Occurrence, human intake and biodegradation of estrogen-like nonylphenols and octylphenols

Background: Long-chain alkylphenols, such as nonylphenols and octylphenols, are man-made compounds with estrogen-like activity and considered to be endocrine disputing chemicals. They are known to influence sexual development and reproduction of humans and other animals, therefore cause health and ecological concerns. Objective: This review aims to identify the key findings presented in recent scientific literature with respect to the presence of long-chain alkylphenols in food, intake by different populations and describe the metabolism by human and the mechanisms to disrupt the estrogenic activity of nonylphenols and octylphenols by bacteria and fungi in the environment. Method: The current knowledge related to the physicochemical properties, source, occurrence, toxic effects, level in foods, human intake, elimination and metabolism of long-chain alkylphenols was summarized. Results: Long-chain alkylphenols have been detected in soil, surface and ground water, sediments, wastewater effluent, air and in most foods. The daily human intake of 4-nonylphenols and 4-octylphenols has been compared among different population. A comprehensive summary of the major degradation pathways and mechanism in bacteria, fungi, yeasts and vertebrates was described. Conclusion: The findings of this review revealed the wide distribution of long-chain alkylphenols in various environments and contamination in foods. Therefore, further investigation of long-term exposure is necessary to comprehensively evaluate the potential health risks to humans. The diverse biodegradation mechanisms can be used in the removal of these compounds before entering food chains. The review provides indication as to how it might be possible to reduce the adverse effects on human health from estrogen-like long-chain alkylphenols.