Aquatic Ecosystems

Pesticides, though not intended for aquatic environments, often contaminate water bodies, impacting water quality and aquatic organisms. Chlorpyrifos, a commonly used organophosphate insecticide, poses significant risks to freshwater ecosystems due to its potential endocrine disruptiveeffects on aquatic organisms like Clarias gariepinus. This study aims to explore the correlation between chlorpyrifos exposure and thyroid hormone parameters in Clarias gariepinus. Eight hundred(800)Juvenile Clarias gariepinus were acquired and acclimatized before exposure to controlled concentrations of chlorpyrifos. Muscle tissue samples were collected for analysis of thyroid hormones, including Thyroxine(Free T4), Triiodothyronine(Free T3), and Thyroid Stimulating Hormone(FT3), using standard techniques. Chlorpyrifos exposure significantly affected T3 levels in C.gariepinus (p<0.05). The control group exhibited the highest T3 level (0.90 ± 0.20), differing significantly from treated groups (CHL 1: 0.72 ± 0.11, CHL 2: 0.74 ± 0.12, CHL 3: 0.66 ± 0.11). Thyroid Stimulating Hormonelevels also showed a significant difference between control (0.70 ± 0.01) and treated groups (CHL1: 0.80 ± 0.10, CHL2: 15.76 ± 7.56). Additionally, T4 levels varied significantly across groups, with the highest in CHL2 (5.9 ± 3.73) and lowest in CHL1 (4.53 ± 1.22).Chlorpyrifos exposure alters thyroid hormone levels in Clarias gariepinus, indicating potential disruption of thyroid function. These findings underscore the ecological risks associated with chlorpyrifos contamination in aquatic ecosystems, warranting further research for informed mitigation strategies to safeguard both aquatic organisms and human health.

Aquatic ecosystems are often subject to contamination by heavy metals due to human and natural activities. This study was conducted to determine the concentrations of heavy metals present in water, sediment and fish samples collected from Ikpoba River, Benin City, Nigeria. Samples were collected over from June to August 2023 and analysed using standard methods. The findings showed that while Cd and Pb were not detected in the water, Ni and Cr exceeded permissible limits. However, the concentrations of Co were within limits. Sediment samples had comparatively low heavy metal content. Benthic fish were found to have higher concentrations of heavy metals than pelagic fish. However, the concentrations of these metals in the samples were below the recommended limits for heavy metals in food. Therefore, it was concluded that the fish in the study area are safe for consumption but the water is not. Hence, routine surveillance and implementation of measures to protect water quality such as prevention of waste discharge are recommended