4.4.5 Tier III - Effluent Elutriate - Water Quality Decision

program to assist in the analysis of effluent elutriate data and the comparisons

with WQS. The EFQUAL application considers and tabulates the EFQUAL

application, along with documentation, and can be downloaded from the USACE

DOTS website at www.wes.army.mil/el/dots. If desired, data analyses procedures

for reducing effluent elutriate data and comparison of effluent with WQS using

manual calculations are available (Appendix B; Appendix B of the ITM

(EPA/USACE 1998); and Palermo 1985 a-d).

4.4.5 Tier III - Effluent Elutriate - Water Quality Decision

After consideration of the Tier III effluent elutriate water quality information,

to include consideration of initial mixing, one of the following conclusions is

reached (Figure 4-2):

1. Information is sufficient to reach an effluent decision regarding water

quality. In this case either:

a. WQS exist for all COC and are met for all COC after consideration of

mixing. No further effluent evaluations are necessary. Or,

b. WQS are exceeded for one or more COC after consideration of

mixing, and management actions should be considered.

2. Information is not sufficient to reach a decision, which includes cases

where there are no applicable WQS or there is concern about interactive

effects. Evaluation of effluent toxicity, or management actions as an

alternative to further evaluation should be considered. If management

actions are selected, no further effluent evaluation is necessary.

In determining the potential level of concern regarding interactive effects, the

number and classes of COCs that may be exceeded and the relative degree of

exceedences should be considered. Interactive effects may be purely additive,

synergistic (the resulting effect is greater that the sum of the effects from

individual COCs), or antagonistic (the resulting effect is less that the sum of the

effects from individual COCs). WQS were developed for single contaminants.

Where several are present and are close to WQS, especially if they are the same

class of contaminants (metals, chlorinated organics, metal-organic complexes,

nonpolar organics, etc), interactive effects may be of concern.

4.4.6 Tier III - Effluent Toxicity Evaluation

Effluent toxicity should be evaluated in Tier III if there are COC for which

there are no WQS or if there is concern regarding potential interaction of multiple

contaminants. Bioassays provide information on the toxicity of contaminants not

included in the WQS and indicate possible interactive effects of multiple

contaminants. Tier III provides for evaluations of effluent toxicity based on use

of the effluent elutriate as a medium to conduct water column toxicity tests.

Tier III toxicity testing assesses the potential toxicity of effluent to appropriate

sensitive water column organisms. As with chemical evaluations of effluent quality,

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Chapter 4

Effluent During Disposal Operations