Baseline of the butyltin distribution in surface sediments (0-20Â cm) of the Elbe estuary (Germany, 2011)

The concentrations of the butyltin (BT) species tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) were measured in the surface sediments (0-20 cm) at 29 sites of the Elbe estuary in 2011. TBT values ranged from 'undetectable' to 41 ng Sn g−1 dry weight (d.w.) with the two highest values measured in the inner section of the estuary near the port of Hamburg (32 and 41 ng Sn g−1 d.w.). TBT, DBT, and MBT showed significant decreases towards the estuarine mouth (Spearman's rho −0.660, −0.685, and −0.583, respectively, p < 0.001). The degradation of TBT, assessed by the BT degradation index (BDI), showed a rising trend from the port of Hamburg towards the mouth of the estuary, though not a significant one (Spearman's correlation, p = 0.066). Annual sedimentation rates did not show any significant correlations (Spearman's correlation) to BT pollution or to the butyltin degradation index (BDI).