Tributyltin Oxide (TBT) has been used as an anti-fouling paint on commercial ships for decades, inhibiting mollusks or barnacles from attaching themselves to ships. However, it has also been recognized as a toxic chemical that causes reproductive defects in and death of crustaceans.
TBT is a common problem on both coasts of North America, and is a growing concern in the great lakes. Pacific Rim Laboratories is one of only a few commercial labs in Canada accredited to perform this low level detection analysis, which detects TBT down to one part per trillion in water and one part per billion in sediment.
Also included in your results are the TBT degradation products Dibutyltin and Monobutyltin. It should be noted that these degradation products are also used in the manufacturing of some plastics, so the source may not be TBT derived.