HEXANE-FILLED DIALYSIS BAGS FOR MONITORING ORGANIC CONTAMINANTS IN WATER

Solvent-filled dialysis bags can (1) detect lipophilic compounds that may otherwise evade detection, (2) provide time-integrated monitoring, (3) serve as biological surrogates when tissue sampling is impractical, and (4) substantially reduce laboratory effort. Bags consisting of regenerated cellulose dialysis tubing (1000 MW cutoff), containing 40 mL of n-hexane, are placed in protective cages which, in turn, can be suspended in surface water or lowered into a well. Exposure to a spring that is contaminated with Arochlor 1248 revealed that, under fairly steady state conditions, uptake is linear over 32 days, resulting in a 100-fold concentration. Bags were perfectly intact, and the contents did not require cleanup prior to analysis, even after exposure for 30 days in a biofouled pond. Fugacity-based bioconcentration kinetics, interpreted with respect to Fickian diffusion, may explain how this system works.