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Simplified Ecological Evaluation

Terrestrial Ecological Evaluation Process- The Simplified Evaluation


The purpose of the simplified terrestrial ecological evaluation process is identify those sites that do not have a substantial potential  for posing a threat of significant adverse effects to terrestrial ecological receptors, and thus remove them from further ecological consideration during the remedial investigation and cleanup process.  

For the remaining sites, the process provides several options, including chemical concentrations that may be used as cleanup levels, and the choice of developing site-specific concentrations using bioassays or conducting a site-specific evaluation.

These evaluation procedures focus on the extent of exposure, exposure pathways, and particular contaminants as key factors in evaluating ecological risk.  The steps do not have to be followed in any specific order, and any one step may be used to determine that no further evaluation is required to support a determination that a site does not pose a substantial threat of significant adverse effects to terrestrial ecological receptors.

Note: To perform this analysis you must have already determined that you qualify to conduct a simplified evaluation at your site.  If you have not yet made this determination, then you should do so now


CRITERIA:

No further evaluation is required if the conditions at the site meet any one of the five simplified screening criteria identified below. They are divided into three categories of analysis: exposure analysis, pathway analysis, and contaminant analysis.

If none of the five simplified screening criteria apply to your site, you may use the chemical concentration numbers listed in Table 749-2 as cleanup levels.   Alternatively, you may always choose to conduct a site-specific evaluation.

Simplified Evaluation Screening Criteria: No further TEE required if any of the conditions below apply.


Exposure Analysis: No further TEE is required if the conditions at your site meet either of the exposure conditions below.

  1. The total area of soil contamination at the site must be less than or equal to 350 square feet; or

          Here is an aid to calculating area.

  1. Land use at the site and surrounding area make substantial wildlife exposure unlikely based on completion of   Table 749-1.   Note: If an experienced wildlife biologist does not conduct the habitat quality evaluation, "high" habitat quality must be assumed.

Pathway Analysis: No further TEE required if the conditions at your site provide no potential exposure pathways from soil contamination to soil biota, plants or wildlife.

  1. There is no potential exposure pathways from soil contamination to soil biota, plants, or wildlife.

Notes for the pathway analysis: 

For a commercial or industrial property, only potential exposure pathways to wildlife need be considered.
Only exposure pathways for priority chemicals of ecological concern listed in Table 749-2 at or above the concentrations provided must be considered.

Incomplete pathways may be due to the presence of man-made physical barriers, either currently existing or to be placed (within a time frame acceptable to the department) as part of a remedy or land use.  To ensure the barriers are maintained, a restrictive covenant shall be required by the department under a consent decree, agreed order, enforcement order, or as a condition in a written opinion letter issued under the Voluntary Cleanup Program.

An institutional control may be required to ensure that this criterion will continue to be met in the future.


If the demonstration is based on a conditional point of compliance, then an institutional control is required to prevent exposure caused by excavation of deeper soil.

If the demonstration is based on commercial or industrial land use, then an institutional control is required to prevent exposure to plants and soil biota in the event of a change in land use.

If the incomplete pathway is due to a man-made physical barrier, then an institutional control is required to ensure that the manmade barrier is maintained.

If the incomplete pathway is based on physical barriers you plan to put in place within a time frame acceptable to the department, then If the barrier placement is not accomplished by that completion date, the site must be reevaluated using existing site conditions.

The requirements and procedures for establishing institutional controls are specified in WAC 173-340-440.

Contaminant Analysis: No further TEE is required if the conditions at your site meet either of the criteria specific to the contaminants at your site. 

  1. No hazardous substances listed in Table 749-2 for which a value is listed is, or will be, present in the soil at  the point of compliance, at a concentration exceeding the value in Table 749-2, using the statistical compliance methods described in WAC 173-340-740(7).  If a hazardous substance listed in Table 749-2 does not have a value listed, then Criteria 5 is applicable.

  2. No hazardous substances listed in Table 749-2 for which a value is listed is, or will be, present in the soil within 6 feet of the ground surface (conditional point of compliance) at concentrations likely to be toxic, or with the potential to bioaccumulate, based on bioassays using methods approved by the department.

Notes for the exposure, pathway, and contaminant analysis: 

If the demonstration is based on a conditional point of compliance, then institutional controls are required to ensure the condition will continue to be met in the future. 

Cleanup remedies that rely on chemical concentrations for industrial or commercial sites in Table 749-2 shall include appropriate institutional controls to prevent future exposure to plants or soil biota in the event of a change in land use.

The requirements and procedures for establishing institutional controls are specified in WAC 173-340-440.

A PDF form is available for documenting your decision-making.

Here you may view an HTML version of the form.

REFERENCE:

WAC 173-340-7492(2)

Please contact David Sternberg if you have any questions or comments about the TEE web pages.

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