The effects of acidification on arsenic concentration and speciation in offshore shallow water system

The effects of acidification on speciation and transportation of arsenic in shallow seawater system were investigated based on data from acidification simulation experiments in lab scale tanks, in which enhanced levels of pCO₂ corresponding to pH_T were processed. The results showed that: (1) the concentration of DIAs (Dissolved inorganic arsenic), As⁵⁺ and As³⁺ in the overlying water increased with experimental CO₂ enrichment; (2) while the ratio of As⁵⁺/As³⁺ decreased; (3) acidification could cause more DIAs transport into the overlying water from sediments or suspended particulate matters, and would be favorable to the existence of As³⁺. Thus, DIAs is available to microorganisms and can be taken in effectively by microorganisms in the shallow water system, resulting in toxic effects of As on microorganisms and thus the inhibition of the growth of microorganisms.