Hydrolytic Reactions in Natural Aquatic Ecosystems

CATALYSIS OF HYDROLYTIC REACTIONS IN NATURAL AQUATIC ECOSYSTEMS 

The complexity of natural aquatic ecosystems necessitates that we examine the ability of naturally occurring species and surfaces to alter the hydrolysis rates of organic pollutants. Failure to realize the potential for catalysis to occur in natural systems can lead to underestimations of hydrolysis rates when extrapolating from laboratory studies. Although this discussion will focus primarily on hydrolytic catalysis in natural water systems, several examples will be presented which demonstrate that components of natural systems also can impede hydrolysis. 

Often there is confusion as to the definition of the term catalysis. A reaction is catalyzed if its rate is accelerated relative to the noncatalyzed pathway. A catalyst serves to alter the reaction mechanism of a chemical process by providing a new pathway with a lower potential-energy barrier. The Union of Pure and Applied Chemistry (lUPAC, 1981) definition of the term catalyst states that a catalyst is a substance that increases the rate of a reaction without modifying the overall standard Gibbs energy change in the reaction the process is called catalysis, and a reaction in which a catalyst is involved is known as a catalyzed reaction.  

---

E. CATALYSIS OF HYDROLYTIC REACTIONS IN NATURAL AQUATIC ECOSYSTEMS... 

---