Butyltins in sediments from Santa Monica and San Pedro basins, California

Butyltins have been measured for the first time in sediments from the deeper waters of the Santa Monica and San Pedro (SM/SP) basins of Southern California borderland. Core samples were collected from water depths ranging from 458 m in the shelf to 906 m in the central basin. Surficial and a few subsurface sections from selected cores were analyzed for butyltins. The dominant components are generally dibutyl and monobutyltins (DBT and MBT, respectively). Microbial degradation of Tributyltin (TBT, the most toxic of the butyltin species) to DBT and MBT during the long range transport to deeper basins, as well as a lack of continuing inputs of TBT in the present times could justify the butyltins signatures found in the region. The levels of butyltins are in the lower range (below detection level, <1, to 14 ng of Sn g(-1)) relative to nearshore sediments. However, the results demonstrate that the butyltins are, indeed, found even in the sediments of the central basins of the Southern California borderland suggesting that deeper global oceanic regimes need to be further investigated for these compounds.