Significant influence of urban human activities and marine input on rainwater chemistry in a coastal large city, China

Jie Zeng; Guilin Han; Qixin Wu; Rui Qu; Qing Ma; Jingwen Chen; Shijun Mao; Xin Ge; Zhong-Jun Wang; Zhiheng Ma

doi:10.1016/j.watres.2024.121657

Significant influence of urban human activities and marine input on rainwater chemistry in a coastal large city, China

Water Res. 2024 Apr 22:257:121657. doi: 10.1016/j.watres.2024.121657. Online ahead of print.

Authors

Jie Zeng¹, Guilin Han², Qixin Wu¹, Rui Qu³, Qing Ma⁴, Jingwen Chen⁵, Shijun Mao⁶, Xin Ge⁴, Zhong-Jun Wang⁷, Zhiheng Ma⁸

Affiliations

¹ Key Laboratory of Karst Georesources and Environment (Guizhou University), Ministry of Education, College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China; North Alabama International College of Engineering and Technology, Guizhou University, Guiyang, 550025, China.
² State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing 100083, China. Electronic address: hanguilin@cugb.edu.cn.
³ State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing 100083, China.
⁴ Key Laboratory of Karst Georesources and Environment (Guizhou University), Ministry of Education, College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China.
⁵ Fujian Key Laboratory of Mineral Resources, Fuzhou University, Fuzhou, 350108, China.
⁶ North Alabama International College of Engineering and Technology, Guizhou University, Guiyang, 550025, China.
⁷ School of Environmental Science and Engineering, Yancheng Institute of Technology, Yancheng, 224051, China.
⁸ School of Geoscience and Technology, Southwest Petroleum University, Chengdu, 610500, China.

PMID: 38663214
DOI: 10.1016/j.watres.2024.121657

Abstract

The coastal urban region is generally considered an atmospheric receptor for terrestrial and marine input materials, and rainfall chemistry can trace the wet scavenging process of these materials. Fast urbanization in China's east coastal areas has greatly altered the rainwater chemistry. However, the chemical variations, determinants, and sources of rainfall are unclear. Therefore, the typical coastal city of Fuzhou was selected for 1-year rainwater sampling and inorganic ions were detected to explore above problems. The findings depicted that rainwater ions in Fuzhou were slightly different from those in other coastal cities. Although NO₃^-, SO₄^2-, Ca²⁺ and NH₄⁺ dominated the rainwater ions, the marine input Cl^- (22 %) and Na⁺ (11 %) also contributed a considerable percentage to the rainwater ions. Large differences in ion concentrations (2∼28 times) were found in monthly scale due to the rainfall amount. Both natural and anthropogenic determinants influenced the rainwater ions in coastal cities, such as SO₂ emission, air SO₂ and PM₁₀ content on rainwater SO₄^2-, NO₃^-, and Ca²⁺, and soot & dust emission on rainwater SO₄^2-, NO₃^-, indicating the vital contribution of human activities. Stoichiometry and positive matrix factorization-based sources identification indicated that atmospheric dust/particles were the primary contributor of Ca²⁺ (83.3 %) and F^- (83.7 %), and considerable contributor of SO₄^2- (39.5 %), NO₃^- (38.3 %) and K⁺ (41.5 %). Anthropogenic origins, such as urban waste volatilization and fuel combustion emission, contributed 95 % of NH₄⁺, 54.5 % of NO₃^- and 41.9 % of SO₄^2-, and the traffic sources contribution was relatively higher than fixed emission sources. The marine input represented the vital source of Cl^- (77.7 %), Na⁺ (84.9 %), and Mg²⁺ (55.3 %). This work highlights the significant influence of urban human activities and marine input on rainwater chemicals and provides new insight into the material cycle between the atmosphere and earth-surface in coastal city.

Keywords: Anthropogenic and marine input; Coastal city; Determinants; Rainwater chemistry; Source identification.