Ecotoxicological effect of zinc pyrithione in the freshwater fish Gambusia holbrooki

Abstract

Currently diverse biocidal agents can be used for distinct applications, such as personal hygiene, disinfection, antiparasitic activity, and antifouling effects. Zinc pyrithione is an organometallic biocide, with bactericidal, algicidal and fungicidal activities. It has been recently incorporated in antifouling formulas, such as paints, which prevent the establishment of a biofilm on surfaces exposed to the aquatic environment. It has also been used in cosmetics, such as anti-dandruff shampoos and soaps. Previously reported data has shown the presence of this substance in the aquatic compartment, a factor contributing to the potential exertion of toxic effects, and there is also evidence that photodegradation products of zinc pyrithione were involved in neurotoxic effects, namely by inhibiting cholinesterases in fish species. Additional evidence points to the involvement of zinc pyrithione in alterations of metal homeostasis and oxidative stress, in both aquatic organisms and human cell models. The present work assesses the potential ecotoxicity elicited by zinc pyrithione in the freshwater fish Gambusia holbrooki after an acute (96 h) exposure. The oxidative stress was assessed by the quantification of the activities of specific enzymes from the antioxidant defense system, such as catalase, and glutathione-S-transferases; and the extent of peroxidative damage was quantified by measuring the thiobarbituric acid reactive substances levels. Neurotoxicity was assessed through measurement of acetylcholinesterase activity; and a standardized method for the description and assessment of histological changes in liver and gills of was also used. Zinc pyrithione caused non-specific and reversible tissue alterations, both in liver and gills of exposed organisms. However, histopathological indices were not significantly different from the control group. In terms of oxidative stress biomarkers, none of the tested biomarkers indicated the occurrence of pro-oxidative effects, suggesting that the oxidative pathway is not the major toxicological outcome of exposure to zinc pyrithione.

Standard and biochemical toxicological effects of zinc pyrithione in Daphnia magna and Daphnia longispina

“…Exposed organisms evidenced inhibition of acetylcholinesterase only after exposure to its degradation products, without changes caused by the parent compound (Mochida et al, 2009). These results were consistent with the study carried out in Gambusia holbrooki exposed to zinc pyrithione, where no changes were observed in acetylcholinesterase activity (Nunes et al, 2015). However, these tests were performed in the absence of light, not allowing its photodegradation and the generation of potentially neurotoxic photodegradation products.…”

“…The acute (48h) assay performed with the fish Oryzias latipes exposed to low concentrations of zinc pyrithione (1-10μg/l) resulted in morphological and respiratory abnormalities (Ohji & Harino, 2017). Among the main reported effects of zinc pyrithione is embryotoxicity even at extremely low levels, alteration in the expression of heat shock proteins, genotoxicity and neurotoxicity (Nunes et al, 2015). The photodegradation of ZnPT (and not ZnPT itself) may result in the formation of two chemicals, namely 2,2′-dipyridyldisulfide [(PS)2] and 2,2′dithiobispyridine-N-oxide [(PT)2], known for their AChE-inhibiting activity (Mochida et al, 2009).…”

Male Reproductive Toxicity of Antifouling Chemicals: Insights into Oxidative Stress-Induced Infertility and Molecular Mechanisms of Zinc Pyrithione (ZPT)

“…Despite the long-standing use of ZPT as a compound with established safety, it has been suggested that metal pyrithiones, including ZPT, may persist in low-light marine environments [44,53,54], such as heavily turbid water columns or areas shaded beneath stationary boats in marinas and harbors [55]. This persistence can lead to the accumulation of ZPT, potentially resulting in adverse effects [56]. Furthermore, research indicates that the breakdown products of zinc pyrithione in the presence of light may impede fish cholinesterase enzyme activity, thereby posing a risk to fish nervous systems [43,44].…”

Antagonism of Metal Pyridinethiones and Their Degradation Products toward Estrogen Receptor α: A Combination of In Vitro, In Vivo, and In Silico Approaches

“…The pro-oxidative effects, neurotoxic effects, developmental toxicity, and reproductive toxicity of MePTs and their degradation products have been reported in several species of aquatic organisms, especially fish. ,,− In particular, ZnPT is classified as being in reproductive toxicant category 1B under REACH regulation (EC) 1272/2008 . Our previous studies found that (PS) 2 induced reproductive toxicity in guppies ( Poecilia reticulata ) by interfering with the hypothalamic–pituitary–gonadal–liver reproductive axis at multiple potential sites, suggesting that it is a potential endocrine-disrupting chemical (EDC). , In particular, transcriptional levels of vitellogenin A and estrogen receptor α (ERα) in male liver tissues were significantly reduced after exposure to (PS) 2 , indicating its anti-estrogenic activities .…”