Comparative toxicity of polychlorinated biphenyls to earthworms Eisenia foetida and Lumbricus terrestris

Abstract

Effects of polychlorinated biphenyls (PCB; Aroclor 1254) in the manure worm, Eisenia foetida, on survival (LC 50/LD 50), and ability of coelomic leukocytes (also called coelomocytes) to form secretory rosettes (SR) and erythrocyte rosettes (ER) with, and to phagocytose antigenic rabbit red blood cells were determined and compared with those published for the earthworm, Lumbricus terrestris. Using a 5-day filter paper contact exposure protocol, LC 50 and LD 50 were 30·4 μg cm −2 and 4500 μg g −1 dry mass, respectively. Nominal PCB exposure concentrations of 5·0 and 10·0 μg cm −2 resulted in tissue levels of 1400 and 2900 μg g −1 dry mass. These body burdens resulted in significant reduction in SR formation by 18 and 52%, respectively. ER formation and phagocytosis were reduced 52 and 61%, respectively, only at the higher tissue concentration. Compared to L. terrestris, E. foetida: (1) accumulated considerably more PCB at each exposure concentration; (2) showed lower LC 50, but higher LD 50; and (3) exhibited effects on coelmocytes only at tissue PCB concentrations that caused some mortality. In terms of lethality and immunomodulation of SR, ER and phagocytosis, E. foetida appears to be more resistant to PCB than L. terrestris.