Historical contamination of the Anacostia River, Washington, D.C.

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 pollution controls over time. There were two main objectives for this investigation: (1) determine current 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 relationship to contaminant events in the upper portions of the cores. Total PAHs showed higher concentrations at depth and lower surface concentrations. 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 chlordane 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 sediments, high concentrations at mid-depths, and declines to intermediate levels at the surface. Ni and Cr followed neither of these patterns closely. We observed that many contaminants appeared in the Anacostia sediments at various times, and reached relatively high concentrations in the past, but are now showing declines in loadings. In some cases, such as PCBs, DDT, chlordane, and Pb from leaded gasoline, these declines can be clearly linked to the discontinuation of their use for environmental reasons. For other contaminants (e.g., PAHs, DEHP, selected metals) these declines are more likely the result of changes in production, usage and waste control.

Decadal re-evaluation of contaminant exposure and productivity of ospreys (Pandion haliaetus) nesting in Chesapeake Bay Regions of Concern

“…This suggests that PCB levels or their bioavailability in the osprey food web on the Anacostia/middle Potomac Rivers have decreased over the past decade. In support of this hypothesis, a reduction in total PCB concentrations in sediments has been reported for the Anacostia, where residues have declined by an order of magnitude over the past 25 years (Velinsky et al, 2011). Due to moderate biomagnification factors from fish to osprey eggs (e.g., 11 times; Henny et al, 2003), these changes in chlorinated biphenyl concentrations in sediments may be translated up the food web.…”

Legacy effects on sediments in river corridors

“…Of the 1.1 million metric tons of PCBs manufactured in the United States between 1929 and 1978, 95% is expected to enter aquatic environments through wastewater effluent, atmospheric fallout from incinerators, and leachate from landfills (Eisler, 1986). PCB concentrations in sediments can decrease with time because of discontinued use (e.g., Velinsky et al, 2011), but the compounds are widely disseminated throughout the bodies of diverse organisms, including humans (Langston, 2010), and concentrations within biota can remain stable with time despite discontinued PCB use (e.g., Morrissey et al, 2013). Because PCBs can concentrate within river sediments, research now explicitly seeks to determine a sediment quality guideline for these contaminants (e.g., Babut et al, 2012).…”

Temporal and spatial patterns in tumour prevalence in brown bullhead Ameiurus nebulosus (Lesueur) in the tidal Potomac River watershed (USA)

“…In addition, raw sewage enters the river through combined sewer outfalls (Velinsky et al . ). Exposure to PCBs, some organochlorine pesticides, PAHs and sewage effluent decrease immune function in fish (O'Halloran, Ahokas & Wright ; Iwanowicz et al .…”

“…The Anacostia is one of three Chesapeake Bay regions of concern for contamination due to elevated sediment concentrations of PAHs, PCBs and organochlorine pesticides, and fish consumption advisories (Velinsky et al . ). Pinkney et al .…”

“…At one extreme is the highly urban Anacostia River, Washington, DC, where contamination is attributed to hazardous waste sites as well as urban runoff (Velinsky et al . ). Other surveys were conducted in more rural or suburban tidal tributaries, where non‐point sources are the dominant sources of contamination.…”