Evaluation of the acute toxicity of IHPLUS® on the biomodel water quality indicator: Poecilia reticulata

Abstract

Conventional agriculture depends on the application of fertilizers in order to achieve higher yields; however, it is necessary to strike a balance between their benefits and the alterations they may cause to ecosystems. International organizations regulate their use and commercialization taking into account their efficacy and safety. IHPLUS^®, produced by the Experimental Station of Pastures and Forages "Indio Hatuey" (Cuba), has shown to be effective in different crops and the purpose of this study is to evaluate the effects on water quality in the bioindicator Poecilia reticulata. The fish were exposed to the product, in a static regime for 96 h, at the concentration effective in agriculture (6 %) or diluted to 10⁶ CFU/mL as recommended by EPA OPPTS 885.4000. A group treated with the 6 % product but sterilized and a control group that received no treatment were also included. They were observed for 30 days post-inoculation and weight, mortality and other sublethal effects were assessed. Subsequently, the mean lethal concentration (LC₅₀) and the influence of pH on fish mortality were determined. It was found that at 6 % it caused adverse clinical events and lethal effect in the biomodel. The histopathological lesions corresponded for both the activated and inactivated products. The LC₅₀ was 3.19 %, the toxicity being associated to the acid pH and not to the microbial load present in the bioproduct. It is concluded that IHPLUS^® is safe for Poecilia reticulata at concentrations below 3 %.