Absence of effects of different types of detergents on the cholinesterasic activity and histological markers of mosquitofish (Gambusia holbrooki) after a sub-lethal chronic exposure

The release of anthropogenic compounds into the aquatic environment has been a particular concern, since some of these substances exhibit biologic activity of different types in non-target species. Among anthropogenic compounds present in the aquatic compartment, detergents are commonly found and may be responsible for physiological modifications in exposed organisms. The impairment of key physiological functions, such as neurotransmission, and tissue damage in some important organs, has been used to assess the effects of several classes of xenobiotics, including detergents, in aquatic organisms. The present study intended to assess the effect of three types of detersive compounds (sodium dodecylsulfate (SDS), benzalkonium chloride (BZC), and Triton X-100 (TX100)) in the acetylcholinesterase activity (AChE) and tissue damage (gills and liver) of Gambusia holbrooki after a chronic exposure to realistic levels of these compounds. SDS, BZC, and TX100 did not cause any significant alteration in AChE. Furthermore, no specific gross morphological changes were also observed in the gills and liver of the exposed individuals. It is possible to conclude that, under ecologically relevant conditions of exposure, both tissue damage and cholinesterasic impairment are not toxicological pathways affected by detergents in G. holbrooki.