History of bioavailable lead and iron in the Greater North Sea and Iceland during the last millennium - A bivalve sclerochronological reconstruction

• Published in: Marine Pollution Bulletin
• Main Authors: Holland, H., Schöne, B., Marali, S., Jochum, K.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2014
• Subjects: Arctica islandica; Iceland
• Online Access: http://hdl.handle.net/11858/00-001M-0000-0024-B068-4

We present the first annually resolved record of biologically available Pb and Fe in the Greater North Sea and Iceland during 1040-2004 AD based on shells of the long-lived marine bivalve Arctica islandica. The iron content in pre-industrial shells from the North Sea largely remained below the detection limit. Only since 1830, shell Fe levels rose gradually reflecting the combined effect of increased terrestrial runoff of iron-bearing sediments and eutrophication. Although the lead gasoline peak of the 20th century was well recorded by the shells, bivalves that lived during the medieval heyday of metallurgy showed four-fold higher shell Pb levels than modern specimens. Presumably, pre-industrial bivalves were offered larger proportions of resuspended (Pb-enriched) organics, whereas modern specimens receive fresh increased amounts of (Pb-depleted) phytoplankton. As expected, metal loads in the shells from Iceland were much lower. Our study confirms that bivalve shells provide a powerful tool for retrospective environmental biomonitoring. (C) 2014 Elsevier Ltd. All rights reserved.