Humic substances reduce bioavailability and toxicity of contaminants
The role of humic substances in the aquatic environment on the availability and toxicity of organic and inorganic contaminants is reviewed. Organic contaminants associated with humics appear to be essentially unavailable for uptake by amphipods, daphnids, and fish. Acute toxicity of these compounds is also diminished proportionally. Since the affinity of organic solutes for binding to humics is related to their hydrophobicity, the effect of humics is significant only for compounds with octanol-water partition coefficients >10/sup 4/. In most cases, association of toxic metals with humics reduces the uptake and toxic effects of the contaminants. However, complex interactions among the toxicants, humic ligands, other transition metals and major cations in solution, and the carrier proteins on biological membranes make it difficult to generalize and predict any reduction in accumulation and toxicity of metals. Humic substances may have secondary effects on uptake and accumulation of toxicants by biota through their role in altering the transport and fate of pollutants.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6497530
- Report Number(s):
- CONF-870410-24; ON: DE87009816
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Terrestrial-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AQUATIC ECOSYSTEMS
BIOLOGICAL AVAILABILITY
CHEMICAL PROPERTIES
ECOSYSTEMS
ELEMENTS
HUMIC ACIDS
INORGANIC COMPOUNDS
MATERIALS
METALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
RESPONSE MODIFYING FACTORS
TOXIC MATERIALS
UPTAKE