The profile of contamination with alkylphenol ethoxylates of some Israeli watercourse rivers and their sediment layers

The ‘hard’ non-biodegradable alkylphenol ethoxylates (APEOs) nonionic surfactants are environmentally persistent and widely used worldwide. The aim of this work is to determine the total concentration and the homological distribution in rivers and there sediments, in central Israel. The concentrations of APEOs in the water of these rivers and in their sediments were found to be 11.83–55.32 μg/L, and 99.68–1,176.61 μg/kg, respectively. The APEOs' concentration level decreases as the sample is taken from a deeper layer of the sediment. A possible explanation for this is that in APEOs molecules, the hydrophilic fraction (CH2-CH2-O) increases the APEOs' absorption into sediment layers close to water, being saturated with water. In addition, the organic biofilm in the sediment layers used as schmutzdecke can reduce the concentration levels of APEOs that penetrates the deep layers of the sediment. The dominant homologues of APEOs in the river watercourse were those with 9–15 units of ethylene oxide (EO). Homologues with 1–12 units of ethylene oxide were found to be the dominant ones in the sediment layers of Hadera and Alexander rivers.