Tetraethyl lead, degradation

In water, tetraalkyl lead compounds are subject to photolysis and volatilization with the more volatile compounds being lost by evaporation. Degradation proceeds from trialkyl lead to dialkyl lead to inorganic lead. Tetraethyl lead is susceptible to photolytic decomposition in water. Triethyl and trimethyl lead are more water-soluble and therefore more persistent in the aquatic environment than tetraethyl or tetramethyl lead. The degradation of trialkyl lead compounds yields small amounts of dialkyl lead compounds. Removal of tetraalkyl lead compounds from seawater occurs at rates that provide half-lives measurable in days (DeJonghe and Adams 1986). 

Artificial and increasingly important sources of lead are exhaust gases of motor vehicles, which contain degraded products of tetraethyl lead. Via atmospheric precipitation, lead is introduced into surface waters. Since it has a high accumulation coefficient its major portion is removed from surface waters by sorption on the bottom sediments. 

---