RESPIRATION INHIBITION KINETIC-ANALYSIS

A protocol was developed for measuring the inhibitory effects of synthetic organic compounds on the biodegradation of naturally occurring (biogenic) organic matter. A tiered approach based on respirometry was employed. In the first tier, compounds were screened to determine if their effects were sufficiently inhibitory to warrant further testing. This was done at an inhibitor concentration of 1000 mg 1-1, or the solubility limit if lower, and at both high and low biogenic substrate concentrations. If a compound caused more than 50% inhibition in a screening test, the stability of its effect was determined next. Finally, compounds causing stable responses were subjected to the respiration inhibition kinetic analysis in which the Monod kinetic parameters describing the biodegradation of butyric acid were measured in the presence of several inhibitor concentrations by using a technique based on that of Cech et al. (Wat. Sci. Technol. 17 (2/3), 259-272, 1985), thereby allowing the effects of inhibitor concentration on biodegradation kinetics to be quantified. Examples of application of the protocol are given. © 1990.