What's the best way to dispose of human waste in coastal environments?

The absolute best way to dispose of human waste in costal environments is to pack the waste out using either a bag-type system or a reusable, washable toilet. Other options include using provided facilities – flush toilets, outhouses, privies, etc. – when available. If no other options are available consider using a cathole dug 6-8 inches deep at least 200 ft. from any water source.