File: ABSTRACT.TXT

                             FGETS
           Food and Gill Exchange of Toxic Substances
                         Version 3.0.18

                U.S. EPA Release, September 1994


         Center for Exposure Assessment Modeling (CEAM)
         U.S. Environmental Protection Agency (U.S. EPA)
            Office of Research and Development (ORD)
         Athens Environmental Research Laboratory (AERL)
                    960 College Station Road
                   Athens, Georgia  30605-2700

                          706/546-3549



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ABSTRACT

                             Summary

FGETS (Food and Gill Exchange of Toxic Substances) is a FORTRAN
simulation model that predicts temporal dynamics of a fish's
whole body concentration (ug chemical/(g live weight fish)) of
nonionic, nonmetabolized, organic chemicals that are
bioaccumulated from either: (a) water only - which is the
predominant route of exchange during acute exposures, or (b)
water and food jointly - which is more characteristic of chronic
exposures (1,2).  FGETS also calculates the time to reach the
chemical's lethal activity by assuming that the chemical elicits
its pharmacological response through a narcotic mode of action.

FGETS considers both the biological attributes of the fish and
the physico-chemical properties of the chemical that determine
diffusive exchange across gill membranes and intestinal mucosa. 
Important biological characteristics addressed by the model are
the fish's gill and intestinal morphometry, the body weight of
the fish, and the fractional aqueous, lipid, and structural
organic composition.  Relevant physico-chemical properties are
the chemical's aqueous diffusivity, molar volume, and the
n-octanol/water partition coefficient (logP), that is used as a
surrogate to quantify chemical partitioning to the fish's lipid
and structural organic fractions.  The chemical's logP is used in
calculating the fish's bioconcentration factor.  Its molecular
volume is used to estimate the chemical's aqueous diffusivity,
and its melting point is used in conjunction with logP to
calculate the chemical's activity within the fish.

FGETS is parameterized for a particular fish species by means of
two morphological/physiological databases that delineate the
fish's gill morphometry, feeding and metabolic demands, and body
composition.  Presently, joint water and food exposure is
parameterized for salmonids, centrarchids, cyprinids, percids,
and ictalurids.

                           References

1.  Barber, M.C., L.A. Suarez, and R.R. Lassiter. 1991.  Modeling
Bioaccumulation Organic Pollutants in Fish with an application to
PCBs in the Great Lakes salmonids. Can. J. Fish. Aquat. Sci., 48:
318-337.

2.  Barber, M.C., L.A. Suarez, and R.R. Lassiter. 1988.  Modeling
Bioconcentration of Nonpolar Organic Pollutants by Fish. Environ.
Toxicol. Chem., 7: 545-558.