[Zope] Zope process memory leak?

I have been watching my zope process carefully now for a few weeks and I have noticed that it seems to have a memory leak. It generally starts off at about 70Mb Ram and then grows up to about 240Mb over about 5 to 10 days. It then forks a new process and starts over again. This seems to have little effect on the usage and apart from the occasional restart of Zope goes unnoticed. I am just curious if this is normal behaviour of have I done something wrong? I am running Zope 2.3.2 on FreeBSD 4.0. My site is not heavily loaded. Daily averages are:- Hits:37582 Files:28587 Pages:13134 Visitors:964 TIA Tom