aquatic toxicity

Veterinary and agricultural surfactants are supposed to be inert additives, yet these substances commonly exert biological side-effects, in given cases synergistic with those of the active ingredients of these preparations. This is explicitly seen in altered toxicity of veterinary or pesticide formulations compared to their active ingredients alone. Neither the individual effects of these excipients, nor such combination effects are well-studied in toxicology, and therefore, possible toxicity consequences are occasionally not being considered at sufficient significance in the authorization, use and control of these substances. Risk assessment of these substances should cover all hazards they may represent, and corresponding levels of exposure. Surfactants used in veterinary and pesticide formulation enter the environment either by direct dispersion or by indirect release through excrement, leaching, sewage waters or sludge, and in turn, create potential exposure to a number of non-target organisms. Biochemical and (eco)toxicological hazards recently identified regarding certain agricultural surfactants include cytotoxicity (on cell lines of epithelial, neural and other tissues, as well as stem cells and tumor cells), endocrine disrupting effects, as well as aquatic ecotoxicity. This Mini Review summarizes toxicological effects identified in our studies in aquatic toxicity tests, in cell viability and cytotoxicity tests, in estrogenic activity assays, correlated with biochemical analysis of the surfactants and their decomposition. The conclusions are hoped to facilitate environmentally precautious revision of surfactants widely used in agriculture.

Fenvalerate is a widely used synthetic pyrethroid insecticide with recognised toxicity to aquatic organisms. This study evaluated its toxic effects on zebrafish (Danio rerio) by assessing mortality, biochemical alterations, and protein profile changes following exposure to 20–100 µg/L fenvalerate. Mortality increased in a concentration- and time-dependent manner. At 20 µg/L, mortality increased from 55% at 24 h to 82% at 96 h, while 40 and 60 µg/L resulted in mortality rising from 62% to 94% and 71% to 99%, respectively. Exposure to 80 µg/L caused 79–100% mortality, and complete mortality was observed at 80 and 100 µg/L after 72 and 96 h, respectively. Sublethal (LC50) exposure induced significant biochemical changes in gill and muscle tissues. Gill protein content decreased from 120.0 ± 1.22 mg/g in controls to 110.0 ± 1.40 mg/g after 96 h, whereas muscle protein declined from 80.2 ± 1.3 to 60.0 ± 2.7 mg/g. Lipid reserves were also markedly reduced, with muscle lipid content decreasing from 4.0 ± 0.46% to 3.1 ± 0.12% and gill lipid content from 6.5 ± 0.22% to 2.5 ± 0.31% after 96 h. SDS-PAGE analysis revealed distinct alterations in protein banding patterns between control and treated fish, indicating fenvalerate-induced changes in protein expression. These findings demonstrate that fenvalerate causes severe concentration- and time-dependent toxicity, leading to increased mortality, depletion of proteins and lipids, and altered protein profiles, highlighting its ecological risk to aquatic organisms and the utility of zebrafish as a sensitive model for pesticide toxicity assessment.