Comparison of temperate and tropical freshwater species' acute sensitivities to chemicals: An update.

Toxicity data for tropical species are often lacking for deriving water quality guidelines (WQGs) and for conducting ecological risk assessment (ERA). To protect and safeguard valuable natural resources and important biodiversity in tropical freshwater ecosystems, a sound framework should be established to assess and manage the ecological risk of an ever-increasing number of chemicals that occur in the tropics. The present study aims to provide a more up-to-date comparison of the species sensitivity distributions (SSDs) between temperate and tropical freshwater species, by incorporating more acute toxicity data that have been documented. Results showed that temperate freshwater species are generally more sensitive to As, Cr, Pb, Hg, carbaryl, chlorpyrifos, DDT, lindane, and malathion than are their tropical counterparts, whereas tropical species tend to be more sensitive to un-ionized ammonia, Mn, chlordane, and phenol. No sensitivity differences were found between temperate and tropical freshwater species to Cu and pentachlorophenol. A general decline in sensitivity trend to chemicals was revealed by comparing taxon-specific SSDs, from crustaceans to mollusks, worms, fishes, and insects. On the basis of calculated 10% hazardous concentration (HC10) ratios from pairwise temperate and tropical SSDs, the temperate-to-tropic safe extrapolation factor was verified and refined as 5 for information. Integr Environ Assess Manag 2019;00:000-000. © 2019 SETAC.