Being a trace element essential for the health of plants, animals and humans, the distribution and concentration of copper in the environment is important. Typically there is 1 µg/l of copper in fresh water supplies. The optimal concentration in living organisms is around 1,000 µg/l and the metabolism normally adjusts the concentration to be within optimum range.
In the ground, copper is normally present in compounds that are not easily soluble in water. Only a limited percentage, normally less than 1%, is available in soluble form for bioavailability. This can be taken up by the roots of plants as required and is then recycled as leaves and wood decay, concentrating in the top 100mm or so of the soil. Additionally or alternatively, copper is replenished when organic manure is spread. Intensive farming without this recycling can lead to copper deficiency that has to be made up when fertiliser is applied.
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