J Am Oil Chem Soc (2012) 89:389–400 399 Table 8 Average dioxin-like PCB contents expressed as dioxin toxicity equivalency determined in studied oil samples (mean value of two parallel determinations for the composite oil sample) Poppy seed oil Rapeseed oil Sesame seed oil Pumpkin seed oil Hempseed oil Linaire oil Borage oil Evening star oil TEQ 1998 Lower bound Medium bound Upper bound TEQ 2005 Lower bound Medium bound Upper bound 0.023 0.024 0.025 0.020 0.023 0.026 0.002 0.013 0.024 0.001 0.013 0.025 0.007 0.018 0.029 0.003 0.015 0.027 0.000 0.012 0.023 0.000 0.013 0.025 0.002 0.013 0.024 0.000 0.013 0.025 0.003 0.014 0.025 0.001 0.013 0.025 0.042 0.043 0.044 0.024 0.027 0.030 0.038 0.039 0.041 0.035 0.038 0.041 results of Skribic et al. and Yagu¨e et al. [35] who reported high contribution of lower chlorinated biphenyls in vege- table oil samples. The proﬁle of PCBs found in the ana- lyzed samples shows a high contribution of low chlorinated congeners. Most probably such a proﬁle is typical for products of plant origin. Concentrations of the most abundant 6 marker PCBs determined in this study were in the low ng g-1 range (except for one sample) and were similar to those reported by Skribic et al. and Marti et al.. An exceptionally high concentration was determined for the borage oil sample (*25,000 pg g-1). High differences in PCB concentration might be caused by regional PCB contamination, but in such a case, the PCB proﬁle would differ, which was not the case in this study. The most probable cause of such a high variability are differences in atmospheric PCB absorption and/or mechanism of PCB deposition in plant fatty tissues. Different pathways of contaminations have already been reported for several plant varieties [36, 37]. Concentrations of dioxin-like PCBs in the studied samples expressed as dioxin toxicity equiv- alent were very low, signiﬁcantly below 0.1 pg TEQ g-1 (even when expressed as the upper bound result). The difference between upper-bound and lower-bound results for many of the analyzed samples did not meet the requirements of the 1883/2006 EC Regulation [5] i.e. - below 20% for TEQ C 1 pg g 1 and within the 25–40% range for TEQ B 1 pg g-1. This is caused by very low TEQ concentrations determined in the analyzed samples. Concentration of the most toxic PCB 126 congener (with the highest assigned TEF value) was below LOQ. The aim of this study was to investigate incidence of various groups of chemical food contaminants in cold- pressed vegetable oils. The environment was found to be the main source of contamination of cold-pressed oils with PCBs, PBDEs and also PAHs, whereas the presence of most of the pesticides may be traced back to agricultural practices. Results of this study indicate that various groups of chemical food contaminants may be found in cold-pressed vegetable oils at relatively high concentra- tions. As it was mentioned earlier, literature data on pres- ence of pesticides, PAHs, PCBs and PBDEs in cold- pressed oils are scarce, therefore it is impossible to assess health risk related to consumption of such oils. The main purpose of this study was to assess the necessity of moni- toring residues of several classes of chemicals in cold- pressed vegetable oils. The presented data clearly expose the problem of cold-pressed oil chemical contamination (mainly by pesticides) rather than giving precise informa- tion on the levels of those substances in the studied group of products. Authors believe that further research on resi- dues of various chemical compounds—especially pesti- cides—in cold-pressed vegetable oils is necessary. Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which per- mits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. 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