Analysis of Total Aluminum and Dissolved Aluminum Louis McDonald and Jeff Skousen Plant & Soil Sciences West Virginia University

Aluminum The GoodThe BadThe Ugly ? 2

Where is the Aluminum? 3

Al 3+ Aluminum – “Free” Ion 4

Al 3+ Complexes Aluminum Complexes Inorganic e.g. fluoride, hydroxide, sulfate, carbonate Organic Al 3+ O 5

Complexes Aluminum Complexes InorganicOrganic Small e.g. acetic, citric hydroxide 6

Al 3+ Complexes Aluminum Complexes InorganicOrganic SmallLarge e.g. acetic, citrice.g. humic acid, fulvic acid hydroxide 7

Al 3+ Complexes Inorganic Organic Small Large Where is the Aluminum? OH - 8

Aluminum Particles By Composition Aluminum hydroxides and oxides Gibbsite (Al(OH) 3 ) Aluminosilicates PhyllosilicatesKaolinite (Si 2 Al 5 (OH)4) Feldspar (KAlSi 3 O 8 ) Kaolinite Al 2 Si 2 O 5 (OH) 4 9

Aluminum Particles By Size LargeMediumSmallV. Small SandsSiltsClaysVery fine clays Colloids – Al on surface does matter 10

Colloids Al 3 + Ca 2+, Mg 2+, K +, etc. 11

Al 3+ Complexes Inorganic Organic Small Large Particles V. Small Small Medium Large Very Small Very Large OH - 12

Al 3+ Complexes Inorganic Organic Small Large Particles Definitely DissolvedDefinitely Solid V. Small Small Medium Large Very Small Very Large OH - 13

Al 3+ Complexes Inorganic Organic Small Large Particles Definitely DissolvedDefinitely Solid V. Small Small Medium Large Very Small Very Large Filter Size Operationally Dissolved OH - 14

The Curious Case of Hydroxide 15 Total Dissolved AlAl 3+ Al(OH) 4 -

16 The Curious Case of Hydroxide

Al 3 Al 1 Al 13 From Casey et al

Al 3+ Complexes Inorganic Organic Small Large Particles Definitely DissolvedDefinitely Solid V. Small Small Medium Large Very Small Very Large Filter Size Operationally Dissolved OH - Polynuclear Al 18

Where is the Aluminum? 19

Al 3+ Complexes Inorganic Organic Small Large Particles Definitely DissolvedDefinitely Solid V. Small Small Medium Large Very Small Very Large Filter Size Operationally Dissolved 20

Al 3+ Complexes Inorganic Organic Small Large Particles Definitely DissolvedDefinitely Solid V. Small Small Medium Large Very Small Very Large Filter Size Operationally Dissolved Why filter? PROPERLY! 21

Al 3+ Complexes Inorganic Organic Small Large Particles Definitely DissolvedDefinitely Solid V. Small Small Medium Large Very Small Very Large Filter Size Operationally Dissolved What do instruments measure? 22

Acidifying Samples + Acid, H + Al 3+ Al – Complexes Al in Solids Al on Surfaces Al 3+ H – Complexes Al in Solids H on Surfaces Dissolved Al Dissolved Al 23

Al 3+ Complexes Inorganic Organic Small Large Particles Definitely DissolvedDefinitely Solid V. Small Small Medium Large Very Small Very Large Filter Size Operationally Dissolved Why might hardness matter? 24

Al 3+ Complexes Inorganic Organic Small Large Particles Definitely DissolvedDefinitely Solid V. Small Small Medium Large Very Small Very Large Filter Size Operationally Dissolved What is toxic? 25

Al 3+ Complexes Inorganic Organic Small Large Particles Definitely DissolvedDefinitely Solid V. Small Small Medium Large Very Small Very Large Filter Size Operationally Dissolved What is toxic? Ingestion or Inhalation 26

Al 3+ Complexes Inorganic Organic Small Large Particles Definitely DissolvedDefinitely Solid V. Small Small Medium Large Very Small Very Large Filter Size Operationally Dissolved What is toxic? Plants, algae 27

Al 3+ Complexes Inorganic Organic Small Large Particles Definitely DissolvedDefinitely Solid V. Small Small Medium Large Very Small Very Large Filter Size Operationally Dissolved What is toxic? Fish acute 28

Al 3+ Complexes Inorganic Organic Small Large Particles Definitely DissolvedDefinitely Solid V. Small Small Medium Large Very Small Very Large Filter Size Operationally Dissolved What is toxic? Fish chronic? 29

Al 3+ Complexes Inorganic Organic Small Large Particles Definitely DissolvedDefinitely Solid V. Small Small Medium Large Very Small Very Large Filter Size Operationally Dissolved What is Total Al? What is dissolved Al? 30

Al 3+ Complexes Inorganic Organic Small Large Particles Definitely DissolvedDefinitely Solid V. Small Small Medium Large Very Small Very Large Filter Size Operationally Dissolved Questions? 31