Bio-toxicological assays to test water and sediment quality

This study assessed the bio-toxicological assays efficacy in the control of effluent waters deriving from purification plants, such as industrial or wastewater discharge and marine sediment collected from the Adriatic sea on the Italian Coast. The analysis was performed using either Acute Toxicity Test containing bioluminescent bacteria or Algal Growth Inhibitory Test (used on sediments only). Furthermore, samples were also characterized by microbiological parameters to search for indicators of faecal contamination. From the 29 samples collected from effluent waters, 6 showed an inhibition of bacterial luminescence higher than 20% and the analysis of EC₅₀ expressed a strong toxicity for 4 of them, whereas 9 of the remaining 23 samples exhibited a bioluminescence stimulation defined as “hormesi.” No samples of marine sediments displayed a reduction of luminescence exceeding 20% with respect to the control. Toxicity tests can represent efficacious tools to detect the presence of pollutants for the preservation of the aquatic system and human health.

Keywords:

• Bio-toxicological assay
• Acute toxicity test
• Algal growth inhibitory test
• Vibrio fischeri
• Dunaliella tertiolecta
• Microorganism indicators
• Bioluminescent bacteria
• Pollution
• Seawater
• Hormesi

Acknowledgments

The authors thank Prof. Ray Pizzuto for his help in editing the manuscript and Dr. Mara Di Giulio for her technical contribution.

Notes

*Negative sign shows hormesi.