Laserfiche WebLink
1 <br /> TASK DESCRIPTIONS <br /> BC - ARCO NORTHERN CALIFORNIA PROGRAM <br /> DRILLING <br /> Soil borings and installation of monitoring wells at saes involve the use of drilling equipment. <br /> The drilling of soil borings involves a mobile drill ng using a hollow stem auger, reverse air <br /> rotary, or dual-tube percussion The collection of soil samples involves using a drop-hammer <br /> assembly The borehole will be backfilled with cement and/or bentonite grout if no well is to <br /> be installed The installation of a monitoring well involves the completion of the open boring ! <br /> with screened and blank casing, the placement of a filter pack, and installing a sanitary seal <br /> Hazards involved with drilling consist of the same chemical hazards and physical hazards <br /> described under Hazard Analysis on pages 4 through 9 Other hazards associated with drilling <br /> include the following <br /> Drilling Equipment Hazards <br /> Drilling involves the use of large and heavy pieces of equipment, especially augers Special <br /> attention is needed when this equipment is pulled overhead Loose clothing and other items may ! <br /> become entangled in the rigging and can result in injury Traffic also presents a hazard to <br /> personnel involved in drilling All field personnel must be aware of all drilling activities and <br /> general traffic at all times <br /> Dust Hazards <br /> Drilling, especially with rotary drills using air percussion, can create high levels of airborne dust. <br /> Inhalation of dusts can result in increased exposures to soilbound chemicals and pneumoconiosis <br /> Overexposure may occur when the dust becomes visible in the normal light. Signs of potential <br /> overexposure are congestion of the nasal passages and irritation of the eyes and respiratory <br /> system <br /> GROUNDWATER SAMPLING <br /> Groundwater sampling is a required element of quarterly monitoring of most sites Samples of <br /> groundwater may be obtained on or near the site from monitoring wells, existing production <br /> (supply) wells, and from seeps or springs Results of groundwater sample analyses not only <br /> provide an indication of water quality at the particular sampling points but taken together can <br /> provide an indication of the extent of contaminant plume movement due to subsurface <br /> groundwater transport. <br /> Groundwater sampling involves well evacuation (purging) using some form of submersible pump <br /> or bailer Groundwater samples should be collected within 2 hours after the well has been <br /> evacuated to assure the sample is representative of aquifer conditions When the recovery of the <br /> well exceeds 2 hours, the well should be evacuated to dryness once and then the well should be <br /> 1711Y?*Z',0I71NOC\NORTHARGO <br /> QMS PSCO <br />