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LONG TERM MONITORING FOR NATURAL ATTENUATION
Citation:
WILSON, J. T. LONG TERM MONITORING FOR NATURAL ATTENUATION. Presented at Ground Water Forum Business Session Agenda, Long Beach, CA, November 13, 2006.
Impact/Purpose:
To inform the public.
Description:
We have good statistical methods to: (1) determine whether concentrations of a contaminant are attenuating over time, (2) determine the rate of attenuation and confidence interval on the rate, and (3) determine whether concentrations have met a particular clean up goal. We do not have good statistical methods to: (1) determine whether the extent of attenuation seen in a five year review is on track to meet the ultimate cleanup goal in a reasonable time frame, or (2) to set reasonable expectations for the extent of attenuation that should be attained at the end of the next five year review cycle. This presentation uses data from an NPL site to illustrate a simple procedure using the t statistic for the difference of means to determine if natural attenuation is on track, and to set reasonable interim goals at the end of each review cycle.