Abstract

CARABALI-RIVERA, Y. S; BARBA-HO, L. E  and  TORRES-LOZADA, P. Determination of leachate toxicity through acute toxicity using Daphnia pulex and anaerobic toxicity assays. Ing. Investig. [online]. 2017, vol.37, n.1, pp.16-24. ISSN 0120-5609.  https://doi.org/10.15446/ing.investig.v37n1.54220.

ABSTRACT The municipal solid waste (MSW) of large cities, in particular the ones of developing countries, is mainly disposed in landfills (LFs), whose inadequate management generates the emission of greenhouse gases and the production of leachates with high concentrations of organic and inorganic matter and, occasionally heavy metals. In this study, the toxicity of the leachates from an intermediate-age municipal landfill was evaluated by ecotoxicity and anaerobic toxicity tests. The acute toxicity assays with Daphnia pulex presented a toxic unit (TU) value of 49,5%, which indicates that these leachates should not be directly discharged into water sources or percolate into the soil because they would affect the ecosystems related to these waters. According to statistical analyses, the leachate toxicity is mainly associated with the inorganic fraction, having the chlorides, calcium hardness and, calcium as the greatest influences on the toxicity. The anaerobic toxicity test showed that in the exposure stage, the methanogenic activity exceeded the control one, which suggests that the anaerobic bacteria easily adapted to the leachate. Therefore, this treatment could be an alternative to mitigate the toxicity of the studied leachates. The inhibition presented in the recovery stage, represented by a reduction of the methanogenic activity, may be because the amount of supplied substrate was not enough to fulfill the carbon and nutrient requirements of the bacterial population present.

Keywords : Daphnia pulex; leachate; municipal landfill; anaerobic toxicity.

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