UNITED STATES GEOLOGICAL SURVEY SELECTED TRACE-ELEMENT AND . ORGANIC CONTAMINANTS IN 0' STREAMBED SEDIMENTS OF THE POTOMAC RIVER BASIN, AUGUST 1992 (~c~ By James M. Gerhart and INTRODUCTION l0 R L Joe/ D. Blomquist This report pre ellls th e re ult of a '-\'\o q s -lf d. lo; Background ABSTRACT urvey of contaminants in strea mbed edi­ melll in selected stream of th e Potomac This report describes the occur­ The U.S. Geo logica l Survey ( SGS) is implementing th e ational Water­ Ri ver Ba in. The report focuses on five rence and distribution of five selected Quality A ssessment ( AWQA) program elec ted contaminants, including two trace contaminants in streambed sediments to de cribe and xplain water-quality co n­ element - lead and mercury-and three at 22 strea m sites in the Potomac ditions and trend s of th e Nation' urface­ organic compound hl01·dane, total River Basin. Lead, mercury, and total wa ter and grou nd-water resources DDT (dichl orodiphenyltrichloroeth ane). DDT (dichlorodiphenyltrichloro­ (Gilliom and oth ers. 1995). One of the ethane) were detected at all sites, and fir. t area s to be studied as part or th e full­ Streambed-sediment samples were co ll ected and chlordane and total PCB's (polychlori­ sca le A WQA program i. th e Potomac composited from a variety of depositional settings nated biphenyls) were detected at Ri ver Basin. where water-quality within stream reaches that averaged 300 feet in length at each sampling site. most sites. At six sites, streambed­ sa mpling ac ti vities for th e study sediment concentrations of contami­ were begun in 1992. A major goal nants were detected at levels with the of th e Potomac Ri ver Bas in tu dy i potential to cause frequent adverse to describe th e cc urrencc and dis­ effects on aquatic organisms that live tribution of a wide vari ety of ph y. i­ in the sediments. Chlordane was ca l, chemica l, and bi ologica l wa ter­ detected at these high levels at sam­ quality charac teri . ti c of trea ms pling sites on the Anacostia Ri ver, the and ground wa ter in th e bas in. North Branch Potomac River, Bu ll Some of th e chemica l com- Run , and Accotink Creek; mercury pound of interes t in th e WQA was detected at these levels at sites program. in cluding many trace cle­ on the South River and the South ments and syntheti c organic com­ Fork Shenandoah River; and total pound . do not eas ily dis. ol e in PCB's were detected at these levels strea mwa ter. but in tead tend to at the site on the Sou th Fork Shenan­ accum ul ate in trcambed s diments doah Ri ver. The highest concentra­ and aq uati c biologica l ti ss ues. When th ese co mp unds accumulate tions of all five contaminants generally in ufficiently high co ncentrati ons occurred at sampling sites down­ in sediment or ti ue , they can ac t stream from areas with industrial as contam inant th at ca n adver. ely plants, urban centers, or orchard and affect th e hea lth of aqu ati c orga n- ag ri cultural activity. The occurrence i m . To addre th e occurrence of these contaminants in streambed and distribution of selec ted trace­ sediments of the Potomac River Basin element and orga nic contaminant · is of concern because the co ntami­ in strea ms in th e Potomac Ri ver nants (1) are environ mentally persis­ Ba in, a survey of contaminants in tent, (2) are avai lable fo r downstream streambed sediments and aquatic transport during high streamflow peri ­ b. ·ca l ti sues wa s conducted in ods, and (3) have the potential to cause adverse effects on the health of aquatic organisms and humans th rough bioaccumulation . MAY 2 8 1996 SR lfBRAR Y Figure 1. Streambed sediments were sam­ pled in August 1992 at 22 stream sites in the 14,670-square-mile Potomac River Basin. Physiographic Provi nces Appalachian Plateau Great Valley subprovince D Blu eRidge and total PCB ' (polyc h Iori nated Piedmont bi phenyls). Lead, mercury, • Triassic Lowlands subprovi nce chl ordane, and total PCB 's were 0 10 20 30 40 50 MILES selected becau e these com- D Coastal Plain 0 10 20 30 40 50 KILOMETERS pounds have been designated as 17 "toxics of concern" by the • Location and number of sampling site Chesapeake Bay Program (Che apeake Bay Program, 199 I a); total DDT wa elected becau e of nati onal concern regarding its environ­ (3) What are some of the importan t environ­ Potomac Ri ver Basin (fig. I). mental effect during the Ia t