Polycyclic aromatic hydrocarbons (PAHs) in surface waters of Ráckevei-Soroksári Danube Branch, Hungary

Abstract

Concentrations of polycyclic aromatic hydrocarbons (PAHs) in the surface waters of Ráckevei-Soroksári Danube (RSD) branch, Hungary were determined at ten sites during eight sampling events from October 2002–April 2004. Low and medium molecular weight PAHs (2–4 rings) varied from a few ng/L to hundreds of ng/L while high molecular weight PAHs (5–6 rings) were present at much lower concentrations (< 0.5–31 ng/L). Generally, concentrations of most of the individual PAHs were not significantly different (p > 0.05) during the different seasons. Concentrations of anthracene, fluoranthene, and pyrene were significantly lower (p < 0.005) in the winter month whereas concentrations of benzo(a) anthracene, chrysne, and benzo(b)fluoranthene were significantly lower (p < 0.05) in the fall season. Possible causes of such distribution in the surface waters of RSD include nature of the inputs of organic matter and different systems of winds or rains of the seasons. Of the total PAHs, the 2–3-ring PAHs contributed to about 78% while 4–6-ring PAHs accounted for 22%. This suggests that the incomplete combustion of fossil hydrocarbons may be the predomainate source of PAHs in surface water of RSD. Seasonally, petroleum and heavy fuel combustion were main sources of PAHs in summer and winter seasons, respectively. However, both sources contribute to PAHs in the spring season. The levels of PAHs in our study were compared with other regions of the world. Concentrations of PAHs in our study were higher than most of the surface waters of Europe, North America, and Australia, but similar to some parts of European and Asian regions.