Materials and equipment

samples are composited and mixed, using a motorized mixer (to ensure a

homogenous sediment sample). Any unused sediment is returned to the con-

tainers, stored at 4 oC, and later discarded if there is no further need for the

sediment.

Materials and equipment

The following items are required to conduct the laboratory test:

a. Twelve to fifteen 22.6-L cylindrical plexiglass units, 120 cm in height

and 15.5 cm in diameter attached to a 30-cm, 2-plexiglass base (Fig-

ure C1). The units should be fitted with a sampling port.

b. Twelve plexiglass plungers, 80 cm in length with a wire hook attached at

the top.

c. Twelve pint-size bottles of mineral oil.

d. Six aquarium pumps (two small-scale units per pump) or some other

source of air supply.

e. Twelve 1-cm-long air stones.

Two plexiglass tubes, 130 cm in length, 7.28-cm inside diameter.

g. Two large funnels, 40.8-cm top diameter, 6.60-cm outside diameter at the

base.

h. Tygon tubing, 3.02-mm inside diameter.

Test procedure

Step 1 - Add contaminated sediment to the units. The contaminated

sediment is mixed, then placed in the bottom of the small-scale units to a depth

of 10 cm (Figure C1). It is important to add the sediment carefully to avoid

splashing on the sides of the units. Three of the units are reserved for capping

material only as described in Step 2.

Step 2 - Add capping material. The capping material is mixed and then

added in varying thicknesses (e.g., 10, 20, and 30 cm) to triplicate units con-

taining the contaminated sediment (Figure C1). Three units with contaminated

sediment receive no cap. An additional three units receive 10 cm each of cap-

ping material only. Units containing contaminated sediment alone and units with

capping material alone serve as controls.

Step 3 - Water addition and unit aeration. For an estuarine or marine

simulation, 10 L of artificial seawater is prepared using artificial sea salts to

Appendix C Capping Effectiveness Tests