Identification of PCB, PAH and Chlordane Source Areas in the Anacostia River Watershed

In 2004 this Anacostia River biomonitoring project used a two-week Asiatic clam (Corbicula fluminea) translocation bioaccumulation protocol in an attempt to find the contaminant source areas of its most highly contaminated first-order tributaries. These tributaries were identified from earlier studies as Lower Beaverdam Creek (PCBs), NorthEast Branch (total PAHs and chlordane) and Watts Branch (total PAHs and chlordane). Clams placed at the Lower Beaverdam Creek Landover Metro site had significant accumulation of PCBs and Aroclors, which dropped to reference control levels in clams at the upstream Corporate Drive site above the Landover Metro/ Ardwick-Ardmore Industrial Park/ New Carrolton Metro area. Clams at the NorthEast Branch Odell Road site had high total PAHs which dropped by 50% at the Virginia Manor Road site upstream, above the Beltsville Industrial Center. Clams at the Riverdale East Branch second order stream near the mouth of the Northwest Branch had high pesticides and chlordane not found upstream. Clams at the Watts Branch Upper site had total PAHs not significantly lower than at other Watts Branch sites. Using comparison with data from previous studies it appeared that clam accumulations of high levels of PCBs, Aroclor and PAHs in the Anacostia watershed were associated with industrial park areas in Prince George’s County. High bioavailable chlordane was not associated with other contaminants or an identifiable industrial park. Clams at the Fort Foote control site had a significantly greater pesticide (endosulfan I) accumulation than other sites and may have detected an endosulfan I spill in the Potomac River in May 2004. The high endosulfan in clams was lost over their two week translocation period at Anacostia watershed sites. Introduction The heavily contaminated tidal freshwater 10 km Anacostia River estuary stems from the Potomac estuary and is the major water body within the District of Columbia. The poor quality of the Anacostia River estuary has been known for years (Freudberg et al.1989, Cummins et al. 1991) and it is considered one of the three most contaminated locations in the Chesapeake Bay. The Anacostia River runs along the lower third of the District and essentially separates Federal buildings and upscale housing from the poorer and mostly minority communities to the south and west. There is a high incidence of cancer and other diseases in this minority community, where there is also subsistence fishing in the Anacostia in spite of a fishing advisory. Anacostia River estuary catfish have tumors related to high polycyclic hydrocarbon (PAH) levels in sediment (Pinkney e.a. 2000), and high tissue levels of polychlorinated biphenyls (PCBs) and chlordane which can be associated with cancer. Fish that yearly migrate into the Anacostia estuary also have been found contaminated (Velinsky and Cummins 1994). Reference: Phelps, HL. 2005. Identification of PCB, PAH and chlordane source areas in the Anacostia River watershed. DC Water Resources Research Institute, Washington, DC 9p. The Anacostia River estuary has very little benthic life and shows sediment toxicity to clam larvae (Phelps 1985, Phelps 1993, Phelps 1995). Most studies of Anacostia River contaminants have focused on water and sediments of the estuary portion (Velinsky et al. 1992, Wade et al 1994, Velinsky and Ashley 2001, AWTA 2002). However, contaminants are increasingly recognized as coming from Anacostia tributaries, with many in Maryland (Warner et al.1997, Phelps 2004, Washington Post 2004). UDC’s WRRC-sponsored clam biomonitoring studies have developed a rapid two-week protocol using Asiatic clams (Corbicula fluminea) translocated from the healthy Potomac to sites in the Anacostia River watershed where they accumulate bioavailable contaminants. These common, non-endangered clams have a high filtration rate, can accumulate toxic contaminants from the water and have been used elsewhere for active freshwater biomonitoring (Dougherty and Cherry 1988, Crawford and Luoma 1993, DeKock and Kramer 1994, Colombo et al 1995). Clam translocation and bioaccumulation has identified one of Anacostia’s five first order tributaries as a source of bioavailable polychlorinated biphenyls (PCBs), two as sources of chlordane, and four as sources of polycyclic hydrocarbons (PAHs). This information is essential for DC’s Mayor to bring to the attention of counties surrounding the District for remediation efforts to achieve a fishable and swimmable DC Anacostia River. The most serious contaminants of the Anacostia from the standpoint of human health are the pesticide chlordane and PCBs which are above FDA action levels in Anacostia fish (Velinsky and Cummins 1994). PCBs are known to be toxic and have been banned but residuals come from a variety of sources (Ahlborg et al. 1994, Safe 1994). Chlordane is a termite pesticide harmful to humans and has been banned for over 20 years but is slow to biodegrade and its accumulation in fish