 However, the wastewater is contaminated with pathogenic organisms and toxic chemicals that constitute a health risk for both farmers and consumers of agricultural products.Water reuse activities in Greater Mexico City officially began in 1984 under the National Program for Efficient Use of Water.This national program included the establishment of new wastewater discharge regulations by the Federal District, and in 1990, provisions were established for an industrial pretreatment program - an important prerequisite for any reclamation and reuse activity.