Time dependence effect of metal toxicology and application in WQC derivation of main water basins in China
The exposure time in acute toxicology experiments can affect not only the accuracy of toxicity data such as lethal concentration 50 (LC50) at the species level, but also the dose-effect relationship establishment of pollutants at the community level. However, previous study on the time dependence of...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-01-01
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| Series: | Ecological Indicators |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S1470160X24015061 |
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| Summary: | The exposure time in acute toxicology experiments can affect not only the accuracy of toxicity data such as lethal concentration 50 (LC50) at the species level, but also the dose-effect relationship establishment of pollutants at the community level. However, previous study on the time dependence of heavy metals is still lacking, and its impact on environmental criteria derivation and risk assessment has not been quantitatively characterized. In this study, the relationship between exposure time and toxicology data of four heavy metals (Cd, Cr, Cu, and Zn) was studied. Time-dependent species sensitivity distribution (SSD) surfaces of Chinese native freshwater species were established. The ecological indicators, including the hazardous concentration for 5% of species (HC5) values and water quality criteria (WQC), were derived for different exposure times. Finally, the dynamic ecological risks of heavy metals in major Chinese water basins were evaluated. The results indicated a linear negative correlation between the acute toxicity data of heavy metals and exposure time, and a decrease in derived HC5 values as exposure time increased. Compared to one-day experiments, the HC5 values for Cd, Cr, Cu, and Zn derived by four-day experiments decreased by 80.87 %, 74.44 %, 67.51 %, and 65.81 %, respectively. Based on the time dependence of the toxicity data, the WQCs for Cd and Cu derived in this study were found to be more stringent than the existing WQCs in China. Dynamic ecological risk assessments revealed that Cu poses a higher ecological risk than the other metals, particularly in the Songhua River, with risk values ranging from 40.4 % to 49.6 %. Therefore, the time dependence of metals should be fully considered in the formulation of acute WQC so as to provide better protection for the water ecosystem security. |
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| ISSN: | 1470-160X |