ASTM D1129-13(2020)e1
(Terminology)Standard Terminology Relating to Water
Standard Terminology Relating to Water
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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
´1
Designation: D1129 − 13 (Reapproved 2020)
Standard Terminology Relating to
Water
This standard is issued under the fixed designation D1129; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
ε NOTE—In accordance with D19 bylaws, approved items were added editorially in February 2023.
absolute filter rating, n—particle size above which 100 % of reference value is not available, accuracy is a description of
particles that are trapped on or within the filter medium. a measure of the degree of conformity of a value generated
D6161 by a specific procedure to the assumed or accepted true
value, including both precision and bias. D6161
absorbance, n—logarithm to the base 10 of the reciprocal of
accuracy, n—measure of the degree of conformity of a single
the transmittance (T). A = log (1 ⁄ T) = –log T. D4691
10 10
test result generated by a specific procedure to the assumed
absorption, n—release for desorption holding of a substance
or accepted true value, and includes both precision and bias.
within a solid by cohesive or capillary forces. D6161
D2777
absorptivity, n—absorbance (A) divided by the product of the
accuracy, n—proportion of the observed count to the true
sample path length (b) and the concentration (c). a = A/bc.
density of a sample. D5392
D4691
accuracy, n—refers to how close a measurement is to the true
accelerated erosion, n—erosion at a rate greater than geologic
or actual value. (See Terminology D1129.) D5906
or natural erosion. D4410
acid error, n—in very acid solutions, the activity of water is
DISCUSSION—Accelerated erosion is usually associated with anthro-
reduced (less than unity) causing a non-Nernstian response
pogenic activities and usually reduces plant cover and increases runoff.
in glass electrodes. A positive error in the pH reading results.
acceptable holding time, n—any period of time less than or
D4127
equal to the maximum holding time. D4841
acidity, n—the quantitative capacity of aqueous media to react
acceptable verification ratio (AVR)—ratio of the difference
with hydroxyl ions.
between measured value of the verification sample and the
acidity, n—quantitative capacity of aqueous media to react
known value added to the verification sample to the square
with hydroxyl ions. D6161
root of the sum of the squares of their associated combined
standard uncertainties. See Eq. 8 in 16.2.13. D7282
acidity, free mineral, n—the quantitative capacity of aqueous
media to react with hydroxyl ions to pH 4.3.
accretion, n—process of sediment accumulation. D4410
acidity, theoretical free mineral, n—the free mineral acidity
accumulator, n—pulsation dampener installed on the suction
that would result from the conversion of the anions of strong
and/or discharge lines of pumps, generally plunger type, to
acids in solution to their respective free acids.
minimize pressure surges and provide uniformity of flow.
D6161 acoustic path, n—straight line between the centers of two
acoustic transducers. D5389
accuracy, n—a measure of the degree of conformity of a value
acoustic path length, n—face-to-face distance between trans-
generated by a specific procedure to the assumed or accepted
true value, and includes both precision and bias. ducers on an acoustic path. D5389
acoustic transducer, n—device that is used to generate acous-
accuracy, n—closeness of agreement between an observed
tic signals when driven by an electric voltage, and
value and an accepted reference value. Where an accepted
conversely, a device that is used to generate an electric
voltage when excited by an acoustic signal. D5389
This terminology is under the jurisdiction of ASTM Committee D19 on Water
and is the direct responsibility of Subcommittee D19.12 on Terminology.
acoustic travel time, n—time required for an acoustic signal to
Current edition approved May 1, 2020. Published June 2020. Originally
propagate along an acoustic path, either upstream or
approved in 1950. Last previous edition approved in 2013 as D1129 – 13. DOI:
10.1520/D1129-13R20E01. downstream. D5389
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
D1129 − 13 (2020)
action level, n—concentration of the analyte of concern at algae, n—major group of lower plants, generally aquatic,
which some further action is required or suggested. D6850 photosynthetic of extremely varied morphology and
physiology, monocellular plants with chlorophyll often
activated carbon, n—granulated or powdered activated carbon
masked by a brown or red pigment. D6161
used to remove tastes, odor, chlorine, chloramines, and some
organics from water. A family of carbonaceous substances alkaline error, n—in alkaline solutions, where hydrogen ion
manufactured by processes that develop adsorptive activity becomes very small, some glass electrodes respond
properties. D6161 to other cations, such as sodium. A negative error in the pH
reading results. By changing the composition of the glass,
activity, n—thermodynamically effective concentration of a
the affinity of the glass for sodium ion can be reduced. Such
free ion in solution. In dilute solutions, ionic activity and
electrodes are known as lithium glass, high-pH, or full-range
concentration are practically identical, but in solutions of
electrodes. D4127
high ionic strength, or in the presence of complexing agents,
activity may differ significantly from concentration. Ionic
alkalinity, n—the quantitative capacity of aqueous media to
activity, not concentration, determines both the rate and the react with hydrogen ions.
