in the transport of bacteria through aquifers has not been well studied. These eukaryotic predators of bacteria in the subsurface appear to be particularly abundant ( dry weight) in organically contaminated aquifer sediments.24,25 At least one organically contaminated sandy aquifer yielded evidence that protists might be more efficient at removing unattached bacteria being advected downgradient than are the organic and mineral coatings on the sediment grains.26 Also, growth of bacteria being transported downgradient in organically contaminated aquifers can be substantial and can offset the losses that occur as a result of attachment.21

The dearth of information on the importance of biologic controls on subsurface bacterial transport is due largely to the fact that many aspects of the subsurface ecosystem are so poorly understood that their effects on bacterial transport are not fully appreciated. A number of the biologic controls are interrelated and difficult to describe mathematically; this makes their study in field experiments difficult. However, the effects of several factors, such as microbial competition, predation, parasitism, and growth, on subsurface bacterial transport are ideal candidates for studies sponsored by the Biological and Environmental Research program that could build on the subsurface ecologic information already collected in previous research.

REFERENCES

1. Price M. Introducing groundwater. New York: Chapman & Hall; 1996. 278 p.

2. Abba F, Orlandi B, Rondelli A. Über die filtrationskraft des bodens und die fotschewemmung von bakterien dutch das grundwasser. Z Hyg Infekt Krankh 1898;31:66-84.

3. Pfuhl E. Über die verschleppung von bakterien durch das grundwasser. Z Hyg Infekt Krankh 1897;25:549-54.

4. Caldwell EL, Parr LW. Ground water pollution and the bored-hole latrine. J Infect Dis 1937;61:148-83.

5. Harvey RW, Garabedian SP. Use of colloid filtration theory in modeling movement of bacteria through a contaminated sandy aquifer. Environ Sci Technol 1991; 25:178-85.

6. Bales RC, Li S, Maquire KM, Yahya MT, Gerba CP, Harvey RW. Virus and bacteria transport in a sandy aquifer at Cape Cod, MA. Ground Water 1995;33:653-61.

7. DeFlaun M, Murray CJ, Holben W, Scheibe T, Mills A, Ginn T, Griffin T, Majer E, Wilson JL. Preliminary observations on bacterial transport in a coastal plain aquifer. FEMS Microbiol Rev. [In press]

8. Harvey RW. In situ and laboratory methods to study subsurface microbial transport. In: Hurse CJ, Knudsen CR, McInerney MJ, Stenzenback LD, Walter MV, editors. Manual of environmental microbiology. Washington, DC: ASM Press; 1997. p 586-9.

9. Champ DR, Schroeter J. Bacterial transport in fractured rock: a field-scale tracer test at the Chalk River Nuclear Laboratories. Water Sci Technol 1988;20:81-7.

10. Bales RC, Gerba CP, Grondin GH, Jensen SL. Bacteriophage transport in sandy soil and fractured tuff. Appl Environ Microbiol 1989;55:2061-7.

11. Garabedian SP, LeBlanc DR. Large-scale natural gradient tracer test in sand and gravel, Cape Cod, Massachusetts. 2. Analysis of spatial moments for a nonreactive tracer. Water Resour Res 1991;27:911-24.

12. Johnson WP, Martin MJ, Gross MJ, Logan BE. Facilitation of bacterial transport through porous media by changes in solution and surface properties. Colloids Surfaces A. Physicochem Eng Aspects 1966;107:263-71.

13. McCaulou DR, Bales RC, McCarthy JF. Use of short-pulse experiments to study bacteria transport through porous media. J Contam Hydrol 1994;15:1-14.

14. McCaulou DR, Bales RC, Arnold RG. Effect of temperature-controlled motility on transport of bacteria and microspheres through saturated sediment. Water Resources Res 1995;31:271-80.

15. Kinoshita T, Bales RC, Maguire M, Gerba CP. Effect of pH on bacteriophage transport through sandy soils. J Contam Hydrol 1993;14:55-70.

16. Yao K, Habibian MT, O'Melia CR. Water and waste water filtration: concepts and applications. Environ Sci Technol 1971;5:1105-12.

17. Harvey, RW. Microorganisms as tracers in groundwater injection and recovery experiments: a review. FEMS Microbiol Rev. [In press]

18. Pieper AP, Ryan JN, Harvey RW, Amy GL, Illangasekare TH, Metge DW. Transport and recovery of bacteriophage PRD1 in a sand and gravel aquifer: effect of sewage-derived organic matter. Environ Sci Technol 1997;31:1163-70.

19. Smith MS, Thomas GW, White RE, Ritonga D. Transport of Escherichia coli through intact and disturbed soil columns . J Environ Qual 1985;14:87-91.

20. Harvey RW. Transport of bacteria in a contaminated aquifer. In: Mallard GE, Ragone SE, editors. US Geological Survey Water Resources Investigations Report 88-4220.

21. Harvey, RW. Parameters involved in modeling movement of bacteria in groundwater. In: Hurst C J, editor. Modeling the environmental fate of microorganisms. Washington, DC: American Society for Microbiology. 1991. p 89-114.

22. Sinclair JL, Ghiorse WC. Distribution of protozoa in subsurface sidements of a pristine groundwater study site in Oklahoma. Appl Environ Microbiol 1978;53:1157-63.



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