The biomass, survival, reproductive and biomarker responses of Helix pomatia to soil contaminated with treated and untreated wastewater.

Abstract

Wastewater treatment facilities in developing countries like South Africa are major sources of contaminants via effluent into the environment, which could portend high toxicity risks for non-target flora and fauna. To this end, a study was conducted to determine the ecotoxicological responses of selected organism to treated and untreated wastewater from the wastewater treatment plants in an industrial town. The snail Helix pomatia was exposed to OECD artificial soil spiked with untreated or treated wastewater at the following concentrations: 0, 25, 50, 75, 100%. The ecotoxicological responses of Helix pomatia to wastewater were determined by assessing the biomass, survival, reproduction and biomarker responses (Catalase ‒ CAT and Acetylcholinesterase ‒ AChE activities). The overall results showed significant effects on the survival, reproduction and biomass of H. pomatia. Similar results were observed for juvenile emergence. An EC50 of 5.751% for egg production and an EC50 of 6.233% for juvenile emergence were determined in the untreated wastewater. Such indices could not be computed for the treated wastewater, indicating a decreased in toxicity between the untreated and the treated samples. For both the AChE and CAT activities, there was no statistical difference between treated and untreated wastewater treatments. The results from this study highlight the toxic effects of untreated wastewater and indicate that treated wastewater (effluent) released from the wastewater treatment plant in Phuthaditjhaba remains suitable for invertebrate fauna such as H. pomatia.