Environmental Engineering Reference
In-Depth Information
Fig. 3 a
Butyltin and
b
phenyltin profiles in the sediment core of a pleasure boat harbor.
Relatively high concentrations of TBT were found in the
upper
6 cm. The decrease
be-
low
mainly reflects the historical use of organotin-containing antifouling paints and input
into the sediment. Degradation products DBT and MBT occur as well. Phenyltins occur
only
below
the
upper
3 cm demonstrating the recent lack of input. After [49]
historic build-up due to the increased use of TBT-containing paints in the
late 1970s. Decreases with depth were paralleled by respective transformation
products. Phenyltin sediment profiles indicate also slow degradation of TPT.
The TPT input ceased as reflected by its lacking at the top of the core. Hence,
sediment profiles likely reflect the historical use of the organotin antifouling
paints rather than degradation alone. These profiles show that TBT is stored
over periods of years or even decades in anoxic sediments, which to a lesser
extent also holds for TPT [14]. Degradation of TBT is also slow in sewage
sludge treatment [30, 50].
4
Contamination of Aquatic Environments
Only after the discovery of detrimental effects of TBT on oysters have efforts
been directed to monitoring its environmental occurrence and assessing its
effects. Widespread and significant pollution of marine [11, 41, 51-77], and
freshwater ecosystems [4, 18, 34, 78-80] has subsequently been reported. TBT
and degradation products DBT and MBT have generally been found in wa-
ter, sediment and biota in developed countries, and recently in developing
