Mercury in lichens and reindeer hair from Alaska: 2005–2007 pilot survey

• Published in: Polar Record
• Main Authors: Lokken, James A., Finstad, Gregory L., Dunlap, Kriya L., Duffy, Lawrence K.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2009
• Subjects: Climate change; Polar Record; Seward Peninsula; St Lawrence Island; Alaska
• Online Access: http://dx.doi.org/10.1017/s0032247409008353; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0032247409008353

ABSTRACT Reindeer and caribou are terrestrial herbivores, that feed on lichens and are used for commercial and subsistence food products. Caribou are a key component of the arctic food web and the bioaccumulation of toxic contaminants, such as mercury (Hg), needs to be monitored to establish a baseline as the arctic environment is impacted by both climate change and future industrial development. A changing climate in Alaska is influencing plant species composition, fire regime, melting and flooding events, and thus, impacting Hg bioavailability in the food chain. Industrial development in Asia is also projected to increase the atmospheric global pool of Hg from increased coal combustion. Reindeer, a domesticated representative of caribou, can be used as a terrestrial biomonitor for metal exposure. In this study total mercury concentrations were measured in lichens and in hair of grazing reindeer on defined ranges across Alaska to establish a baseline for future hypothesis development and testing regarding Hg deposition. The Hg mean level for Seward Peninsula lichens on the Davis Range was 37.4 ng g −1 , on the Gray Range 47.1 ng g −1 , on the Kakaruk Range 42.2 ng g −1 , and 41.7 ng g −1 on the Noyakuk Range. Lichen Hg levels on St. Lawrence Island was 46.6 ng g −1 . Methyl mercury levels in lichens were found to be below detection levels. Reindeer grazing on these ranges had mean Hg hair levels of 14.6 ng g −1 (Davis herd), 83.4 ng g −1 (Gray herd), and 40.3 ng g −1 (Noyakuk herd). Two reindeer on St. Lawrence Island had an average of Hg of 43.0 ng g −1 . Sample sizes ranged from n = 2 to n = 11. Hg mean levels in lichen on Seward Peninsula were higher than Hg means of two ranges in northern Mongolia. The Hg levels observed in this study indicate that Hg levels in Alaska are low at this time and pose no risk to the health of reindeer or human subsistence harvesters. A significant relationship between Hg in lichens on the ranges and the Hg in reindeer on those ranges has not been established. There are ...