I have a slightly older computer, and so far I have been running Brink okay on the minimum settings, but I noticed there is no way to turn shadows completely off.

Is there a workaround to lower the graphics settings further than what is allowed in-game? It seems like even under the advanced settings there isn't much to be done.

This should help you out:

http://www.gamesas.com/index.php?/topic/1187924-ati-fps-fix/