As tequila is produced, there are byproducts much like any other distilled spirit. Here in the states, the EPA has pretty strict rules regarding how the byproducts are handled and disposed of. Looks like things are a little different south of the border.
For every liter of tequila produced, distilleries throw away 10 liters of hot liquid waste (called vinaza), as well as 5 to 6 kilos of fibrous agave plant (called bagasse). Government rules are supposed to control how the vianza is properly disposed of, but there is very little regulation in effect. When improperly dumped, the vianza is extremely acidic, and contains an oil that renders the soil impenetrable. Eventually the vianza works its way down the cracks in the soil, and contaminates water tables.
In the wine world, vintners are very respectful of their surrounding environment. In fact, they have to in order to produce quality grapes vintage after vintage. So think twice about ordering that frozen margarita.