extent of chemical reactions. D4127
alkalinity, n—quantitative capacity of aqueous media to react
activity coefficient, n—factor, γ, that relates activity, A, to the
with hydrogen ions. “M” alkalinity is that which will react
concentration, C of a species in solution: with acid as the pH of the sample is reduced to the
methylorange endpoint of about 4.5. “P” alkalinity is that
A 5 γC
which reacts with acid as the pH of the sample is reduced to
The activity coefficient is dependent on the ionic strength
the phenolphthalein end point of 8.3. “M” is the total
of the solution. Ions of similar size and charge have similar
alkalinity which is the sum of hydroxide, carbonate, and
activity coefficients. D4127
bicarbonate contents, “P” includes all the hydroxyl and half
the carbonate content. D6161
activity standard, n—standardizing solution whose value is
reported in terms of ionic activity. If the electrode is
alkyl benzene sulfonate (ABS)—generic name applied to the
calibrated using activity standards, the activity of the free,
neutralized product resulting from the sulfonation of a
unbound ion in the sample is determined. D4127
branched-chain alkylated benzene. See also Terminology
D459. D2330
adenosine triphosphate—see ATP. D6161
alluvial channel—see alluvial stream. D4410
adsorption, n—holding of a substance onto the surface of a
solid by chemical surface forces, without forming new
alluvial deposit—sediment deposited by the action of moving
chemical bonds. D6161
water. D4410
aerobic bacteria, n—bacteria that require oxygen for growth.
alluvial fans—sediment deposited in the shape of a segment of
See bacteria, aerobes. D6161
a cone formed because of a sudden flattening of a stream
gradient especially at debouchures of tributaries on main
aerosol, n—any solid or liquid particles, with a nominal size
stream flood plains. D4410
range from 10 nm to 100 μm, suspended in a gas (usually
air). D5544
alluvial stream, n—stream whose boundary is composed of
appreciable quantities of the sediments transported by the
agglomeration or flocculation, n—coalescence of dispersed
flow and which generally changes its bed forms as the rate of
suspended matter into large flocs or particles that settle
flow changes. D4410
rapidly. D4410
alleviation, n—process of accumulating sediment deposits at
aggradation, n—geologic process by which stream beds, flood
places where the flow is retarded. D4410
plains, and the bottoms of other water bodies are raised in
elevation by the deposition of material eroded and trans-
alluvium, n—general term for all fluvial deposits resulting
ported by water from other areas. D4410
directly or indirectly from the sediment transport of (mod-
ern) streams, thus including the sediments laid down in
aggregate, n—granular material such as sand, gravel, or
riverbeds, flood plains, lakes, fans, and estuaries. D4410
crushed stone. D6161
alpha (α), n—velocity-head coefficient that adjusts the velocity
air header, n—pipe running within a cassette that distributes
head computed on basis of the mean velocity to the true
the air to the individual modules or aerators. D6161
velocity head. D5129
air scour, v—distributing air over the entire area at the bottom
alpha (α), n—velocity-head coefficient that adjusts the velocity
of a filter media flowing upward or immersed membrane to
head computed on basis of the mean velocity to the true
improve the effectiveness of filtration or backwashing or to
permit the use of lower backwash water flow rate, or both.
D6161
For a more complete discussion of terms relating to synthetic detergents and
air stripping, v—removal of volatile substances from a water
their significance, refer to McKinney, R. E., “Syndets and Waste Disposal,” Sewage
solution by passing a gas through the solution. D6161 and Industrial Wastes, Vol 29, Part 6, June 1957, pp. 654–666.
