Estuarine sediment controls on trace metal distributions

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1982

OSTI ID:5369800

Davies-Colley, R J

The sedimentary partitioning of copper and cadmium was studied with the goal of predicting the environmental fate of these metals in estuaries. Five solid phases: synthetic hydrous oxides of iron and manganese, montmorillonite clay, a synthetic aluminosilicate gel, and estuarine humic substances (EHS) extracted from a natural sediment were chosen to simulate components responsible for trace metal binding in oxidized sediments. The uptake of copper and cadmium by these model phases in artificial seawater was measured as a function of pH and salinity. Affinity of the model phases for cadmium as measured by K/sub p/, the slope of the linear adsorption isotherm, was in the following order: manganese > iron > EHS > aluminosilicates > montmorillonite. Copper binding affinities were much higher than those of cadmium but the relative order of affinity of the phases was similar except for copper binding by EHS for which K/sub p/ was relatively higher (exceeding that of iron). The measured K/sub p/ values were used to calibrate a simple model for predicting partitioning and total metal uptake by sediments. This model predicts that cadmium uptake by estuarine sediments is dominated by iron while both iron and organics are important for copper. In anaerobic sediments thermodynamic calculations suggest that copper and cadmium concentrations are determined by equilibria involving solid sulphides and bisulphide and polysulphide complexes. The results of this investigation will aid in assessing the environmental significance of metal-contaminated estuaries.

• OSTI ID: 5369800
• Country of Publication: United States
• Language: English

Related Subjects

520200* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ALUMINIUM COMPOUNDS
ALUMINIUM SILICATES
ANAEROBIC CONDITIONS
BINDING ENERGY
CADMIUM
CHALCOGENIDES
CLAYS
COMPLEXES
CONTAMINATION
COPPER
ELEMENTS
ENERGY
ESTUARIES
HUMUS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
IRON COMPOUNDS
IRON OXIDES
MANGANESE COMPOUNDS
MANGANESE OXIDES
MATERIALS
METALS
MONTMORILLONITE
OXIDES
OXYGEN COMPOUNDS
POLLUTION
SEDIMENTS
SILICATES
SILICON COMPOUNDS
SULFIDES
SULFUR COMPOUNDS
SURFACE WATERS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
UPTAKE
WATER POLLUTION