The research is clear here. Modern CCA treatments (the only one with arsenic) require preservatives to be applied first which prevent leaching of arsenic. There

The research is clear here. Modern CCA treatments (the only one with arsenic) require preservatives to be applied first which prevent leaching of arsenic. There has never been a study that I can find which shows a genuine risk of arsenic toxicity from eating from a treated garden bed where crops are planted at least a few cm from the edge of the bed. And if that's not enough, choose one of the many other treatment options, or line your bed with a proven-safe polythene liner, or use untreated timbers that are resistant to rot like cedar/macrocarpa. If you have any real research to show that any of these options are unsafe I would love to read it.