Zero. the exposure to air, salt or fresh water, etc would both kill HIV. In addition, the water would dilute it out as well. There has never been HIV transitted this way and if you had such an exposure, you will not be the first person to get HIV this way - it will not happen. There is no reason for concern or testing. EWH
If you are asking the same question about hepatitis c, the answer is no, no way. EWH