Temporal dynamics of dioxin contamination of reindeer offal from Russian Far North regions

Reindeer herding is vitally important activity in Russian Far North regions. Meat and offal (liver, kidneys, etc.) are readily consumed by indigenous people and also exported, therefore the problem of reindeer products safety in view of chemical contamination is of both scientific and practical interest. Here, we report levels of dioxins in 64 individual samples of reindeer liver (Rangifer tarandus tarandus and Rangifer tarandus sibiricus) originating from four main reindeer-herding regions of Russia with broad geographical distribution from western to eastern border of the country, including Murmansk Oblast, Komi Republic, Nenets Autonomous Okrug and Yamalo-Nenets Autonomus Okrug. Persistent organic pollutants (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans) were determined by high-resolution gas chromatography-mass spectrometry and expressed as WHO toxic equivalents (WHO-TEQ). Dioxin pollution has shown clear geographical distribution. It is the highest at the Kola Peninsula and generally decreases to the east. In particular, dioxins concentration in reindeer liver varied from 40.5 ± 10.1 pg WHO-TEQ/g of fat in Nenets Autonomus Okrug to 14.8 ± 3.7 pg WHO-TEQ/g of fat in Yamalo-Nenets Autonomus Okrug. A comparison with the previous data showed significant increase of dioxin levels in reindeer liver from selected regions over the last 2 years. Taking into account growing interest to reindeer liver processing for food production, our data give further insight in possible risk of longtime consumption of reindeer offal.