Environ. Scl. Techno/. 1982, 16, 666-676
( 5 ) Eaton, A. Enuiron. Geol. 1979, 2, 333. (6) Luoma, S. N.; Bryan, G. W. In “Chemical Modeling in Aqueous Systems”; Jenne, E. A,, Ed.; American Chemical Society: Washington, D.C., 1979; p 577. I Sunda, G. W.; Guillard, R. R. L. J. Mar. Res. 1976,34,511. ’ Anderson, D. M.; Morel, F. M. M. Limnol. Oceanogr. 1978, 23, 283. Lal, D. Science (Washington, D.C.) 1977, 198, 997. Parsons, T.R. In “Chemical Oceanography”; Riley, J. P., Skirrow, G., Eds.; Academic Press: London, 1975; Vol. 2, p 365. Gibbs, R. J. In “Estuaries, Geophysics and the Environment”; National Academy of Sciences: Washington, D.C., 1977; p 104. Jenne, E. A. In “Molybdenum in the Environment”; Chappel, W. R., Petersen, K., Eds.; Marcel Dekker: New York, 1976; Vol. 2, p 425. Neihof, R. A.; Loeb, G. I. Limnol. Oceanogr. 1972,17, 7. Hunter, K. A. Limnol. Oceanogr. 1980, 25, 807. Hunter, K. A.; Liss, P. S.Nature (London) 1979,282,823. Suarez, D. L.; Langmuir, D. Geochim. Cosmochim. Acta 1976, 44, 589. Gamble, D. S.; Underdown, A. W.; Langford, C. H. Anal. Chem. 1980,52, 1901-1903. Stevenson, F. J. In “Environmental Biogeochemistry”; Nriagu, J. O., Ed.; Ann Arbor Science: Ann Arbor, MI, 1976; VO~. 2, pp 519-541. Saar, R. A.; Weber, J. H. Anal. Chem. 1980,52, 2095. Benjamin, M. M.; Leckie, J. 0. J. Colloid. Interface Sci. 1981, 79, 209. Davis, J. A.; Leckie, J. 0. J . Colloid Interface Sci. 1978, 67, 90. Benjamin, M. M.; Leckie, J. 0. In “Contaminants in Sediments”; Baker, R. A,, Ed.; Ann Arbor Science: Ann Arbor, MI; 1980; Vol. 2, p 305.
(23) Kerndorff, H.; Schnitzer, M. Geochim. Cosmochim. Acta 1980, 44, 1701. (24) Luoma, S.N.; Jenne, E. A. In “Radioecology and Energy Resources: Proceedings of the Fourth National Symposium on Radioecology”; Cushing, C. E., Ed.; Ecological Society of America; Dowden, Hutchinson and Ross: Stroudsburg, PA; Spec. Publ. No. 1, 1976; p 283. (25) Luoma, S.N.; Bryan, G. W. J.Mar. Biol. Assoc. U.K. 1978, 58, 793. (26) Luoma, S. N.; Bryan, G. W. Sci. Total Enuiron. 1981,17, 165. (27) Luoma, S. N.; Jenne, E. A. In ”Trace Substances in Environmental Health”; Hemphill, D. D., Ed.; University of Missouri Press: Columbia, MO, 1976; p 343. (28) Guy, P. D.; Chakraborti, C. L.; McBain, D. C. Water Res. 1978, 12, 21. (29) Tessier, A.; Campbell, P. G. C.; Bisson, M. Anal. Chem. 1979, 51, 844. (30) Swallow, K. C. Ph.D. Thesis, Massachusetts Institute of Technology, Cambridge, MA, 1978. (31) Davis, J. A,; Leckie, J. 0. Environ. Sci. Technol. 1978,12, 1309. (32) Harvey, R. W. Ph.D. Thesis, Stanford University, Stanford, CA, 1981. (33) Benjamin, M. M.; Leckie, J. 0. Environ. Sci. Technol. 1982, 16, 162. (34) Hohl, H.; Stumm, W. J. Colloid Interface Sci. 1976,55,281. (35) Huang, C. P.; Stumm, W. J. Colloid Interface Sci. 1973, 43, 409. (36) Bowden, J. W. et al. Nature (London) 1973,245, 81.
Received for review April 20,1981. Accepted May 11,1982. This research was supported in part by National Science Foundation Grant No. CME-79-22079.
Chlorinated Hydrocarbons and Radionuclide Chronologies in Sediments of the Hudson River and Estuary, New York Rlchard F. Bopp,” H. James Simpson, Curtis R. Oisen,t Robert M. Trler, and Nadia Kostyk Lamont-Doherty Geological Observatory of Columbia University, Palisades, New York 10964, and Department of Geological Sciences, Columbia University, New York, New York 10027
The Hudson River received discharges of at least several hundred tons of PCBs from two General Electric capacitor manufacturing facilities in the upper part of the drainage basin over the period between ca. 1950 and 1976. Measurements of PCB compositions and amounts in sediment cores throughout the tidal Hudson (-250 km) indicate that maximum concentrations occurred in the early 1970s, probably due to removal of a dam just downstream of the release area in 1973. Significant decreases in surface sediment PCB concentrations have occurred since about 1973, well before monitored releases of PCBs from the manufacturing facilities ceased in 1976,probably primarily as the result of dilution and burial of the most highly contaminated sediments released upon removal of the dam with soils from the drainage basin. Declines in the concentrations of chlorinated hydrocarbon pesticides and fallout radionuclides since the mid- 1960s and reactor-released radionuclides over the period 1971-1975 have also been established from sediment core measurements. Introduction The most effective general policy for reducing impacts t Current address: Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37880.