´1
D1129 − 13 (2020)
velocity head. It is assumed equal to 1.0 if the cross section amphoteric, adv—capable of acting as an acid or a base.
is not subdivided. D5243 D6161
alpha (α), n—velocity-head coefficient that represents the ratio
anaerobic bacteria, n—bacteria that do not use oxygen.
of the true velocity head to the velocity head computed on
Oxygen is toxic to them. See bacteria, anaerobes. D6161
the basis of the mean velocity. It is assumed equal to 1.0 if
analate addition, n—variation of the known addition measure-
the cross section is not subdivided. For subdivided sections,
ment technique in which the sample (analate) is added to a
a is computed as follows: D5130
reagent containing the ion being measured. The electrode is
k
i
placed in the reagent, and the sample concentration is
S D
(
A
i
calculated from the change in electrode potential after the
α 5
K
T
addition of the sample. D4127
A
T
analate subtraction, n—variation of the known subtraction
where:
measurement technique in which the sample (analate) is
K and A = the conveyance and area of the subsection
added to a reagent containing an ion that reacts with the
indicated by the subscript i, and
species being determined. The electrode is placed in the
K and A = the conveyance and area of the entire cross
T T
reagent, the change in electrode potential is observed when
section.
the sample is added, and the sample concentration calcu-
lated. D4127
alpha (α), n—dimensionless velocity-head coefficient that
represents the ratio of the true velocity head to the velocity
analyte, n—a possible sample component whose presence and
head computed on the basis of the mean velocity. It is
concentration is of interest.
assumed equal to unity if the cross section is not subdivided.
analyte, n—chemical or constituent being determined. D5463
For subdivided sections, a is computed as follows: D5388
k
analytical column, n—chromatography column that contains
i
S D
( 2
a
i the stationary phase for separation by ion exchange. The
α 5
K
column is packed with anion exchange resin that separates
T
A
T the analytes of interest based on their retention characteris-
tics before detection. D6994
where:
k and a = the conveyance and area of the subsection analytical column, n—column used to separate the anions of
indicated by the subscript i, and
interest. D5996
K and A = the conveyance and area of the total cross
T T
analytical column, n—ion exchange column used to separate
section indicated by the subscript T.
the ions of interest according to their retention characteristics
alpha particle (α), n—particle consisting of two protons and
prior to detection. D6581
two neutrons emitted from the nucleus of an atom during
analytical column set, n—combination of one or more guard
radioactive decay. D7316
columns, followed by one or more analytical columns used
alpha particle detection efficiency, n—in the measurement of
to separate the ions of interest. All of the columns in series
radioactivity, that fraction of alpha particles emitted by a
then contribute to the overall capacity and resolution of the
source which are identified as alpha particles by the counter.
analytical column set. D6581
D7283
analytical column set, n—combination of one or more guard
alpha-to-beta spillover, n—in the measurement of
columns followed by one or more analytical columns.
radioactivity, that fraction of alpha particles emitted by a
D5996
source which are misclassified as beta particles. D7283
analytical columns, n—combination of one or more guard
alum, n—aluminum sulfate, AL (SO ) XH O (X = 14-18), a
2 4 3 2
columns followed by one or more separator columns used to
coagulant. D6161
separate the ions of interest. It should be remembered that all
ambient temperature, n—temperature of the surroundings,
of the columns in series contribute to the overall capacity of
generally assumed to be 20–25°C. D6161
the analytical column set. D4327
American Water Works Association—see AWWA. D6161
analytical columns, n—combination of one or more guard
columns followed by one or more separator columns used to
American Water Works Association Research
separate the ions of interest. It should be remembered that all
Foundation—see AWWARF. D6161
of the columns in series contribute to the overall capacity of
amorphous, adj—noncrystalline, devoid of regular cohesive
the analytical column set. D5542
structure. D6161
analyze, v—to determine the relationship of parts or the value
amperometric systems, n—those instrumental probes that
of a particular parameter. D5851
involve the generation of an electrical current from which
the final measurement is derived. D888 analyzer—see monitoring system. D3864
´1
D1129 − 13 (2020)
-10 -4
angstrom (A), n—unit of length equaling 10 metres, 10 commonly move upstre
...
