Yes, the pond is not very large and the soil in the area is I believe highly acidic (pine needles, etc.) and red in color. So, the pond's not exactly a swimming hotspot though I've seen people fishing in it before. It's not inhospitable, but if you want to swim you'll want to visit the park's swimming pool, which is open during the summer.
Check out Turn Key's 2003 trip report for Bastrop for more info:
Bastrop SP, Texas 12/03