Determination of single and combined toxic effects of phenanthrene and fluoranthene polyaromatic hydrocarbons in Gammarus pulex

Polycyclic aromatic hydrocarbons (PAHs) are organic compounds commonly found in air, water, and soil. Today, the amount of PAHs obtained from petroleum-derived fuels and incomplete combustion processes in the environment is increasing. The importance of PAHs toxicity in aquatic organisms, including invertebrates, has emerged, including PAH toxicities, bioaccumulation properties, endocrine disruption, and tissue-specific toxicity. Regarding these aspects, in order to determine the toxicity of PAHs, the neurotoxic, oxidative stress and exposure effects of Floranthens (Flu) and Phenantrene (Phe) PAHs individually and together on Gammarus pulex, an aquatic indicator organism, were determined quantitatively. For this purpose fistly, Flu, Phe and Flu + Phe acute toxicity (LC50) values were determined as 5.88 ± 0.23, 8.31 ± 0.57 and 7.00 ± 0.33 mg/L, respectively. Neurotoxic (Acetylcholinesterase), oxidative stress (Glutathione S-Transferase) and exposure effect (Cytochrome P450) were determined by exposing G. pulex organism individuals to sublethal concentrations for 14 days in proportion to the determined LC50 value. When acetylcholinesterase (AChE) enzyme levels were compared with the control group, a statistically significant inhibition was observed at the end of 7 and 14 days in G. pulex model animals. When the exposure effect of cytochrome P450 (CYP1A1) was compared with the control group, no statistically significant change was observed in all application groups at the end of the 7th day, and at the end of the 14th day, a statistically significant increase was found in the CYP1A1 enzyme levels when compared to the control group. When Glutathione S-Transferase (GST) enzyme activities were compared with the control group, a significant inhibition was observed between the groups after 7 and 14 days of exposure. In this study, it was determined that G. pulex exposed to different concentrations of Phe and Flu PAHs individually or in combination, caused statistically significant changes in the enzyme levels, which are biotransformation enzymes (CYP1A1, GST) and a biomarker of neurotoxicity (AChE). It was concluded that biomarkers CYP1A1, GST and AChE are useful biomarkers.