HISTORICAL FLUXES OF PARTICLE-BOUND POLLUTANTS FROM DECONVOLVED SEDIMENTARY RECORDS

A deconvolution method to extract the historical input records of particle-associated pollutants from their sedimentary profiles, influenced by mixing, is developed. The method operates in the time domain and requires that an equal number n of time and depth intervals be appropriately chosen. An n multiplied by n matrix E of pollutant concentrations as a function of time and depth for unit influx is generated by forward programs, and the historical influxes are calculated by inverting E and multiplying with the actual concentration profile of the pollutant. Application of the method to Pb, Zn, and Cd in several Lake Michigan sediment cores shows that pollution with these metals started around 1894 in the southern part of the lake and 15-30 years later further north. Additional study results are discussed.