DETERMINATION OF ORGANOTIN COMPOUNDS IN THE FOODWEB OF A SHALLOW FRESH-WATER LAKE IN THE NETHERLANDS

An extensive study on the presence of nine organotin compounds (OTs) i n a freshwater foodweb was made, using newly developed analytical proc edures in order to obtain insight in accumulation and degradation proc esses. Tributyltin (TBT), Triphenyltin (TPT) and their degradation pro ducts were detected. Zebra mussels, eel, roach, bream, pike, perch, an d pike perch and cormorant showed high OT body concentrations. At the lower trophic levels, phenyltin concentrations were higher in benthic species while butyltin concentrations were higher in pelagic species. This indicates that TBT is passed on primarily via the water, while TP T is passed on to a larger extent via the sediment. At the higher trop hic levels, net bioaccumulation of TPT was greater than that of TBT, r esulting in relatively higher TPT concentrations. High concentrations of biodegradation products of TBT, but not of TPT, were found in the l ivers of fish and birds, which indicates that TBT is more easily metab olized than TPT. A comparison with literature data of fish lethal body concentrations revealed that fish in the field may be endangered. Wit h birds, the highest concentrations of OTs were present in liver and k idney and not in subcutaneous fat, which confirms that OTs accumulate via different mechanisms than traditional lipophilic compounds, As a w hole the OT concentrations found in the foodweb may be considered to b e quite alarming.