The pre- or post-amendment microbial ecology of a contaminated aquifer is better represented by in situ biofilms than planktonic organisms in sampled groundwater. By conventional means subsurface biofilm sampling requires coring of aquifer sediments and extraction of viable microorganisms or biomarkers (lipids, DNA, etc.). However, the efficiency of these extractions varies with the geochemistry of the sediments. We propose that biofilms characteristic of aquifer conditions can be rapidly and efficiently collected using a biofilm sampling system or "bug trap" based on Bio-Sep® technology. Bio-Sep® consists of 3-4 mm diameter spherical beads engineered from a composite of 25% aramid polymer (Nomex) and 75% powdered activated carbon (PAC) with a porosity of 75%. The median pore diameter is 1.9 microns, however, large macropores (> 20 microns) also exist inside the beads. Beads are surrounded by an ultrafiltration-like membrane with pores of 1-10 microns and the internal surface area is greater than 600 m²/g. Bio-Sep® beads may be heated to 300 ^oC for sterilization and to render the beads free of fossil biomarkers. Potential remediation amendments may be incorporated into the Bio-Sep® beads during fabrication by entrapment or post-fabrication by adsorption onto the PAC component of the beads. The availability of these nutrients inside the bead would be expected to alter the community structure of biofilms formed in the bead. We propose that incubation of "baited" and non-baited beads or bug traps in groundwater monitoring wells in contaminated aquifers will allow rapid and efficient prediction of the effects of amendments on in situ microbial ecology at significantly lower costs than field injections of the amendments. This poster discusses the slow release properties of Bio-Sep® beads baited with potential remediation amendments and provides examples of their use in evaluating amendments for groundwater remediation.