|CAS number||, , ,|
|Jmol-3D images||Image 1|
|Molar mass||220.35 g/mol|
|Appearance||Light yellow viscous liquid with phenolic smell |
|Melting point||−8 – 2 °C|
|Boiling point||293 to 297 °C|
|Solubility in water||6 mg/L (pH 7)|
|Main hazards||low level endrocrine disruptor|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
|(what is: / ?)|
Nonylphenol is a family of closely related organic compounds. This collection of compounds is a precursor to commercially important detergents, nonylphenol ethoxylates. These compounds and their degradation products have attracted attention as pervasive contaminants and endocrine disruptors in the environment.
Structure and basic properties
Nonylphenols fall into the general chemical category of alkylphenols. The structure of NPs may vary. The nonyl group can be attached to the phenol ring at various locations, usually the 4- and, to lesser extent, the 2-positions, and can be either branched or linear. A branched nonylphenol, 4-nonylphenol, is the most widely produced and marketed nonylphenol. The mixture of nonylphenol isomers is a pale yellow liquid, although the pure compounds are colorless. The nonylphenols are moderatley soluble in water  but soluble in alcohol.
Nonylphenol arises from the degradation of Nonylphenol ethoxylates in the environment. Nonylphenol ethoxylates fall into the general chemical category of alkylphenol ethoxylates (APEs). NPEs are a clear to light orange color liquid. Nonylphenol ethoxylates are nonionic in water, which means that they have no charge. Because of this property they are used as detergents, cleaners, emulsifiers, and a variety of other applications. They are amphipathic, meaning they are hydrophilic and hydrophobic, which allows them to surround non-polar substances like oil and grease, isolating them from water.
Nonylphenols are produced by acid-catalyzed alkylation of phenol with a mixture of nonenes. To make NPEs, manufacturers treat NP with ethylene oxide under basic conditions. Since its discovery in 1940, nonylphenol production has increased exponentially, and between 100 to 500 millions pounds of nonylphenol are produced annually, meeting the definition of High Production Volume Chemicals.
One organism, the velvet worm, produces nonylphenol as a component of its defensive slime. The nonylphenol coats the ejection channel of the slime, stopping it from sticking to the organism when it is secreted. It also prolongs the drying process long enough for the slime to reach its target.
Nonylphenol is used in manufacturing antioxidants, lubricating oil additives, and the production of NPEs. Nonylphenol exthoxylates have a variety of industrial and household uses including detergents, emulsifiers, wetting and dispersing agents, antistatic agents, demulsifiers and solubilisers. APEs are a component of some household detergents outside of Europe.
Another surfactant and APE nonoxynol, which was once used as intravaginal spermicide and condom lubricant, was found to metabolize into free nonylphenol when administered to lab animals. Nonoxynol-9 is also used as a surfactant in cleaning and cosmetic products.
Prevalence in the environment
Many products that contain nonylphenol and nonylphenol ethoxylates have "down-the-drain" applications, such as laundry detergents, so the contaminants are frequently introduced into the water supply. In sewage treatment plants, nonylphenol ethoxylate degrades into nonylphenol, which is found in river water and sediments as well as soil and groundwater. Nonylphenol photodegrades in sunlight, but its half-life in sediment is estimated to be more than 60 years. Although the concentration of nonylphenol in the environment is decreasing, it is still found at concentrations of 4.1 μg/L in river waters and 1 mg/kg in sediments.
The occurrence of nonylphenol in soil is not as well studied as its presence in aquatic environments. A major concern is that contaminated sewage sludge is frequently recycled onto agricultural land. The degradation of nonylphenol in soil depends on oxygen availability and other components in the soil. Mobility of nonylphenol in soil is low.
Health and environmental hazards
Nonylphenol is considered to be an endocrine disruptor due to its weak ability to mimic estrogen and in turn disrupt the natural balance of hormones in affected organisms. The effect is weak because nonylphenols are not very close structural mimics of estradiol, but the levels of nonylphenol can be sufficiently high to compensate.
The effects of nonylphenol in the environment are the feminization of aquatic organisms, decreased male fertility, and decreased survival in young fish. Nonylphenol can cause endocrine disruption in fish by interacting with estrogen receptors and androgen receptors. In the liver NP can disrupt steriodogenesis and can interfere with the level of FSH (follicle-stimulating hormone) released from the pituitary. Concentrations of NP that inhibit reproductive development and function in fish also damaged kidneys, decreased body weight, and induced a stressed behavior.
