Alot depends on where the system is located. down in Texas or in one of the dryer states its probably ok. Up where I live in Western New York, we get alot of rain and have cold wet ground conditions for half of the year. These systems work great in the summer but not so good in the fall, winter and spring.
Coliform bateria can travel hundreds of feet in grounbdwater and where there are coliforms there is a host of other nasty microbes. I have gone scuba diving in some of the lakes around here where there are no sewers. Typically there is a sludge blanket dozens of feet thick on the bottom.
Eating fish from water like that likely won't kill you in the short term, but I for one don't find it too appealing.
