Atmospheric Wet Deposition of Trace Elements to a Suburban 
Catchment in Northern Virginia

K.M. Conko ¹, and K.C. Rice ² (U.S. Geological Survey, Water Resources, ¹Reston, VA 20192; 703-648-5799; 
and ²Charlottesville, VA 22903, e-mail kmconko@usgs.gov)

Lake Anne, one of many real-estate lakes in Northern Virginia, was developed in 1964 and its outflow is a sub-tributary 
of the Potomac River, the second largest tributary of the Chesapeake Bay.  The 2.67 km2 Lake Anne catchment (26 km west of 
Washington, D.C., 13 km east of Dulles International Airport) is densely populated and heavily developed with individual and 
multi-family dwellings and commercial establishments. While only 6% of the Potomac River catchment is classified as urban/suburban, 
considering the possible magnitude of anthropogenic influence, these areas may contribute disproportionally larger amounts of potential 
contaminates to the Bay.  

Wet atmospheric deposition was collected for one calendar year (1998) in this small, well-characterized, suburban catchment.  
Precipitation samples were collected on an integrated bi-weekly basis with an automated collector modified for trace elements.  The samples 
were analyzed for As, Cd, Cr, Cu, Mn, Ni, Pb, V and Zn by ICP-MS. Seasonal trends in volume-weighted concentrations were observed 
for most elements, with a summer maximum corresponding to the peak acidity in regional precipitation. The annual wet fluxes for As, Cd and 
Pb are similar to those previously reported for a remote site on Catoctin Mountain (80 km northwest of Lake Anne), as well as sites in 
the Chesapeake Bay Atmospheric Deposition Study, indicating a regional atmospheric signal for these elements. The fluxes for Cu and Zn, 
however, are at least two times higher at Lake Anne, compared to the previous studies at remote sites.  These results suggest a local source in 
the Lake Anne catchment, possibly from high urban traffic volumes through the resuspension of tire wear (Zn) and brake-lining wear (Cu).

Conko, K.M., and Rice, K.C., 2000, Atmospheric wet deposition of trace elements to a suburban catchment in Northern Virginia:  AGU Spring Meeting, May 2000, Washington, D.C., EOS Transactions, May 9, 2000.

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