ASTM D5754-95(2000)
(Guide)Standard Guide for Displaying the Results of Chemical Analyses of Ground Water for Major Ions and Trace Elements-Trilinear Diagrams for Two or More Analyses
Standard Guide for Displaying the Results of Chemical Analyses of Ground Water for Major Ions and Trace Elements-Trilinear Diagrams for Two or More Analyses
SCOPE
1.1 This guide describes the category of water analysis diagrams that use two-dimensional trilinear graphs as a technique for displaying the common chemical components from two or more complete analyses of natural ground water (see Section 3) on a single diagram. This category includes not only trilinear-shaped diagrams but also the diamond- or parallelogram-, rectangular-, or square-shaped graphs that have trilinear subdivisions.
1.2 This guide is the first of several documents to inform professionals in the field of hydrology with the traditional graphical methods available to display ground water chemistry.
Note 1--Subsequent guides are planned that will describe the other categories of diagrams that have been developed to display ground water chemical analyses. (1)A guide for diagrams based on data analytical calculations will include those categories of water analysis graphs in which one analysis is plotted on each diagram (for example, the pattern, bar, radial, and circle diagrams). (2)A guide for statistical diagrams will include those categories of water analysis graphs in which multiple analyses are analyzed statistically and the results plotted on the diagram (for example, the box, etc.).
1.3 Numerous methods have been developed to display the ions dissolved in water on trilinear diagrams. These diagrams are valuable as a means of interpreting the physical and chemical mechanisms controlling the composition of water.
1.4 The most commonly used trilinear methods were developed by Hill (1-3), Langelier and Ludwig (4), Piper (5,6), and Durov (7-13). These techniques are proven systems for interpreting the origin of the ions in natural ground water and for facilitating the comparison of results from a large number of analyses.
Note 2--The use of trade names in this guide is for identification purposes only and does not constitute endorsement by ASTM.
1.5 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project's many unique aspects. The word "Standard" in the title of this document means only that the document has been approved through the ASTM consensus process.
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Designation: D 5754 – 95 (Reapproved 2000)
Standard Guide for
Displaying the Results of Chemical Analyses of Ground
Water for Major Ions and Trace Elements—Trilinear
Diagrams for Two or More Analyses
This standard is issued under the fixed designation D5754; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 1.5 This guide offers an organized collection of information
or a series of options and does not recommend a specific
1.1 This guide describes the category of water analysis
course of action. This document cannot replace education or
diagrams that use two-dimensional trilinear graphs as a tech-
experienceandshouldbeusedinconjunctionwithprofessional
nique for displaying the common chemical components from
judgment. Not all aspects of this guide may be applicable in all
two or more complete analyses of natural ground water (see
circumstances. This ASTM standard is not intended to repre-
Section3)onasinglediagram.Thiscategoryincludesnotonly
sent or replace the standard of care by which the adequacy of
trilinear-shaped diagrams but also the diamond- or
a given professional service must be judged, nor should this
parallelogram-,rectangular-,orsquare-shapedgraphsthathave
document be applied without consideration of a project’s many
trilinear subdivisions.
unique aspects. The word “Standard” in the title of this
1.2 This guide is the first of several documents to inform
document means only that the document has been approved
professionals in the field of hydrology with the traditional
through the ASTM consensus process.
graphicalmethodsavailabletodisplaygroundwaterchemistry.
NOTE 1—Subsequent guides are planned that will describe the other 2. Referenced Documents
categories of diagrams that have been developed to display ground water
2.1 ASTM Standards:
chemical analyses.
D596 Practice for Reporting Results ofAnalysis of Water
(1) A guide for diagrams based on data analytical calculations will
D653 Terminology Relating to Soil, Rock, and Contained
include those categories of water analysis graphs in which one analysis is
Fluids
plotted on each diagram (for example, the pattern, bar, radial, and circle
diagrams).
D1129 Terminology Relating to Water
(2) A guide for statistical diagrams will include those categories of
wateranalysisgraphsinwhichmultipleanalysesareanalyzedstatistically 3. Terminology
and the results plotted on the diagram (for example, the box, etc.).
3.1 Definitions—Except as listed as follows, all definitions
1.3 Numerous methods have been developed to display the
are in accordance with Terminology D653.
ions dissolved in water on trilinear diagrams. These diagrams
3.1.1 anion—an ion that moves or would move toward an
are valuable as a means of interpreting the physical and
anode; the term is thus nearly always synonymous with
chemical mechanisms controlling the composition of water.
negative ion.
1.4 The most commonly used trilinear methods were devel-
3.1.2 cation—an ion that moves or would move toward a
opedbyHill(1-3), LangelierandLudwig(4),Piper(5,6),and
cathode; the term is thus nearly always synonymous with
Durov (7-13). These techniques are proven systems for inter-
positive ion.
preting the origin of the ions in natural ground water and for
3.1.3 equivalent per million (epm)—for water chemistry, an
facilitating the comparison of results from a large number of
equivalent weight unit expressed in English terms and also
analyses.
expressed as milligram-equivalent per kilogram. When the
concentration of an ion, expressed in parts per million (ppm),
NOTE 2—The use of trade names in this guide is for identification
is multiplied by the equivalent weight (combining weight)
purposes only and does not constitute endorsement by ASTM.
factor (see equivalent weight factor) of that ion, the result is
expressed in epm.
