title: Global-scale patterns in anthropogenic Pb contamination reconstructed from natural archives.
abstract: During the past two centuries metal loads in the Earth's atmosphere and ecosystems have increased significantly over pre-industrial levels. This has been associated with deleterious effects to ecosystem processes and human health. The magnitude of this toxic metal burden, as well as the spatial and temporal patterns of metal enrichment, is recorded in sedimentary archives across the globe. This paper presents a compilation of selected Pb contamination records from lakes (n = 10), peat mires (n = 10) and ice fields (n = 7) from Europe, North and South America, Asia, Australia and the Northern and Southern Hemisphere polar regions. These records quantify changes in Pb enrichment in remote from source environments. The presence of anthropogenic Pb in the environment has a long history, extending as far back as the early to mid-Holocene in North America, Europe and East Asia. However, results show that Pb contamination in the Earth's environment became globally ubiquitous at the beginning of the Second Industrial Revolution (c.1850-1890 CE), after which the magnitude of Pb contamination increased significantly. This date therefore serves as an effective global marker for the onset of the Anthropocene. Current global average Pb enrichment rates are between 6 and 35 times background, however Pb contamination loads are spatially variable. For example, they are >100 times background in Europe and North America and 5-15 times background in Antarctica. Despite a recent decline in Pb loads in some regions, most notably Europe and North America, anthropogenic Pb remains highly enriched and universally present in global ecosystems, while concentrations are increasing in some regions (Australia, Asia and parts of South America and Antarctica). There is, however, a paucity of Pb enrichment records outside of Europe, which limits assessments of global contamination.
authors.affiliation: GeoQuEST Research Centre, School of Earth and Environmental Sciences, University of Wollongong, Wollongong, New South Wales, 2522, Australia. Electronic address: s.marx@uow.edu.au.
authors.forename: Samuel K
authors.initials: SK
authors.lastname: Marx
authors.affiliation: GeoQuEST Research Centre, School of Earth and Environmental Sciences, University of Wollongong, Wollongong, New South Wales, 2522, Australia.
authors.forename: Shaqer
authors.initials: S
authors.lastname: Rashid
authors.affiliation: Climate Research Group, School of Geography, Planning and Environmental Management, The University of Queensland, St Lucia, QLD 4072, Australia.
authors.forename: Nicola
authors.initials: N
authors.lastname: Stromsoe
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000864:Antarctic Regions; D001208:Asia; D001272:Atmosphere; D001315:Australia; D017753:Ecosystem; D005060:Europe; D019015:Geologic Sediments / Q000032:analysis*; D000075322:Heavy Metal Poisoning; D006801:Humans; D046448:Ice Cover / Q000737:chemistry*; D007221:Industry; D060106:Lakes; D007854:Lead / Q000032:analysis*; D009656:North America; D011041:Poisoning; D012987:Soil / Q000737:chemistry*
chemical_list: D000393:Air Pollutants; D012987:Soil; D007854:Lead
keywords: Environmental archives; Global contamination; Heavy metals; Lead