Comparison of nonlinear least squares and log transformation procedures for calculating volatilization coefficients

A nonlinear least squares procedure and a log transformation procedure for calculating first-order rate coefficients from experimental concentration-versus-time data were compared using laboratory measurements of the volatilization from water of 1,1,1-trichloroethane and 1,2-dichloroethane and the absorption of oxygen by water. Ratios of the nonlinear least squares to log transformation volatilization and absorption coefficients for 77 tests ranged from 0.955 to 1.08 and averaged 1.01. Comparison of the maximum, minimum, and mean root-mean-square errors of prediction for six sets of coefficients showed that the errors for the nonlinear least squares procedure were almost always smaller than the errors for the log transformation procedure.