Authorities are working to find the source of a potentially dangerous chemical found in the blood of firefighters at an Adelaide station.

Testing is underway at an Adelaide fire station after staff were found to have concerning blood levels of a chemical used in firefighting foam.

The Metropolitan Fire Service recently conducted more than 200 tests on past and present staff, with nine firefighters at the Largs North station returning concerning samples.

The MFS will conduct further testing at the Largs North station on Tuesday to determine the possible cause of the PFAS chemical exposure, which could be from food produced in a vegetable garden on the site.

The PFAS chemicals have been linked to cancer in studies overseas and have been the subject of a recent inquiry into their use on air force bases in Australia.

The MFS says samples will be taken at the site by contracted specialists working with the brigade's scientific officer.

The investigation comes as the Department of Defence released details of PFAS contamination at the RAAF base at Edinburgh in Adelaide's north.

It said in samples taken on-base, PFAS had been detected in soil, surface water and shallow groundwater at "above the human health guidance values", with stormwater and shallow groundwater identified as pathways for PFAS movement off the base.

In samples taken off-base, PFAS concentrations above the human health guidance values were limited to shallow groundwater and fish and yabbies within a local wetland.

The results from samples taken at private properties were below human health guidance values.