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MAR-24-99 16 43 From WOODWARD CLYDE ¢ T-735 P 16/34 Job-482 The No-Purse Scenario 0 (Lessons Learned) Thomas Wayne„Kabis Sibak Industries Liuuted,Inc 1520 J Industrial Avenue lrecondido,California state(92o25) 800-794-6244 Abstract Obtammg representative groundwater samples,without benefit of well purging,from most groundwater monitoring walk using newly designed sampling equipment is now possible A review of current published and unpublished literature has revealed a new, growing,and viable trend in the groundwater investigation industry Owing to the most recent move in both government and the private sector to spend less on envirortmental clean-up activitles,and since the act of purging is,in and of itself a very costly enterprise, the no-purge scenario is gaining wide acceptance Recent studies conducted at sites in several states have all reached the same conclusion,that purging a groundwater monitoring well when using a sampling instrument capable of obtaining depth-discrete samples is unnecessary in order to obtain a representative sample In an attempt to obtain representative samples of groundwater from beneath any site, environmental investigators have had to deal with many variables The variables included m their scrutiny are proper well construction, consideration of parameters to be sampled for, appropriate selection of sampling device,and the methods employed ® to retrieve a representahve sample Researchers,groundwater scientists and envircrtmeiital engineers have dealt with the problems of proper well construction, but the reminder of the variables have been dealt with only cursorily until very recently The results of recent studies using the 1tABIS SamplerTm suggest that the no-purge method is both a valid alt*rr;ative to the method(s)commonly accepted as standard practice for UST and RCRA/CERCLA sites w much of the United States,and +wiII provide data which is adequate to superior, ensuring environmentally protective risk management and decision making at the great ma;onty of sites Background The essential importance of groundwater quality is now recognized as development of groundwater continues to expand Monitoring of groundwater quality is becoming increasingly more unportant due to public womes over chemical contanunabon The development of new equipment and techniques for measuring contaminants ani minute concentrations without the additional production of hazardous and tosuc wastes has been added to a list of sampling concerns Accuracy and cost savings top the list of concerns surrounding the sampling and monitonng of groundwater The measure of cost savings when engaging in groundwater sampling is calibrated with many standards The most common standards involve the expenditure of manpower and raw materials for the collection of any one sample, suite of samples or for the conduct of an entire program of groundwater sampling The expenditure of manpower and use of raw materials takes on a much more complicated meaning when viewed through an established sampling plan and to a greater extant,when compiling and publishing a sampling plan 1 of 16 VW94 4 22 PM