Copper in Water

Copper in Water

Copper ionized from salts occurs in natural waters only in trace amounts up to 0.05 mg/L. Higher concentrations would indicate a source pollution.

The chloride, nitrate and sulfate of divalent copper are highly soluble in water, but the carbonate, hydroxide, oxide and sulfide are not. Therefore, cupric ions introduced into natural waters at a pH of 7 or above will quickly precipitate as the hydroxide or as basic copper carbonate.

As a result, copper ions are not likely to be found in natural waters or in ground water. Copper is found in traces in all plant and animal life and is essential for nutrition. The physiological function of copper is involved in the metabolism of iron for the utilization of iron by blood forming organs.

The toxicity of copper to aquatic organisms varies significantly. Not only with different species, but also with the physical and chemical characteristics of the water such as its temperature, hardness, turbidity and carbon dioxide content.

In hard water, the toxicity of copper salts is reduced by precipitation of copper carbonate or other insoluble compounds. Copper concentrations as low as 0.1 to .5 mg/L have been reported toxic to bacteria and other microorganisms.

Copper has a tendency to act synergistically with several other elements or compounds. For instance, copper acts synergistically with chlorine together to increase the toxicity to fish. The sulfates of copper and zinc and of copper and cadmium are synergistic also in their toxic effect on fish.

Synergism has been noted between copper and mercury and between copper and chloro-organic compounds. Experiments with rainbow trout in soft and hard waters showed synergism at higher concentrations in soft water although the threshold concentrations for the mixture of copper and zinc was about the same that would be expected on the assumption that there was no synergism.

In hard water, no synergism between copper and zinc was evident.
Lead is found in some natural waters in solution as much as 0.4 to 0.8 mg/L where mountain limestone and galena are found.

Each of the heavy metals is discussed briefly.
Lead in Water
Nickel in Water
Zinc in Water

Next Topics…
Non-Metals in Water

Chemical Water Quality Parameters
Pesticides in Water
Oil in Water

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