Approved sampling and analysis procedures

Ecology-approved methods

We have approved the sampling and analytical methods referenced in the following sources for use under the MTCA Cleanup Regulations.

Common approved methods

This table includes some commonly used analytical methods for specific hazardous substances and matrices from the sources above. It also has some additional analytical methods we’ve approved. This table does not include our approved analytical methods for sediment and aquatic tissue, which are in the Sediment Cleanup User's Manual (SCUM).

The methods are identified by the hazardous substance (or class of substances) and by the environmental matrix where the substance is sampled: drinking water, aqueous media (e.g., groundwater), solids (e.g., soil), and air.

Table footnotes

1. This method measures arsenic species: total inorganic arsenic (As), arsenite (As³⁺), arsenate (As⁵⁺), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA).
2. This method can quantitate total iron as well as ferrous (Fe²⁺) and ferric (Fe³⁺) iron.
3. Use this method for methyl mercury analysis.
4. This method should not be used for mercury analysis.
5. Qualitative/semi-quantitative method to identify presence and type of hydrocarbons; for quantitative results, use other NWTPH methods.
6. Lower reporting limits are achieved using selected ion monitoring (SIM) and even lower levels can be achieved using isotope dilution (e.g. for very low-level 1,4-dioxane analysis); this method is used for carcinogenic PAHs (benzo[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, chrysene, dibenz[a,h]anthracene, and indeno[1,2,3-cd]pyrene).
7. Not recommended for 1,4-dioxane (use EPA 8270E-SIM instead).

Changes to the approved methods

We will update the list of approved methods as needed. When we add or remove a method from this list, we will announce it in the Contaminated Site Register. Anyone may propose another method for Ecology review and approval.

Which Ecology-approved methods should I use at my site?

The sampling and analytical methods you use must be appropriate for the contaminated site, the media being analyzed, the hazardous substances being analyzed for, and the anticipated use of the data. Under certain circumstances we may require modifying a method or using more than one method.

Petroleum releases have specific minimum testing requirements, found in Table 830-1 in WAC 173-340-900.

Always use an Ecology-accredited laboratory

All environmental data submitted to Ecology must be generated by an Ecology-accredited laboratory, unless otherwise approved by Ecology.

Make certain that the laboratory is accredited for the specific analytical method and environmental matrix you need. A laboratory might be accredited for only certain methods or matrices (such as for solid and chemical materials, but not specifically for aqueous or air). Note some methods accredited for solid and chemical materials cover some aqueous or air samples. Check our Lab Search database to find which labs are accredited for a specific analytical method and environmental matrix or to list the specific analytical methods for any accredited lab.