Cl/Br ratios and chlorine isotope evidences for groundwater salinization and its impact on groundwater arsenic, fluoride and iodine enrichment in the Datong basin, China

Sensor based on β - NiOx hybrid film/multi-walled carbon nanotubes composite electrode for groundwater salinization inspection

“…However, the most critical situation was identified in untreated waters, where the contents of this nutrient achieved values of 600 ± 13 mg L−1. There are several natural and anthropogenic sources, being the most influential factors the inadequate disposal of highly saline industrial effluents, contamination of soils with industrial byproducts, incorrect land management, percolation of contaminated areas, erosion of the constituent rocks of the aquifer, and ocean water intrusion [1], [4], [5], [6], [7], [8], [27]. Still, the attained results also showed a positive impact of the employed conventional treatments, but they seem not yet sufficient to reach the maximum permitted limit (20 mg L−1) established by World Health Organization [10] and United States Environmental Protection Agency [40] for drinking-water.…”

“…Groundwater is the most important natural drinking-water supply of the population and thus, all possible actions of monitor-ing, preservation and sustainable use of this finite resource should be investigated [1][2][3][4]. Unfortunately, groundwater reserves are very susceptible to contamination by natural (saline intrusion; leaching of contaminated areas by rainfall action; chemical trans-formation and dissolution of minerals contained in the aquifer rock formation) and/or anthropogenic events (improper disposal of solid and liquid wastewaters from industrial, commercial and domestic activities; leaks of sewage from cesspools built improp-erly; leaching by irrigation of agricultural areas; among others), limiting groundwater multiple use [1,5].…”

“…Unfortunately, groundwater reserves are very susceptible to contamination by natural (saline intrusion; leaching of contaminated areas by rainfall action; chemical trans-formation and dissolution of minerals contained in the aquifer rock formation) and/or anthropogenic events (improper disposal of solid and liquid wastewaters from industrial, commercial and domestic activities; leaks of sewage from cesspools built improp-erly; leaching by irrigation of agricultural areas; among others), limiting groundwater multiple use [1,5]. The joint effects of these factors with the extended period of drought in semi-arid zones may worsen the groundwater quality, especially by salinization processes [1,4,6].…”

Effects of water-sediment interaction and irrigation practices on iodine enrichment in shallow groundwater

“…With an arid/semi-arid climate, the annual average precipitation of the Datong basin is between 225 and 400 mm with 75 to 85% of rainfall occurring in July and August, and annual evaporation is above 2000 mm. Groundwater table changes from >20 m below the land surface in the margin area to approximately 2~3 m in the central area with fluctuations caused by irrigation activities (Li et al, 2016). Except for some poor saline soils in the central area, most of the soils in the Datong basin have been cultivated for agriculture for centuries.…”

“…In the Datong basin, high iodine concentrations up to 1890 µg/L have been detected in the shallow groundwater from the discharge area where the groundwater condition is characterized by lower flow rate, long residence time and (sub)reducing conditions (Li et al, 2014;Li et al, 2013). Recently, periodic irrigation practices using deep groundwater and surface water as the irrigation sources have the potential to change the shallow groundwater environment through water table fluctuation (Li et al, 2016). The variation of the groundwater evironment might further influence the geochemical cycling of iodine in the shallow aquifer due to the sensitivity of iodine species to the redox potential of groundwater system.…”