A precautionary swim advisory has been issued Thursday for all Duval County beaches after possible contamination due to Hurricane Dorian, according to the Florida Department of Health's Duval County office. 

According to the advisory, there is not only a concern for dangerous surf conditions but also a concern for a possible elevation in the ocean's toxicity levels, due to possible stormwater drainage.

Ocean testing is expected to happen Thursday morning to determine the water quality at all public Duval County beaches. The results of that testing should be available within 24 hours, according to FDOH-Duval.

FDOH-Duval is advising residents of Duval County to avoid contact with and swimming in any ocean water until those results are released. 

They should also avoid contact with any floodwater from rivers, lakes and streams as it could contain fecal matter from sewage systems, agricultural and industrial waste or septic tanks. 

Test result information for saltwater beaches can be found here. For test result information for freshwater beaches, contact the Environmental Health Section of the FDOH-Duval where the freshwater beach is located for information.