In this study, the occurrence of 17 toxicologically-relevant polychlorinated dibenzo-dioxins and furans (PCDD/PCDFs) and 12 dioxin-like polychlorinated biphenyls (dl-PCBs) was investigated in livers of sheep from Lower Saxony, Germany. The aim of the monitoring was to get a state-wide picture on the contamination level of sheep liver samples. Seventy two out of 77 investigated sheep liver samples exceeded the European maximum tolerance level for PCDD/PCDFs of 6.0 pg WHO-PCDD/F-TEQ g(-1) fat with measured average, median and maximum values of 23.9, 18.3 and 161 pg WHO-PCDD/F-TEQ g(-1) fat, respectively. Seventy-one samples also exceeded the cumulative maximum tolerance level of 12.0 pg WHO-PCDD/F-PCB-TEQ g(-1) fat set in the EU for the sum of PCDD/PCDFs and dl-PCBs in livers of sheep and derived products. Average, median and maximum measured values were 42.9, 33.9 and 204 pg WHO-PCDD/F-PCB-TEQ g(-1) fat, respectively. In the meat of the sheep only low amounts of PCDD/Fs or dl-PCBs were detected that never exceeded the respective maximum tolerance levels. The results did not show any significant differences in contamination between female or male sheep. Also no correlation was found between the age of the animals and the burden of their livers with PCDD/PCDFs or dl-PCBs. Health risks from the casual consumption of sheep livers are almost unlikely but can also not be excluded for individuals frequently consuming sheep livers with average contamination levels. Almost no difference was observed in the burden of contamination of sheep liver samples between rural and municipal areas or between areas located near or apart from waterways. In conclusion, the results yielded a picture of a varying but high level of contamination of sheep livers most likely caused by physiological differences compared to other animal species and by the ubiquitous environmental contamination primarily assignable to historic dioxin and PCB sources.
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