Ecotoxicological consideration of some industrial chemicals on three biological sentinels

Abstract

Ecotoxicological effects of industrial detergent (Neatex) and corrosion inhibitor (Norust CR 486) commonly released into the Nigerian environment were studied using laboratory toxicity test. These industrial chemicals are used copiously in the environment as if they do not have any ecotoxicological effects. Fish, shrimp and earthworms were exposed to varying concentrations of the test chemicals using the Organisation for Economic Cooperation and Development (OECD) # 203, 218 and 207 protocols respectively. The methods were employed because they give consistent and reproducible data. The water, sediment and soil ratings indicate that both chemicals were toxic to the organisms and the estimated 4, 10 and 14 days lethal concentration (LC50) showed that the corrosion inhibitor was more toxic than the industrial detergent. In the earthworm bioassay, the estimated LC50 showed that Norust CR 486 (207.61 ± 14.09 mg/kg) was more toxic than Neatex (413.82 ± 0 mg/kg). In the fish bioassay, results showed that death cause to older species may lead to elimination of potentially reproductive organisms. The  muscle glycogen levels of fish exposed to the test chemicals significantly decreased when compared with the levels measured in the control group. Depletion in the muscle glycogen level reported was 67% (Neatex) and 75% (Norust CR 486) at the end of the 28-day experiment. Similarly, there was significant difference in surfactant bioaccumulation in fish (gills, gut and muscle tissue) for the test chemicals at levels of (p < 0.05). The observed sensitivity of the test organisms to both chemicals indicate that appropriate safety measures such as adherence to standard operating procedures should be applied before use and disposal of  surfactant-containing chemicals since the test chemicals were toxic in the three media. This would ensure that the biotic components of the Nigerian Niger Delta ecosystem are prudently protected.

Keywords: Toxicity, fish, shrimp, earthworm, surfactant, muscle glycogen.