Details

Autor(en) / Beteiligte

• Liu, Chao
• Guo, Huaming
• Fan, Wendi
• Xu, Rui
• Han, Shuangbao
• Gao, Bingying
• Zhao, Bo
• Jiang, Chunping

Titel

Hydrogeological controls on chromium enrichment along the groundwater flow path in the Baiyangdian Catchment, North China Plain

Ist Teil von

• The Science of the total environment, 2023-10, Vol.893, p.164890-164890, Article 164890

Ort / Verlag

Netherlands: Elsevier B.V

Erscheinungsjahr

2023

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Although the natural occurrence of high chromium (Cr) groundwater has been intensively investigated in bedrock or sedimentary aquifers, the impacts of hydrogeological conditions on dissolved Cr distribution are poorly understood. In this study, groundwater samples from recharge mountain area (Zone I) through runoff area (Zone II) to discharge area (Zone III) were taken from bedrock and sedimentary aquifers approximately along the flow path in Baiyangdian (BYD) catchment, China, to reveal how hydrogeological conditions and hydrochemical evolution contributed to Cr enrichment in groundwater. Results showed that dissolved Cr was dominated by Cr(VI) species (>99 %). Around 20 % of studied samples had Cr(VI) exceeding 10 μg/L. Groundwater Cr(VI) was of natural origin, which generally increased along the flow path, and high concentrations (up to 80.0 μg/L) were observed in deep groundwater of Zone III. At the local scales, geochemical processes including silicate weathering, oxidation, and desorption under weakly alkaline pH, predominately contributed to Cr(VI) enrichment. Principal component analysis showed that oxic conditions were the principal control of Cr(VI) in Zone I, and geochemical processes (especially Cr(III) oxidation and Cr(VI) desorption) predominantly enhanced groundwater Cr(VI) enrichment in Zones II and III. However, at the regional scale, Cr(VI) enrichment was dominantly facilitated by the low flow rate and recharge of paleo-meteoric water due to the long-term water-rock interaction in the BYD catchment. [Display omitted] •Groundwater Cr(VI) generally increased along the flow direction.•Cr(VI) was mobilized via silicate (e.g. hornblende) weathering, Cr(III) oxidation and desorption from Fe oxides.•The sluggish flow rate favored Cr(VI) enrichment in regional groundwater.•Geochemical processes crucially controlled Cr(VI) mobility in local deep groundwater.