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i wCarbon concentration with time is observed) A significant departure from a near zero or negative trend slope will trigger implementation of the trigger activation response strategy Groundwater monitonng data will be analyzed serruannually and the results will be issued with the third quarter groundwater monitoring report Conditions under which a trigger event may result are discussed below Three primary scenarios were recognized as being possible disruptions to the existing steady- state system (the "system" is the intrinsic remediation volume being monitored) (1) an increase in dissolved hydrocarbon concentration at the source location occurs, (2) attenuation is inhibited somewhere within the system, or(3)the groundwater flow rate through the system increases As a result of any one (or combination) of the disruption scenarios mentioned, dissolved hydrocarbon concentrations could significantly increase, either at the source location or at a location somewhere within the treatment volume The increase in dissolved hydrocarbon concentration would be observed either at monitoring wells near the source, or at wells used to monitor the compliance boundary If the system adapts to the increased hydrocarbon load, it is likely the data analysis results, performed using data collected after the initial hydrocarbon concentration increase, would not change dramatically But if the system does not adapt, or attenuation is inhibited, the data analysis results would show a significant increasing (positive slope) dissolved hydrocarbon trend over time Before implementing the trigger activation response strategy, trigger validation would be done by reviewing the data • and circumstances under wluch the system changed 3.2.5 Trigger Condition The trigger activation response (Figure 10)will be implemented whenever 1 The venfied concentration of any target compound in any compliance boundary well exceeds the water quality goal(Section 3 12), or 2 The concentration versus tune trend for any target compound in any compliance boundary well exhibits a rate of increase which indicates the water quality goal will be reached or exceeded (1)before the next sched- uled sampling event, or (2) before the time required to implement the trig- ger activation response 3.2.6 Trigger Activation Response Strategy Figure 10 shows the sequence of actions that will be completed in the event a trigger condi- tion is verified r 3201337B/1918REV 14 August 31, 1995 r