As a result, these operations can pose a threat to our natural water resources. Collecting, treating and recycling greenhouse effluent is one of the best solutions to this environmental problem. Many states now require a water discharge permit to control irrigation runoff. These permits regulate the level of discharge that flows into surface and groundwater reserves. In many situations quantitative discharge standards are vague and each case is based by the best professional judgment of the regulatory agency.
Monitoring is very important in the overall process of treating greenhouse runoff.
Knowing what contaminants are present and their relative concentrations, is the basic information required for developing a management plan. Nitrates, salts, pesticides and pathogenic organisms are the principal contami-nants to be on the lookout for. Many of the tests for these materials are quite expensive to run. Also, sampling technique, handling and analytical methodlolgy can impact the results and interpretation. Table 1 provides a list of labs that are currently conducting runoff analysis.