ThisguideisunderthejurisdictionofASTMCommitteeD18onSoilandRock
3.1.3.1 Discussion—
and is the direct responsibility of Subcommittee D18.21 on Ground Water and
Vadose Zone Investigations.
Current edition approved August 15, 1995. Published September 1995.
2 3
The boldface numbers in parentheses refer to the list of references at the end of Annual Book of ASTM Standards, Vol 11.01.
this guide. Annual Book of ASTM Standards, Vol 04.08.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 5754 – 95 (2000)
(1) For a completely determined chemical analysis of a patterns. Freeze and Cherry (17) state,“ Hydrochemical facies
water sample, the total epm value of the cations will equal the are distinct zones that have cation and anion concentrations
total epm value of the anions (chemically balanced). The describable within defined composition categories.” The defi-
plotted values on the water analysis diagrams described in this nition of a composition category is commonly based on
guide can be expressed in percentages of the total epm subdivisionsofthetrilineardiagram,asdescribedbyBack (16,
(although all illustrations are in milliequivalent per litre) of the 18).
cations and anions of each water analysis. In order to use the
3.1.7 milliequivalentperlitre(meq/L)—forwaterchemistry,
diagrams, analyses must therefore be converted from ppm to
an equivalent weight unit expressed in metric terms and also
epm by multiplying each ion by its equivalent weight factor
expressed as milligram-equivalent per litre. The result is
and determining the percent of each ion of the total cation or
expressed in meq/L when the concentration of an ion, ex-
anion.
pressed in mg/L, is multiplied by the equivalent weight
(2) For a completely determined chemical analysis of a (combining weight) factor (see equivalent weight factor)of
water sample, the total value of the cations will equal the total that ion.
value of the anions (chemically balanced). The plotted values
3.1.8 milligrams per kilogram (mg/kg)—for water chemis-
on the water analysis diagrams described in this guide are
try, a weight-per-weight unit expressed in metric terms. The
expressed in percentages of the total milliequivalent per litre
number of mg of solute (for example, Na) per kg of solution
(meq/L) of the cations and anions of each water analysis. In
(water). For example, if the total weight of the solution (one
ordertousethediagrams,analysesmustthereforebeconverted
million mg/kg) has 99% solvent and 1% solvent, this is the
from milligram per litre (mg/L) to meq/L by multiplying each
same as 990000 mg/kg solution and 10000 ppm solute in the
ion by its equivalent weight factor and determining the percent
1000000 mg/kg of solution.
of each ion of the total cation or anion.
3.1.9 milligrams per litre (mg/L)—for water chemistry, a
3.1.4 equivalent weight factor—also called the combining
weight-per-volume unit expressed in metric terms. The weight
−3
weight factor and reaction coefficient, this is used for convert-
in mg (10 g) of the solute within the volume (L) of solute
ing chemical constituents expressed in ppm to epm and mg/L
and solution. The weight can be also expressed in micrograms
−6
to meq/L (see equivalent per million and milliequivalent per
(µm) (10 g). The use of the mg/L unit is the world-wide
litre). To determine the equivalent weight factor, divide the
standard for the analysis and reporting of water chemistry.
formulaweightofthesolutecomponentintothevalenceofthe
3.1.9.1 Discussion—The ppm and mg/L values of the con-
solute component:
stituents in natural ground water are nearly equal (within
anticipated analytical errors) until the concentration of the
~valencesolutecomponent!
~equivalentweightfactor!5
~formulaweightsolutecomponent! dissolved solids reaches approximately 7000 mg/L. A density
(1)
correction should be used when computing ppm from mg/L
(14) for highly mineralized waters.
To then determine the equivalent weight (meq/L) of the
3.1.10 natural ground water—as defined for this guide,
solute component, multiply the mg/L value of the solute
water positioned under the land’s surface that consists of the
component times the equivalent weight factor, as follows;
basic elements, hydrogen and oxygen (H O), and numerous
~meq/Lsolutecomponent!5~mg/Lsolutecomponent!
major dissolved chemical constituents, such as calcium (Ca),
3~equivalentweightfactor!
magnesium (Mg), sodium (Na), potassium (K), carbonate
(2)
(CO ), bicarbonate (HCO ), chloride (Cl), and sulfate (SO ).
2+ 3 3 4
For example, the formula weight of Ca is 40.10 and the
3.1.10.1 Discussion—
ionic charge is 2 (as shown by the 2+), and the equivalent
(1) In special cases, other major constituents can include
weightvalueiscomputedtobe0.9975meq/Lforavalue of 20
aluminum (Al), boron (B), fluoride (F), iron (Fe), nitrate
mg/L Ca:
(NO ), and phosphorus (PO ). Minor and trace elements that
3 4
~2!
can occur in natural ground water vary widely, but they can
~0.9975meq/LCa!5~20mg/LCa!3 (3)
~40.10!
include arsenic (As), copper (Cu), lead (Pb), mercury (Hg),
3.1.4.1 Discussion—Many general geochemistry publica-
radium (Ra), and zinc (Zn). In addition, natural ground water
tions (14) and water encyclopedias (15) have a complete table
may contain dissolved gases, such as hydrogen sulfide (H S),
of equivalent weight factors for the ions found in natural
carbon dioxide (CO ), oxygen (O ), methane (CH ), ammonia
2 2 4
ground water.
