Environmental conditions affecting re‐release from particulate matter of 4‐Nonylphenol into an aqueous medium.

4‐nonylphenol is a persistent organic pollutant with endocrine‐disrupting properties. A nonpolar product of microbial degradation derived from the surfactant nonylphenol polyethoxylate, 4‐nonylphenol is capable of long‐range transport attached to particulates. Bioactive concentrations of 4‐nonylphenol have been found in the surface water, soils, snow, and particulate matter of the Eastern Sierra Nevada Mountains (USA) hundreds of miles from their origins. As a result of particulate deposition, seasonal and glacial snow pack concentrations measured 20 to 100 times higher than in surface waters. Batch desorption assays were run on particulate matter dosed with 4‐nonylphenol. Desorption was measured in 63 to 500 μm particles under 2 different temperature conditions with varying fractions of organic carbon in turbulent or undisturbed states. Lower temperatures (4 °C) decreased the mean percentage of 4‐nonylphenol released from particulates in disturbed and undisturbed conditions, whereas the mean percentage of 4‐nonylphenol released at 20 °C was reduced by agitation. The effect of agitation at 4 °C was not practically or statistically significant. Particulates with a higher percentage of organic carbon (75%) released very little of the bound 4‐nonylphenol (0.53%) compared with particulates containing 4 to 5% of organic carbon that released up to 13%. Larger particles released the least amount of 4‐nonylphenol, whereas smaller particles released the most amount. Water and sediment samples taken from below the Palisades Glacier in the Sierra Nevada Mountains showed the greatest 4‐nonylphenol concentrations directly below the glacier, implying that glacial particulates will release adsorbed 4‐nonylphenol. Environ Toxicol Chem 2019;38:350–360. © 2018 SETAC [ABSTRACT FROM AUTHOR]