Chemical properties of soda lakes and pans

A review of the defining chemical properties of soda lakes and pans was recently published by Emil Boros and Marina Kolpakova. The aim of the study was to evaluate the definition of water chemical type, with particular attention to soda brine characteristics. Authors assessed ionic composition and pH values on a large geographic scale and broad salinity (TDS) range of Eurasian inland saline surface waters, in order to rectify the considerable confusion about the exact chemical classification of soda lakes and pans.


The large geographic scale distribution of the assessed lakes and pans in the dataset by countries and references.

Soda brines were divided into “Soda” and “Soda-Saline” types based on dominant ions exceeding an equivalent percentage of 25 (> 25e%) of the total cations or anions. The application of the proposed terminology of “Soda” and “Soda-Saline” chemical types for soda brines can help reduce the level of misunderstanding between cross-disciplinary researches and also provide a clearer picture of chemical features. Proposed classification of soda brines does not change the widely accepted classification of chemical water types, but it gives a precise vision to researchers from different fields for studying the environment in each particular case. Analysis clearly demonstrates that pH measurement alone is not a reliable indicator for classifying the soda chemical type of inland saline surface waters.

As a practical consideration of the review, authors are working on an online data input web tool for a worldwide database of the soda and saline chemical types of inland surface waters supported by Google Satellite raster data via OpenLayers plugin. This special tool requires the location of the sites by points or polygons and also allows uploading some basic geographical and limnological data. The most practical innovation of this web application will be the classification panel, where users can upload the concentration of major ions and automatically acquire the appropriate chemical type of the water. More information about this free service can be requested from the corresponding author.

Reference: Boros E, Kolpakova M (2018) A review of the defining chemical properties of soda lakes and pans: An assessment on a large geographic scale of Eurasian inland saline surface waters. PLoS ONE 13(8): e0202205.

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