AQUATIC HAZARD ASSESSMENT OF A CONTAMINATED SURFICIAL

AQUIFER DISCHARGE INTO THE BUSH RIVER, MARYLAND (U.S.A.)*

DENNIS T. BURTON¹, JOSEPH L. DILORENZO², TOMMY R. SHEDD³ and

JOHN G. MROBEL⁴

¹ University of Maryland, Wye Research and Education Center; PO. Box 250, Queenstown, MD 21658, U.S.A.;

² Najarian Associates, One Industrial Way, West, Eatontown, NJ 07724, U.S.A.;

³ U.S. Army Medical Research and Materiel Command, U.S. Army Center for Environmental Health Research, Fort Detrick, Frederick, MD 21 702, U.S.A.;

⁴ U.S. Army Aberdeen Proving Ground, Directorate of Safety, Health and Environment, Aberdeen Proving  Ground, MD 21010, U.S.A.

(* author for correspondence, e-mail: dbl24@umail,umd.edu, fax : 410 827 9039)

(Received 11 April 2001; accepted 13 November 2001)

Abstract. An aquatic hazard assessment of contaminated groundwater in a surficial aquifer as conducted at Beach Point which is located in the Edgewood Area of the U.S. Army Garrison, Aberdeen Proving Ground, Maryland. Toxicity was detected at various groundwater concentrations by seven of 10 toxicity test systems exposed to a mixture of heavy metals and chlorinated aliphatic hydrocarbons.  When estimated maximum acceptable toxicant concentrations (MATC) were established, the data for algae, invertebrates, and fish suggested that the groundwater would not be harmful at a concentration of 10% groundwater by volume. Likewise, no genotoxicity (Ames and SEC assays), development toxicity WTAX), or chronic histopathology (9-month fish test) occurred at 10% groundwater by volume. Near-field (ULINE model) and far-field (dye-tracer model) screening level dilution models were run to estimate the dilution of the groundwater discharge plume from Beach Point into the Bush River. The groundwater was considered to be a potentially excessive hazardous material to the biota in the Bush River when a number of conservative assumptions regarding contaminant distribution and discharge rate of the aquifer were used in the hazard assessment. By modeling the groundwater emanating from Beach Point as the dilution of a discharge from a line diffuser, the potential water quality impacts were judged to be minimal if State of Maryland surface water discharge criteria for a mixing zone were used for the discharge of groundwater to the Bush River.