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CAMBRIA <br /> Water Sampling <br /> Water samples,if they are collected from the boring,are either collected using a driven HydropuncO <br /> type sampler or are collected from the open borehole using bailers The groundwater samples are <br /> decanted into the appropriate containers supplied by the analytic laboratory Samples are labeled, <br /> placed in protective foam sleeves,stored on crushed ice at or below 4°C,and transported under chain- <br /> of-custody to the laboratory Laboratory-supplied trip blanks accompany the samples and are analyzed <br /> to check for cross-contamination An equipment blank may be analyzed if non-dedicated sampling <br /> equipment is used <br /> Grouting <br /> If the borings are not completed as wells, the borings are filled to the ground surface with cement <br /> grout poured or pumped through a tremae pipe <br /> MONITORING WELL INSTALLATION, DEVELOPMENT AND SAMPLING <br /> Well Construction and Surveying <br /> Groundwater monitoring wells are installed to monitor groundwater quality and determine the <br /> groundwater elevation, flow direction and gradient Well depths and screen lengths are based on <br /> groundwater depth,occurrence of hydrocarbons or other compounds in the borehole,stratigraphy and <br /> State and local regulatory guidelines Well screens typically extend 10 to 15 ft below and 5 ft above <br /> the static water level at the time of drilling However,the well screen will generally not extend into or <br /> through a clay layer that is at least three ft thick <br /> Well casing and screen are flush-threaded,Schedule 40 PVC Screen slot size vanes according to the <br /> sediments screened, but slots are generally 0 010 or 0 020 inches wide A rinsed and graded sand <br /> occupies the annular space between the boring and the well screen to about one to two ft above the <br /> well screen A two ft thick hydrated bentonite seal separates the sand from the overlying sanitary <br /> surface seal composed of Portland type I,11 cement <br /> Well-heads are secured by locking well-caps inside traffic-rated vaults finished flush with the ground <br /> surface A stovepipe maybe installed between the well-head and the vault cap for additional security <br /> The well top-of-casing elevation is surveyed with respect to mean sea level and the well is surveyed <br /> for horizontal location with respect to an onsite or nearby offsite landmark <br /> • <br /> Page 2 of 3 <br />