NASCIMENTO, Samanda Costa do.
Résumé:
Contamination of the terrestrial ecosystem caused by landfill leachate can cause irreparable
damage to soil organisms, as well as to human health. Thus, the aim of this study was to
determine the ecotoxicity of in natura landfill leachate using earthworms of the species Eisenia
andrei and seeds of Solanum lycopersicum, Lactuca sativa and Brassica oleracea as test
organisms. Leachate samples were collected at the Campina Grande Landfill, Paraíba, Brazil.
The effluent ecotoxicity in Eisenia andrei earthworms was determined by means of lethality
tests (preliminary, definitive and recontamination) and escape behavior; and in seeds by
determining root growth, relative root growth, relative seed germination, germination index and
EC50. The results showed that the leachate caused a lethal effect on earthworms from
concentrations of 25% (26 mL.kg-1
), presenting a LC50 of 53% (55.06 mL.kg-1
) for the
preliminary test and 56% (58.5 mL.kg-1
) for the definitive. Furthermore, it was observed that
the higher concentrations caused deformations in the bodies of the organisms and behavioral
change. The recontamination test did not show a high lethal effect, however, it caused serious
damage to earthworms of the species Eisenia andrei, such as the stimulus to self-mutilation.
The leakage test showed that all leachate concentrations in the soil, including the lowest (10
and 14%), caused the organisms to escape, with a loss of habitat in the pollutant concentration
in 53.8% (55.8 mL .kg1
). The effluent phytotoxicity showed variations between the analyzed
samples and between the species, whose species sensitivity scale was cabbage (EC50= 7.55%)
< lettuce (EC50 = 8.52%) < tomato (EC50= 12.20%). It was also found that fresh leachate is
more phytotoxic than preserved leachate, in which the preserved sample had an overestimated
EC50 value. Regarding the test organisms used in this study, the three seed species were more
sensitive than the earthworms, as they had lower EC50 values, which shows that the earthworms
were more resistant to contamination. It was concluded that the leachate was toxic for the
studied species, so that the use of test organisms proved to be excellent bioindicators of
environmental contamination.
