CONTENTS 



PAGE 



Part 1. — ExPEKiiiEXTAL Work 145 



Iiitioduction 145 



Solid wastes 146 



Soluble copper compounds 148 



Distribution of copper compounds throughout the Clifton-Morenci 



mining and Gila River irrigated district 150 



Sources of copper 150 



Processes by which copper is added to the water supply 151 



Table of solubilities of copper compounds 152 



Copper in ores and tailings from Clifton-Morenci district 155 



Dissolved copper in river, irrigating and ground waters below 



the Clifton-Moreuci district 15(5 



Copper in ores and tailings from Clifton-Morenci district 155 



Miscellaneous soils unaffected by mining detritus 159 



Copper in vegetation from upper Gila farms 159 



Copper in vegetation from other localities 160 



Copper in flesh and bones of a pig 161 



Distribution of copper in plants with root systems exposed to cop- 

 per compounds 162 



Corn plants grown in soils containing copper 162 



Water cultures 166 



Toxicity of copper solutions to plant roots in water culture 168 



Stimulation effects in water cultures 171 



Effects of soil upon toxicity of copper solutions 175 



Irrigation experiments 177 



Cultural experiments 181 



Pot cultures with treated soils 181 



Pot cultures with field soils 186 



Pot and plot cultures 188 



Field samples of soils and vegetation 189 



Use of copper sulphate to kill moss in irrigating ditches 192 



Physiological observations on toxic effects of coi)per salts 193 



Quantitative Avork 193 



Reactions of copper with growing points 199 



Varying resistance of individual cells to copper 203 



Diagnosis of copj^er injury 203 



Part II. — General Discussion 207 



Preliminary statement 207 



Accumulations of copper 207 



Possible effects upon health 209 



Amounts and significance of copper in aerial vegetation 210 



Amoxuits and significance of copper in root systems 212 



