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First seen: Younger leaves
Signs:Leaves show wide band of yellow and smaller.
Natural Sources: Grass Clippings, sawdust, wood shavings.

Copper defiency in barley. Young leaves die off

Description: Copper is a soft malleable metal used for coins, plumbing, electrical wiring, cooking utensils, dishes, and ornamental jewelry. It has been used for over 2000 years, and was one of the first metals used by ancient civilizations.

Deficiency signs: Immobile so youngest leaves first show sign of deficiency. Growing leaf tips start to die.

Copper deficiency can show as a brown spotting on citrus
Toxicity: Copper toxicity is a common occurrence, and often appears after copper sulfate has been used as a pesticide. Copper toxicity is rapid and complete plant death.

Conditions: Copper is less available in alkaline soils, and in peat based soils and media. Keep nutrient water pH at 7.0 or less to keep copper available to plants.

Copper needs in plants

Copper is an essential mineral for both plants and animals, but can be deadly in higher doses. It is used by the plant in the formation of chlorophyll, and is used to transport fluids.

Copper deficiency in plants

Copper deficiency first appears on the youngest leaves, showing up as yellowing, then dying leaf tips. In some plants, yellow patches appear on stems just below leaf nodes and later the patches can bulge out and fill with fluid.

Copper deficient plants are pale from a lack of chlorophyll, and bear little or no fruit. Their growth including root growth is poor and leaves are mottled.

Cereal crops are particularly sensitive to copper deficiency (Gupta, 1979), and the copper must be supplied when the plant is young, or grain will not form (Stout, 1939). Grains are higher in copper content than stems or leaves of most plants.

Concentrations of copper in plants depend upon soil factors, plant species, stage of maturity, yield, crop management, climate and soil pH. Copper declines as plants mature and is lower in alkaline soils (McDowell, 1985).

Copper may affect the flavor of tomato, squash and cucumber and all are dwarfed and discolored when copper is deficient.

Natural copper in soils ranges from 5 to 5000 ppm (Mitchell, 1944), and soil deficiency translates to food deficiency.

Correcting copper deficiency in plants

Copper is often reduced in peat-based soils or media. Copper sulfate can be added to water and used as a foliar spray for plants. It is often sprayed with lime to ensure the copper remains on foliage. This spray is called Bordeaux mixture and it is a common spray for use in fungal infections, and can be toxic to the plant if too strong in copper.

Copper toxicity in plants

Excess copper in most plant systems leads to rapid death with actively growing areas of the plant dying first.

Since too much copper can be lethal, it is important to keep copper levels low throughout the systems. Copper toxicity can also occur through the use of copper vessels or a water delivery system, so copper plumbing or copper vessels should not be used in hydroponic systems.

Too much copper can be introduced to plants in Bordeau mixture to control pests, or the use of copper laden sewage sludges. Excess copper in most plant systems leads to rapid death with actively growing areas of the plant dying first. Copper of 0.5 ppm is an adequate supply for hydroponic systems.

Remedy for copper toxicity

In a small system, the nutrient water can be filtered with freshwater mussels to remove excess copper. The blue mussel can detoxify copper waters due to uptake of the metal (Brown 1972) and the fresh water pearl mussel, Margaterifera margaretafera can accumulate copper in its body (Chaisemartin, 1977).

Copper needs in humans

Copper is involved in building body tissues such as proteins that surround blood vessel walls and the myelin sheath around nerve fibers. It also is in enzymes important to energy metabolism. It is an anti-inflammatory and may affect taste perception (Faelten, 1981).

Copper is an essential part of an enzyme, lysyl ixidase, that weaves collagen and elastin, so reduced copper diet can lead to weak blood vessels and hemorrhaging.

