At several of the public coastal beaches in my city, water lapping at the shore or sitting around at low tide occasionally has a foamy border. Many of these beaches are at or near industrial sites (some active, some not). I'm wondering:
What kinds of tools or tests could be used to see whether the foam is naturally-occurring sea foam vs. pollution?
What specific things would I be looking for to distinguish the two?
The city has accessible channels for reporting pollution, so I'd be able to share info with them if the foam turns out to be questionable.
Thank you for any thoughts, ideas, or additional questions!