"We also found metals in the exhaust." (Ulrike Lohmann)
"We detected 16 different metals." (Ulrike Lohmann)
"Besides others we also found aluminum and barium.They come from the kerosene, from engine lubricant oil. And aluminum can also come from the turbines." (Ulrike Lohmann)
"Jet fuel contains aluminum and barium." (Ulrike Lohmann)
Motoröl lubricant oil
Measurements in parts per millions (Ulrike Lohmann): ElementxxxxxxxxxxxxxMobile Jet A-1 FuelxxxxMobile Jet II Oil Calciumxxxxxxxxxxxxx113,5xxxxxxxxxxxxxxxxxx30,82 Vanadiumxxxxxxxxxxxxxx3,59xxxxxxxxxxxxxxxxxx1,82 Aluminiumxxxxxxxxxxxxx3,08xxxxxxxxxxxxxxxxxx4,35 Leadxxxxxxxxxxxxxxxxxx1,98xxxxxxxxxxxxxxxxx>0,1 Ironxxxxxxxxxxxxxxxxxx1,69xxxxxxxxxxxxxxxxxx1,77 Magnesiumxxxxxxxxxxxxx1,46xxxxxxxxxxxxxxxxxx2,25 Titaniumxxxxxxxxxxxxxx1,45xxxxxxxxxxxxxxxxxx6,01 Sodiumxxxxxxxxxxxxxxxx1,05xxxxxxxxxxxxxxxxxx1,28 Copperxxxxxxxxxxxxxxxx0,96xxxxxxxxxxxxxxxxx(...) Antimoniumxxxxxxxxxxx>0,1xxxxxxxxxxxxxxxxxxx1,15 Chromiumxxxxxxxxxxxxx(...)xxxxxxxxxxxxxxxxxx1,09
Summing up: According to Ulrike Lohmann there are three sources of aluminum, barium and other metals for in context of usual airplane operations: 1. Kerosene; 2. Engine lubricant oil; 3. Normal wear of the turbines.
"It's in any case urgent to regulate aircraft engines exhaust." (Prof. Dr. Ulrike Lohmann, ETH Zürich, Switzerland)