Radionuclide Contaminant Burdens in Arctic Marine Mammals Harvested During Subsistence Hunting

Abstract

ABSTRACT. We conducted gamma spectrometric analyses on more than 200 arctic marine mammal tissue samples. These samples were primarily provided by subsistence hunters from northern Alaska, with a smaller number of samples from the Resolute region in Canada. The majority of samples (>90%) had detectable levels of the anthropogenic radionuclide 137 Cs, with a mean level observed in all samples of 0.67 Bq kg -1 dry weight ± 0.81 (SD). Converted to wet weight, the mean was 0.21 Bq kg -1 ± 0.19 SD. The median activity observed was 0.45 Bq kg -1 dry weight (0.18 Bq kg -1 wet weight) with a range from detection limits to 6.7 Bq kg -1 dry weight (1.1 Bq kg -1 wet weight). These findings confirm expectations that current anthropogenic gamma emitter burdens in marine mammals used in the North American Arctic as subsistence food resources are well below activities that would normally merit public health concern (~1000 Bq kg -1 wet weight). Some differences among species and tissues were observed. Beluga tissues had slightly higher mean burdens of 137 Cs overall, and epidermis and muscle tissues in bowhead and beluga whales typically had higher burdens than other tissues analyzed. Low levels of the neutron activation product 108m Ag (half-life 418 yr.), probably bioaccumulated from bomb fallout sources, were observed in 16 of 17 beluga livers analyzed, but were not found in any other tissues of beluga or in any other species sampled. A subset of 39 samples of various tissues was analyzed for the alpha and beta emitters 239,240 Pu and 90 Sr. Plutonium levels were near the threshold of detectability (~0.1 Bq kg -1 dry weight) in 6 of the 39 samples; all other samples had no detectable plutonium. A detectable level of Ag has not been previously reported in any marine mammal livers, all of our analytical measurements indicate that only very low levels of anthropogenic radioactivity are associated with marine mammals harvested and consumed in the North American Arctic. Ag (demi-vie 418 années), dont la bioaccumulation est probablement due à des retombées de bombes atomiques, mais on n'en a observé aucune trace dans les autres tissus du bélouga ou de toute autre espèce échantillonnée. On a analysé un sous-ensemble de 39 échantillons provenant de tissus divers pour savoir s'ils contenaient des émetteurs alpha et bêta 239,240

Radiocaesium (137Cs) in marine mammals from Svalbard, the Barents Sea and the North Greenland Sea

“…However, it would appear from our data that these potential sources currently have little impact on marine mammals in the European Arctic. Cooper et al, (2000) reported average 137 Cs activities in muscle samples for a variety of marine mammal species from Alaska and Canada, including polar bears, ringed seals and bearded seals that were similar to those seen in this study and other studies done in the European Arctic. The global distribution of radionuclide contamination in marine mammals shows that values are generally higher in the northern hemisphere than in the southern.…”

“…Additionally, due to the subsistence harvesting of some marine mammals by arctic indigenous peoples there is a need for information on current radionuclide burdens, so that accurate assessments can be made concerning potential doses to man. Cooper et al (2000) reported radionuclide contaminant burdens for several marine mammals in northern Alaska and Canada to be low. Similar species-specific data in the literature for marine mammals in the European Arctic is scarce.…”

Transfer of radionuclides in aquatic ecosystems – Default concentration ratios for aquatic biota in the Erica Tool

“…This has arisen because of a requirement to provide analogues for protected species within Europe, as these are often the types of biota for which assessments are required (Copplestone et al, 2003). Furthermore, the geometric components of the original FASSET reference organism have been replaced by related ICRP Reference Animals and Plants (RAPs) where the similarity justifies this procedure.…”

“…The first three options were used as preferential approaches. The main sources of information for Code 3 (CR values recommended in previous reviews or derived from previously published reviews) were IAEA (2001) and Copplestone et al (2003). Options 4 and 6e8 were not applied for freshwater organisms.…”

137Cs, 40K and 210Po in marine mammals from the southern Baltic Sea

“…Thus, data are available from other regions, including the Arctic, Asian and European coastal waters, Lake Baikal and the Caspian and Black Seas. These studies reported average levels of 137 Cs that varied between 0.2 and 17 Bq kg −1 wet weight (w.w.) (Cooper et al, 2000;Yoshitome et al, 2003;Gwynn et al, 2005;Andersen et al, 2006;Malta & Carvalho, 2011). Cesium-137 levels in tissues of marine mammals have been suggested as chemical marker for radioactive pollution in the marine environment, and correlations between tissue levels and seawater levels have been reported (Yoshitome et al, 2003).…”