Do you have Akismet plugin installed on your WordPress site? if not, I would add this plugin. This plugin helps removes spam. Also, you will have to delete the comments that you feel do not make sense that is, comments that do not help your niche, just delete them. The ones that do, you can approve. I had the same issue with one of my sites.

As the others say, Alismet (it will want to charge you, but slide the slider to zero!) also it is still worth checking your spam comments from time to time, to see if there are any good ones sent there by accident. Then delete them all as spam comments in your spam folder still take up space in your database

yeah you want to activate Akismet. I made the same mistake on my very first wordpress site and if you do not address it soon it will get worse. I ended up getting hundreds of spam comments a day sent from automated blog comment software. When I finally figured out what Akismet was for I still had to spend hours trashing each comment - a mistake I will not make again lol.

Hi Helen. I'm a noob so probably not much help, but have you got the Akismet plugin? Also, have you considered moderating comments before they're posted? Just a couple of thoughts!