Hydrolytic stability of chemicals—a comparison of EPA and OECD protocols and suggestions for a combined universal method

Comparison of the most recent EPA and OECD guidelines shows that there are small but significant differences in the protocols recommended for determining the rates of hydrolysis of industrial chemicals for environmental hazard assessment. The detailed conditions given in these guidelines, such as purity and concentration of active ingredient, co‐solvent, pH, buffer type and concentration, temperature, sampling times, and methods of analysis, have been examined in relation to their effects on the accuracy of the measured rates of hydrolysis. It is suggested that the two protocols could be made more similar while still obtaining results that will be sufficiently accurate for estimations of abiotic environmental persistence.