(NH ), argon (Ar), helium (He), and radon (Rn). Neutrally
3.1.5 grains per U.S. gallon (gpg)—for water chemistry, a charged mineral species such as silicate (SiO ), naturally
weight-per-volume unit; also, for irrigation water, it can be occurring organics such as tanic acids and colloidal materials,
expressedintonsperacre-foot(ton/acre-ft).Theweight(grains and particulates such as bacteria viruses and naturally charged
or tons) of solute within the volume (gallon or acre-foot) of pollen spores.
solution.Agrain is commonly used to express the hardness of
(2) Most natural ground water is part of the hydrologic
water, where one grain is equal to 17.12 ppm CaCO .
cycle, which is the constant circulation of meteoric water as
3.1.6 hydrochemical facies—as described by Back (16), the vapor in the atmosphere as a result of evaporation from the
diagnostic chemical character of water solutions in aquifers. earth’s surface (land and ocean), liquid and solid (ice) on and
These facies reflect the effects of chemical processes in the under the land as a result of precipitation from the atmosphere,
lithologic environment and the contained ground water flow and liquid returned to the ocean from the land. A very small
D 5754 – 95 (2000)
amount of the ground water may be magmatic water originat- 4.5 Detailed descriptions and applications for the following
ingfromrocksdeepwithinthecrustoftheearth.Otherground more commonly used water analysis diagrams are given:
water is connate in that it is trapped in sediments and has not 4.5.1 Hill geochemical pattern diagram,
moved actively in the hydrologic cycle for a period measured 4.5.2 Langelier and Ludwig water classification diagram,
in geologic time. 4.5.3 Piper water analysis diagram, and
(3) While moving through the hydrologic cycle, chemical 4.5.4 Durov water classification diagram.
4.6 Automated procedures (computer-aided graphics) for
elements in the water are exchanged with other ions and
dissolved into and precipitated out of the water, depending on basic calculations and the placement of analysis plot symbols
onto computer-generated water analysis diagrams are de-
reactions with air and other gases, rock minerals, biological
agents, hydraulic pressure, and ambient temperature. The scribed.
4.7 A list of references is cited and provided for additional
chemicalcompositionofnaturalgroundwaterrangesfromthat
similar to distilled water with a minor amount of dissolved information.
4.8 Abibliography (non-referenced documents) is provided
solids to a brines, with at least 100000 mg/L dissolved solids
(19). (Naturally occurring brine has been analyzed with more for further sources of information.
than 300000 mg/L dissolved chemical solids.)
5. Significance and Use
3.1.11 Parts per million (ppm)—for water chemistry, a
dimensionless ratio of unit-of-measurement per unit-of-
5.1 Many thousands of water samples are collected each
measurement expressed in English terms. One part per million
yearandthechemicalcomponentsaredeterminedfromnatural
isequivalentto1mgofsoluteto1kgofsolution.Forexample,
ground water sources.
if the total weight of the solution (1000000 ppm) has 99%
5.2 A single analysis can be interpreted easily regarding
solventand1%solute,thisisthesameas990000ppmsolvent
composition and geochemical type; however, it is difficult to
and 10000 ppm solute in the 1000000 parts of solution.
comprehendallofthefactorsofsimilarities,interrelationships,
3.1.12 water analysis—a set of data showing the concen- and differences when large numbers of analyses are being
tration of chemical ions as analyzed from a water sample. In
compared.
this guide, it normally includes the common constituents as 5.3 One of the methods of interpreting the implication of
found in natural ground water (see 3.1.10).
these chemical components in the water is by displaying a
3.1.13 water analysis diagram—as used in this guide, a number of related water analyses graphically on a visually
graphical display method for multiple water analyses. This summarizing water analysis diagram.
method can be used to assist in scientific interpretation of the 5.4 The water analysis diagrams described in this guide
occurrence of cations and anions in natural ground water. The
display the percentages of the individual cation and anion
method consists of various combinations of triangular-shaped weights of the total cation and anion weights on graphs shaped
cation and anion diagrams and diamond- or square-shaped
as triangles, squares, diamonds, and rectangles.
integrated cation and anion diagrams. The sides of the dia-
NOTE 3—The concentration of dissolved solids determined for each
grams are divided into equal parts (commonly fifty 2% or ten
analysis is not evident by the plotted location. Scaled symbols, usually
10% segments) for representing the percentage of each of the
circles, can represent the amount of dissolved solids for each analysis
cations or anions within the total cation or anion concentration
plotted on the diagrams.
(100%).The plotted positions of the cations and anions on the
5.5 Classification of the composition of natural ground
diagrams offer an indication of the origin of a
...
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