reported on the efficiency of concentration of viruses by the commonly used beef extract organic flocculation method, which depends on virus adsorption-elution from an organic floc. They reported large differences in the efficiency of this method for the concentration of different enteroviruses. The efficiency of concentration was as follows: coxsackievirus B4, 9%; echovirus 1, 7%; coxsackievirus B3, 98%; and poliovirus 1,40%.Bitton et al. (ZO), using nonfat dry milk as an organic flocculant for virus reconcentration, also observed that the efficiency of concentration of poliovirus 1 and coxsackievirus B3 was almost 10-fold greater than that of echovirus 1.These results appear to confirm our data and indicate major differences in the adsorptive behavior of group I viruses (coxsackievirus B4, echovirus 1)and group I1 viruses (poliovirus 1and coxsackievirus B3). In summary, it would appear that the adsorption of certain types and strains of viruses is more susceptible to the influence of soil pH, organic matter, and exchangeable iron and aluminum than that of others. Certain types of coliphages may be better models for some types of enteroviruses than others. These differences should be taken into consideration in both field and laboratory studies on virus adsorption and migration through soil. L i t e r a t u r e Cited (1) Craun, G. F. Ground Water 1979,17,183. (2) Gerba, C. P.; Wallis, C.; Melnick, J. L. J . Irrig. Drain. Diu., Am. Soc. Ciu. Eng. 1975,101,157. ( 3 ) Goyal, S. M.; Gerba, C. P. Appl. Enuiron. Microbiol. 1979,38, 241. (4) Landry, E. F.; Vaughn, J. M.; Thomas, M. Z.; Beckwith, C. A. Appl. Environ. Microbiol. 1979,38,680.
(5) Enfield, C. G.; Harlin, C. C.; Bledsoe, B. E. Soil Sci. Soc. A m , J . 1976,40, 243. (6) Melnick, J. L.; Rennick, V.; Hampil, B.; Schmidt, N. J.; Ho, H. H. Bull. W. H.0. 1973,48,263. (7) Malherbe, H. H.; Strickland-Cholmley, M. Arch. Gesamte Virusforsch. 1967,22, 235. (8) Rovozzo, G. C.; Burke, C. N. “A Manual of Basic Laboratory Techniques”; Prentice-Hall: Englewood Cliffs, NJ, 1973; pp 165-77. (9) Remington, R. D.; Schork, M. A. “Statistics with Applications to the Biological and Health Sciences”; Prentice-Hall: Englewood Cliffs, NJ, 1970. (10) Nie, N. H.; Hull, C. H.; Jenkins, J. G.; Steinbrenner, K.; Bent, D. H. “Statistical Package for the Social Sciences”, 2nd ed.; McGraw-Hill: St. Louis, MO, 1974. (11) LaBelle, R. L.; Gerba, C. P. Appl. Enuiron. Microbiol. 1979,38, 93. (12) Gerba, C. P.; Goyal, S. M.; Hurst, C. J.; LaBelle, R. L. Water Res. 1980,14,1197. (13) Bitton, G.; Masterson, N.; Gifford, G. E. J . Enuiron. Qual. 1976, 5,370. (14) Carlson, G. F., Jr.; Woodward, F. E.; Wentworth, D. F.; Sproul, 0. J . J . Water Pollut. Control Fed. 1968,40, R89. (15) Lefler, E.; Kott, Y. Isr. J. Technol. 1974,12, 298. (16) Schaub, S. A,; Sorber, C. A. Appi. Enuiron. Microbiol. 1977,33, 609. (17) Burge, W. D.; Enkiri, N. K. J . Enuiron. Qual. 1978, 7,73. (18) Drewry, W. A,; Eliasson, R. J . Water Pollut. Control Fed. 1968, 40, R257. (19) Morris, R.; Waite, W. M. Water Res. 1980,14,791. (20) Bitton, G.; Feldberg, B. N.; Farrah, S. R. Water,Air, Soil Pollut. 1979,12,187.
Received for reuiew November 10, 1980. Revised May 1, 1981. Accepted May 1,1981, This work was supported i n part by research grant R-805,292 from the Environmental Protection Agency.
