Nonylphenol and Nonylphenol Ethoxylates in Fish, Sediment, and Water from the Kalamazoo River, Michigan

A survey measuring concentrations of nonylphenol (NP) and its ethoxylates (NPEs) in fish was performed in the Kalamazoo River, Michigan, USA, in 1999. Of 183 fish ana- lyzed, 59% had no detectable NP or NPE. Detected concentra- tions were reported to range from 3.3 (limit of detection) to 29.1 ng NP/g wet weight. To further explore the means of exposure of NP and NPE in the fish, concentrations of NP and its mono-through tri-ethoxylates (NPE1-3) were measured in fish, sediment, and water collected near two wastewater treat- ment plants on the Kalamazoo River in 2000. Samples were analyzed using exhaustive steam distillation with concurrent liquid extraction. Nonylphenol ethoxycarboxylates (NPE1-3C) were also analyzed in water. Concentrations of NP and NPEs in fish were less than the method detection limits (MDLs) in all the samples except one fish, which contained 3.4 ng NP/g wet weight, just above the detection limit of 3.3 ng/g. Three of 36 sediments and 1 of 24 water samples contained detectable concentrations of NP or NPE1. NPE2, NPE3, and NPEC were not detected in water samples. Alkylphenol ethoxylates, particularly nonylphenol ethoxylates (NPEs), are widely used nonionic surfactants. NPEs are used as detergents, emulsifiers, wetting agents, and dispersing agents in household and industrial products and in agricultural applica- tions. These compounds enter wastewater treatment plants (WWTPs) through domestic and industrial discharges. Effi- cient biological wastewater treatment processes generally re- move approximately 95% of the NPEs (Naylor 1995). In the sewage treatment process, NPEs aerobically degrade to nonyl- phenol (NP), mono- and di-ethoxylates (NPE1-2) and ethoxy carboxylates (NPECs) (Figure 1). Some of the degradation products, such as NP, are more lipophilic and tend to sorb to organic surfaces. For instance, log 10 octanol-water partitioning coefficient (Kow) of NP is in the range of 4.2 to 4.5 (McLeese