1.

Wash the equipment with a nonphosphate detergent.

2.

Rinse the equipment with tap water.

3.

Rinse the equipment with dilute (0.1N) hydrochloric or nitric acid.

4.

Rinse the equipment with reagent water.

Dilute hydrochloric acid is preferred over nitric acid when cleaning stainless steel because

nitric acid may oxidize the steel.

In all cases, waste decontamination fluids should be containerized until the

investigators determine (e.g., through analytical testing) whether the fluids should be treated

or disposed of as hazardous waste.

All equipment should be allowed to dry thoroughly in a dust free environment. If the

equipment is not to be used again immediately, it should be packaged and properly stored to

protect it from dust and dirt. Equipment may be wrapped in aluminum foil (shiny side on the

outside) and placed in a plastic bag. A label should be affixed to the outside wrapping

summarizing the decontamination procedure and stating the date of decontamination.

Decontaminated sampling equipment should not be placed on the ground or on other

contaminated surfaces prior to insertion in the well.

7.3.5

Collecting Ground Water Samples

Monitoring well sampling should always progress from the well that is expected to be

least contaminated to the well that is expected to be most contaminated, to minimize the

potential for cross contamination of samples that may result from inadequate decontamination

of sampling equipment. Samples should be collected and containerized according to the

volatility of the target analytes. The preferred collection order for some of the more

common ground water analytes is as follows (Barcelona et al., 1985b):

1.

Volatile organics (VOAs or VOCs) and total organic halogens (TOX);

2.

Dissolved gases and total organic carbon (TOC);

3.

Semivolatile organics (SMVs or SVOCs);

4.

Metals and cyanide;

5.

Major water quality cations and anions;

6.

Radionuclides.

November 1992

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