One think I can think of right now is having a cron job periodically run a command like
zpool status -x and check to see if it returns anything other than
all pools are healthy. If so, then it would fire off an email. (Unfortunately, I'm still learning things so I can't write the script myself, but I've been looking for someone who has.)
Another thought is have the status report get emailed emailed to you and have your email program look for key words like "checksum mismatch" because zpool errors will show up in those logs.
Unfortunately, I don't believe there is a built in Email Alerts for anything, which is a little surprising. I never looked for them before, but I kind of expected them there after setting up my ReadyNAS. Not only will it alert me of a drive failure/failing (increase in sectors being swapped out), but if a drive fails and my data is at risk, it will shutdown to protect the data.