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i 0 City of Ripon Wastewater Treatment Plant Groundwater Sampling Protocol The sampling field method employed by ECOLOGIC Engineering, City of Ripon, or its representatives is as described below: 1) The covers of the monitoring wells should be removed and loose material cleared from the edges. A propane torch may be used to briefly burn the frame of the well cover including any debris inside the box and around the well casing. The compression cap is then removed and placed top down on the well cover. 2) Groundwater surface depth is then measured to within 0.01 feet by lowering an electronic tape into the well while passing it through a cloth soaked in hypochlorite solution. The water depth shall be measured relative to the top of the north quadrant of the PVC well casing. After measurement, the water level tape should be rolled onto the reel while it was wiped with a cloth soaked in a dilute chlorine solution. A well volume is then calculated based on the cross-sectional area of the well casing times the water column height(well depth from well logs minus depth to water surface). The minimum purge volume is subsequently determined by multiplying the computed well volume by three. No annular space estimate is included in computing the purge volume. 3) Submersible stainless steel and/or plastic pump(s) with a plastic discharge hose are generally used for purging and sampling, although pre-cleaned disposable bailers may also be used. The pump, hose and cord should be rinsed in potable water and a dilute chlorine solution for disinfection,running the pump during each rinsing/disinfection to flush water through the impeller and hose. If soil particles are observed on or in the pump or discharge hose an additional cleansing with a detergent such as Alconox®should be employed. Following cleansing/disinfection,the pump and discharge hose are lowered into the well, avoiding contact with the cover frame, ground etc. The technician shall use rubber gloves during sampling and change or clean/disinfect them each time any potentially contaminated surface is touched. New gloves should be rinsed in chlorine solution prior to handling field and/or sampling equipment. 4) After priming and pumping a small amount of water through the hose (to remove any remaining liquid in the hose), the discharge rate should be assessed, by measuring the time to fill a one-gallon container. This time is them multiplied by the well purge volume as calculated in step 2) above. The time to purge three volumes should be rounded up by approximately 5 minutes. Alternatively, a graduated bucket or other container may be used to measure the volume of water removed during purging. 5) Once the pump is started,the time of discharge should be recorded. A sample should be collected following the removal of each computed well volume and pH, EC, and temperature measured with a multimeter. All wells should be allowed to stabilize to within 10% of the previous well volume reading, with regards to pH, EC, and temperature,prior to sampling. 6) Prelabled sample bottles, polyethylene and sterilized glass are introduced into the discharge stream of the pump after removing a minimum of three well volumes and after pH, EC, and temperature had stabilized. Required preservatives are generally prepared and placed in the sample bottles in the laboratory prior to the sampling event. All samples for