Alkylphenols like nonylphenol and bisphenol-A have estrogenic effects in the body. They are known as xenoestrogens. Estrogenic substances and other endocrine disruptors are compounds that have hormone-like effects in both wildlife and humans. Xenoestrogens usually function by binding to estrogen receptors and acting competitively against natural estrogens. Nonylphenol has been shown to mimic the natural hormone 17β-oestradiol, and it competes with the endogeous hormone for binding with the oestrogen receptor. Alkylphenols like nonylphenol and related compounds are found in pesticides and industrial chemicals. Nonylphenol was discovered to have hormone-like effects by accident because it contaminated other experiments in laboratories that were studying natural estrogens that were using polystyrene tubes. The detergent nonylphenol ethoxylate is harmful when it degrades into nonylphenol in sewage treatment plants. Unfortunately, there exist limited articles on the endocrine activity of nonylphenol in comparison to BPA. One study conducted in Italian women showed that nonylphenol was one of the highest contaminants at a concentration of 32 ng/mL in breast milk when compared to other alkylphenols octylphenol, nonylphenol monoethoxylate, and two octylphenol ethoxylates. The study found a positive correlation between fish consumption and the concentration of NP in breast milk. This is a large problem because breast milk is the main source of nourishment for newborns, who are in early stages of development where hormones are very influential. Elevated levels of endocrine disruptors in breast milk have been associated with negative affects on neurological development, growth and memory function.
Nonylphenol also induces proliferation of breast tumor cells.
Diet seems the most significant source of exposure of NPs to humans. For example, food samples were found with concentrations ranging from 0.1 to 19.4 µg/kg in a diet survey in Germany. In Taiwan NP concentrations in food ranged from 5.8 to 235.8 µg/kg. Seafood in particular was found to have a high concentration of NP.
Drinking water does not represent a significant source of exposure in comparison to other sources such as food packing materials, cleaning products, and various skin care products. Concentrations of nonylphenol in treated drinking water varied from 85 ng/L in Spain to 15 ng/L in Germany.
The production and use of nonylphenol and nonyphenol ethoxylates is prohibited in the European Union due to its effects on health and the environment. In Europe, due to environmental concerns, they also have been replaced by more expensive alcohol ethoxylates, which are less problematic for the environment due to their ability to degrade more quickly than nonylphenols.
The European Union has included NP on the list of priority hazardous substances for surface water in the Water Framework Directive. They are now implementing a drastic reduction policy of NP's in surface waterways. The Environmental quality standard for NP was proposed to be 0.3 ug/l. In the USA, the EPA set criteria that recommended the NP concentration should not exceed 6.6 ug/l in fresh water and 1.7 ug/l in saltwater. In other Asian and South American countries there is still a large amount of APE's and little regulation. In Europe, due to environmental concerns, NPEs have been replaced by more expensive alcohol ethoxylates, which are less problematic environmentally.
- Record of Nonylphenol, mixed isomers in the GESTIS Substance Database from the IFA, accessed on 6 April 2011
- Sonnenschein, Carlos, and Ana M. Soto. "An Updated Review of Environmental Estrogen and Androgen Mimics and Antagonists." The Journal of Steroid Biochemistry and Molecular Biology 65.1-6 (1998): 143-50.
- EPA. 2010. Nonylphenol (NP) and Nonylphenal Ethoxylates (NPEs) Action Plan. February, 2014.
- Soares, A., B. Guieysse, B. Jefferson, E. Cartmell, and J.n. Lester. "Nonylphenol in the Environment: A Critical Review on Occurrence, Fate, Toxicity and Treatment in Wastewaters." Environment International 34.7 (2008): 1033-049.
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- "Review article: Nonylphenol in the environment: A critical review on occurrence, fate, toxicity and treatment in wastewaters" A. Soares, B. Guieysse, B. Jefferson, E. Cartmell, J.N. Lester Environment International 2008, Volume 34, Pages 1033-1049. doi:10.1016/j.envint.2008.01.004 PMID 18282600
- Minnesota Pollution Control Agency Statewide Endocrine Disrupting Compound Monitoring Study, 2007 - 2008
- Nonylphenol, Environmental Working Group
- Katherine E. Liney, Josephine A. Hagger, Charles R. Tyler, Michael H. Depledge, Tamara S. Galloway, Susan Jobling. "Health Effects in Fish of Long-Term Exposure to Effluents from Wastewater Treatment Works." Environ Health Perspect. 2006 April; 114(Suppl 1): 81–89. Published online 2005 October 21. doi: 10.1289/ehp.8058
- Asimakopoulos, Alexandros G., Nikolaos S. Thomaidis, and Michael A. Koupparis. "Recent Trends in Biomonitoring of Bisphenol A, 4-t-octylphenol, and 4-nonylphenol." Toxicology Letters 210.2 (2012): 141-54. Web.
- Ademollo et al., 2008 N. Ademollo, F. Ferrara, M. Delise, F. Fabietti, E. Funari Nonylphenol and octylphenol in human breast milk. Environ. Int., 34 (2008), pp. 984–987
- Official Journal of the European Union: DIRECTIVE 2003/53/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 18 June 2003 amending for the 26th time Council Directive 76/769/EEC relating to restrictions on the marketing and use of certain dangerous substances and preparations (nonylphenol, nonylphenol ethoxylate and cement), July 17, 2003
- A. David, H. Fenet, E. Gomez "Alkylphenols in marine environments: distribution monitoring strategies and detection considerations". Mar. Pollut. Bull., 58 (2009), pp. 953–960