, 2006). However, if our results from the beginning of the decade are compared to results shown by Hites et al. (2004), where fish were sampled with skin in 2002, results are quite similar. During our sampling, the skin of the fish was carefully scraped to include the subcutaneous

fat in the samples. Subcutaneous fat was excluded in skin-off samples reported by Shaw et al. (2006). A TWI for dioxins and dl-PCBs was established in 2001 by the Scientific Committee of Food (SCF, 2001), and the food safety of these compounds in salmon is discussed below. PCB6, also called indicator PCBs, represents about 50% of the sum of non-dioxin-like (ndl)-PCBs in food and are used by EFSA as indicator of the content of ndl-PCBs in food (EFSA, 2005). Our PCB6 results revealed certain differences amongst the years, which may be due to different geographical origins of the fish oil Epigenetics Compound Library used in the feed. However, no long term trend was observed. There was no correlation between dioxins and dl-PCBs with

PCB6 in our samples (results not shown). This may also be due to differences amongst the fish oils used in commercial fish feed. Furthermore, it supports the EFSA conclusion that the ratios between PCB6 and dioxins and/or dl-PCBs varies greatly amongst different foods and countries (EFSA, Tariquidar in vitro 2005). Most Western countries have banned the use of the pesticides included in this study. However, these contaminants are still present in our environment due to their persistence. Moreover, DDT is currently still used in certain parts of the world to limit the spread of vector borne diseases, such as ZD1839 supplier malaria (WHO, 2011). Our results show a decline in the levels of DDT and its metabolites

in Norwegian farmed salmon from 2002 to 2011, which is consistent with the decline of DDT in fish feed in the same period (Sissener et al., 2013). The other pesticides presented in this paper do not exhibit any time trends since most of the data are below, or close to, the LOQ. Therefore all pesticides analysed in the course of the years were compiled and presented as medians (Fig. 4B). In the report by Hites et al. (2004), the pesticides showing the highest abundance in farmed salmon, apart from the sum of DDT, were dieldrin and toxaphene. In our study, however, these two pesticides were found in considerably lower amounts. This may be due to a decrease through the years which are not reflected in our historical data since pesticides have only been analysed since 2006. The EU has established maximum levels in commercial foodstuff for several of the contaminants discussed in this paper. None of the samples in our study had contaminant levels which exceeded the maximum limits set, so we focused on TWI which is a measure of acceptable risk during a lifetime of exposure. We have not included contributions from other food sources to the total exposure of contaminants.