The main factor which may influence BPA, OP and NP concentrations in phytoplankton of the Gulf of Gdansk are anthropogenic sources of these compounds. BPA production in the EU is about 16 times higher than alkylphenol production (ICIS Chemical Business, 2008), which translates to higher bisphenol A concentrations in water samples and organisms inhabiting the Gulf of Gdansk. BPA concentrations in the years 2011–2012 were on average between a few and over ten times higher than for 4-tert-octylphenol and 4-nonylphenol, and were characterized by the highest variability. In water they ranged between 20.8 and 198.6 ng dm−3 ( Staniszewska et al., 2015) and in phytoplankton (fraction 25–100 μm) between 26.3 and 968.3 ng g−1d.w. ( Fig. 2).