Water Characteristics Assessment, Bioaccumulation and Health Risk Evaluation of Possible Ingestion of Toxic and Essential Metals in Chromidotilapia guntheri Sourced from Ada River, West Africa

Abstract

The water ecosystem has been acclaimed to be polluted with various chemicals that may pose possible risks to the biota therein and affect the end consumers who ingest them via the food chain system. This study evaluates the water characteristics, bioaccumulation and non-carcinogenic risk potentials in the ingestion of toxic metals like (Cu, Fe, Zn, Mn and Pb) in Chromidotilapia guntheri from Ada River. Samples were collected for six months (3 months dry and wet correspondingly) to cover the hydrological season. Chromidotilapia guntheri was collected by local fishermen with a local trap. No ethical considerations were needed for this study. Standard methods were used in the determination of the water characteristics. The findings from the study showed that all the parameters were significant (p>0.05) across all the stations studied. The seasonal assessment of the water parameters was highly significant (p<0.001) for DO, BOD₅, Ca, Mg, NO₃, PO₄, Cl, Cu, Pb and Mn. For water temperature, air temperature, pH, EC, TDS, Alkalinity, SO₄, hardness, Fe and Zn correspondingly, they were significant (p<0.05) across all the stations studied. Similarly, the seasonal variations of the heavy metals in the fish tissues showed that there was a significant difference (p<0.05) in Cu for both the wet and dry periods. However, Pb, Fe, Mn and Zn showed no significant difference (p>0.05) for both seasons. The average concentrations of Zn, Mn, Fe, Pb and Cu in the muscles of Chromidotilapia guntheri were 0.355±0.062, 0.824±0.803, 6.825±3.730, 0.163±0.053 and 0.779±0.522 mg/kg individually. The results obtained from this study show that the analyzed metals have Bioaccumulation Factors (BAFs) >1 which was also greater than the concentrations in water. This shows that the organism accumulated more metals in its muscles than what is found in its water environment. This may cause non-carcinogenic health issues like foodborne sickness, diarrhea and food intoxication. The results of the Hazard Index (HI) 0.127 of Chromidotilapia guntheri show that all the metals were less than the threshold value of 1. The results of the THQ (Target Hazard Quotient) showed the variations of the metals as Cu (0.040)> Mn (0.014)> Pb (0.002)> Fe (0.000)> Zn (0.000) correspondingly. More so, the results of the EDI (Estimated Daily Intake) showed the following rank pattern Fe>Mn> Cu> Zn > Pb. The low values (<1) observed for the HI, THQ and EDI, indicate that the species of fish is good for human ingestion at this period of study without any non-carcinogenic health risks. We recommend continuous monitoring of the Ada River to ascertain the trend of water characteristics and bioaccumulation of heavy metals in the water to regulate the possible activities causing this effect. There has not been any study on the bioaccumulation and health risks of this species. So, this stands as the research gap of this study.