The relative sensitivity of freshwater species to antimony(III): Implications for water quality guidelines and ecological risk assessments

Abstract

Antimony (Sb) is a pollutant in many jurisdictions, yet its threat to aquatic biota is unclear. Water quality guidelines (WQGs) for Sb are not well established and large uncertainty factors are commonly applied in derivation. We constructed freshwater species sensitivity distributions (SSDs) for Sb(III) using available acute toxicity data sourced from temperate and tropical regional studies. A tiered ecological risk assessment (ERA) approach using risk quotients (RQs) was applied for characterisation of risks presented by Sb(III) concentrations measured in the freshwater environment. Multiple parametric models were fitted for each SSD, with the optimal model used to derive the 5% hazardous concentration (HC5), defined as protective of 95% of species, and the corresponding predicted no effect concentration (PNEC). The HC5 values for whole and temperate SSDs were estimated at 781 and 976 μg L Sb(III), respectively, while the PNECs for both datasets were 156 and 195 μg L Sb(III), respectively. Due to limited tropical data, a temperate-to-tropic extrapolation factor of 10 was used to estimate an interim PNEC for tropical regions of 20 μg L Sb(III). Based on published freshwater Sb(III) concentration values across a range of locations, potential ecological risks posed by Sb(III) in some freshwater systems studied would be classified as medium to high risk, but the majority of locations sampled would fall into the low ecological risk category. Our results facilitate the understanding of toxic effects of Sb(III) to freshwater species but also demonstrate that data for Sb ERA are extremely limited.

Ecotoxicological Differences of Antimony (III) and Antimony (V) on Earthworms Eisenia fetida (Savingy)

“…Since there is limited study on Sb’s acute toxicity in E. fetida , it was discovered that Sb’s toxicity to other receptors is linked to its form variations. Some studies suggest aquatic organisms are more sensitive to Sb (III) than Sb (V) [ 37 ]. The toxicity of Sb (III) is 10 times that of Sb (V) in an aqueous solution [ 38 ].…”

Influences of Particles and Aquatic Colloids on the Oxidation of Sb(III) in Natural Water

“…At the same time, antimony ore also exists in the environment extensively, associated with copper ore, silver ore, and so forth . Because of its widespread use, Sb pollution in the environment has received attention, and biogeochemical cycle of Sb has become the focus of research recently. − There are two naturally occurring redox states of Sb, namely, Sb­(III) and Sb­(V). , The toxicity of Sb­(III) is greater than that of Sb­(V), while the mobility of Sb­(V) is stronger than that of Sb­(III) . Antimony enters the aquatic environment mainly in the form of Sb­(III), but Sb is mainly present as Sb­(V) in natural water .…”

“…6,7 The toxicity of Sb(III) is greater than that of Sb(V), while the mobility of Sb(V) is stronger than that of Sb(III). 8 Antimony enters the aquatic environment mainly in the form of Sb(III), but Sb is mainly present as Sb(V) in natural water. 9 However, the oxidation rate and mechanism of Sb(III) to Sb(V) transition in natural water remains unclear.…”