Potential of Hydrogen (pH)

pH is an important parameter that reflects the chemical conditions of a solution. In water, it is a measure of the hydrogen ion concentration ranked on a scale of 1.0 (acidic) to 14.0 (alkaline). The pH can control the availability of nutrients, biological functions, microbial activity, and the behavior of chemicals. Because of this, monitoring or controlling the pH of soil, water, and food or beverage products is important for in many applications.

Chlorine

Chlorine can be added to water for disinfection. Once dissolved in water, Free chlorine forms hypochlorous acid, which can kill disease-causing microbes. Free chlorine that is consumed by a mode of action or is rendered ineffective by other organic compounds becomes Combined chlorine (chloramines). Total chlorine is a sum of both Free and Combined chlorine. Only Free chlorine is effective for sanitation applications.

Hardness

Hardness is a measure of the soap consuming capacity of water. The term comes from an expression of how difficult or “hard” it is to wash clothes with the water. In general, hard water forms solid deposits comprised of mainly calcium and magnesium salts (scaling) while soft water may be corrosive. While some hardness may be acceptable in certain water quality applications, others require zero hardness to prevent scaling and damage to equipment. To optimize these processes it may be important to monitor calcium and magnesium levels separately, along with total hardness.

Turbidity

Turbidity is a measurement of the amount of light that is scattered by material in the water when exposed to a beam of light. The higher the intensity of scattered light, the higher the turbidity. Material that causes water to be turbid include particles (clay, silt, inorganic and organic matter), dissolved compounds, algae, and other microscopic organisms. Particles also provide attachment places for other pollutants, notably metals and bacteria. For this reason, turbidity readings can be used as an indicator of potential pollution in a water body.

Electrical conductivity (EC)

Electrical conductivity is a measure of the amount of salts in soil (salinity of soil) or water. For soil, it is an excellent indicator of nutrient availability and loss, soil texture, and available water capacity. These factors can affect the amount of water and nutrients available for plant use and the activity of soil micro-organisms, which influences key soil processes such as the emission of greenhouse gases, including nitrogen oxides, methane, and carbon dioxide. Excessive salts hinder plant growth by affecting the soil and water balance.

Sodium Adsorption Ratio (SAR)

The sodium adsorption ratio (SAR) is an irrigation water quality parameter. It is determined from the concentrations of the main alkaline and earth alkaline cations (sodium, calcium, magnesium) present in the water sample, or pore water extracted from a soil sample. SAR is also a standard diagnostic parameter for the sodicity hazard of a soil. SAR allows assessment of the state of flocculation, or of dispersion of clay aggregates, in a soil. In general, higher SAR numbers reflect poorer suitability of the soil or water for agriculture applications.

Suspended and Dissolved Solids

It may be important to obtain more detailed information than can be provided from a turbidity measurement. Total Suspended Solids (TSS) is a measurement of the total solids in a water or wastewater sample that are retained by filtration. Total dissolved solids (TDS) are the amount of organic and inorganic materials, such as metals, minerals, salts, and ions, dissolved in a particular volume of water.

Inorganic anions

While electrical conductivity is an excellent indicator of overall ion content, quantifying the specific anions present in an environmental soil or water sample is sometimes necessary. Common anions typically present in water and soil samples include chloride (Cl–), fluoride (F–), bromide (Br–), nitrate (NO3–), nitrite (NO2–), phosphate (PO4–), and sulfate (SO4–).

Alkalinity

While pH can provide an overall assessment of alkalinity and electrical conductivity is an excellent indicator of overall ion content, quantifying the common anions specifically associated with alkalinity is sometimes necessary. Total Alkalinity is most frequently expressed in mg/L as CaCO3. The measured values for hydroxide (OH–), bicarbonate (HCO3–), and carbonate (CO32–) can also be requested.

Cyanide (CN–)

Cyanide is a naturally occurring small anion present and released from the breakdown of complex molecules found in certain plants and seeds. Industrially, hydrogen cyanide is immensely useful in the production of synthetic fibers and resins. Cyanide is normally found in wastewater from metal-finishing operations and waste storage sites. Prolonged exposure even low levels of cyanide can result in nervous system damage, hypothyroidism, and liver and kidney damage.