Review of the Persistence of Nonylphenol and Nonylphenol Ethoxylates in Aquatic Environments

Abstract

Alkylphenol ethoxylates, in particular nonylphenol ethoxylates, are widely used nonionic surfactants that are discharged in high quantities to sewage treatment plants and directly to the environment in areas where there is no sewage or industrial waste treatment. This article reviews the treatability of nonylphenol ethoxylates and nonylphenol in sewage treatment plants and their persistence in aquatic environments. Nonylphenol ethoxylates can be biologically degraded in sewage treatment plants and in natural environments. Some of the degradation products, including nonylphenol, are more persistent than the parent surfactants and they are found in receiving waters of sewage treatment plants. Nonylphenol in particular is found at high concentrations in some sewage sludges that may be spread on agricultural lands. While some sewage treatment plants discharge significant amounts of nonylphenol ethoxylate degradation products in their final effluents and digested sludges compared to what enters the plant, others degrade nonylphenol ethoxylates more or less completely. The differences in treatment efficiency of such compounds and their degradation products among different sewage treatment plants have been attributed to the load of the surfactants in influent streams, plant design and operating conditions, and other factors such as temperature of treatment. The highest nonylphenol ethoxylate elimination rates were achieved in plants characterized by low sludge-loading rates and nitrifying conditions. In natural waters, it appears that parent nonylphenol ethoxylates are not persistent, but some degradation products may have moderate persistence, especially under anaerobic conditions. Recent results from mesocosm experiments indicate moderate persistence of nonylphenol in sediments, with half-lives of 28 to 104 days. Microbial acclimation to the chemicals is an important determinant of persistence vis-à-vis biodegradation. Sunlight photodegradation of such products is also likely important. Further research on the persistence in natural environments of the lower ethoxylate and carboxylate degradation products, as well as nonylphenol, is necessary. Based on the limited data available, nonylphenol and the lower ethoxylates and carboxylates are persistent in groundwater. They are also persistent in landfills under anaerobic conditions, but they do not appear to be persistent in soil under aerobic conditions. Recommendations are made for further research in order to more fully characterize the treatability of nonylphenol ethoxylates and their degradation products in sewage treatment plants and their persistence in the natural environment.

Synthesis and characterization of polyethoxylate surfactants derived from phenolic lipids

“…(vi) Isomerization of cardanol (4). Cardanol (5.3 g) was stirred and heated in diethylene glycol (2 mL) containing triethanolamine (1.31 g, 8.79 mmol) and potassium hydroxide (2.51 g, 44.8 mmol) at 180-190°C under nitrogen.…”

“…t-Nonylphenol ethoxylates have many industrial, commercial, institutional, and domestic uses since they are very efficient and cost-effective surfactants. The environmental occurrence of alkylphenols and their ethoxylates has been reviewed extensively (3,4), although only raw materials of petrochemical origin were discussed and no reference was made to phenolic materials derived from natural sources. However, a preliminary publication (5) described the use of cashew phenolic lipids for producing ethoxylates as well as their biodegradability.…”

Kinetics of the oxidation of endocrine disruptor nonylphenol by ferrate(VI)

“…Endocrine disruptors (EDs) are compounds that mimic natural hormones in the endocrine system thus causing adverse effects on human and wildlife (Maguire 1999). One of the examples of EDs is nonylphenol (NP), which has the capacity to bind human estrogen receptors, causing disruption in hormonal regulatory system (Ning et al 2007).…”

Pollution of NPEOs in four municipal sewage treatment plants in the north of China

“…Consequently, these small metabolites have been extensively detected in the environment. Moreover, these small metabolites were reported to be more toxic, easier to be bioaccumulated, and easier to be concentrated in the sediment [1][2][3][4][5][6][7][8]. More recent studies have revealed that some of these small metabolites, mainly NP and NP1EO, bear endocrine disrupting activity.…”