I posted a note here, let's see if i can find test results. here photos, there was oil pipe cleaning sludge, along with biogenic oils. the chemical smell of oil was very strong <1 ft from the water surface.
Production waste is briny, and will sink!
keep in mind, after 20 minutes of exposure getting the samples out of this ditch, i was in minor respiratory distress from chemical exposure. i took the next day off to sleep it off. not for kids.