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Handbook of Plant Nutrition - chapter 10

10 Copper Copper is one of the oldest known metals and is the 25th most abundant element in the Earth’s crust. The words ‘aes Cyprium’ appeared in Roman writings describing copper, to denote that much of the metal at the time came from Cyprus. | CRC_DK2972_Ch010.qxd 7 14 2006 12 13 PM Page 29 1Q Copper David E. Kopsell University of Wisconsin-Platteville Platteville Wisconsin Dean A. Kopsell University of Tennessee Knoxville Tennessee CONTENTS 10.1 The Element Copper.293 10.1.1 Introduction.293 10.1.2 Copper Chemistry.294 10.2 Copper in Plants .294 10.2.1 Introduction.294 10.2.2 Uptake and Metabolism .294 10.2.3 Phytoremediation .313 10.3 Copper Deficiency in Plants.314 10.4 Copper Toxicity in Plants.315 10.5 Copper in the Soil.316 10.5.1 Introduction.316 10.5.2 Geological Distribution of Copper in Soils .317 10.5.3 Copper Availability in Soils .317 10.6 Copper in Human and Animal Nutrition.321 10.6.1 Introduction.321 10.6.2 Dietary Sources of Copper.321 10.6.3 Metabolism of Copper Forms.321 10.7 Copper and Human Health.322 10.7.1 Introduction.322 10.7.2 Copper Deficiency and Toxicity in Humans .322 References.323 10.1 THE ELEMENT COPPER 10.1.1 Introduction Copper is one of the oldest known metals and is the 25th most abundant element in the Earth s crust. The words aes Cyprium appeared in Roman writings describing copper to denote that much of the metal at the time came from Cyprus. Refinement of copper metal dates back to 5000 BC. The metal by itself is soft but when mixed with zinc produces brass and when mixed with tin produces bronze. Copper is malleable ductile and a good conductor of electricity. In its natural state it is a reddish solid with a bright metallic luster. 293 CRC_DK2972_Ch010.qxd 7 14 2006 12 13 PM Page 29 294 Handbook of Plant Nutrition 10.1.2 Copper Chemistry Copper has an atomic number 29 and atomic mass of 63.55. It belongs to Group I-B transition metals. The melting point of copper is 1084.6 C. Copper occurs naturally in the cuprous I Cu and cupric II Cu2 valence states. There is a single electron in the outer 4s orbital. The 3d10 orbital does not effectively shield this outer electron from the positive nuclear charge and therefore the 4s1 electron is difficult to remove from the