of certified reference materials (CRMs). Recoveries of analytes were between 80 and 119%, while the repeatability in terms of relative standard deviations (RSDs) was in the range from 1.2 to 15.5%. The measured values for both analyzed CRMs agreed with the provided consensus values, revealing the recovery of reference concentrations in 72-119% range. The elaborated method met the sensitivity criterion according to Commission Recommendation 2014/118/EU on monitoring of BFRs in food products for majority of the compounds. The concentrations of polybrominated diphenyl ethers (PBDEs) in real samples determined by HPLC-APPI-Orbitrap-MS method and validated gas chromatography-high-resolution mass spectrometry (GC-HRMS) method were found to be in a good agreement.

Method development for the simultaneous determination of polybrominated, polychlorinated, mixed polybrominated/chlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls and polybrominated diphenyl ethers in fish.

An analytical methodology was developed for simultaneous determination of five groups of persistent organic pollutants (POPs) including polybrominated, polychlorinated and mixed brominated-chlorinated dibenzo-p-dioxins and dibenzofurans (PBDD/DFs, PCDD/DFs and PXDD/DFs, respectively), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in fish samples. The presented analytical approach was based on well established and robust method for determination of PCDD/DFs and PCBs, which was augmented with gas chromatography coupled to high resolution mass spectrometry (GC-HRMS) to include PBDEs, as well as poorly investigated PBDD/DFs and PXDD/DFs at toxicologically significant levels. Intensive clean-up and fractionation procedures in combination with optimized instrumental parameters provided reliable detection and quantification of these compounds. The application of (13)C12-labeled surrogates of analyzed compounds allowed the internal standardization and accurate measurement of selected contaminants. The developed procedure was validated while taking into account the Commission Regulation (EU) 252/2012 requirements for PCDD/DFs and PCBs, and was used to measure the occurrence of priority POPs in Baltic wild salmon.

Ultra high performance liquid chromatography-time-of-flight high resolution mass spectrometry in the analysis of hexabromocyclododecane diastereomers: method development and comparative evaluation versus ultra high performance liquid chromatography coupled to Orbitrap high resolution mass spectrometry and triple quadrupole tandem mass spectrometry.

An efficient ultra high performance liquid chromatography (UHPLC)-time-of-flight high resolution mass spectrometry (TOF-HRMS) method was elaborated for the determination of hexabromocyclododecane (HBCD) diastereomers in fish samples and compared against UHPLC-Orbitrap-HRMS and UHPLC-triple quadrupole (QqQ) tandem MS (MS/MS) techniques. The TOF-HRMS analyzer was operated at high resolution (>10000 full width at half maximum (FWHM)) with scanning the m/z range from 600 to 700, to achieve picogram quantitation limits. The effects of various operational parameters on the instrumental response were systematically investigated. Evaluation of the influence of sample clean-up procedure steps on signal suppression effect including removal of the matrix components by means of destructive acidic treatment or non-destructive gel permeation chromatography (GPC), and additional Florisil column chromatography step showed that the analytical response of UHPLC-TOF-HRMS system is much more affected by the presence of matrix components in the final extracts in comparison with UHPLC-Orbitrap-HRMS and UHPLC-QqQ-MS/MS systems. The method was robustly validated and used for the analysis of eel (Anquilla anquilla) samples originating from a Latvian lake. UHPLC-TOF-HRMS showed a suitable performance under the optimized conditions: recoveries for three selected diastereomers in the range of 99-116%; repeatability and intermediate precision expressed as relative standard deviation (RSD) in the ranges of 2.3-7.1% and 2.9-8.1%, respectively. The elaborated method achieved instrumental limits of quantification (i-LOQ) of 0.9-4.5pg on column that were suitable for the trace analysis of three HBCD diastereomers, corresponding to the method limits of quantification (m-LOQ) of 7.0-29pgg(-1) wet weight (w.w.). The efficiency of UHPLC-TOF-HRMS method was evaluated by comparing the performance characteristics and analytical data from real samples with the validation data and real sample results obtained by applying UHPLC-Orbitrap-HRMS and UHPLC-QqQ-MS/MS techniques for the analysis of HBCD in the same fish samples. Statistical assessment of the experimental data by means of the Fiedman's test revealed that UHPLC-TOF-HRMS, UHPLC-QqQ-MS/MS and UHPLC-Orbitrap-HRMS techniques produced adequate and similar results regarding the HBCD content in fish samples. The presence of HBCD diastereomers was confirmed in all the analyzed eels at concentrations up to 554pgg(-1) w.w. for total HBCD and a diastereomer pattern typical for aquatic biota was observed with strong predominance of α-HBCD. The UHPLC-TOF-HRMS is an appropriate technique for diastereomer-specific quantification of HBCD content in fish samples.

Polychlorinated dibenzo-p-dioxins, dibenzofurans and dioxin-like polychlorinated biphenyls in food and feed in Latvia in 2009-2011.

