390 contaminants of food. These groups of substances are not uniform, they include numerous compounds differing in their chemical structure. PCBs and PBDEs each include 209 so-called congeners possessing different chlorination/ bromination level and/or substituent position on the mol- ecule [1, 2]. PAHs comprise a wide range of chemicals build of at least two connected aromatic rings [3]. Pesti- cides form a very diversiﬁed group of chemicals belonging to more than 100 different chemical classes. Due to widespread use of pesticides in agriculture, their residues in food are practically unavoidable. It is estimated that more than 1,000 active substances are or were in the past used for plant/crop protection [4]. Residues of PAHs, PCBs and PBDEs in food are mainly related to the envi- ronment, into which these chemicals are brought mainly by some human activities. However, small amounts of PCBs and relatively high amounts of PAHs may originate as by- products of natural processes: PAHs are predominantly formed by incomplete combustion of organic materials [3], whereas small amounts of PCBs might be formed during combustion of materials containing carbon and chlorine. Maximum permitted levels of selected food chemical contaminants including PAHs (B[a]P) and dioxin-like PCBs are speciﬁed in the 1881/2006 European Commis- sion (EC) Regulation [5]. Maximum permitted levels of pesticide residues in food products are speciﬁed in the 299/2008 EC Regulation [6]. On the other hand, neither non-dioxin-like PCB nor PBDE maximum levels have been deﬁned within the European Union (EU) food policy. However, according to the 2006/794 EU Recommendation [7], levels of non-dioxin-like PCBs should be monitored in foodstuffs in order to determine PCB back-ground levels. Polybrominated biphenyl ethers are a relatively new group of food chemical contaminants. PBDEs are manu- factured as ﬂame retarding agents to be added to numerous consumer goods, including textiles, synthetic ﬁbers, plas- tics [8]. Due to similarities between chemical structure/ physical properties/chemical properties of PCBs and PBDEs, some concerns regarding circulation of these latter substances in the environment are still arising. Even if PCBs were banned from the industrial production in 1970s, they are still commonly found within the environment. Several studies indicate that PBDEs may also be widely distributed throughout the environment since residues of these substances have been found in vast majority of tested environmental/food samples [9, 10]. The aim of this study was to investigate concentrations of selected PAHs, PCBs, PBDEs and pesticides in several cold-pressed vegetable oils used as ﬂavoring agents or regarded as possessing extraordinary nutritional value. Pumpkin seed oil, linaire oil, poppy-seed oil, hempseed oil, borage oil, sesame seed oil, evening star oil and rape seed oil were investigated. Literature data on presence of the 123 J Am Oil Chem Soc (2012) 89:389–400 mentioned contaminants in the above listed oils are scarce. Concentrations of the following contaminants were determined: • 12 dioxin-like PCBs listed in the 1881/2006 EC Regulation (congeners # 77, 81, 105, 114, 118, 123, 126, 156, 157, 167, 169 and 189) and Benzo(a)-pyrene. • 6 non-dioxin-like PCBs listed in the 2006/794 EC Recommendation (congeners # 28, 52, 101, 138, 153 and 180). • 15 U.S. EPA Priority PAHs (Naf, Acy, Ace, Fluo, Phe, Ant, Flua, Pyr, B[a]A, Chry, B[b]F, B[k]F, DB[ah]A, B[ghi]P, IndP) [11]. • 14 PBDEs (congeners # 17, 28, 47, 66, 71, 85, 99, 100, 138, 153, 154, 183, 190 and 209). • 74 pesticides belonging to various chemical classes (those that are most frequently identiﬁed in food products). Materials and Methods Vegetable Oil Samples Cold-pressed oils available on the retail market were used. Poppy seed oil, rapeseed oil, sesame seed oil, pumpkinseed oil, hempseed oil, linaire oil, borage oil and evening star oil were taken into the investigation. Three samples of dif- ferent oil brands were mixed up in equal proportions to prepare a composite (laboratory) oil sample of the given type. Only a single sample of hempseed oil was obtained and used for analyses. Due to high number of sophisticated and time consuming determinations composite samples were used to assess the presence of investigated com- pounds in studied types of cold pressed vegetable oils. Laboratory made spiked samples used for the assess- ment of the analytical method performance were made by the addition of known amount of analytical standards to vegetable oil samples without detectable amounts of the studied compounds. PCB-, PBDE- and pesticide-spiked samples were prepared in the same manner as reported in our previous paper [12, 14]. PAH-spiked samples were prepared by the addition of the known amount of standard dissolved in cyclohexane. Spiking concentrations of the studied compounds are given in Tables 1, 1, 3. Chemicals Only Pestiscan-grade solvents were used in this study. Acetonitrile, dimethylsulfoxide, hexane, cyclohexane, dichloromethane, methanol, and ethyl acetate were supplied by Lab Scan (Dublin, Ireland). Analytical-grade anhydrous silver nitrate, sodium sulfate and sulfuric acid (96%) were