(137)Cs and (40)K in gray seals Halichoerus grypus in the southern Baltic Sea

This study presents levels of (137)Cs and (40)K concentrations in the placentas of seals gathered in the period 2007–2015. The mean activity of (137)Cs and (40)K was 5.49 Bq kg(−1)w.w. and 136.6 Bq kg(−1) ww respectively. Statistically significant correlation was observed between the (137)Cs activities in placenta and in herring—the staple food for seals. The concentrations of (137)Cs and (40)K were also determined in other tissues (muscle, liver, lung, and brain) of wild seals. The concentrations of (137)Cs were from 2.59 Bq(−1) ww (lungs) to 24.3 Bq kg(−1) ww (muscles). The transfer factor values for (137)Cs (seal tissue/fish) ranged from 0.89 to 2.42 in the case of the placentas and from 1.35 to 8.17 in the case of the muscle. For adults seal, the effective dose from (137)Cs was 2.98 nGy h(−1). The mean external radiation dose to pup was 0.77 nGy h(−1) from (137)Cs and 6.69 nGy h(−1) from (40)K.