ABSTRACT
The disposal of large amounts of coal mining waste chemically modifies the soil, and this may change the structure and activity of soil fauna. The objective of this investigation was to study the ecotoxicological effects of depositions of pyritic waste (coal plus pyrite) in two soils collected in Santa Catarina, Argissolo Vermelho-Amarelo (Ultisol) e Nitossolo Háplico (Hapludox), at the application rates of 0, 2.5, 5, 10, and 20 % of that residue. Survival and reproduction of Enchytraeus crypticus and germination of Avena sativa and Lotus corniculatus were tested. The pH value, regardless of the type of soil, decreased as the rate of pyritic waste increased. Pyritic waste at the lowest rate resulted in negative effects on E. crypticus, as shown by reduction in the adult survival rate and no reproduction. In survival and reproduction testing of enchytraeids, the value of LC50 (estimated concentration that can cause negative effects on the survival and germination of 50 % of a group of organisms) was below 4 %, and EC50 (negative effects on reproduction) was less than 2.5 % for both soils. Exposure of A. sativa to the two soils did not have a toxic effect, nor did exposure of L. corniculatus to Hapludox. However, in the Ultisol, contamination caused effects at the lowest rate for L. corniculatus. In the seed germination test, only L. corniculatus showed sensitivity in the Ultisol (LC50<4 %). High sensitivity to the application of pyritic residue adversely affects soil organisms, both in the short term and long term.
pyritic waste; Enchytraeus crypticus; Avena sativa; Lotus corniculatus
