Hydrolysis is a transformation process in which an organic molecule, RX, reacts with water, forming a carbon-oxygen bond (oxygen atom of water molecule) and cleaving a carbon-X bond in the original molecule.  The products of a hydrolysis reaction are usually less of an environmental concern than the parent compounds because the products are usually more polar compounds that are less hydrophobic than the original molecules and therefore behave differently in the environment (6).  The net reaction is commonly defined as a direct displacement of X by OH:

 R-X    +    H₂O    --->     R-OH   +   X^-  +   H⁺                      (1)

Where X can represent a variety of functional groups.  Pesticides that are derivatives of carboxylic acids have functional groups that are subject to hydrolysis.  For this case study we are studying a derivative known as a carbamate which involves an amide and ester linkage.

Chemists have identified many mechanisms that can be classified as hydrolysis reactions.  March (1985) lists eight mechanisms for ester hydrolysis.  We will consider only three of those mechanisms that chemists have classified based on pH.  In the case of acid-catalyzed hydrolysis, an acid, usually a proton (H⁺) catalyzes the bond breaking and bond making process.  Because the proton is not consumed in the reaction, the process is referred to as acid-catalyzed hydrolysis.  The rate of the reaction depends on the proton concentration; thus, the rate increases as the pH decreases.  Acid-catalyzed hydrolysis is dominant below pH 6.  In the case of base-mediated hydrolysis, hydroxyl (OH^-) behaved as a nucleophile and is consumed in the reaction.  This pathway is often referred to as alkaline hydrolysis.  The rate of reaction depends on the hydroxyl concentration and increases with increasing pH.  Alkaline hydrolysis is dominant above pH 7 or 8.  In the third type of hydrolysis, the rate of reaction is independent of the acid-base concentration (pH independent).  This process is often referred to as neutral hydrolysis.  Neutral and alkaline hydrolysis are the most common reactions within the pH range common to the environment (8).

The process of hydrolysis can be distinguished from several other possible reactions between organic chemicals and water such as elimination, addition to carbon-carbon bonds, isomerization, and decarboxylation.  In such types of reactions, oxygen atom or water molecule is not incorporated into the transformation product; consequently, these reactions are not hydrolysis reactions even if they do occur in water (9).