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
´1
Designation: D1129 − 13 (Reapproved 2020)
Standard Terminology Relating to
Water
This standard is issued under the fixed designation D1129; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
ε NOTE—In accordance with D19 bylaws, approved items were added editorially in February 2023.
absolute filter rating, n—particle size above which 100 % of reference value is not available, accuracy is a description of
particles that are trapped on or within the filter medium. a measure of the degree of conformity of a value generated
D6161 by a specific procedure to the assumed or accepted true
value, including both precision and bias. D6161
absorbance, n—logarithm to the base 10 of the reciprocal of
accuracy, n—measure of the degree of conformity of a single
the transmittance (T). A = log (1 ⁄ T) = –log T. D4691
10 10
test result generated by a specific procedure to the assumed
absorption, n—release for desorption holding of a substance
or accepted true value, and includes both precision and bias.
within a solid by cohesive or capillary forces. D6161
D2777
absorptivity, n—absorbance (A) divided by the product of the
accuracy, n—proportion of the observed count to the true
sample path length (b) and the concentration (c). a = A/bc.
density of a sample. D5392
D4691
accuracy, n—refers to how close a measurement is to the true
accelerated erosion, n—erosion at a rate greater than geologic
or actual value. (See Terminology D1129.) D5906
or natural erosion. D4410
acid error, n—in very acid solutions, the activity of water is
DISCUSSION—Accelerated erosion is usually associated with anthro-
reduced (less than unity) causing a non-Nernstian response
pogenic activities and usually reduces plant cover and increases runoff.
in glass electrodes. A positive error in the pH reading results.
acceptable holding time, n—any period of time less than or
D4127
equal to the maximum holding time. D4841
acidity, n—the quantitative capacity of aqueous media to react
acceptable verification ratio (AVR)—ratio of the difference
with hydroxyl ions.
between measured value of the verification sample and the
acidity, n—quantitative capacity of aqueous media to react
known value added to the verification sample to the square
with hydroxyl ions. D6161
root of the sum of the squares of their associated combined
standard uncertainties. See Eq. 8 in 16.2.13. D7282
acidity, free mineral, n—the quantitative capacity of aqueous
media to react with hydroxyl ions to pH 4.3.
accretion, n—process of sediment accumulation. D4410
acidity, theoretical free mineral, n—the free mineral acidity
accumulator, n—pulsation dampener installed on the suction
that would result from the conversion of the anions of strong
and/or discharge lines of pumps, generally plunger type, to
acids in solution to their respective free acids.
minimize pressure surges and provide uniformity of flow.
D6161
acoustic path, n—straight line between the centers of two
acoustic transducers. D5389
accuracy, n—a measure of the degree of conformity of a value
generated by a specific procedure to the assumed or accepted acoustic path length, n—face-to-face distance between trans-
ducers on an acoustic path. D5389
true value, and includes both precision and bias.
acoustic transducer, n—device that is used to generate acous-
accuracy, n—closeness of agreement between an observed
tic signals when driven by an electric voltage, and
value and an accepted reference value. Where an accepted
conversely, a device that is used to generate an electric
voltage when excited by an acoustic signal. D5389
This terminology is under the jurisdiction of ASTM Committee D19 on Water
and is the direct responsibility of Subcommittee D19.12 on Terminology.
acoustic travel time, n—time required for an acoustic signal to
Current edition approved May 1, 2020. Published June 2020. Originally
propagate along an acoustic path, either upstream or
approved in 1950. Last previous edition approved in 2013 as D1129 – 13. DOI:
10.1520/D1129-13R20E01. downstream. D5389
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
D1129 − 13 (2020)
action level, n—concentration of the analyte of concern at algae, n—major group of lower plants, generally aquatic,
which some further action is required or suggested. D6850 photosynthetic of extremely varied morphology and
physiology, monocellular plants with chlorophyll often
activated carbon, n—granulated or powdered activated carbon
masked by a brown or red pigment. D6161
used to remove tastes, odor, chlorine, chloramines, and some
organics from water. A family of carbonaceous substances alkaline error, n—in alkaline solutions, where hydrogen ion
manufactured by processes that develop adsorptive activity becomes very small, some glass electrodes respond
properties. D6161
to other cations, such as sodium. A negative error in the pH
reading results. By changing the composition of the glass,
activity, n—thermodynamically effective concentration of a
the affinity of the glass for sodium ion can be reduced. Such
free ion in solution. In dilute solutions, ionic activity and
electrodes are known as lithium glass, high-pH, or full-range
concentration are practically identical, but in solutions of
electrodes. D4127
high ionic strength, or in the presence of complexing agents,
activity may differ significantly from concentration. Ionic alkalinity, n—the quantitative capacity of aqueous media to
activity, not concentration, determines both the rate and the react with hydrogen ions.
