Fig. 2. Degradation of linear alkylbenzene sulfonate (LAS) and nonylphenol (NP) in the top-15-cm soil layer in the lysimeters during the 110-d experimental period. Each point represents the average concentration of samples from three lysimeters and one duplicate measurement, and the error bars represent the standard deviation. Inserted in the top right corner are the first-order degradation curves for Days 10 to 110 with equations and correlation coefficients (r²): log([LAS]_t/[LAS]₀) = –0.01512 x t – 0.7060 (r² = 0.9239); log([NP]_t/[NP]₀) = –0.00812 x t – 0.3522 (r² = 0.9132).