Behavioural Toxicity of a Combined Oilfield Chemicals on African Catfish (Clarias gariepinus) (Burchell 1822)

Abstract

The toxicity of the combination of xylene and diesel at a 50:50 ratio on the African catfish (Clarias gariepinus) was investigated using a static bioassay for 96hrs. No significant difference (P>0.05) was observed in the Physicochemical parameters of the experimental water after exposure for 24 hours among the different concentration gradients and the controlled unit. Although there was an increased variation along the concentration gradient observed after 96hours. The behavioral responses of the test fish from 24-96 hours of exposure show normal behavioral responses in the control. C. gariepinus exposed to 25 ml/l to 50 mg/l concentration of the toxicant showed normal behavior from 24 to 48 hours. Afterward, the fish that were active stopped swimming and remained static for a while in response to the sudden changes in the surrounding environment. Generally, fish exposed to higher concentrations such as 100 ml/l to 250 ml/l of the test chemicals showed progressive hyperventilation and abnormal behavior like gulping air, erratic swimming movement, very fast swimming, jumping, and displaying vigorous jerky movement suffocation, and loss of reflex. A faster operculum and tail beat movement was also observed with Spiraling. The behavioral responses increased significantly (P<0.05) with an increase in concentration per time as compared to the control group of fish. The noticeable behavioural difference was recorded for the different concentrations of the test chemical. An eco-friendly chemical that is within the acceptable limits recommended by WHO and DPR should be used in well stimulation and cleaning for sustainable biodiversity and a healthy aquatic environment.

Ecotoxicity of commonly used oilfield-based emulsifiers on Guinean Tilapia (Tilapia guineensis) using histopathology and behavioral alterations as protocol

“…Behavioural changes in fish can serve as indicators of stress, discomfort, or toxicological effects caused by exposure to chemical substances as suggested by. 20 The fish in the control group exhibited normal behaviour throughout the observation period. This indicates that the absence of surfactant exposure did not cause any significant disruption to their normal swimming patterns or responses to the environment.…”

“…These alterations in TBF can be attributed to the neurotoxic effects of the surfactants, which may affect the fish's central nervous system and disrupt motor coordination. 20 The initial increase in TBF from 24 to 48 h suggests a compensatory response of T. guineensis to the chemical stressor. 2 The fish may exhibit hyperactivity or increased swimming behaviour as an adaptive strategy to cope with the adverse effects of the surfactants.…”

“…39 Overall, the observed behavioural changes in Guinean tilapia exposed to different concentrations of aqueous surfactants indicate a progressive deterioration of normal swimming patterns, increased stress levels, and compromised physiological functioning. According to Davies and Uedeme-Naa, 20 These behavioural responses serve as indicators of the toxic effects of surfactants on fish and highlight the need to assess and minimize the environmental impacts of surfactant exposure on aquatic organisms.…”

“…These changes can have cascading effects on the entire food web, influencing predator-prey dynamics and ecosystem stability. 20 The physiological responses of fish to oilfield chemicals extend beyond behavioural changes. Substances released during oil recovery processes can enter the bloodstream of fish, affecting organs and vital functions.…”