Octylphenol and nonylphenol in surface water of Ráckevei-Soroksári Danube branch, Hungary.

Concentrations of 4-octylphenol (OP) and 4-nonylphenol (NP) in surface water samples were determined at 10 sites during eight samplings (October 2002 to April 2004) at Ráckevei-Soroksári Danube (RSD) branch, Hungary. OP levels in surface waters ranged from <0.0016 to 0.0907 microg L(-1), whereas NP concentrations varied from <0.008 to 0.428 microg L(-1). The highest concentrations were found at a specific site, which receives input from an industry. A seasonal trend with higher concentrations of OP and NP was observed in waters during the warmer months. Concentrations of OP and NP in surface water were compared with other reported concentrations around the world. The concentrations of NP in RSD were found to be below the reported toxic concentrations for marine and freshwater species.