Baseline of the butyltin distribution in surface sediments (0–20 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).