H.3.5 Greenhouse operation and bioaccumulation techniques

Sediment pH. Ten (10) g (ODW to nearest 0.001 g) of original wet, AD, or

ADW sediment are weighed into a tall 50-ml Pyrex glass beaker. Twenty

(20) mL of distilled water are added and the mixture is stirred with a polyethy-

lene rod until all particles are saturated. The mixture is stirred with a magnetic

stirrer for 1 min every 15 min for 45 min. After 45 min, the pH electrode is

placed into the solution above the surface of the sediment and the pH is read on a

pH meter (Folsom, Lee, and Bates 1981).

Organic matter. OM is determined by weight loss on ignition at 550 oC on

AD and ADW sediment. Procedure No. 209E (American Public Health Associa-

tion 1976) is used for this test. A 5-g subsample (ODW) is weighed to the

nearest 0.001 g and dried at 105 + 2 oC until constant weight (48 hr). Five (5) g

(ODW to the nearest 0.001 g) of sediment is weighed and combusted at

550 + 5 EC for 24 hr in a muffle furnace. The sample is allowed to cool to room

temperature in a moisture desiccator and weighed to the nearest 0.001 g. Weight

loss on ignition is calculated and reported as percent OM using the following

formula:

weight oven-dry sediment-weight combusted sediment

%OM =

100

weight oven-dry sediment

H.3.5 Greenhouse operation and bioaccumulation techniques

Four replicates of each sediment condition are prepared by placing 4,500 g

(ODW) of sediment (one 500-mL scoop-full at a time) into each prepared 7.6-l

Bain-Marie container. Seedlings of the appropriate plant species are transplanted

into the wetland sediment or in premoistened terrestrial sediment. Four

replicates of reference sediment or soil are also prepared and planted with four

replicates each of SA or CE. The replicates are randomly placed on tables in the

greenhouse. Day length of 16 hr is maintained. Light fixture faces should be

130 cm from the top of the 19.0-L bucket. The 130-cm height allows maximum

potential plant growth to occur without damage from the heat produced. Lights

are arranged in a pattern of alternating a high-pressure sodium lamp and a high-

pressure multi-vapor halide lamp. Alternating the lamps provides an even

photosynthetic active radiation (PAR) distribution pattern of 1,200

uEinsteins/m2. The temperature of the greenhouse is maintained at 32+ 2 EC

maximum during the day and 21 + 2 EC minimum at night to simulate a summer

environment. Relative humidity is maintained as close to 100 percent as

possible, but never less than 50 percent. Soil/sediment moisture content is

maintained between 30 and 60 MPa (field capacity is 30 MPa) by adding RO

water as necessary. Soil moisture tensiometers, placed in each container, are

monitored daily and water added when tensiometers read greater than 60MPa.

RO water is added to the outer container up to the level of the inner container

and allowed to move through holes in the bottom of the inner container. When

tensiometers read less than 40 MPa, the water is siphoned from the outer

container.

Appendix H Plant Bioaccumulation Procedures