Occurrence of organophosphorus flame retardant and plasticizers in three volcanic lakes of central Italy.

The concentration levels, distribution, and seasonal fluctuations of 12 organophosphorus flame retardants and plasticizers (OPs), of which some are reported to be toxic to aquatic organisms, were investigated in lakes from June 2006 to June 2007. Three volcanic lakes located in the Lazio area (Central Italy) and characterized by a different anthropical impact were selected. Analysis of lake water samples showed that in closed ecosystems (hydrogeological systems), such as small volcanic lakes, OP contamination may occur even in the absence of industries and treated or untreated waste discharges. The selected substances were found at ng/L concentrations in all lakes. In the two more anthropized lakes tributyl phosphate and tripropyl phosphate were the most abundant OPs, with peaks of respectively 784 and 951 ng/L. Maximum pollution levels were reached in October-November, and concentrations decreased to a minimum value in March-April. Chlorinated OPs showed the same trend, but their concentrations were 1 order of magnitude lower and the level decreasing was shifted with respectto alkyl OPs. On the contrary, tris(2-butoxyethyl) phosphate concentrations were quite similar among all water samples analyzed, indicating that their sources were different in nature. One of the three lakes is an important source of drinkable water, so nine wells situated in its neighborhood were also examined. No correlation between lake water and groundwater contamination could be found.