Toxicity of Selected Pesticides on the Microbial Pollution Bio-indicator, Pseudomonas aeruginosa


  • Anwuli U. Osadebe The University of Port Harcourt
  • Confidence C. A. Ubochi University of Port Harcourt


Ecotoxicity, Pseudomonas aeruginosa, Dichlorvos, Paraquat, Pesticide, median lethal concentration


Pesticides are well known to impact on non-target organisms such as vulnerable bio-indicator species in aquatic and non-aquatic environments. Pseudomonas aeruginosa is a known bioindicator for heavy metal, wastewater and polycyclic aromatic hydrocarbon pollution. This study explored the effects of varying concentrations (0.01 mg/L – 100 mg/L) of the organophosphorus insecticide, dichlorvos and the organochlorine herbicide, paraquat on P. aeruginosa isolated from river water to ascertain mortality rates, median lethal concentrations (LC50), lowest observed effect concentrations (LOEC) and the no observed effect concentrations (NOEC) using a 96 h acute toxicity bioassay. P. aeruginosa was isolated and enumerated using cetrimide agar while the toxicity parameters were determined via probit regression analysis. There was a general decline in abundance of P. aeruginosa, and correspondingly, a rise mortality levels, as exposure period and pesticide concentrations increased. Survival rates of 0% were obtained at 72 h and 48 h and above for paraquat and dichlorvos respectively at the highest pesticide concentration of 100 mg/L. Dichlorvos was found to be more toxic to P. aeruginosa than paraquat as the LC50, LOEC and NOEC were determined as 0.032 mg/L, 0.0042 mg/L and 0.0015 mg/L respectively for dichlorvos. The values obtained for paraquat were 0.44 mg/L, 0.0053 mg/L and 0.0017 mg/L for LC50, LOEC and NOEC respectively. The findings of this study raise concerns for the indiscriminate use of pesticides as they may impact negatively on vital ecosystem players.




How to Cite

Osadebe, A. U., & Ubochi, C. C. A. (2022). Toxicity of Selected Pesticides on the Microbial Pollution Bio-indicator, Pseudomonas aeruginosa. Archives of Ecotoxicology, 4(3), 84–89. Retrieved from



Research Paper