[Regional Variation Analysis of Lead （Pb） Ecological Risks in Surface Waters Across China]

The regional variability of water quality criteria and ecological risks of lead （Pb） in surface water in China was analyzed. The biological effectiveness of Pb was corrected according to the biological ligand model （BLM）， the species sensitivity distribution （SSD） method was used to derive the long-term water quality criteria of Pb， and the correction equations of hardness and pH to the long-term water quality criteria of Pb were obtained. Combined with the distributions of hardness， pH， and Pb concentration in surface water， the regional variability of Pb long-term water quality criteria and risk quotient distributions in China was elucidated. It was found that the distribution of long-term Pb criteria ranged from 0.1 to 4.2 μg L^-1， and the distribution of risk quotients ranged from 0.01 to 8.9 among different cities in China after correcting for hardness and pH. Contribution analyses revealed the differences in the contributions of Pb concentration， pH， and hardness to Pb risk among different river basins. The study emphasized the critical importance of considering regional water chemistry parameters when developing Pb water quality criteria and suggested that the Pb risk in surface waters of Haidong City， Xining City， Ngari Prefecture （Tibet）， Linxia Hui Autonomous Prefecture， Gannan and Ganzi Tibetan Autonomous Prefecture， and Wuwei City deserve focused attention.