4.5. Ammonia release during dredging activities
Guidance is frequently requested on the impacts of ammonia release during dredging of contaminated sediments, including both the dredging operation and the ocean disposal of the spoil. In a detailed examination of porewater ammonia release during a dredging
and dumping operation at a Queensland harbour site, sampling at the dumpsite after the dumping operation found that concentrations in the pore water of the dumped sediments had declined from 30–40 mg/L total NH3–N/L in samples from the barge prior to dumping, to 22 lg/L within 10 min of disposal and