Experimental/Manipulative Studies (cont.)

ERDC TN-DOER-C23

September 2001

the 1970's known as the Dredged Material Research Program (DMRP). The DMRP laid the

foundation for many of the tests and procedures used to assess dredged material today, and the FVP

was designed as a follow-on program to refine and improve these tools for regulatory implementa-

tion. The FVP was one of the first experimental/manipulative type validation studies and was

designed to evaluate these proposed tests for the USACE/USEPA effects-based testing program

prior to regulatory implementation. A principal objective of the aquatic portion of the FVP was to

verify the predictive accuracy of proposed biological tests by measuring the same response in the

same selected species in both laboratory bioassays and in the field. Additional objectives included

determining the variability and reproducibility inherent in the test method and evaluating the

correlation between tissue residues in field-exposed organisms and effects observed in both the

laboratory and the field (Gentile et al. 1987).

Although numerous marine species representing four different phyla were evaluated as part of the

FVP including annelids (N. arenaceodentata, Nephtys incisa), molluscs (Mytilus edulis, Yoldia

limatula, and Mulinea lateralis), arthropods (Ampelisca abdita and Mysidopsis bahia), and fish

(Menidia menidia, Cyprinodon variegatus, Ammodytes americanus, Paralichthys dentatus, and

Pseudopleuronectes americanus), only biological testing with N. incisa, M. edulis, A. abdita, and

M. bahia were included in the field validation portion of the study. The remaining species were

evaluated for suitability as test organisms and to assess variability and reproducibility of proposed

laboratory bioassay test methods.

The dredged material evaluated in the FVP was collected from Black Rock Harbor (BRH),

Bridgeport, CT. A historical dredged material disposal site in Central Long Island Sound (CLIS)

was selected as the disposal site for the BRH material and the subsequent field monitoring portion

of the FVP. The reference sediment used for comparison was collected from the South Reference

site of the CLIS. The BRH dredged material contained moderate to high concentrations of

polychlorinated biphenyls (PCBs) (6.4 ppm), polycyclic aromatic hydrocarbons (PAHs) (142 ppm),

and metals including copper (2,900 ppm), chromium (1,480 ppm), zinc (1,200 ppm), lead (380

ppm), nickel (140 ppm), cadmium (24 ppm), and mercury (1.7 ppm) (Peddicord 1988; Rogerson,

Schimmel, and Hoffman 1985).

Stations used to monitor the biological effects in this study were located along the primary axis of

current flow (east to west) at the CLIS disposal site. Stations were located at the center of the mound

and 200, 400, and 1,000 m to the east along the primary axis of current flow to represent a gradient

of decreasing exposure (Figure 1). The site was monitored at these locations for a year preceding

disposal of the dredged material and for 3 years post-disposal. Results of acute and chronic

laboratory tests conducted on the material just prior to disposal were compared with effects observed

in the field following disposal. In addition, material was periodically collected from the disposal

mound and evaluated using the laboratory tests to determine whether laboratory test results

correlated with changes in field response.

Of the toxicity tests/end points evaluated, measures of mortality, scope for growth (SFG), repro-

duction, and population response were recommended for predisposal permit testing. Of these end

points, only mortality and SFG could be directly validated in field-exposed organisms. Results from

laboratory tests measuring survival indicated that only tests with the amphipod A. abdita showed

significant mortality directly related to the percentage of BRH sediment. Additionally, laboratory