tissues is one basis for the 1994 Anacostia fishing advisory. Translocated clams accumulated chlordane in the lower NorthEast Branch and Watts Branch tributaries (Phelps 2000, 2002). High PAH levels in sediment are identified with sediment toxicity and fish tumors (Pinkney et al 2000). PAHs from oils and manufacturing and combustion byproducts are a major contaminant of the Anacostia estuary but are not bioaccumulated by fish so active clam biomonitoring is needed to find sources. The primary objective of this 2004 study was to use active clam biomonitoring to locate the uncontaminated upstream portions of the major Anacostia tributaries contributing PCBs, PAHs, and chlordane (Phelps 2004). The second objective was to continue the involvement and training of UDC undergraduate students in research on DC’s Anacostia River. Methodology Asiatic clams (Corbicula fluminea) were collected from May through September at the healthy nearby Potomac River estuary control site of Fort Foote (MD). Clams collected by along-shore sieving were selected from the same cohort, 20 30 mm, and kept cool and dry before 20-30 were placed in mesh shellfish cages at the tributary sites within 24 hours (Table 1). As clams can accumulate a maximum of contaminants within one to two weeks (Phelps 2004) they were collected after two weeks exposure. The 15 30 clams were washed, depurated for 24 hours in three changes of spring water at room temperature and briefly frozen to open shells and extract tissues. The combined frozen tissues were sent to the certified Severn-Trent Laboratory (STL), Burlington, VT for chemical analyses. The STL EPA Priority Pollutant tissue analysis included 21 pesticides, 28 polychlorinated biphenyl (PCB) congenors, 6 Aroclors, 18 polycyclic hydrocarbons (PAHs), and six metals of interest (As, Cd, Cr, Cu, Fe, and Zn), and percent lipid. Results were available within five weeks. The STL analytical variability has been determined as SD = 0.175 (mean) 1.12 (n = 9) (Phelps 2002). Statistical comparison between sites was by t test and the 95% confidence limits of the mean were calculated as 2.05 SD = 0.36 (mean). Analytical error was considered the most significant since clam tissues were pooled for analysis. The sites chosen for biomonitoring were located on the Anacostia watershed first order tributaries where previously translocated clams had accumulated high PCBs (Lower Beaverdam Creek), chlordane (NorthEast Branch and Watts Branch), and PAHs (NorthEast Branch and Watts Branch) (Phelps 2003, Phelps 2004). Not all tissue contaminants were examined at each site. Results The GPS site locations and clam translocation dates are in Table 1, listed in order of date. The Riverdale East Branch site clams had to be replaced four times. Translocated clam survival was 97 100%. Table 1. Clam site locations listed by translocation date. Date Date Site (Code) UTM GPS placed collected Northing Westing 5/13 5/13 Fort Foote, MD (FF5/04) 3846’458” 07701’752” 5/13 5/27 Watts Branch Upper, DC (WBU) 3858’357” 07654’619” 5/27 Landover Metro Yard, MD (LMT) 3855’932” 07653’355” 5/27 Riverdale West Branch, MD (RVW) 3857’582” 07655’557” 6/1 6/15 NorthEast Branch 04, MD (NEB04) 3857’621” 07855’583” 6/15 Odell Road, MD (ODR) 3858’375” 07655’509” 6/15 Virginia Manor Road, MD (VMR) 3903’522” 07653’909” 7/20 8/10 Corporate Drive, MD (CRD) 3856’318” 07651’646” 8/28 9/9 Riverdale East Branch, MD (RVE) 3857’644” 07655’572” Contaminants detected in clam tissues were summarized by the total accumulation of each type (tmetals, tPAHs, tPCBs tAroclors and tpesticides), with alpha and beta chlordane additionally summed as tChlr (Table 2). FF control was the average of Fort Foote clams with eight previous Fort Foote samples from 1999 to 2003 (Phelps 2004). Table 2. Clam tissue contaminant concentration totals (μg/Kg) at sites by tributary. Site tMetalx.001 tPAH tPCB tArocl. tPest. tChlr. FF Control (average) 77 376 93 140 72 Potomac Fort Foote 116 60 76 116 169* 38 Lower Beaverdam Creek Landover Metro 24 --366* 630* 97 50 Corporate Drive 70 267 105 120 93 83* NorthEast Branch NorthEast Branch 69 923* 86 149 74 40 Riverdale West Branch 21 142 62 62 27 Riverdale East Branch ------246* 144* Odell Road 2196* --188 ----Virginia Manor Rd 66 996* 72 149 31 19 Watts Branch Watts Branch Upper 23 1088* --120 55 30 _________________________________________________________________ * Significantly (95%) greater than FF control Figure 1. The Anacostia River watershed with some sites labeled. The NorthEast Branch tributary clam total PAH and pesticide data was combined with NorthEast Branch first and second order stream data from earlier studies (Phelps 2004) (Fig. 2). Figure 2. NorthEast Branch clam tissue concentrations of total polycyclic hydrocarbons (tPAHx .1) and total pesticides (tPest) at the NorthEast Branch downstream site just above head of tide and at second order stream sites proceeding upstream (Phelps 2004). Error bars show 95% analytical confidence limits. All sites were in Maryland. NORTHEAST BRANCH CLAM PAH AND PESTICIDE TOTALS