extent of chemical reactions. D4127
alkalinity, n—quantitative capacity of aqueous media to react
activity coefficient, n—factor, γ, that relates activity, A, to the with hydrogen ions. “M” alkalinity is that which will react
concentration, C of a species in solution:
with acid as the pH of the sample is reduced to the
methylorange endpoint of about 4.5. “P” alkalinity is that
A 5 γC
which reacts with acid as the pH of the sample is reduced to
The activity coefficient is dependent on the ionic strength
the phenolphthalein end point of 8.3. “M” is the total
of the solution. Ions of similar size and charge have similar
alkalinity which is the sum of hydroxide, carbonate, and
activity coefficients. D4127
bicarbonate contents, “P” includes all the hydroxyl and half
the carbonate content. D6161
activity standard, n—standardizing solution whose value is
reported in terms of ionic activity. If the electrode is
alkyl benzene sulfonate (ABS)—generic name applied to the
calibrated using activity standards, the activity of the free,
neutralized product resulting from the sulfonation of a
unbound ion in the sample is determined. D4127
branched-chain alkylated benzene. See also Terminology
D459. D2330
adenosine triphosphate—see ATP. D6161
alluvial channel—see alluvial stream. D4410
adsorption, n—holding of a substance onto the surface of a
solid by chemical surface forces, without forming new
alluvial deposit—sediment deposited by the action of moving
chemical bonds. D6161
water. D4410
aerobic bacteria, n—bacteria that require oxygen for growth.
alluvial fans—sediment deposited in the shape of a segment of
See bacteria, aerobes. D6161
a cone formed because of a sudden flattening of a stream
gradient especially at debouchures of tributaries on main
aerosol, n—any solid or liquid particles, with a nominal size
stream flood plains. D4410
range from 10 nm to 100 µm, suspended in a gas (usually
air). D5544
alluvial stream, n—stream whose boundary is composed of
appreciable quantities of the sediments transported by the
agglomeration or flocculation, n—coalescence of dispersed
flow and which generally changes its bed forms as the rate of
suspended matter into large flocs or particles that settle
flow changes. D4410
rapidly. D4410
alleviation, n—process of accumulating sediment deposits at
aggradation, n—geologic process by which stream beds, flood
places where the flow is retarded. D4410
plains, and the bottoms of other water bodies are raised in
elevation by the deposition of material eroded and trans-
alluvium, n—general term for all fluvial deposits resulting
ported by water from other areas. D4410
directly or indirectly from the sediment transport of (mod-
ern) streams, thus including the sediments laid down in
aggregate, n—granular material such as sand, gravel, or
riverbeds, flood plains, lakes, fans, and estuaries. D4410
crushed stone. D6161
alpha (α), n—velocity-head coefficient that adjusts the velocity
air header, n—pipe running within a cassette that distributes
head computed on basis of the mean velocity to the true
the air to the individual modules or aerators. D6161
velocity head. D5129
air scour, v—distributing air over the entire area at the bottom
alpha (α), n—velocity-head coefficient that adjusts the velocity
of a filter media flowing upward or immersed membrane to
head computed on basis of the mean velocity to the true
improve the effectiveness of filtration or backwashing or to
permit the use of lower backwash water flow rate, or both.
D6161
For a more complete discussion of terms relating to synthetic detergents and
air stripping, v—removal of volatile substances from a water
their significance, refer to McKinney, R. E., “Syndets and Waste Disposal,” Sewage
solution by passing a gas through the solution. D6161 and Industrial Wastes, Vol 29, Part 6, June 1957, pp. 654–666.
