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Acute toxicity of antimony pentavalent to neonatal Daphnia magna and the influence of water quality parameters were investigated, and enzymatic activities of organisms at environmentally relevant levels of antimony were determined. EC 50 values of antimony to neonatal D. magna were 90.3 and 63.8 mg/L at 24 and 48 h of exposure, respectively. Dissolved organic matter (FA and HA) and cation (Ca2+, Mg2+ or Na+) had significant protective effects on D. magna against antimony toxicity. With increasing pH in the range from 7.4 to 8.5, increase of EC 50 were observed due to the competition of OH- on biotic ligands. Based on the biotic ligand model (BLM) concept, stability constants for the binding of Sb(OH) 6 - and OH- to the biotic ligand were estimated, and the Log K XSb (OH) 6 - and Log K XOH - were 3.137 and 2.859, respectively. Moreover, antimony exposure in low concentrations significantly increased MDA levels and maybe exert oxidative stress to the organisms. Antimony can also induce toxicity in D. magna by affecting oxidative stress and neurotransmitter systems. The relatively comprehensive toxicological data can contribute to the toxicity prediction and ecological risk assessments of antimony. [Display omitted] • FA and HA weaken Sb toxicity to Daphnia magna. • Ca2+, Mg2+ and Na+ have significant protective effects against Sb toxicity. • Low levels of Sb exhibit oxidative stress and neurotoxicity on Daphnia magna. • Constants for the binding of Sb(OH) 6 - with the competition of OH- was calculated. [ABSTRACT FROM AUTHOR]

Antimony (Sb) persists in environmental media and can be toxic to aquatic organisms and humans. Although China is the primary Sb-producing country, the levels of Sb contamination and their potential risk to water resources remain unclear. This study provides an overview of Sb contamination in surface water and centralized drinking water sources across China and assesses its potential ecological and human health risks. Species sensitivity distribution was used to derive acute and chronic aquatic life criteria for Sb, which were 511.7 μg/L and 148.3 μg/L, respectively. Zooplankton were determined to be the most sensitive species, and fish were the least sensitive. Sb contamination in China is more serious than other countries. Risk quotients were used to assess the ecological risks of Sb. Chronic ecological risk quotients of 0.0013–27.39 were identified for surface water located near Sb mines. The highest values indicate high risk, particularly for zooplankton species. Exposure characteristics for the Chinese population across age group, sex, season, and region were used to assess the non-carcinogenic risk of Sb in centralized drinking water sources in China. Hazard quotients of 0.001–0.99 were found for these centralized drinking water sources. The non-carcinogenic risk posed by Sb was acceptable in the majority of locations, except in Hunan Province, which had the highest hazard quotient (approximately 1). This province contains the main Sb mining area in China, which poses a relatively large threat to human health. The Sb health risk for children was significantly higher than adults, but there was no significant difference in risk between men and women. The Sb drinking water guidance value to protect human health was calculated to be 19.65 μg/L for Chinese population. The results of this ecological and human health risk assessment highlight the importance of clean Sb production to reduce the negative effects of Sb contamination in China. [Display omitted] • Antimony (Sb) constitutes an ecological risk in surface water near mines in China. • Sb poses a high health risk to residents in Southern China. • The acute and chronic Sb criteria for native Chinese freshwater organisms are 511.7 and 148.3 μg/L, respectively. • The Sb drinking water guidance value to protect human health is recommended to be 19.65 μg/L for the Chinese population. [ABSTRACT FROM AUTHOR]