Aquatic safety assessment for cationic and amphoteric surfactants

Abstract

Many toxic xenobiotics entering aquatic environments exert their effects through redox cycle. Oxidative stress, incorporating both antioxidant defenses as well as oxidative damage, is a common effect in organisms exposed to xenobiotics in their environment. The present study proposed to evaluate the acute effects of benzenthonium chloride (quaternary ammonium compound with cationic proprieties) and cocamidopropyl betaine (zwitterionic compound with amphoteric proper) on antioxidant defense mechanisms and lipid peroxidation in Cyprinus carpio organs (liver, intestine, kidneys and gills). We assessed the level of oxidative stress biomarkers (superoxide dismutase – SOD, catalase - CAT, glutathione peroxidase - GPx, glutathione reductase -GR, glutathione S transferase - GST, glucose -6- phosphate dehidrogenase – G6PDH) and the levels of lipid peroxidation - LPO through malondialdehide -MDA of 1mg/l toxic substance nominal concentration after 96h exposure period. LPO and antioxidative enzymatic mechanisms displayed different responses in the investigated tissues. We observed that the action of toxic substances is selective at organs levels. The liver and gills were the most affected by toxic action of both tested surfactants compared with the controls. At liver, gills and kidneys level, after 96h toxic exposure, significant modifications were observed in case of CAT, G6PDH, GPx, GST and Gred. In all organs LPO installation was observed which indicate oxidative damage of tissues induced by accumulation of reactive oxygen species (ROS). The biochemical analysis led to the conclusion that antioxidant enzymes showed deficit in ROS balance at all tissues levels which induce oxidative stress in fish organs.