EXTRACTION EFFICIENCIES OF HYDROCARBONS FROM NIAGARA RIVER WATER

Significant concentrations of C-12 to C26 n-alkanes, fluoranthene and pyrene were found in dichloromethane extracts of filtered Niagara River water at pH 12 after the water had been thoroughly extracted at pH 1. Over 40 sampling days, the total concentration of n-alkanes, fluoranthene, and pyrene in the basic extracts was roughly 60% of the total in the acidic extracts plus suspended solids combined. Spike recovery experiments with 31 n-alkanes and polynuclear aromatic hydrocarbons demonstrated that the phenomenon (a) did not occur in distilled water; (b) occurred in Niagara River water, regardless of whether the initial extraction of filtered water was performed at acidic or neutral pH; and (c) was not simply the result of incomplete extraction at acidic or neutral pH. These findings support earlier studies that suggested that concentrations of lipophilic organic chemicals in Niagara River water may be underestimated when determined by the usual technique of extraction at neutral pH.