Presentation on theme: "PH It is defined as the negative common logarithm of the concentration of hydrogen ions [H + ] in moles/liter: pH = -log 10 [H + ]. The concentration of."— Presentation transcript:
pH It is defined as the negative common logarithm of the concentration of hydrogen ions [H + ] in moles/liter: pH = -log 10 [H + ]. The concentration of hydrogen ions is commonly expressed in terms of the pH scale. Low pH corresponds to high hydrogen ion concentration and vice versa.
a Pourbaix diagram, also known as a potential/pH diagram or Eh/pH diagram. The diagrams are named after Marcel Pourbaix (1904–1998), the Russian-born chemist who invented them. In sedimentary environments the concept of geochemical facies is best illustrated on an Eh-pH diagram, a diagram delineating the stability field of certain minerals in terms of the proton concentration (pH) and electron concentration (Eh). Eh and REDOX: the ability of an environment to supply electrons to an oxidizing agent, or to take up electrons from a reducing agent.
Eh-pH predominance diagram for aqueous chromium at 25 °C (Cr tot = 1 µM).
Specific conductance (SpC) is a measure of the concentration of soluble salts in solution. Conductance is also a readily available field test which enables a worker to compare a new sample with previously analyzed samples quickly and easily. CriteriaValuesAuthority Total Dissolved Solids (TDS) 500 mg/l EPA 440/ Sodium plus Potassium 200 mg/l EPA 440/ Chloride250 mg/l EPA 440/ Nitrate450 mg/l EPA 440/ Total Hardness150 mg/l EPA 440/ Specific Conductance 750 µmhos/cm or µS/cm U.S. Salinity Lab. Irrigation Recommendations
Alkalinity (AT) is a measure of the ability of a solution to neutralize acids to the equivalence point of carbonate or bicarbonate.
Type of waters:Specific Conductance (µS/cm) Eh (millivolts) pH (pH units) rain water2 to to freshwater lakes/streams 2 to to ground water50 to 50, to brinesup to 500, to -600near neutral ocean water~ 50, to landfill leachate10,000variablenear neutral acid mine drainageup to 500, to +800below 5 wetlands / bogs50 to 50, to -100variable Typical ranges of values for some water field measurements. From: Sanders, L.L., 1998, A Manual of Field Hydrogeology: Prentice-Hall, NJ, 381p.