Salts

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Chemistry Matters has extensive experience investigating salinity contamination and characterizing salts and salt sources in soil or water at a wide variety of sites and jurisdictions. Specifically, our team specializes in salinity source and background fingerprinting, association analyses, calculating site-specific guidelines for various salinity parameters, isotope analyses, and risk assessments.

Salinity is the quantity of dissolved salt in water or the salt content in a given mass of material (soil, sediment, etc.). The major salinity cations and anions include calcium (Ca2+), magnesium (Mg2+), potassium (K+), sodium (Na+), carbonate (CO32-), chloride (Cl), and sulphate (SO42-). The concentrations of these anions and cations in soil or water affect the values of typically measured and regulated salinity parameters such as electrical conductivity (EC) and sodium adsorption ratio (SAR). Elevated values or concentrations of salinity parameters in soil or water can negatively affect both soil and water quality.

Naturally elevated salinity ions may be present at varying concentrations in soil, surface water, or groundwater and often exceed applicable regulatory guideline values. Employing methods to properly characterize salinity impacts and background conditions excludes naturally elevated inorganic parameters as potential chemicals of concern and eliminates unnecessary investigation, risk assessment, and/or remediation. Elevated salinity in background can be the result of weathering, land use (i.e., agricultural cultivated cropland or pasture), soil type (i.e., solonetzic soil), and/or naturally occurring geochemistry processes (i.e., dissolution).

Salt Figure 1: Naturally Occurring Root Zone Salinity in Solonetzic Soil (Alberta Agriculture and Forestry)

Salt Figure 1: Naturally Occurring Root Zone Salinity in Solonetzic Soil (Alberta Agriculture and Forestry)

Chemistry Matters has developed the Salinity Assessment Tool (SAT) to assess a wide variety of sites. The SAT integrates site-specific conditions and laboratory analytical data to generate risk-based results (factoring in soil type, land use, and potential receptors) that quantify the severity of salinity impacts at a site. The analysis uses a combination of risk-based evaluation and visual outputs to provide a comprehensive result that identifies impacted samples.

An evaluation of the trends of potentially naturally occurring salinity ions measured in background samples can be used to develop fingerprints that are representative of naturally occurring or background conditions. The salinity fingerprints of any collected samples can be compared to background in order to differentiate naturally occurring or background salinity fingerprints from anthropogenic salinity fingerprints. Multivariate statistical analysis (specifically, Principal Component Analysis and Hierarchical Cluster Analysis) is used in combination with the SAT to validate the results. If carefully evaluated (i.e., by sample depth or material type), trends observed in salinity data may be used to fingerprint background soil or water salinity parameters and differentiate samples with naturally occurring salinity concentrations, anthropogenic salinity concentrations, or a combination of both.

Radar plots are created by SAT for visual representation of the data. The plots use the salinity ion percentages from the SAT calculations to create fingerprints of the data. When Site sample fingerprints match the background fingerprint, the sample is assumed to be non-impacted as the ratio of ions within the sample have not been altered by an anthropogenic source, regardless of location or salinity concentrations in mg/kg.

Salt Figure 2: Example of Salinity Data Analysis Completed Using the SAT

Salt Figure 2: Example of Salinity Data Analysis Completed Using the SAT

In addition to the application of the SAT for salinity fingerprinting and source characterization, Chemistry Matters has experience applying isotope analyses (i.e., Cl or Br in groundwater and surface water) and association analyses (i.e., evaluating molar ratios such as Cl/Br) to assess, characterize, and differentiate between various salts and salinity impacts/sources, including from road salts.

Chemistry Matters has staff with certification to use the Subsoil Salinity Tool (SST), which is a software program used to develop site-specific Tier 2 soil and/or groundwater remediation guidelines for salts and salinity parameters (specifically, chloride) below the root zone (>1.5 mbgs). Two levels of Tier 2 subsoil salinity guidelines can be developed using the SST program (Tier 2A or Tier 2B). The Tier 2A approach requires a lower level of Site characterization than Tier 2B, but both offer the same level of ecological and human health protection. When site-specific conditions do not meet the generic SST model assumptions, a Tier 2A or Tier 2B assessment cannot be applied, requiring the implementation of a Tier 2C approach (involves the use of more sophisticated fate and transport modeling).

Salt Figure 3: Example Background EC and Chloride Profiles Used For Background Characterization via the SST

Salt Figure 3: Example Background EC and Chloride Profiles Used For Background Characterization via the SST


Salt Figure 4: Example Vertical Source Area Profile and Source Areas Dimensions (Alberta Government)

Salt Figure 4: Example Vertical Source Area Profile and Source Areas Dimensions (Alberta Government)


Salt Figure 5: Example SST Guidelines Output

Salt Figure 5: Example SST Guidelines Output

If you have sites with potential salinity issues or need to chemically or isotopically fingerprint salt for an investigation, contact Chemistry Matters Inc. for more information on how to bring any site to closure in the most effective manner.

Click Here to watch Lacey Harbicht’s full presentation: Identifying Natural Salinity on Sites with Elevated Salinity Concentrations

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