We investigated the degradation of 17beta-estradiol (E(2)), 17alpha-ethinylestradiol (EE(2)), bisphenol-A (BPA), and 4-n-nonylphenol (4-n-NP) in river water-sediment and groundwater-aquifer material under aerobic and anaerobic conditions. The results showed rapid degradation of all four compounds in both media with >90% of the four compounds degraded within the first 2 to 4 d under both conditions. However, degradation rates were extremely slow for the remaining period. Model derived 50% dissipation time (DT50) values in river water-sediment slurries ranged from 0.24 to 1.5 d (E(2)), 0.29 to 1.1 d (EE(2)), 1.2 to 1.4 d (BPA), and 0.42 d (4-n-NP), while the 90% dissipation time (DT90) values for the four endocrine-disrupting chemicals (EDCs) ranged from 0.9 to 2.8 d under both conditions. A minor difference was observed in DT50 and DT90 values for the four EDCs in groundwater- aquifer material under aerobic conditions as compared with river water-sediment. Under anaerobic conditions, DT90 values ranged from >1,000 d (EE(2)) to >300 d (BPA), in groundwater-aquifer material. Degradation of the four compounds under anaerobic conditions was attributed to the sulfate-, nitrate-, and iron-reducing conditions within the tested media; however, it was postulated that overall degradation of the compounds was also influenced by abiotic factors, accounting for nearly 6 to 40% (river water- sediment) and 0 to 18% (groundwater-aquifer material) under the two conditions tested.