Large Volume Samples for Organic Compound Determinations

Assorted Sensitive Inorganic Species NOf, NH4+, Fe(II)

Trace Metals for Mobile Substance Load+++


Trace Metal Samples for Specific Geochemical Imformation+++

S a, Sensitive Inorganics i

Major Cations and Anions

Essential Elements

Water-Level Measurements

Representative Water Access

Verification of Representative Water Sample Access

Sample Collection by Appropriate Mechanism

Minimal Sample Handling

Head-Space Free Samples

Minimal Aeration or Depressurization

Minimal Air Contact, Field Determination

Adequate Rinsing against Contamination

Minimal Air Contact, Preservation


Pump water until well purging parameters (e.g., pH, TC'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/cations, alkalinity. Do not filter: TOC, TOX, volatile organic compound samples. Filter other organic compound samples only when required.

Samples for determinations of 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.

Storage Transport

Minimal Loss of Sample Integrity Prior to Analysis

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

* Denotes samples that should be filtered to determine dissolved constituents. Filtration should be accomplished preferably with inline filters and pump pressure or by N2 pressure methods. Samples for dissolved gases or volatile organics should not be filtered. In instances where well development procedures do not allow for turbidity-free samples and may bias analytical results, split samples should be spiked with standards before filtration. Both spiked samples and regular samples should be analyzed to determine recoveries from both types of handling.

** Denotes analytical determinations that should be made in the field.

FIG. 9.15.4 Generalized flow diagram of groundwater sampling protocol. (Reprinted from U.S. Environmental Protection Agency, 1993, Subsurface characterization and monitoring techniques, a desk reference guide, Vol. 1, USEPA/625/R-93/003a [May] U.S. EPA.)



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