Digestive kinetics determines bioavailability of pollutants. Final report, 1 July 1993--30 September 1998
The bioavailability of sedimentary contaminants to animals in harbor sediments was addressed by studying the mechanisms by which animals solubilize contaminants during feeding and digestion. Digestive physiology work on many different animal species revealed patterns of enzymes, surfactants and dissolved organic matter that correlate with feeding mode, phyletic position, and diet. Incubation of digestive fluids to dissolve contaminants from polluted sediments was developed to provide numerical estimates of bioavailability, and showed that much higher fractions of total contaminant loading are available than predicted by currently established, aqueous equilibrium approaches. The kinetics of reactions are slow enough that variations in feeding rates will influence overall bioavailability. Experimental manipulations showed mechanisms of bioavailability. Dissolved amino acids, in the form of enzyme proteins and hydrolyzed food, are responsible for solubilization of metals such as copper. At high levels, copper can inactivate digestive enzymes. Metals in sedimentary sulfide minerals were largely impervious to digestive fluid attack. Surfactants are responsible for most solubilization of polycyclic aromatic hydrocarbons (PAH), though other agents also appear to play a role. Bioavailability of both metals and PAH can be limited by saturating the digestive agents responsible for their dissolution.
- Research Organization:
- Maine Univ., Orono, ME (United States)
- OSTI ID:
- 6479580
- Report Number(s):
- AD-A-362241/XAB; CNN: N00014-93-1-1210
- Country of Publication:
- United States
- Language:
- English
Similar Records
In vitro digestive fluid extraction as a measure of the bioavailability of sediment-associated polycyclic aromatic hydrocarbons: Sources of variation and implications for partitioning models
Digestive solubilization of sediment-associated pollutants: In vitro extraction vs. in vivo bioavailability
Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AQUATIC ORGANISMS
BIOLOGICAL AVAILABILITY
DIGESTION
METALS
POLYCYCLIC AROMATIC HYDROCARBONS
SEDIMENTS
WATER POLLUTION
AROMATICS
ELEMENTS
HYDROCARBONS
ORGANIC COMPOUNDS
POLLUTION
540320* - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)
560300 - Chemicals Metabolism & Toxicology