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Polychlorinated biphenyls (PCB) congeners were determined in water samples, sediments, and animal species in the frame of a survey of the River Arrone (Central Italy, near Rome) after a major contamination episode. Animal species were selected on the basis of their living and feeding habits and evaluated as candidate bioindicators of PCB pollution in this lotic ecosystem. Total PCB concentrations in water were found to be low (ng/L level), and in sediments, ranged from about 10 to 200 μg/kg dry weight, depending on the distance from the contamination source. PCB patterns in sediments showed a prevalence of higher chlorinated congeners over time. Concentrations in macroinvertebrates ( Calopteryx splendens and Anax imperator ) ranged from 60 to 400 μg/kg dry weight, showing significantly different species to species patterns. PCB concentrations were almost parallel in sediments for different sampling stations, while differences in patterns among species can be explained in terms of bioaccumulation/excretion mechanisms. Freshwater shrimps ( Palaemonetes antennarius ) were not found close to the contamination source, as a consequence of their extreme sensitivity to chemicals, and showed a peculiar pattern (almost exclusively determined by congeners 153, 138, and 180) probably originating from biodegradation mechanisms. Fish samples ( Rutilus erythrophthalmus ) showed the highest concentrations, as a combination of feeding habit, lipid content, and, probably, less effective biodegradation/excretion pathways. Congener patterns closely match those of Aroclor 1260, which originates from the contamination source. This study confirms that congener physical and chemical parameters, different degradation rates, feeding habits, and mobility of the analysed aquatic organisms, metabolism, and excretion mechanisms, are to be considered to explain the distinctive PCB patterns of different samples.

A sampling campaign for the determination of phthalate acid esters (PAEs) levels in freshwaters and sediments of rivers and lakes of the Rieti District (central Italy) was carried out in 1994. Sixty-six water samples, collected in three series, and thirteen sediment samples were analyzed by gas chromatography/mass spectroscopy (GC/MS). The analytical results on water samples showed a direct relation of PAEs levels with the input of urban or industrial treated wastewaters near the sampling point. Because of their tendency to be adsorbed on sediments, the presence of PAEs was limited to within a few kilometers of the source of contamination. Accumulation factors in sediment samples, in fact, ranged from 10 to 100.