Tequila leaves big envirnomental hangover (2)

Eight years after planting, the blue agave is ready for harvest. Its leaves are removed in order to extract the "piña", or heart of the plant, from the ground.

The pineapple-shaped hearts are set to bake 50 to 72 hours in brick ovens or steel tanks. The hearts soften and release the sugars used for fermentation.

In the fermentation process, the sugars are mixed with leavening, converting them into alcohol. The liquid is distilled twice, generally in stills made of copper or steel. The result is tequila, which can then be aged in oak barrels - "añejo" on the bottle's label indicates it has been aged.

In 1996, the Secretariat (ministry) of Environment and Natural Resources introduced standards for the degree of toxicity permitted in the waste and vinaza, which were to be adopted by the tequila industry in 2000. But none of the distilleries comply with all of the rules.

According to the standards, one liter of vinaza can generate no more than 150 milligrams of "biochemical oxygen demand" (BOD), a measurement of the quantity of the gas consumed in the biodegradation of the organic material in the water.

But each liter of vinaza emits about 25,000 milligrams of BOD, an indicator that permits measurements of water contamination.

According to the Jalisco State Environment Secretariat, only one of the 67 tequila factories there heeds the law on discharge of waste into rivers and lakes.

In 2007, the authorities conducted 197 inspections, found irregularities at 51 distilleries, and shut down two of them.

Due to increased tequila consumption within Mexico and abroad, the cultivation of blue agave has expanded to other regions.

"They are growing in a protected forest, invading several hectares, where it has replaced the encino trees," said Adriana Hernández, an activist with the non-governmental Save the Forest Committee, dedicated to protecting El Nixticuil forest.

El Nixticuil, declared a protected area in December 2005, extends across 1,850 hectares in the Jalisco municipality of Zapopán, 550 km from the Mexican capital.

The tequila industry has taken slow steps towards recognizing its polluting responsibilities. Some distilleries are neutralizing the acidity of the wastewater, and cool down the vinaza before discharging it, and produce compost from the agave pulp.

In 2010, two vinaza treatment plants are slated to begin operating.

In Hernández's opinion, there is no single solution to the environment problem. "The most common now is composting. In addition, they are trying to remove the oil coming from the cooked agave before distilling so that the vinaza is more environmentally friendly," said the researcher.