The distribution and potential impact of two centuries of lead deposition as recorded by lake sediments from northeastern North America


We evaluated anthropogenic Pb deposition along a west-east transect from the Adirondack, New York, USA (ADIR) region, the Vermont-New Hampshire-Maine, USA (VT-NH-ME) region, and Nova Scotia, Canada (NS) region using 47 ^210^Pb-dated lake sediment records. We used ^210^Pb-normalized Pb inventories to evaluate cumulative deposition and breakpoint analysis to evaluate possible differences in timing among regions. Peak Pb concentrations exceeded the consensus-based probable effect concentration of 128 mg/kg in almost all ADIR (1314) and VT-NH-ME (1218) lakes. Cumulative deposition of anthropogenic Pb decreased from west to east (ADIR region: 797-1,364 mg/m^2^, VT-NH-ME region: 333-1,209 mg/m^2^, NS: 53-425 mg/m^2^), and the initiation of anthropogenic Pb deposition occurred progressively later along the same transect (ADIR region: AD 1869-1900, VT-NH-ME region: AD 1878-1905, NS region: AD 1894-1925). Our data suggest that potentially harmful concentrations of Pb may still exist in freshwater sediments of high deposition areas, and that west-east transport of Pb is likely a major component of Pb deposition in all three regions.

Science of The Total Environment (submitted)