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C CALCULATING DESIGNATED LEVELS Water Quality Standards Obtain information on the Obtain information on the from the applicable site of waste discharge. waste to be discharged. Water Quality Control Plans What bodies of water may be or have been affected ? What factors may influence What are the beneficial uses the attenuation of waste of those bodies of water ? constituents as they migrate to water? What are the water quality objectives to protect those beneficial uses ? What numerical water quality limits Estimate the magnitude will implement all applicable of the attenuation of water quality objectives ? constituents between waste and water at the site. Choose the most limiting of those water quality limits. Water Quality Goal , Attenuation Factor Is there a consistent ratio of total to leachable waste Leachability Factor constituent concentrations ? of the state. For the site in question, wastes having soluble con- stituent concentrations in excess of their calculated Designated Levels are assumed to pose a threat to wa- ter quality and are classified as "designated wastes". These wastes are required to be discharged to waste management units which isolate them from the envi- ronment. Environmental Attenuation Factors There are a variety of natural processes which act to attenuate (reduce the concentrations of) waste con- stituents as they migrate through the environment. These processes, which are collectively grouped under the term "environmental fate", include sorption, chemical binding, ion exchange, filtration, diffusion, Page 4 TOTAL DESIGNATED LEVEL Figure 5 dispersion, dilution, chemical reaction, biodegradation, and partitioning. By collecting data on the waste con- stituents and on the site in question, the amount or degree of attenuation which would be expected to oc- cur as the constituents migrate from the location of waste discharge to either ground or surface water may be estimated. In The Designated Level Methodology, the smallest degree of attenuation that would be expected to occur for the particular constituent at the specific site of discharge is approximated by an "environmental attenuation factor". The greater the amount of attenua- tion that is expected to occur, the larger the attenuation factor that would be assigned. As shown in Figure 6, there are a variety of site- specific and constituent -specific characteristics which influence the magnitude of attenuation that may be Sumrnary of The Designated Level Methodology