´1
D1129 − 13 (2020)
velocity head. It is assumed equal to 1.0 if the cross section amphoteric, adv—capable of acting as an acid or a base.
is not subdivided. D5243 D6161
alpha (α), n—velocity-head coefficient that represents the ratio
anaerobic bacteria, n—bacteria that do not use oxygen.
of the true velocity head to the velocity head computed on
Oxygen is toxic to them. See bacteria, anaerobes. D6161
the basis of the mean velocity. It is assumed equal to 1.0 if
analate addition, n—variation of the known addition measure-
the cross section is not subdivided. For subdivided sections,
ment technique in which the sample (analate) is added to a
a is computed as follows: D5130
reagent containing the ion being measured. The electrode is
k
i
placed in the reagent, and the sample concentration is
S D
( 2
A
i
calculated from the change in electrode potential after the
α 5
K
T
addition of the sample. D4127
A
T
analate subtraction, n—variation of the known subtraction
where:
measurement technique in which the sample (analate) is
K and A = the conveyance and area of the subsection
added to a reagent containing an ion that reacts with the
indicated by the subscript i, and
species being determined. The electrode is placed in the
K and A = the conveyance and area of the entire cross
T T
reagent, the change in electrode potential is observed when
section.
the sample is added, and the sample concentration calcu-
lated. D4127
alpha (α), n—dimensionless velocity-head coefficient that
represents the ratio of the true velocity head to the velocity
analyte, n—a possible sample component whose presence and
head computed on the basis of the mean velocity. It is
concentration is of interest.
assumed equal to unity if the cross section is not subdivided.
analyte, n—chemical or constituent being determined. D5463
For subdivided sections, a is computed as follows: D5388
k
i analytical column, n—chromatography column that contains
S 2D
(
a
the stationary phase for separation by ion exchange. The
i
α 5
K
T column is packed with anion exchange resin that separates
A
the analytes of interest based on their retention characteris-
T
tics before detection. D6994
where:
k and a = the conveyance and area of the subsection
analytical column, n—column used to separate the anions of
indicated by the subscript i, and interest. D5996
K and A = the conveyance and area of the total cross
T T
analytical column, n—ion exchange column used to separate
section indicated by the subscript T.
the ions of interest according to their retention characteristics
alpha particle (α), n—particle consisting of two protons and
prior to detection. D6581
two neutrons emitted from the nucleus of an atom during
analytical column set, n—combination of one or more guard
radioactive decay. D7316
columns, followed by one or more analytical columns used
alpha particle detection efficiency, n—in the measurement of
to separate the ions of interest. All of the columns in series
radioactivity, that fraction of alpha particles emitted by a
then contribute to the overall capacity and resolution of the
source which are identified as alpha particles by the counter.
analytical column set. D6581
D7283
analytical column set, n—combination of one or more guard
alpha-to-beta spillover, n—in the measurement of
columns followed by one or more analytical columns.
radioactivity, that fraction of alpha particles emitted by a
D5996
source which are misclassified as beta particles. D7283
analytical columns, n—combination of one or more guard
alum, n—aluminum sulfate, AL (SO ) XH O (X = 14-18), a
2 4 3 2
columns followed by one or more separator columns used to
coagulant. D6161
separate the ions of interest. It should be remembered that all
ambient temperature, n—temperature of the surroundings,
of the columns in series contribute to the overall capacity of
generally assumed to be 20–25°C. D6161
the analytical column set. D4327
American Water Works Association—see AWWA. D6161
analytical columns, n—combination of one or more guard
columns followed by one or more separator columns used to
American Water Works Association Research
separate the ions of interest. It should be remembered that all
Foundation—see AWWARF. D6161
of the columns in series contribute to the overall capacity of
amorphous, adj—noncrystalline, devoid of regular cohesive
the analytical column set. D5542
structure. D6161
analyze, v—to determine the relationship of parts or the value
amperometric systems, n—those instrumental probes that
of a particular parameter. D5851
involve the generation of an electrical current from which
the final measurement is derived. D888 analyzer—see monitoring system. D3864
´1
D1129 − 13 (2020)
-10 -4
angstrom (A), n—unit of length equaling 10 metres, 10 commonly move upstream, and are accompanied by, and in
-8 -9
umetres, 10 centimetres, and 3.937 × 10 in. The symbol phase with, waves on the water su
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: D1129 − 13 (Reapproved 2020) D1129 − 13 (Reapproved 2020)
Standard Terminology Relating to
Water
This standard is issued under the fixed designation D1129; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
ε NOTE—In accordance with D19 bylaws, approved items were added editorially in February 2023.
