Determining rainwater chemistry to reveal alkaline rain trend in Southwest China: Evidence from a frequent-rainy karst area with extensive agricultural production

Zeng, Jie; Yue, Fu-Jun ✉; Li, Si-Liang; Wang, Zhong-Jun; Wu, Qixin; Qin, Cai-Qing; Yan, Ze-Long

English Article (Journal Article) Scientific
Published: ENVIRONMENTAL POLLUTION 0269-7491 1873-6424 266 Paper: 115166 , 11 p. 2020
  • X. Földtudományok Osztálya: A
  • SJR Scopus - Health, Toxicology and Mutagenesis: D1
  • Earth and related Environmental sciences
Rainwater chemistry plays an important role in the earth-surficial ecosystem, but studies on rainwater chemical composition of karst agro-ecosystem are rare. To explore the rainwater alkalization and the provenance of components responsible for neutralization, two-years chemical monitoring of rainwater was carried out in a karst agricultural catchment in Southwest China. The main findings suggest that SO42-, NO3-, Ca2+, and NH(4)( )(+)are the principal ions. All the ionic contents show distinctly seasonal variation (highest in winter) in response to variations in seasonal precipitation because the rain-scour process can efficiently remove atmospheric materials. Source identification indicates that Cl- and Na+ are mainly derived from marine input whereas SO42+ and NO3- are controlled by anthropogenic emission, in particular, fixed emission sources. The source of NH4+ is attributed to intense agricultural production, while Ca2+ and Mg2+ are mainly derived from calcite dissolution. The rainwater alkalization caused by the seasonal acid neutralization (via basic components, Ca2+ and NH4+) is beneficial to crop growth but also reflect agricultural overfertilization. Sulfur controlled the total wet acid deposition (68%-94%) and could be a potential agent of weathering. (C) 2020 Elsevier Ltd. All rights reserved.
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2023-12-06 12:45