[2] Unlike sulfate, selenate is a somewhat good oxidizer; it can be reduced to selenite or selenium.

[3] In strongly acidic conditions, the hydrogen selenate ion, HSeO−4, is formed.

[7] The level at which selenium becomes toxic varies from species to species and is related to other environmental factors like pH and alkalinity that influence the concentration of selenite over selenate.

[8] Selenate and other forms of selenium are highest in areas where ancient seas have evaporated.

These areas are enriched in selenium and over millennia, biologic adaptation has occurred.