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Sampling and Analysis Plan - Addendum Specific to Field Sampling Plan for Delivery Order TO42
Section 4 - Decontamination Procedures
All equipment that may directly or indirectly come into contact with samples will be decontaminated in a designated decontamination area. These include casing, drill bits, drilling rods, auger flights, portions of drill rigs that stand above boreholes, sampling devices, and downhole instruments. In addition, the contractor will take care to prevent the sample from coming into contact with potentially contaminating substances such as tape, oil, engine exhaust, corroded surfaces, and dirt.
The following procedure will be used to decontaminate large pieces of equipment such as casing, drill bits, pipe and rods, and those portions of the drill rig that may stand directly over a boring or well location or that comes into contact with casing, auger flights, pipe, or rods. The external surfaces of equipment will be washed with high-pressure hot water and if, necessary, scrubbed until all visible dirt, grime, grease, oil, loose paint, rust flakes, etc., are removed. The equipment shall then be rinsed with potable water. The inside surfaces of casing, drill rod, and auger flights will also be washed as described.
The following procedure will be used to decontaminate sampling and drilling devices such as split spoons, core barrels, and bailers that can be hand-manipulated. For sampling and smaller drilling devices, the equipment will be scrubbed with a solution of potable water and Alconox, or equivalent laboratory-grade detergent. Then the equipment will be rinsed with copious quantities of potable water followed by ASTM Type II reagent water. (If equipment has come into contact with oil or grease, rinse the equipment with pesticide-grade methanol followed with pesticide-grade hexane.) The equipment will be air dried on a clean surface or rack, such as Teflon�, stainless steel, or oil-free aluminum elevated at least 2 feet above ground.
Reagent-Grade II water, methanol, and hexane will be purchased, stored, and dispensed only in glass, stainless steel, or Teflon containers. These containers will have Teflon caps or cap liners. It is the contractor�s responsibility to assure these materials remain free of contaminants. If any question of purity exists, new materials will be used. Methanol and hexane are to be stored in the firehouse flammable liquids storage locker or at CSSA�s hazardous materials pharmacy, when not in use.
Drill rigs, drill pipe and other equipment that does not come into contact with the sample medium will be decontaminated with a steam cleaner before initial use and after each borehole is completed. Drill bits will be decontaminated with a steam cleaner prior to use at each boring or monitoring well location. If hot water cleaning alone is found to be ineffective, the equipment may be scrubbed with laboratory-grade detergent, then rinsed with high-pressure steam. All visible dirt, grime, grease, oil, or loose paint will be scrubbed until it has been removed. When possible, drilling will proceed from the �least� to the �most� contaminated sites.
Casing, centralizers, and well screens will either be certified clean by the manufacturers or will be decontaminated by steam cleaning.
Prior to well development, equipment such as pumps on surge blocks will be decontaminated by flushing or pumping laboratory-grade detergent solution, potable water, then ASTM Type II reagent water (reagent Grade II water) through the internal components in the order listed below. The exterior of the pump inlet hose will be steam cleaned.
Sampling equipment includes augers, continuous-core samplers, hand trowels, bailers, pH meters, conductivity meters, shovels, knives, spatulas, and composition bowls that directly contact samples. The following steps must be followed when decontaminating this equipment:
Set up a decontamination area at the site. The decontamination area should progress from �dirty� to �clean� and end with an area for drying decontaminated equipment. At a minimum, clean plastic sheeting must be used to cover the ground, tables, or other surfaces on which decontaminated equipment is to be placed. However, sampling equipment to be used for organic sample collection will not come into contact with plastic after the final rinse, and oil-free aluminum foil must be used. Plastic sheeting must also be placed to capture reagent Grade II water, hexane, and methanol used for rinsing equipment.
Wash the item thoroughly with soapy, laboratory-grade detergent solution. Do not submerge pH meters or conductivity meters. Use a stiff-bristle brush to dislodge any clinging dirt. Disassemble any items that might trap contaminants internally before washing. Do not reassemble until decontamination is complete, and items are dry.
Rinse the item in clear potable water. Rinse water should be replaced as needed, generally when cloudy.
Rinse the item with ASTM Type II reagent water.
Rinse equipment with pesticide grade methanol.
Rinse equipment with pesticide grade hexane.
After drying, wrap the cleaned item in oil-free aluminum foil for storage at least 2 feet above the ground.
After decontamination activities are completed, collect disposable gloves, boots, and clothing. Place contaminated items in proper containers for disposal.