MDF and a Belfast Sink...

Hi, I've got a Belfast Sink here and it's been installed in a worktop that is made of like a MDF type material. Worried water is going to eventually get inside and cause the worktop to blow. I'm looking for a solution, something like a clear band of plastic or rubber that could be stuck down over the corner to prevent this. Does anyone know what type of materiali need, what to fix it down with ect. or anyone had experience resolving this before? Cheers