Concentrations are reported of hexabromocyclododecanes (HBCDs) and tetrabromobisphenol-A (TBBP-A) in water (n = 27), sediment (n = 9), and fish samples (n = 30) from nine English lakes. Seasonal variation in concentrations in water is minimal. Concentrations of TBBP-A range from 140 to 3200 pg L(-1) (water), 330 to 3800 pg g(-1) dry weight (sediment), and <0.29 to 1.7 ng g(-1) lipid weight (fish). Those of SigmaHBCDs range between 80 and 270 pg L(-1) (water), 880 and 4800 pg g(-1) dry weight (sediment), and 14 and 290 ng g(-1) lipid weight (fish). Aqueous concentrations of SigmaHBCDs and TBBP-A are significantly positively correlated, indicating a common source. Average +/-sigma(n) "freely-dissolved" phase proportions are 47 +/- 4.7% (SigmaHBCDs) and 61 +/- 2.9% (TBBP-A). Average field-derived bioaccumulation factors are 5900, 1300, 810, and 2100 for alpha-, beta-, gamma-, and SigmaHBCDs, respectively. Tetrabromocyclododecadienes are detected in all sediments, with pentabromocyclododecenes present in some. This suggests HBCD degrades via sequential loss of HBr. The delta-HBCD meso form was quantified in 43% of fish samples (1.0-11% SigmaHBCDs). Its absence from temporally and spatially consistent water and sediment samples suggests it is formed via bioisomerization. While HBCD chiral signatures are racemic in water and sediment, our data reveal enantiomeric enrichment of (-)alpha-HBCD and (+)gamma-HBCD in fish.