The influence of humic acid on the biological effects of selected trace metals

Miscellaneous · Fri Jan 01 00:00:00 EST 1988

OSTI ID:7243149

Stackhouse, R A

The influence of humic acid (HA) on the biological effects of cadmium, hexavalent chromium, and two forms of trivalent chromium was assessed using common freshwater invertebrates. The acute toxicity was determined using Daphnia pulex, while D. magna was used in bioaccumulation studies. Final concentrations of HA tested were 0, 0.5, 5, and 50 mg/l. Humic acid was observed to significantly increase, decrease, or not influence both the acute toxicity and bioaccumulation of cadmium depending on HA concentration and time point examined. Additionally, dialysis studies were used to determine the influence of HA on the bioavailability of the metals. As with the biological effects, HA had little influence on the bioavailability of hexavalent chromium, while having a greater influence on cadmium and chromic chloride. There was a HA concentration dependent pattern of binding (a maximal decrease in percent free metal followed by metal release from HA) observed with cadmium and chromic chloride. This metal release from HA may have resulted from an associated time dependent decrease in pH of the surrounding water. Humic acid had little influence on the bioavailability of chrome lignosulfonate.

• Research Organization: Northeast Louisiana Univ., Monroe, LA (USA)
• OSTI ID: 7243149
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
CADMIUM
TOXICITY
CHROMIUM
HUMIC ACIDS
BIOLOGICAL EFFECTS
BIOLOGICAL ACCUMULATION
BIOLOGICAL AVAILABILITY
DAPHNIA
TIME DEPENDENCE
TRACE AMOUNTS
ANIMALS
AQUATIC ORGANISMS
ARTHROPODS
BRANCHIOPODS
CRUSTACEANS
ELEMENTS
INVERTEBRATES
METALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
TRANSITION ELEMENTS
560300* - Chemicals Metabolism & Toxicology