Particulate organic matter governs the vulnerability of soil mercury in Himalayan valleys - Huhu Kang; Miaoxin Ji; Junming Guo; Xiaohong Liu; Lingyu Gao; Jie Huang; Shichang Kang; Xingle Qu; Zhiwei Liu; Xiufeng Yin; Qianggong Zhang (Journal of Hazardous Materials, 2026)