666
Envlron. Sci. Technol., Vol. 16, No. 10, 1982
of toxic chemicals on aqueous systems is to limit or eliminate discharges at their source. However, in some cases the degree of contamination with persistent toxic chemicals is sufficient to warrant consideration of remedial activities such as dredging and containment of the most highly contaminated sediments to reduce exposure of human populations through pathways such as consumption of fish. One such case is the Hudson River, which received substantial discharges of at least several hundred tons of polychlorinated biphenyls (PCBs) over the period of ca. 1950-1976 (1). The composition of PCBs in Hudson sediments and their spread throughout the entire axis of the tidal Hudson has been reported elsewhere (2, 3). We discuss here the time history of PCB concentrations in Hudson sediments, which can be deduced from measurements of core samples. Temporal variations of chlorinated hydrocarbon pesticide residues in the same samples are also examined. A number of similar investigations have employed natural and man-made radionuclides to provide a time frame for studying the accumulation of anthropogenic pollutants associated with recent sediments in natural water systems. Hom et al. ( 4 )used radiometric dating to study PCB and DDE accumulation in the Santa Barbara Basin; Robbins and Edgington (5) described the accumulation of fallout radionuclides in Lake Michigan
0013-936X/82/0916-0666$01.25/0
0 1982 American Chemical Soclety
ED)
B - (147.7)
3d
selected extracts with concentrated H2S04 (14), which removed some interfering peaks and quantitatively destroyed dieldrin, and by alkali treatment (15) of selected extracts, which produced dehydrochlorination products from chlordane, DDD, and DDT. As an indication of the precision of the reported analyses, two separate portions of 14 of the sediment samples were analyzed. The average coefficient of variation was 6.5% for PCBs, 5.2% for pp'-DDD, 13% for dieldrin, and 7.4% for a- and ychlordane. All concentrations of chlorinated hydrocarbons and activities of radionuclides are reported on a per dry weight of sediment basis. More detailed descriptions of our analytical procedures have been reported elsewhere (2, 3, 11, 12, 16). Results and Discussion
Mil19
Figure 1. Map of the Hudson River and Estuary with core locations denoted In parentheses by kilometer polnt (kmp). Tidal currents extend upstream to a dam just downstream of the confluence of the Mohawk and Upper Hudson Rivers.
sediments; Goldberg et al. (6-8) reconstructed trace metal chronologies for Narragansett Bay, Chesapeake Bay, and the Savannah River Estuary sediments utilizing natural and fallout radionuclides as time indicators; Wakeham et al, (9) referenced data on natural radionuclides in a study of polycyclic aromatic hydrocarbons in recent lake sediments; Cutshall et al. (10) interpreted kepone profiles in James River sediment cores based on fallout radionuclide measurements. We have been analyzing fallout and reactor-derived radionuclides in Hudson River sediments for the past decade in conjunction with studies of the accumulation of recent, fine-grained sediments (11,12) and associated trace metals (13) and trace organics (3). In the present study, geochronology of the core profiles has been determined primarily from analyses of fallout and reactor nuclides for which the history of inputs is well documented. Experimental Section Sediment samples from the Hudson were collected with a gravity corer, with a piston corer, or by hand coring at sites ranging from near the upstream end of the fresh-water reach of tidal waters to New York harbor, which has ambient salinities of about two-thirds of that of the open ocean (Figure 1). Sections of the cores were analyzed for 13Ts,IWs, and @Coby nondestructive y-ray spectrometry using a lithium-drifted germanium detector and a multichannel analyzer. Portions of the samples were analyzed for fallout 239,240Pu by a spectrometry. PCB and chlorinated hydrocarbon pesticide measurements were made by electron-capture gas chromatography. Standards were obtained from the EPA at Research Triangle Park, NC, and run at least daily. Pesticide peak assignments were made with use of retention times on two glass columns, a 6 ft X 2 mm i.d. column packed with 1.5% OV-17/1.95% QF-1 on 80-100 mesh Chromosorb W H P and a similar column packed with 4% SE30/6% OV-210 also on 80-100 mesh Chromosorb W HP. The latter column was employed routinely for sample quantification. Additional confirmation of peak assignments was obtained by treating
Radionuclides and Time Stratigraphy in Hudson Sediments, As a result of their affinity for a wide range of chemical substances including radionuclides, PCBs, and chlorinated hydrocarbon pesticides, the fine-grained sediments of estuarine systems contain a recoverable chronology of many ubiquitous environmental pollutants. The estuarine geochemistry of the substances discussed is strongly influenced by partitioning between water and particle phases. In all cases, the preference for particle phases is great enough to leave an identifiable signal in the sediments and to prevent significant postdepositional redistribution via solution processes (3,16). Accumulation patterns and transport rates of fine-grained sediments in large estuaries are quite complicated in space and time, especially in systems that have been significantly perturbed by dredging activities. Most of the total surface area of the tidal Hudson a t present experiences relatively little net sediment accumulation (
