Triazophos-induced Respiratory and Behavioral Effects and Development of Adverse Outcome Pathway (AOP) for short-term Exposed Freshwater Snail, Bellamya Bengalensis

Abstract

The physiological effects of triazophos were examined using respiratory and behavioral endpoints in Bellamya bengalensis under a 96-hour acute exposure regime. Physiological manifestation of respiratory stress was measured using the rate of oxygen consumption while behavioral toxicity was measured using crawling reflexes, touch response, and mucus production. The threshold effect values for LOEC (Lowest Observed Effect Concentration), NOEC (No Observed Effect Concentration), and MATC (Maximum Acceptable Toxicant Concentration) at 96 h were 0.40, 0.60, and 0.075 mg/l, respectively. Definitive 96 h acute exposures for both respiratory and behavioral endpoints tests were determined using a control group and concentrations ranging from 0.40 to 1.60 mg/l monitored for 24, 48, 72, and 96 h. Test organisms irrespective of exposure concentration demonstrated an initial rise in oxygen consumption rate after 24 h, followed by a progressive decrease in toxicant concentration and exposure period. The in silico structural analysis presents triazophos as having an electrophilic toxic structure similar to choline esterase inhibitors, and also capable of inducing oxidative stress. The AOP highlighted neurotoxicity and oxidative stress as plausible pathways of triazophos toxicity in mollusk species.

Keywords: Behavioural alteration; Bellamya bengalensis; Organophosphate; Oxygen consumption rate; Triazophos.