Ecotoxicity of liners impregnated with resisns – a Microtox bioassay

The aim of the study was to evaluate the toxicity of moulders of felt liners impregnated with resins. After the mounting of the liners in sewerage, the explorer has revealed a decrease in the efficiency of treatment in biological units. The putative cause of this phenomenon might have been an increase in the toxicity of the sewage flowing through the pipes with resin impregnated liners. In order to confirm this thesis, the moulders of the liners were taken to the laboratory to investigate their acute toxicity by a Microtox assay. Two types of liners – impregnated with styrene resin and impregnated with styrene-free resin – were tested. Both moulders were incubated in different media (raw wastewaters, synthetic wastewaters, and distilled water) and under several incubation conditions. The obtained extracts were subjected to Microtox 81.9% Screening Test. The chosen, questionable in the terms of screening results, sample was further subjected to 81.9% Basic Test. The obtained results clearly indicate that the ecotoxicity of the moulders of liners impregnated with styrene-free resin is the issue of concern. The results are surprising, as the substitution of styrene by other components in curable resins is aimed at improving their toxicity properties. However, the styrene-free resin revealed to be responsible for an increase in the sewage toxicity. These results prompt undertaking the ecotoxicity monitoring of materials used in sewerage renovations – not only for the environment protection, but also for the prevention of possible problems in wastewater treatment plants exploitation.