Table 11206 Generalized Groundwater Sampling Protocol

Step

Goal

Recommendations

Hydrologic measurements Well purging

Sample collection Filtration and preservation

Field determinations Field blanks and standards

Sample storage and transport

Establish nonpumping water level.

Remove or isolate stagnant H2O which would otherwise bias representative sample.

Collect samples at land surface or in well-bore with minimal disturbance of sample chemistry.

Filtration permits determination of soluble constituents and is a form of preservation. It should be done in the field as soon as possible after collection.

Field analyses of samples will effectively avoid bias in determining parameters and constituents which do not store well; e.g., gases, alkalinity, pH.

These blanks and standards will permit the correction of analytical results for changes which may occur after sample collection: preservation, storage, and transport.

Refrigerate and protect samples to minimize their chemical alteration prior to analysis.

Pump water until well purging parameters (e.g., pH, T, iT 1 Eh) stabilize to ±10% over at least two successive well volumes pumped.

Pumping rates should be limited to —100 mL/min for volatile organics and gas-sensitive parameters.

Filter: Trace metals, inorganic anions and cations, alkalinity. Do not filter: TOC, TOX, volatile organic compound samples; other organic compound samples only when required.

Samples for determining gases, alkalinity, and pH should be analyzed in the field if at all possible.

At least one blank and one standard for each sensitive parameter should be made up in the field on each day of sampling. Spiked samples are also recommended for good QA/QC.

Observe maximum sample holding or storage periods recommended by the Agency. Documentation of actual holding periods should be carefully performed.

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