several mental implications of the occurrence of At each of the 22 sampling sites, decade . The report de cribes the re ult these contaminant s in streambed sed i­ fine-grained streambed sediment were of treambed- edi ment ampling at 22 men ts? coll ected and compo ited from a vari ety tream site throughout the Potomac of depositi onal setting within stream River Ba in in Augu t I 992, and addre - Streambed-Sediment Sampling reaches th at averaged about 300 feet in e the fo llowing questi ons about the and Analysis length . Samples were coll ected from the occurrence and di stribution of the five The sampling site that were selected top I inch of fine-grain ed sediments u ing contami nant in streambed sediments of for a sessin g the occurrence and di stribu­ a scoop in wadeabl e streams or a dredge the ba in : ti on of contaminants in streambed sedi ­ in deeper streams; sampling equipment ( 1) Which stream ite have streambed sedi ­ ments in the Potomac Ri ver Ba in cover a was con tructed fro m inert materi als. All ments with elevated concentrations of range of phy iographic ettings (fig. I), sites were sampled during low streamflow th ese contaminant s? tream izes (table I), and land u es. conditions when no fine-grained sedi ­ (2) What i the re lation between elevated con ­ Drain age areas for the 22 sites generall y ments were in suspension in the water centrations of these contam inant in range from about 20 to I 2,000 square column. Each ample was sieved into treambed ed iments and potenti al mile (tabl e I), and incl ude parts of the 7 subsamples in the field fo r laboratory up. tream contam inant sources? physiographic provinces and subprovince analy i . and parts of th e fo ur States in the 2 Contaminants in Streambed Sediments Table 1. Streambed-sediment sampling sites in the Potomac River Basin, August 1992 Drainage Sampling area, in site square number Station number Station name miles 1 01595000 North Branch Potomac River at Steyer, Md. 73.0 2 01596500 Savage River near Barton, Md. 49.1 3 01600000 North Branch Potomac River at Pinto, Md. 596 4 01603000 North Branch Potomac River at Cumberland, Md. 875 5 01608000 South Fork South Branch Potomac River near Moorefield, W. Va. 283 6 01611500 Cacapon River near Great Cacapon, W. Va. 677 7 01614500 Conococheague Creek at Fairview, Md. 494 8 01616500 Opequon Creek near Martinsburg, W. Va. 272 9 01617800 Marsh Run at Grimes, Md. 18.9 10 01618000 Potomac River at Sheperdstown, W. Va. 5,936 11 01625000 Middle River near Grottoes, Va. 375 12 01627500 South River near Harriston, Va. 212 13 01631020 South Fork Shenandoah River below Cabin Run at Front Royal, Va. 1,647 14 01634000 North Fork Shenandoah River near Strasburg, Va. 768 15 01636500 Shenandoah River at Millville, W.Va. 3,040 16 01639000 Monocacy River at Bridgeport, Md. 173 17 01644000 Goose Creek near Leesburg, Va. 332 18 01651010 Anacostia River near Bladensburg, Md. 130 19 01652589 Potomac River below Oxon Creek at Alexandria, Va. 11 ,880 20 01654000 Accotink Creek near Annandale, Va. 23.5 21 01657000 Bull Run near Manassas, Va. 147 22 01661050 St. Clement Creek near Clements Md. 18.5 amples for trace-e lement ana lys i Nati onal Wat er-Quality Laborat ory in for a va ri ety of 1 urposes (tabl e 2). The were sieved through a 63 -micrometer Arvada, olo. Ch lord ane. total Dl T. and uses f many of th ese cont aminants ha e nylon filter, digested to complete di sso lu­ total P B's were determined by dual ca p­ been regul ated r bann cl in the last sever­ ti on. and analyz d fo r 45 trace e l eme nt ~ . illary-column gas chroma tography with al decade because of an incrca ·eel a1 arc­ Lead wa.· determined by inducti ely cou­ eleCll·o n-ca pture detection (Foreman and ne. of th e ad erse effect th ey can have pl ed pia ma-atomic em iss ion . pec trome­ oth er . 1995). on animal and human health. ome of try (Briggs, 1990). and mercury was th eir adver e effect on human hea lth are determined by cold apor-a tomic abso rp ­ li. ted in table 2. ti on ·pectrophotometry (O'Leary and oth ­ OCCURRENCE AND The unit of streambed-sediment con­ ers. 1990). Samp les for rganic-com­ DISTRIBUTION OF centration u. ed in thi report are part per pound analys is were sieved through a 2- SELECTED CONTAMINANTS million (ppm) fo r trace element s and parts millimeter stain less-s teel sieve and ana­ per bi llion (ppb) for organi compounds.