Concentrations of butyltin compounds in animals at higher trophic levels such as conger eels were lower than those in zooplankton and detritus at the base of the food chain, suggesting that through bioaccumulation of butylins food web was not intensive. The pollutant TBT when taken up by eelgrass or adsorbed by detritus, on the other hand, was believed to be rapidly degraded to the less toxic MBT by the plant or microorganisms living in the detritus.