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' 3 2 GROUNDWATER SAMPLING On May 22, 23, and 27, 1997, groundwater samples were collected from fourteen ' monitoring and/or vapor extraction wells Prior to the collection of groundwater samples, the monitoring wells were purged of a minimum of three well volumes of water and until pH, conductivity, and temperature stabilized The wells were allowed to recover to at least 80 percent of their ongmal static groundwater levels prior to sampling The following are procedures for well monitoring, well purging, and water sampling ' 1 All equipment was washed prior to entering the well with an Alconox solution, p 9 followed by two tap water rinses and a deionized water rinse ' r e wells, e depth-to-water was measured using 2 Prior #o purging ng th d p g an Solinst ' groundwater interface probe to an accuracy of approximately 0 01 foot The measurements were made to the top of the well casing on the north side ' 3 Monitoring wells at the site were prepared for sampling by purging the well of approximately 3 well volumes of water using a 2-inch or 4-inch diameter polyvinyl chloride (PVC) bailer 4 One well volume was calculated using the following equation ' V = 314x7481 xhr,2 where V = one well volume ' h = (d,-d2) r, = the radius of the well in feet ' 5 Water samples were collected with a Teflon bailer after the well had been purged and water in the well had equilibrated to approximately 80 percent of the static water level or for 2 hours, whichever occurred first The water collected was ' immediately decanted into laboratory-supplied vials and bottles The containers were overfilled, capped, labeled, and placed in a chilled cooler prior to delivery to the laboratory for analysis ' 6 Chain-of-custody procedures,roceduresincludingchain-of-custody forms, were used to document water sample handling and transport from collection to delivery to the laboratory for analyses 2 F TransferlRepoR1CALTRANSICalty097V710174gmN7 lin