C.2.2 Procedure (Cont.)

less than 5 percent moisture on a dry weight basis. The material should be

mixed daily to facilitate the drying process. When drying is complete the

sediment is ground to again pass a 2-mm screen. This material is referred to as

the air-dried sediment and will be evaluated in the SLRP for organics and

nutrients.

Step 1c. Chemical Oxidation. Chemical and microbial oxidation of iron

sulfides in some sediment may result in the formation of sulfuric acids and a

significant reduction of pH. This may have a substantial increase in the

solubility of metals. The SLRP addresses this by oxidation with hydrogen

peroxide. The air-dried sediment or wet sediment oven-dried for 48 hr at 95 EC

may be used for this procedure. After drying is complete, 30 percent hydrogen

peroxide (H2O2) is added to rapidly oxidize the sediment, simulating long-term

effects of the oxidation of iron sulfides. A pretest is necessary to determine the

amount of H2O2 necessary to fully oxidize the sediment. Dried sediment (10 g)

is placed in a 250-mL beaker and 30 percent H2O2 is slowly added in 10-ml

increments, each time observing for an effervescent reaction. When there is no

longer an oxidation response from additional inputs of H2O2, the process is

complete. The amount of H2O2 used is multiplied times 10 and used in the

oxidation procedure below; however, no more than 500 mL total should be used.

A large open-top glass container, such as a 4-L beaker is used for the

oxidation process. Clear glass allows for easy viewing of the reaction process.

The large volume is required because of the violent bubbling that occurs as the

H2O2 reacts with the sediment. An amount of 100 g of the air-dried or oven-

dried sediment is placed in the beaker and 100 mL of H2O2 is slowly added. A

glass stirring rod is used to ensure adequate mixing. Allow sufficient time for

the H2O2 to react, and wait until the reaction stops before proceeding to and

more H2O2. Once the entire volume of H202 is determined in the pretest has

been added, allow the reaction to cease and the material to cool to room

temperature before handling. If the pretest indicates H2O2 in excess of 500 mL is

required, do not exceed. Instead, after addition of a total of 500 mL to the

sediment, cover the beaker with a watch glass and allow setting overnight. Bring

the sediment back to dryness by placing in an oven at 95 EC for 48 hr. The

sediment is now ready to be reground and used to prepare runoff samples.

Step 2. SLRP Runoff Water Preparation. The SLRP requires the

preparation of simulated runoff water using wet, unoxidized and dry, and

oxidized sediment using sediment: water ratios corresponding to the suspended

solids concentrations shown in Tables C1 and C2. Each ratio for the sediment

condition should be replicated three times. For purposes of describing runoff

quality from CDFs, the term total contaminants refers to unfiltered samples and

dissolved refers to filtered samples. Volume of sample for each of the sediment

conditions described below is dependent on the required chemical analysis.

Typically, 4 L will be sufficient volume to evaluate priority metals, PAHs,

PCBs, and selected nutrients. The volume required by the analytical laboratory

should first be determined and the necessary volume required can then be

generated. Both dissolved and total contaminants may be determined however,

only dissolved is generally necessary for water quality comparisons. If total

contaminant determinations are required the values can be determined by

Appendix C Test Procedures for Surface Runoff Discharges