Altered levels of endocrine biomarkers in juvenile barramundi (Lates calcarifer; Bloch) following exposure to commercial herbicide and surfactant formulations

Abstract

Agricultural pesticides that are known endocrine disrupting chemicals have been detected in waters in the Great Barrier Reef catchment and lagoon. Altered transcription levels of liver vitellogenin (vtg) have been documented in wild populations of 2 Great Barrier Reef fisheries species and were strongly associated with pesticide-containing runoff from sugarcane plantations. The present study examined endocrine and physiological biomarkers in juvenile barramundi (Lates calcarifer) exposed to environmentally relevant concentrations of commercial herbicide (ATRADEX(®) WG Herbicide, DIUREX(®) WG Herbicide) and surfactant (ACTIVATOR(®) 90) formulations commonly used on sugarcane in the Great Barrier Reef catchment. Estrogenic biomarkers (namely, liver vtg messenger RNA and plasma 17β-estradiol) increased following exposure to commercial mixtures but not to the analytical grade chemical, suggesting an estrogenic response to the additives. In contrast, brain aromatase (cyp19a1b) transcription levels, plasma testosterone and 11-ketotestosterone concentrations, and gill ventilation rates were not affected by any of the experimental exposures. These findings support the assertion that exposure to pesticide-containing runoff from sugarcane plantations is a potential causative agent of altered liver vtg transcription levels in wild barramundi. Whether exposure patterns in the Great Barrier Reef catchment and lagoon are sufficient to impair fish sexual and reproductive development and ultimately influence fish population dynamics remains to be determined. These findings highlight the need to consider both active and so-called inert ingredients in commercial pesticide formulations for environmental risk assessments.

Estrogenic activities of diuron metabolites in female Nile tilapia (Oreochromis niloticus)

“…Some studies have shown that DCA may be more toxic than diuron (Giacomazzi and Cochet, 2004;Scheil et al, 2009;Da Rocha et al, 2013); however, studies regarding the toxicity of other metabolites (DCPMU, DCPU) are still limited. A recent study observed that diuron metabolites (mainly DCPMU, DCPU) have antiandrogenic activities in male Nile tilapia (Pereira et al, 2015), although no effect was observed for diuron, which is consistent with another recent study that did not observe estrogenic or antiandrogenic effects of diuron in juvenile barramundi (Lates calcarifer) (Kroon et al, 2015). Additional documented effects of diuron and its metabolites (DCA) in teleosts include morphological (Mhadhbi and Beiras, 2012;Gagnon and Rawson, 2009), biochemical (Sanchez-Muros et al, 2013), physiological (Vinggaard et al, 2000;Miranda et al, 2008;Scheil et al, 2009) and behavioral alterations (Saglio and Trijasse, 1998).…”

Managing threats and restoring wetlands within catchments of the Great Barrier Reef, Australia

“…In benthic microalgae, PSII‐inhibiting herbicides reduce growth (Magnusson, Heimann, & Negri, ) and modify diatom community composition (Wood, Mitrovic, Lim, & Kefford, ). In amphibians and fish, atrazine causes osmoregulatory disturbance that affects gill histopathology, gonadal morphology, reproductive fitness, and the dynamics of fish populations (Kroon, Hook, Metcalfe, & Jones, ). The long‐term ecological effects of exposure to herbicides in the GBR region are currently poorly understood.…”

Global transcriptomic profiling in barramundi (Lates calcarifer) from rivers impacted by differing agricultural land uses

“…In other regions, pesticides are thought to be contributing to declining fish populations or to a lack of recovery of fish populations following habitat restoration . To date, very little work has examined the influence of modern‐use pesticides on fish populations in the Great Barrier Reef Catchment Area .…”