2.3.5 Reference Material for Plant and Animal Uptake Evaluations

Test procedures are conducted with the control material in the same way as with

the dredged material samples. Excessive mortality or other unacceptable response

in the control material indicates a problem with test conditions or organisms and

can invalidate the test.

Control water in biological tests with effluent or runoff (Chapters 4 and 5) is

often the culture water in which the test organisms have been maintained in the

laboratory. Control soil in biological tests of plant and animal uptake under

terrestrial conditions (Chapters 8 and 9), or control sediments in aquatic and

wetland tests, is often the soil or sediment within which the test plants or animals

resided prior to collection in the field, or within which they were maintained in the

laboratory. Generic control soils or sediments consisting of field-collected or

laboratory prepared soil or sediment may also be appropriate in some cases.

Under certain circumstances, it may be appropriate to use specialized control

soil or sediment to help discern the potential contribution of a known variable to

the results of a test. For example, if the dredged material samples being tested are

very fine-grained, it may be desirable in some cases to use a grain-size control (a

soil or sediment physically similar to the dredged material and essentially free of

contaminants) in addition to the standard control to indicate the degree to which

the test plants' or animals' response may be influenced by the grain size of the test

soils or sediments.

2.3.5 Reference Material for Plant and Animal Uptake Evaluations

Appropriate reference material is an integral component of testing for

evaluation of uptake of COC by plants and animals (Chapters 8 and 9). A

reference soil is used in terrestrial evaluations, and reference sediment is used in

wetland and aquatic evaluations. In these evaluations, it is important to clearly

distinguish between control and reference materials and that both be properly

selected and used in testing for effects of dredged materials on plants or animals

and evaluating the results.

Reference material concept. Reference soil or sediment is the key to

evaluating the need for management actions for plants or animals. After a test has

been accepted by the control soil or sediment, reference soil or sediment results

provide the point of comparison (reference point) against which any potential

effects of the dredged material are evaluated. With a proper reference sediment,

this will identify the extent, if any, to which the dredged material may cause

conditions different from those at the reference site.

The essential characteristic of reference soil or sediment is that it reflects

environmental conditions that would have existed in the vicinity of the CDF if

dredged material had never been placed there, but all the other influences on

environmental quality at the site had occurred. The reference soil or sediment

reflects the environmental quality in the vicinity of the CDF because of all

influences except dredged material discharges and is as free of COC as the

vicinity of the CDF. In addition to this essential characteristic, the physical

characteristics of reference soil or sediment should be sufficiently similar to the

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Chapter 2 Structure and Approach of the UTM