Dependencies of metal toxicity or availability to aquatic organisms on free metal ion concentrations in solution may in fact be rather widespread phenomena. The existence of such dependencies should allow one to predict changes in the response of an organism to a particular metal through knowledge of the variations in the aqueous chemistry of the metal. Variables such as the total concentration of the metal in question, pH, alkalinity, the concentration of natural chelators, the concentration of competing metals, and the presence of adsorptive surfaces all can affect the concentration of free metal ion and thus affect the response of an organism to that metal.
Literature Cited (1) Sunda, W., Guillard, R.R.L., J. Mar. Res., 34,511-29 (1976). (2) Anderson, D. M., Morel, F.F.M., Limnol. Oceanogr., in press. (3) Andrew, R. W., Biesinger, K. E., Glass, G. E., Water Res., 11, 309-15 (1977). (4) Armstrong, F.A.J., Williams, P. M., Strickland, J.H.D., Nature, 211,481-7 (1966). (5) Vernberg, W. B., DeCoursey, P. J., Kelly, M., Johns, D. M., Bull. Enuiron Contam. Tonicol., 17,16-24 (1977). (6) Westernhagen, H. von, Rosenthal, H., Sperling, K. R., Helgo, Wiss. Meeresunters., 26,416-33 (1974).
(7) . . Westernhaeen. H. von.. Dethlefsen.. V.., Rosenthal., H.., ibid.., 27., 268-72 (197g. ’ (8) Jones, M. B., Mar. Biol., 30. 13-20 (1975). (9) Rosenberg, R., Costlow, J. D., Jr., ibid., 38,291-303 (1976). (10) Manahan, S. E., Smith, M. J., Enuiron. Sci. Technol., 7,829-33 (1973). (11) Walker, J. B., Arch. Biochem. Biophys., 46,l-11 (1953). (12) Walker, J. B., ibid., 53,l-8 (1954). (13) Cossa, D., Mar. Biol., 34,163-7 (1976). (14) , . Kramer. H. J.. Neidhart., B.., Bull. Enuiron. Contam. Toxicol.. 14,699-704 (1975). (15) SDraeue. J. B.. Nature, 220.1345-6 (1968). (16) Bioi&, V. M., Shaw, T. L:, Shurben, D. G., Water Res., 8, 797-803 (1974). (17) Zitko. P.. Carson. W. V.. Carson. W. G.. Bull. Environ. Contam. ?oxicol.; 10,265-71 (1973). (18) Stephenson, R. R., Taylor, D., ibid., 14,304-8 (1975). (19) Sillen, L. G., Martell, A. E., Chem. Sac. London, Special Publ. no. 17 and no. 25 (1964,1971). Received for review June 3,1977.Accepted October 6,1977. Reference to trade names i n this manuscript does not imply endorsement by the National Marine Fisheries Seruice, NOAA. Research supported by a cooperative agreement between the Energy Research and Development Administration and the National Marine Fisheries Service.
Enrichment of Micronutrients, Heavy Metals, and Chlorinated Hydrocarbons in Wind-Generated Lake Foam S. J. Eisenreich” Environmental Engineering Program, Department of Civil and Mineral Engineering, University of Minnesota, Minneapolis, Minn. 55455
A. W. Elzerman’ and D. E. Armstrong Water Chemistry Laboratory, University of Wisconsin, Madison, Wis. 53706
Wind-generated lake foam was collected from Lake Mendota, Wisconsin, and analyzed for selected chemical and physical characteristics. The foam was enriched significantly in particulate matter of diverse composition and inorganic and organic forms of P, N, and C; heavy metals (Zn, Cd, Pb, Cu, Fe); major cations (Na, K, Ca, Mg); and chlorinated hydrocarbons. Lake foam was comprised primarily of proteinaceous and carbonaceous matter and exhibited chemical properties similar to surface microlayers. The accumulation of chemical components is of ecological significance and may facilitate research on air-water and organic-inorganic interactions. ~~
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Inorganic and organic matter accumulates at the air-water interface in surface microlayers of both marine and freshwater environments ( 1 , 2 ) . Under certain wind conditions (>4 m/s) Langmuir circulation cells are generated, thereby creating alternating areas of upwelling and downwelling water ( 3 ) .Convergence a t the zone of downwelling results in the accumulation of particulate matter from within the lake or derived from the atmosphere, and surface-active material, noted by the formation of foam lines or windrows lying nearly parallel to the prevailing wind direction on the lake surface. Current patterns may also result in the accumulation of masses of foam parallel to the shoreline. Szekielda et al. ( 4 ) have noted that foam lines also form a t Present address, Department of Chemistry, Woods Hole Oceanographic Institution, Woods Hole, Mass. 02543. 0013-936X/78/0912-0413$01 .OO/O
0 1978 American Chemical Society
frontal convergence zones in estuarine environments. The foam is derived from surface-active, particulate, or associated matter on the surface and in the water. Information on the chemical composition of sea and freshwater surface films from which foam is likely derived suggests the foam should be enriched in fatty acids, esters and alcohols, trace metals, chlorinated hydrocarbons, proteinaceous matter, and inorganic and organic forms of P, N, and C (5-9). The occurrence of microorganisms, phytoplankton, and zooplankton in surface microlayers (SM’s) and induced convergence lines suggests a potentially important role of wind-generated foam in the aquatic environment (10-12). Major consequences of foam enrichment may be the direct introduction of microcontaminants such as pesticides, polychlorinated biphenyls (PCB’s),and toxic metals into the food web through surface organisms, induced chemical and physical interactions between foam components, and transport of surface material to the atmosphere. Wind-generated foam and surface microlayers have received little attention in freshwater systems. Available information suggests that freshwater SM’s also accumulate microcontaminants (13).Baier (14) has analyzed destabilized foam from Lake Chautauqua (N.Y.) by multiply attenuated internal reflection IR and found that petroleum hydrocarbons and natural proteinaceous matter predominated. Later, Baier et al. ( 7 ) found stable sea and freshwater foams from widely varying localities were composed primarily of glycoprotein and proteoglycan polymers of biological origin along with particulate silica from diatom remains. Surface microlayers of Volume 12, Number 4,April 1978
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Table 1. Metal Concentrations in Destabilized Lake Foam Metal
Na Db KD Ca D Mg D Zn T D Cd T D Pb T D Cu T D Fe T D
Concn, mg/L Rang.
3.38-9.10 2.00-15.0 30.0-48.6 27.2-36.8 0.02-2.26 0.01-0.64 0.0001-0.34 0.0001-0.06 0.02-5.91 0.01-2.41 0.14- 1.4 1 0.09-1.14 7.50- 12.9 5.85-13.1
’Average of 30 sets of determinations.
Enrichment
Av
Range
Av
4.76 5.60 35.7 31.5
1.1-3.1 1.4-10.7 1.3-2.0 1.O- 1.4 7-753 10-800 1-1700 1-600 10-2960 10-300 70-705 90-1 140 125-2 15 146-328
1.6 4.0 1.5 1.2 293. 408. 544. 300. 1110. 198. 448. 452. 240. 962.
0.88 0.41 0.11 0.03 2.21 0.63 0.90 0.45 11.3 8.99
*
2.96 1.40 24.0 26.4 0.003 0.001 0.0002 0.0001 0.002 0.001 0.002 0.001 0.04 0.01
D = dissolved metal (
