Butyltin and phenyltin compounds in river i bay sediments of Tokyo

The occurrence and current status of butyltin and phenyltin compounds were investigated in sediments collected from the Arakawa and Sumida Rivers and Tokyo Bay in 2000. A series of butyltin and phenyltin compounds, including monobutyltin (MBT), dibutyltin (DBT), tributyltin (TBT), monophenyltin (MPT), diphenyltin (DPT), and triphenyltin (TPT) was detected by gas chromatography-mass spectrometry (GC-MS). The total concentrations of the butyltin (MBT + DBT + TBT) and phenyltin (MPT + DPT + TPT) compounds ranged from 25.7 to 116 and from non-detectable levels to 22.4 ng g' (as Sn), respectively. The concentrations of the organotin (OT) compounds in sediments were relatively lower than those of the samples collected in 1984. OT compounds accounted for 124% (as Sn) of total Sn in the sediments. Among the OT compounds investigated, MBT was the most prevalent in the sediments.     

Tin concentrations in river / bay sediments of Tokyo in 1984 and 2000

Abstract

To analyze in greater detail the fate and behavior of toxic organotin compounds in the environment, total tin (Sn) concentrations were determined for sediments of the Arakawa River, the Sumida River, and Tokyo Bay by using a graphite furnace atomic absorption spectrophotometer (GFAAS). Sn concentrations in 2000 were compared with those of 1984 (8 years before the regulation on tributyltin-based antifouling paint) as well as with other heavy metals (Cu, Ni, Pb, and Zn). The Sn concentrations ranged from 1.04 to 4.43 mg kg^?1 for sediments sampled in 2000. Although the average concentration of Sn in the sediments was low compared with that of 1984, the concentration tended to increase at several sites in 2000. Moreover, the Sn concentration showed significant correlations with the Cu, Ni, Pb, and Zn concentrations. These results suggest that a significant proportion of the overall Sn content in these sediments was probably introduced from the sources other than antifouling paint. The metals extracted from air-dried sediments with 0.1 m HCl showed that the mobility and bioavailability of Sn was low compared with those of other heavy metals.