Geochronology for Mercury Pollution in the Sediments of the Saguenay Fjord, Quebec John N. Smith”? and Douglas H. Loring* Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada B2Y 4A2
Introduction
In 1971, high levels of mercury (0.5-10 pg g-l) were measured in fish in the Saguenay Fjord and in the Saguenay River, Quebec. As a result, restrictions were placed on the commercial exploitation of certain species of fish. Some of the mercury was of natural origin, but most is believed to stem from industrial sources ( I ) . As in other countries, the chlor-alkali industry was identified as the major source of industrial mercury pollution in aquatic systems, and government regulations were implemented in Canada in 1971 to limit discharges from chlor-alkali plants into the environment. Sediment samples collected from the Saguenay Fjord between 1964 and 1974 revealed that the fjord sediments were contaminated with mercury (0.5-12 pg g-l) apparently released from a chlor-alkali plant situated on the Saguenay River at Arvida (Figure l ) , 24 km above the head of the fjord ( I , 2). A series of cores collected in 1976 was analyzed for both
+Chemical OceanograpKy Division, Atlantic Oceanographic Laboratory. t Marine Ecology Laboratory. 944
Environmental Science & Technology
Hg and the radionuclides zloPb and 137Csin order to determine sedimentation rates in the fjord ( 3 ) and the geochronology of mercury contamination in the sediments. The detailed pattern of Hg deposition throughout the fjord is discussed in this paper, and mercury fluxes to the sediments are estimated for the period 1940-1976. Field a n d Laboratory M e t h o d s
Sediment cores for Hg analyses were collected a t seven stations (Figure 2) whose locations approximately correspond to those at which gravity cores (50 mm in diameter) had been collected in 1974 (2).The coring device was a Lehigh gravity corer which uses a 10-cm diameter PVC pipe as a combination core barrel and liner. The cores were stored upright at 4 “C and subsequently X-radiographed and extruded in the laboratory. Sediment subsamples were collected at l-cm intervals for ZlOPb, 137Cs, and Hg analyses by using a modified 10-cm3 syringe. zloPb activities were determined by a-particle counting of zlOPodeposited on silver disks, and 13’Cs measurements were conducted with a GeLi detector as outlined in Smith and Walton ( 3 ) .Sediment subsamples for Hg and organic-carbon analyses were air dried and stored in airtight
0013-936X/81/0915-0944$01.25/0 @ 1981 American Chemical Society
The recent (1940-1976) geochronology of Hg pollution in the Saguenay Fjord, Quebec, has been determined in a suite of sediment cores by using the 210Pb dating method. Contamination of fjord sediments by anthropogenic Hg began in 1948 f 3 yr, a date that coincides with the construction of a chlor-alkali plant a t Arvida on the Saguenay River and identifies this plant as the major source of Hg pollution in the fjord. Hg fluxes to the sediments attained maximum values in the 1960s and early 1970s and subsequently decreased throughout the fjord during the period 1971-1 76. Both the timing and the magnitude of the decreases in g fluxes are
consistent with compliance of the chlor-alkali plant with government regulations imposed in 1971, limiting Hg discharges in liquid effluent from chlor-alkali plants in Canada. The fast response of changes in the sedimentary Hg flux at the head of the fjord to changes in the Hg input function is consistent with a water residence time for Hg of less than 1month while a considerably delayed response in the sedimentary Hg flux in the deep inner basin of the fjord indicates that the Hg residence time in the water column of this region has an upper limit of the order of 5-10 yr.
bottles. Mercury was determined in duplicate for each sample by digesting the sediment in concentrated HNO3 and HzS04. The dissolved sample was analyzed by using a cold vapor atomic absorption technique comparable to that described by Hatch and Ott ( 4 ) .Readily oxidizable organic matter was determined by the wet oxidation method (cold HzS04) described by Loring and Rantala ( 5 ) . One of the cores (3111,
station 18) was examined for mi.crofossi1 assemblages, and the geological and geochemical analyses of this core are reported elsewhere (6, 7).
PI
72’
62‘
46‘
48.
ALUMINUM SMELTER d ALUMINUM SMELTER8 CHLOR-ALKALI PLANT X FLUORSPAR PROCESSING THERMAL ELECTRICITV *PAPER PRODUCTS
7P
I
I
7P
Figure 1. Location of the Saguenay Fjord in eastern Quebec, Canada. A chlor-alkali plant which is the inferred source of Hg pollution in the Saguenay River and Fjord is located at Arvida.
Environmental Setting The Saguenay Fjord occupies a long (93 km) narrow (1-6 km) glacial valley that joins the St. Lawrence estuary at Tadoussac (Figure l).Water circulation has a two-layer estuarine component with the deep, well-mixed, and oxygenated water inside the fjord being subject to intrusions of saline water from the St. Lawrence estuary over a shallow (20 m) sill. Salinities in surface waters (depths less than 3 m) increase seaward from 0.5%0near the mouth of the Saguenay River to 28%0 near the sill of the deep basin (Figure 2) and range up to 31%0near the bottom of this basin. The highest suspended matter (SPM) concentrations (20 mg L-l) occur in the surface (
