Geographical Distribution and Potential for Adverse Biological Effects of Selected Trace Elements and Organic Compounds in Streambed Sediment in the Connecticut, Housatonic, and Thames River Basins, 1992-94 By Robert F. Breault and Sandra L. Harris Abstract exceed sediment-quality guidelines over a wider geographical area, although usually by lower Streambed-sediment samples were collected ratios of contaminant concentration to sediment- in 1992-94 at selected sites in the Connecticut, quality guideline than the organic compounds. Housatonic, and Thames River Basins to determine the geographical distribution of trace elements and organic compounds and their INTRODUCTION potential for adverse biological effects on aquatic organisms. Chromium, copper, lead, mercury, The Connecticut, Housatonic, and Thames River Basins study unit is one of 59 National Water-Quality nickel, zinc, chlordane, DDT, PAHs, and PCBs Assessment (NAWQA) study units nationwide. The were detected in samples from throughout the study unit drainage basin comprises an area of almost basins, but concentrations of these constituents 16,000 mi2 and extends through parts of the Province of generally were lowest in the northern forested Quebec, Canada, eastern Vermont, western New Hamp- drainage basins and highest in the southern shire, west-central Massachusetts, nearly all of Connect- urbanized drainage basins of Springfield, icut, and small parts of New York and Rhode Island. Massachusetts, and Hartford, New Haven and The study unit is entirely within the New Bridgeport, Connecticut. Possible anthropogenic England Physiographic Province (Fenneman, 1938), a sources of these contaminants include industrial plateau-like upland that rises gradually from the sea but effluent; municipal wastewater; runoff from includes numerous mountain ranges and individual agricultural, urban and forested areas; and peaks. Altitudes range from sea level in coastal Con- atmospheric deposition. necticut to 6,288 ft at the peak of Mount Washington in the White Mountains of New Hampshire (fig. 1). Some organic compounds pose the greatest Major streams in the study unit generally flow threat to biological organisms in terms of from north to south and all ultimately drain into Long exceedances of sediment-quality guidelines; those Island Sound at the southern border of Connecticut. compounds are present at sufficiently high The study unit encompasses varied land uses (fig. 2), concentrations to potentially cause severe effects from forested wilderness in the north to densely popu- at several locations in the basins. Some trace lated cities in the south. About 78 percent of the land is elements represent the most geographically forested, 12 percent is used for agriculture, and 10 per- widespread threat to living organisms. These cent is classified as urban (Mitchell and others, 1977). Introduction 1 71˚ 73˚ 72˚ EXPLANATION CANADA 45˚ ELEVATION ABOVE MEAN SEA LEVEL 1250 METERS, 4101.3 AND ABOVE 300 METERS, 984.3 FEET VERMONT MAINE 150 METERS, 492.2 FEET SEA LEVEL TO 10 METERS, 0 TO 32.8 FEET Mount Washington 44˚ NEW HAMPSHIRE NEW YORK 43˚ 70˚ MASSACHUSETTS 42 ˚ RHODE NEW YORK CONNECTICUT ISLAND ATLANTIC OCEAN LONG ISLAND SOUND 41˚ 0 10 20 30 40 50 MILES Base from U.S. Geological Survey Digital Line Graphs, 1989 0 10 20 30 40 50 KILOMETERS Universal Transverse Mercator 1:100,000 scale Figure 1. Topographic shaded relief map of the Connecticut, Housatonic, and Thames River Basins. 2 Trace Elements and Organic Compounds in Stream Sediments, Connecticut, Housatonic, Thames River Basins, 1992-94 71˚ EXPLANATION 73˚ 72˚ LAND USEÐFrom Mitchell and others (1977) Urban CANADA 45 ˚ Agriculture Forest BOUNDARY OF MAJOR BASINS BOUNDARY OF STUDY UNIT VERMONT MAINE 44˚ NEW HAMPSHIRE NEW YORK 43˚ ATLANTIC OCEAN 70˚ MASSACHUSETTS 42 ˚ RHODE NEW YORK ISLAND CONNECTICUT LONG ISLAND SOUND 41˚ Base from U.S. Geological Survey Digital Line Graphs, 1989 0 10 20 30 40 50 MILES Universal Transverse Mercator 1:100,000 scale 0 10 20 30 40 50 KILOMETERS Figure 2. Generalized land use in the Connecticut, Housatonic, and Thames River Basins. Introduction 3 The study unit occupies less than one-half of maximize the coverage of major basins in the study 1 percent of the total area of the Nation, but is inhab- unit, with specific locations along rivers selected to ited by 2 percent of the Nation’s Population—about insure the availability of fine-grained sediments and 4.5 million persons (Grady and Garabedian, 1991). wadeable access to the sites for sample collection. Population density ranges widely across the study Using these criteria, 43 sites were selected for unit, from sparsely populated, rural agrarian, and sampling and separated into four groups by river wilderness of Northern Vermont and New Hamp- basin—Connecticut