G.3.1.2 Taxonomy.

next generation of cocoons. E. fetida has a maximum life expectancy of 4 to 5

years, although between 1 and 2 years is more usual.

Eisenia fetida is an epigeic species (i.e., they live and feed on the surface)

that rarely inhabits agricultural soils but is found in compost piles, manure piles,

and other disturbed sites rich in organic matter. The rate of soil consumption in

the laboratory by E. fetida individuals weighing 300 mg has been estimated at 16

mg soil/individual/day (Stafford and Edwards 1985).

Worms digest the microorganisms from ingested soil and organic debris,

which illustrates their interactions with the soil environment. Independently of

whether mineral matter or fibrous organic material was ingested, approximately

2.5 h were required at 25 EC for E. fetida to pass ingesta from mouth to anus

(Hartenstein, Neahauser, and Narahara 1981).

G.3.1.2 Taxonomy.

The taxonomic status of what Bouch (1992) calls the complex is unclear in

the literature. Some authors consider this complex to consist of two subspecies,

E. fetida fetida and E. fetida andrei, while other authors consider the complex to

consist of two separate species, E. fetida and Eisenia andrei. This guide chooses

to use the subspecies designations. The dorsal surface of E. f. andrei is uniformly

reddish, while E. f. fetida is striped or banded. Bouch (1992) states that the

andrei form is relatively homogeneous, while fetida may be multispecific. It is

recommended that the andrei form be used as the test organism, that is,

E. f. andrei.

G.3.2 Laboratory procedures

Culture of Test Organisms. Earthworms are obtained through either

culture procedures or from commercial vendors.

Age. Tests with E. fetida tests should use sexually mature fully clitellate

earthworms.

Experimental Design. Decisions concerning the various aspects of

experimental design, such as the number of replicates, the number of test

containers, and the mass of earthworms, should be based on the amount of tissue

material needed for chemical analysis.

Test Material. Test materials are (1) the dredged material being evaluated,

(2) reference soil, and (3) control material such as earthworm culture media for

use in evaluating test acceptability.

Test Containers. Test material is placed in transparent Plexiglas cylinders

30 cm deep and 15 cm in diameter. The cylinder ends are closed with a 17-cm

PVC and either 340 Nytex mesh or cotton muslin cloth. The bottom end is then

placed in a 20-cm-diam plastic dish of test water to allow water movement into

the substrate and allow earthworms to move into areas of optimum moisture.

Appendix G Animal Bioaccumulation Test Procedures