That piece of particle board being 2 in thick would probably be fine since you're only going a couple inches over the table that it's sitting on... It is the worse wood to get since it's basically sealed up saw duat. You're going to absolutely want to seal the particle board because if you get any water on it raw it's done.

More important question is, is that dining room table... Have a couple friends sit on the side of it to see if it can support that much water.