As temperature influences the toxic effects of chemicals, so does chemical exposure influence the temperature tolerance of an organism. The consequences of this harmful reciprocal relationship on four freshwater fish are explored in a new study published in the latest issue of Environmental Toxicology and Chemistry.
The authors evaluated the effects of three organic chemicals commonly found in the environment: endosulfan, chloripyrifos and phenol. The first two are used as agricultural pesticides, and phenol is a common industrial chemical and a component in plant extracts. Four fish species, dwelling in different habitats in Australia, were selected for the tests.
As demonstrated in previous studies, exposure to sublethal concentrations of certain chemicals can cause stresses that limit an organism's ability to survive or tolerate changes in environmental factors such as temperature.
As expected, with the exception of phenol, the current study confirms that prior exposure to sublethal concentrations of the chemicals affects the ability of fish to tolerate progressive temperature increases.
According to the authors, the relationship between temperature and lethality is complex. The study suggests that rising global temperatures and the presence of environmental contaminants may influence the survival of many organisms but additional research is needed to understand the magnitude of the effect.