River, Housatonic River, shire, to densely populated urban areas of southern Thames River, and Long Island Sound Coastal Massachusetts and Connecticut (fig. 3). Rivers (fig. 4 and table 1). Streambed sediment quality throughout the Streambed-sediment samples were collected study unit has been adversely affected by various during three sampling periods; June-November human activities and at some locations the sediments 1992, July-September 1993, and August-September have been contaminated by trace elements and 1994. A total of 87 samples were collected from the organic compounds. Streambed sediments are 43 sampling sites. A total of 45 samples were natural accumulators of these constituents; collected for trace-element analysis (one sample at sediments have the capacity to concentrate and each site and two replicate samples) and 42 samples integrate trace elements and organic compounds were collected for organic-compound analysis (no from multiple natural, agricultural, and industrial sample was taken at site 7) At each of the 43 sources. The occurrence of trace elements and sampling sites, fine-grained streambed sediments organic compounds in streambed sediments reflect were collected from a variety of depositional settings not only recent but also past inputs to the stream within stream reaches and composited. The samples system that have been remobilized through the were collected during summer or autumn low flows erosion of sediment stored in streambanks, soils, and to minimize seasonal variability and the amount of floodplains (Horowitz and others, 1988). fine-grained sediments in suspension. The samples The chemistry of streambed sediment were collected from the top 1 to 2 cm of fine-grained influences the biotic quality of a stream as aquatic sediments using a stainless-steel scoop, following organisms ingest particulate matter and accumulate nationally consistent protocols (Shelton and Capel, trace elements and organic compounds (Forstner and 1994). Wittmann, 1979; Luoma, 1983). The accumulation Samples for inorganic-constituent analysis of trace elements and organic compounds in aquatic were wet-sieved through a 63-µm mesh organisms can cause various physiological problems polyethylene sieve, digested to complete dissolution, and even death of the organisms. Subsequent and analyzed for 45 inorganic constituents. Details ingestion of aquatic organisms transfers the of inorganic dissolution and analytical methods are accumulated contaminants upward through the food provided in Arbogast (1990). Samples for organic- chain. constituent analysis were wet-sieved through a 2- The purpose of this report is to describe (1) the mm stainless-steel sieve and analyzed for 32 geographic distribution of selected trace elements organochlorine compounds, including total PCBs, and organic compounds in streambed sediments in and 64 semi-volatile organic compounds at the U.S. mainstem channels and major tributaries in the Geological Survey’s National Water-Quality Connecticut, Housatonic, and Thames River Basins, Laboratory (NWQL) in Arvada, Colorado. Details of and (2) the potential frequency of adverse effects of organic separation and analytical methods are those elements and compounds on benthic provided in Wershaw and others (1987) and Fishman organisms. Sampling sites were selected to (1993). 4 Trace Elements and Organic Compounds in Stream Sediments, Connecticut, Housatonic, Thames River Basins, 1992-94 71˚ 73˚ 72˚ EXPLANATION POPULATION DENSITY, IN CANADA 45˚ PERSONS PER SQUARE MILEÐ From U.S. Department of Commerce Bureau of Census (1991) Less than 25 25 to 150 VERMONT 151 to 500 MAINE 501 to 1,500 More than 1,500 BOUNDARY OF STUDY UNIT BOUNDARY OF MAJOR BASINS 44˚ TOWN BOUNDARY NEW HAMPSHIRE NEW YORK 43˚ 70˚ MASSACHUSETTS 42 ˚ RHODE NEW YORK ISLAND CONNECTICUT LONG ISLAND SOUND 41˚ 0 10 20 30 40 50 MILES 0 10 20 30 40 50 KILOMETERS Base from U.S. Geological Survey Digital Line Graphs, 1989 Universal Transverse Mercator 1:100,000 scale Figure 3. Population density by town in the Connecticut, Housatonic, and Thames River Basins, 1990. Introduction 5 71˚ EXPLANATION MAJOR DRAINAGE BASINS 73˚ 72˚ Thames Connecticut CANADA 45˚ Housatonic Long Island Sound BOUNDARY OF STUDY UNIT .8 SAMPLING SITE AND VERMONT NUMBERÐsee table 1 8 . .7 MAINE .9 44˚ .10 .11 NEW HAMPSHIRE .12 13 NEW YORK . 43˚ 14 . .17 .18 . 15 . 16 32 .20 .19 21 70˚ 34 . .. ATLANTIC OCEAN 33 . 3 MASSACHUSETTS .35 .23 22 . 42˚ . CONNECTICUT 4 . RHODE NEW YORK 25 . 24 1 ISLAND 38 . .28 .36 26 . 27 . .29 2 5 . .37 39 . 31 6 40 . 30 . 41 42 .43 . LONG ISLAND SOUND 41˚ 0 10 20 30 40 50 MILES 0 10 20 30 40 50 KILOMETERS Base from U.S. Geological Survey Digital Line Graphs, 1989 Universal Transverse Mercator 1:100,000 scale Figure 4. Location of streambed-sediment