Copper in rocks is likely to be more mobile under this type of condition, as opposed to alkaline
..... (-3, 0, +3 and +5) but in natural waters is mostly 
found in inorganic form as ... By contrast, arsenic is perhaps unique in being 
relatively mobile under reduced ... species will be more important at neutral and 
alkaline pH in the presence of ... Arsenic speciation (arsenite and arsenate) 
against pH.