Environ Monit Assess (2011) 183:307–328 DOI 10.1007/s10661-011-1923-z Historical contamination of the Anacostia River, Washington, D.C. David J. Velinsky · Gerhardt F. Riedel · Jeffrey T. F. Ashley · Jeffrey C. Cornwell Received: 6 May 2010 / Accepted: 8 February 2011 / Published online: 15 March 2011 © Springer Science+Business Media B.V. 2011 Abstract The tidal Anacostia River in Washington DC has long been impacted by various sources of chemical pollution over the past 200 years. To explore more recent inputs of various chemicals, six sediment cores were collected for dating and chemical analysis in the downstream section of the tidal Anacostia River. Profiles of contaminants in sediment cores can be useful in determining management direction and effectiveness of pollu- tion controls over time. There were two main ob- D. J. Velinsky (B ) · J. T. F. Ashley Patrick Center for Environmental Research, The Academy of Natural Sciences, 1900 Benjamin Franklin Parkway, Philadelphia, PA 19103, USA e-mail: velinsky@ansp.org G. F. Riedel Smithsonian Environmental Research Center, PO Box 28, 647 Contees Wharf Road, Edgewater, MD 20137, USA e-mail: riedelf@si.edu J. T. F. Ashley School of Science and Health, Philadelphia University, Schoolhouse Lane and Henry Ave., Philadelphia, PA 19144, USA e-mail: ashleyj@philau.edu J. C. Cornwell UMCES Horn Point Laboratory, University of Maryland, P.O. Box 775, Cambridge, MD 21613-0775, USA e-mail: cornwell@hpl.umces.edu jectives for this investigation: (1) determine cur- rent sediment contaminant levels; (2) determine a historical perspective of the sediment changes in contamination using 137 Cs and 210 Pb dating. The determination of an age–depth relationship using 210 Pb and 137 Cs dating gave somewhat different results, suggesting that the assumptions of 210 Pb dating were not met. Using the 137 Cs horizon allowed an assignment of approximate sediment accumulation rates and hence an age–depth re- lationship to contaminant events in the upper portions of the cores. Total PAHs showed higher concentrations at depth and lower surface con- centrations. In the upper sections, PAHs were a mixture of combustion and petrogenic sources, while at depth the signature appeared to be of natural origins. Total PCBs, DDTs and chlor- dane concentrations showed a maximum in recent sediments, decreasing towards the surface. PCBs had lower molecular weight congeners near the surface and higher molecular weights at depth. A phthalate ester, DEHP, appeared in the mid 1940–1950s, and decreased towards the surface. Trace elements fell roughly into three groups. Fe, Mn, and As were in approximately constant proportion to Al, except in some deeper, sandy sediments, where they showed enrichments linked to redox conditions. Ag, Cd, Cu, Hg, Pb, and Zn had low concentrations in the deepest sed- iments, high concentrations at mid-depths, and declines to intermediate levels at the surface. Ni