DEGRADATION AND METABOLISM OF TETRAETHYLLEAD IN SOILS

The objective of this study was to determine the disappearance of the leaded gasoline enhancer tetraethyllead (TEL), formation of degradatio n products, and mass balance in nonsterile and autoclaved Leon and Mad ison soils. Ethyl-1-C-14-labeled TEL was used so that mineralization r ates of TEL and mass balance could be determined. C-14-TEL in nonsteri le and autoclaved surface and subsurface samples of the two soils disa ppeared rapidly, and ionic ethyllead products, water soluble nonlead o rganic products and bound residues were rapidly formed. A small fracti on (less than or equal to 7.74%) of C-14-TEL in nonsterile soil sample s was mineralized to (CO2)-C-14 in 28 days. Triethyllead (TREL) was th e major ionic ethyllead product detected in both nonsterile and autocl aved soils; diethyllead (DEL) was occasionally detected. Recovery of C -14 from mass balance studies for all nonsterile and autoclaved soil s amples after 28 days of incubation was poor, less than 50% of the C-14 applied. It appears that unknown volatile and/or gaseous organic prod ucts were the major degradation products of TEL in soils. Based on the observations of more rapid initial disappearance of C-14-TEL, more ra pid formation and more rapid disappearance of C-14-DEL, and occurrence of (CO2)-C-14 production in nonsterile soils, it was concluded that b oth biological and chemical degradation contributed to the degradation of TEL in soils, with chemical degradation bring the major factor.