got another evil question for ya
There are two lakes, A and B, into which industrial wastes containing

massive amounts of biodegradable hydrocarbons and arsenic pesticides

were previously discharged.
Arsenic is present in its oxidized form, arsenate,
which has a high affinity to surfaces of particulate matter and so it normally

precipitates in sediments.
Before the lakes are stratified during the summer
and hence their bottom zone becomes anoxic, they have almost identical

water chemistry except that in Lake A, sulfate is measured at mM

concentrations while nitrate is undetectable, and in Lake B nitrate is detected

at mM concentrations but sulfate is below detection. Based on the

perspective of microbial bioenergetics, in which lake would you expect an

arsenic contamination problem when soluble arsenic accumulates in the

water column over the summer?
Please explain your answer.