Nonylphenol polyethoxylates (NPEO) are a group of non-ionic surfactants commonly used in industrial and consumer products. Previous research suggested that nonylphenol (NP), a degradation product of NPEO, can act as an estrogen-mimicking compound causing hermaphroditic tendencies in aquatic organisms. A study was carried out to evaluate the amount of NP bioaccumulated in the bay scallop (A. irradians) tissue under both static aqueous conditions and spiked sediment samples. This is an abstract of a paper presented at the 227th ACS National Meeting (Anaheim, CA 3/28/2004-4/1/2004)