Container Cleaning

Due to the sensitivity of tests examining waterborne trace metals, sample containers must be thoroughly cleaned. The following schedule must be followed for the preparation of all sample bottles and accessories, whether glass, polyethylene, polypropylene or Teflon:

• Wash with detergent and tap water

• Rinse with 1:1 nitric acid

• Rinse with tap water

• Rinse with 1:1 hydrochloric acid

• Rinse with tap water

• Triple rinse with distilled (or deionized) water SAMPLE PRESERVATION

Water samples are susceptible to rapid physical or biological reactions that may take place between sampling and analysis. This time period can exceed 24 hr due to laboratory capacity needed to handle unpredictably varying amounts of samples resulting from aleatory rainfalls (Geiger 1981).

Preservation techniques are recommended to avoid sample changes resulting in large errors. Refrigeration of samples at 4°C is commonly used in fieldwork and helps to stabilize samples by reducing biological and chemical activity. All samples except metals must be refrigerated.

In addition to refrigeration, specific techniques are required for certain parameters. They consist of the addition of chemical compounds, biocides, etc. More detailed information can be found in EPA 1979a, 1980b.

The decision to eliminate a portion of the drainage system from further sampling must include a review of data QA/QC procedures. Review of contaminant data for drainage systems must be performed to ensure that analytical results are properly interpreted, and that detection of potential sources is not missed because of field or laboratory constraints.

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