During 2009-2011 a monitoring programme for 17 polychlorinated dibenzo-p-dioxins (PCDDs)/polychlorinated dibenzofurans (PCDFs) and 12 dioxin-like polychlorinated biphenyls (DL-PCBs) was conducted in the Latvian food and feed market. Using ISO 17025-accredited analytical methodology, investigation of 121 food (milk, dairy products, meat, eggs, fish, fish products) and 66 feed samples (fish meal and oil, compound and mineral feed, vegetable and animal fats) was performed. Most samples showed contamination below the European Commission (EC) Regulation No. 1881/2006 and Commission Directive 2006/13/EC limits. Average total toxicological equivalent (total-TEQ(1998)) concentrations within the food sample groups, except fish and fish products, ranged between 0.41 and 15.1 pg total-TEQ(1998) g(-1) fat. Fish and fish products showed contamination levels from 0.18 to 46.0 pg total-TEQ(1998) g(-1) fresh weight (f.w.). Fifty-seven per cent of cod liver samples were non-compliant. The most contaminated feed samples were fish meal and fish oil. A comparison with WHO-TEF(2005) data is given.

New perspectives on diastereoselective determination of hexabromocyclododecane traces in fish by ultra high performance liquid chromatography-high resolution orbitrap mass spectrometry.

A new analytical method is presented for diastereoisomer-specific identification and quantitation of hexabromocyclododecanes (HBCD) in fish samples. The method is based on extraction of the target analytes from samples with a mixture of organic solvents, with further three-stage clean-up including destructive removal of matrix components with sulphuric acid and acid-impregnated silica gel, and Florisil adsorption column chromatography. Ultra high performance liquid chromatography (UPLC) coupled with high resolution (HR) Orbitrap mass spectrometry featuring heated electrospray ionization (HESI-II) interface operated in negative ion mode was employed for the identification/quantitation of contaminants. The developed methodology was robustly validated in terms of recovery, repeatability, intermediate precision, linear calibration ranges, limits of detection and quantitation, and used for analysis of twenty five Baltic wild salmon (Salmo salar) samples. Under the optimized conditions, recoveries for selected analytes were within the range of 91.4-103.6%, and the repeatability and intermediate precision in terms of relative standard deviations (RSDs) were in the ranges 1.6-8.3% and 1.6-12.5%, respectively, for all three validation levels. The elaborated method achieved instrumental limits of quantification (i-LOQ) of 1.3-3.0pg on column for three HBCD diastereoisomers corresponding to the method LOQ of 0.005-0.012ngg(-1) wet weight (w.w.) The presence of HBCD diastereoisomers was confirmed in all the analyzed Baltic salmon samples in the concentration range of 0.39-3.82ngg(-1) w.w. with an average of 1.59ngg(-1) w.w. for total HBCD. The diastereomer pattern typical for aquatic biota was observed with strong predominance of α-HBCD. The newly developed methodology could be employed for a regular diastereomer-specific monitoring of HBCD content in fish samples, representing a good alternative to existing LC-MS/MS methods in terms of sensitivity and accuracy, and providing further possibilities for inclusion of other contaminants in the scope of analysis.

Content of polychlorinated dibenzo-p-dioxins, dibenzofurans and dioxin-like polychlorinated biphenyls in fish from Latvian lakes.

Seventeen polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDFs) of the highest priority as well as twelve dioxin-like polychlorinated biphenyls (dl-PCBs) were analyzed in the muscle tissues of the following freshwater fish species sampled from eleven Latvian freshwater lakes: perch (Perca flavescens), carp (Cyprinus carpio), eel (Anguilla rostrata), bream (Abramis brama), chub (Leuciscus cephalus), pike (Esox lucius), sheatfish (Silurus glanis) and roach (Rutilus). To analyze the selected persistent organic pollutants in fish matrices, an optimization of EPA-1613 and EPA-1668A clean-up procedures was carried out, followed by validation of the analytical procedure according to Commission Regulation (EC) No 1883/2006. The adopted analytical procedure was in compliance with requirements of the more recent Commission Regulation (EU) No 252/2012. Modifications of carbon column chromatography clean-up and separation steps were used for treatment of the fish samples. Other clean-up procedure stages were performed according to the methods EPA-1613 and EPA-1668A and involved gel permeation chromatography (GPC), as well as manual acidic silica and Florisil column chromatography for purification and fractionation of the samples. An isotope dilution method was used for the qualitative and quantitative determination of individual congeners. Analytes of interest were separated and detected using gas chromatography - high resolution mass spectrometry. The concentration of PCDD/PCDFs and dl-PCBs in freshwater fish and eel samples ranged from 0.05 to 8.0 pg WHO(1998)-PCDD/PCDF-PCB-TEQ g(-1) fresh weight. These levels are below the EU maximum permissible limits although calculation of the content of these compounds relative to the weight of fat shows contamination levels similar to those found in Baltic herring and sprats, that are known to be highly contaminated. A difference in congener pattern between the Baltic Sea fish and freshwater fish was detected with lower contribution of 2,3,4,7,8-PeCDF to the contamination of inland water fish.