PCDDs (dioxins) and PCDFs (furans) in selected UK lake and reservoir sites - Concentrations and TEQs in sediment and fish samples

This paper describes a study that was designed to increase present knowledge of the levels and behaviour of atmospherically derived PCDD/Fs in UK freshwaters. Sediment and fish samples were taken from four freshwater locations where the main sources of PCDD/Fs were thought to be atmospheric. Total concentrations in sediments ranged from 500-5000 ng kg(-1) dry weight, and toxic equivalents (I-TEQs) between 5-100 ng kg(-1) dry weight. Sedimentary evidence was used to derive total inputs of PCDD/Fs to the lakes and from this it seems probable that two of the sample sites receive inputs of PCDD/Fs largely from the atmosphere, and that the remaining two sites receive additional inputs from local or regional sources. PCDD/Fs were present in all fish samples taken, with total concentrations between 100-800 ng kg(-1) wet weight and TEQs between 1-20 ng kg(-1) wet weight. These values were consistent with those found in other international studies. Whilst results provide some evidence for within-site similarities between different fish types, they did not suggest any similarities between the same species at different sites. There was no evidence for a relationship between total PCDD/F concentrations in sediment and fish, although relationship between 2378-substituted isomer levels in some sediment and fish samples was noted.