Human daily needs for copper

The National Research Council recommends 2 mg/day, with average US intake from 2.5 to 5.0 mg/day. Only 5 to 10% of copper ingested is absorbed in stomach and upper intestine. Dietary phosphates and high levels of calcium, iron, zinc, chlorine or molybdenum reduce absorption of copper. Severe diarrhea can result from excess Molybdenum and deficient Copper, so a Cu:Mo ratio of 2.0:1.0 is critical with 4.0:1.0 a better ratio.

Deficiency in humans

Copper deficiency can lead to profuse diarrhea, a condition called "scours" in calves (Davis, 1946). Anemia can result from a copper deficiency due to the iron copper ratio in the body.

Excess cadmium (Hennig, 1974), cobalt (Marsten 1948 b,c), zinc (Havivi 1965) or molybdenum (Hennig 1974) can reduce available copper.

Iron deficiency can be caused by a lack of copper, necessary for iron absorption. Excess vitamin C can reduce available copper in diet. Copper helps body oxidize vitamin C and works with this vitamin in formation of elastin.

Copper deficiency has been noted in formulated diets such as baby formula (Tanaka, 1980), liquid protein diets (Klevay, 1979a) and cholesterol lowering diets of 1 mg copper per day (Klevay, 1978) and standard hospital diets of 3/4 mg Cu day (Klevay 1979b).

The amount of copper in the US diet has fallen since 1942 and this could be related to the rising coronary artery disease (Klevay, 1976) and atherosclerosis (Schroeder, 1974).

There is a direct link between the intake of copper, zinc, cadmium, chromium and the incidence of leukemia, cancer of the intestine, prostate, breast and skin, perhaps due to the anti-selenium effect (Schrauzer, 1977).

Remedy for copper deficiency

Copper can be added to drinking water 2 to 3 mg/liter to prevent deficiencies (Farmer et al, 1982). Supplying water may have problems (Smith and Moon, 1976).

Copper jewelry for joint pain

Copper bracelets have long been used to cure rheumatism (Whitehouse 1977). A bracelet around the wrist loses about 2 mg copper a day (Walker 1976a,b) and the Cu+ can pass through the skin so it can enter the body (Walker 1977)(Powy, 1977). If the copper bracelets have any medical value is still unknown. If a copper article is used it can leave black marks on skin. Also, copper jewelry should be actual copper, not copper plated.

Copper toxicity

Toxicity can reduce the stability of vitamins A and C and can reduce the ability of enzymes in the human body.

Wilson's disease is an inherited tendency to accumulate copper in the liver and brain. Copper sulfate has been used as a lethal poison with a dose of 7.5g resulting in death.

Copper poisoning can also occur due to the use of copper vessels for cooking or serving vessels. When foods containing vinegar are cooked in copper vessels toxicity may result (Galippe, 1877). Sauerkraut, apples, cider, beer, wines and vinegar also dissolve the metal. Tea in a copper kettle can be deadly (Nicholas, 1968).

The content in hot water is also increased through the passage of copper pipes (Pierarad, 1979). Food cooked in copper also loses its vitamin C (Hess, 1921, 1922). The copper content of the food rises as the food becomes more acidic or when the water temperature increases. Copper can also come from pollutants in the water supply. About 7.6 grams of copper sulfate is a lethal dose for human adults.

A copper vessel kills typhoid germs in one hour (Stewart, 1905).

Remedy for copper toxicity

Molybdenum and sulfur (together) treat copper toxicity, a process that can take 5 to 6 weeks.

Use of copper for illness

Copper salts have been used for over 2000 years in both Egyptian and Chinese cultures, for the treatment of illness (Owen 1981). Paracelsius in Greece used copper for tuberculosis, and it has been used in the treatment of cholera and typhoid.


Symptoms of Deficiency Symptoms of Toxicity Found in Recommended Daily Allowance RDA adults Maximum Therapeutic Repair
Anemia, weakness, hypothyroidism

Toxicity can reduce the stability of vitamins A and C and can reduce the ability of enyzmes

Brazil nuts, soy lecithin, almonds, margarine, cornmeal

2 mg

1 mg to 3 mg

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