absolute filter rating, n—particle size above which 100 % of particles that are trapped on or within the filter medium. D6161
absorbance, n—logarithm to the base 10 of the reciprocal of the transmittance (T). A = log (1 ⁄ T) = –log T. D4691
10 10
absorption, n—release for desorption holding of a substance within a solid by cohesive or capillary forces. D6161
absorptivity, n—absorbance (A) divided by the product of the sample path length (b) and the concentration (c). a = A/bc. D4691
accelerated erosion, n—erosion at a rate greater than geologic or natural erosion. D4410
DISCUSSION—
Accelerated erosion is usually associated with anthropogenic activities and usually reduces plant cover and increases runoff.
acceptable holding time, n—any period of time less than or equal to the maximum holding time. D4841
acceptable verification ratio (AVR)—ratio of the difference between measured value of the verification sample and the known
value added to the verification sample to the square root of the sum of the squares of their associated combined standard
uncertainties. See Eq. 8 in 16.2.13. D7282
accretion, n—process of sediment accumulation. D4410
accumulator, n—pulsation dampener installed on the suction and/or discharge lines of pumps, generally plunger type, to
minimize pressure surges and provide uniformity of flow. D6161
accuracy, n—a measure of the degree of conformity of a value generated by a specific procedure to the assumed or accepted
true value, and includes both precision and bias.
accuracy, n—closeness of agreement between an observed value and an accepted reference value. Where an accepted reference
This terminology is under the jurisdiction of ASTM Committee D19 on Water and is the direct responsibility of Subcommittee D19.02 on Quality Systems, Specification,
and Statistics.
Current edition approved May 1, 2020. Published June 2020. Originally approved in 1950. Last previous edition approved in 2013 as D1129 – 13. DOI:
10.1520/D1129-13R20.10.1520/D1129-13R20E01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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value is not available, accuracy is a description of a measure of the degree of conformity of a value generated by a specific
procedure to the assumed or accepted true value, including both precision and bias. D6161
accuracy, n—measure of the degree of conformity of a single test result generated by a specific procedure to the assumed or
accepted true value, and includes both precision and bias. D2777
accuracy, n—proportion of the observed count to the true density of a sample. D5392
accuracy, n—refers to how close a measurement is to the true or actual value. (See Terminology D1129.) D5906
acid error, n—in very acid solutions, the activity of water is reduced (less than unity) causing a non-Nernstian response in glass
electrodes. A positive error in the pH reading results. D4127
acidity, n—the quantitative capacity of aqueous media to react with hydroxyl ions.
acidity, n—quantitative capacity of aqueous media to react with hydroxyl ions. D6161
acidity, free mineral, n—the quantitative capacity of aqueous media to react with hydroxyl ions to pH 4.3.
acidity, theoretical free mineral, n—the free mineral acidity that would result from the conversion of the anions of strong acids
in solution to their respective free acids.
acoustic path, n—straight line between the centers of two acoustic transducers. D5389
acoustic path length, n—face-to-face distance between transducers on an acoustic path. D5389
acoustic transducer, n—device that is used to generate acoustic signals when driven by an electric voltage, and conversely, a
device that is used to generate an electric voltage when excited by an acoustic signal. D5389
acoustic travel time, n—time required for an acoustic signal to propagate along an acoustic path, either upstream or
downstream. D5389
action level, n—concentration of the analyte of concern at which some further action is required or suggested. D6850
activated carbon, n—granulated or powdered activated carbon used to remove tastes, odor, chlorine, chloramines, and some
organics from water. A family of carbonaceous substances manufactured by processes that develop adsorptive properties. D6161
activity, n—thermodynamically effective concentration of a free ion in solution. In dilute solutions, ionic activity and
concentration are practically identical, but in solutions of high ionic strength, or in the presence of complexing agents, activity
may differ significantly from concentration. Ionic activity, not concentration, determines both the rate and the extent of chemical
reactions. D4127
activity coefficient, n—factor, γ, that relates activity, A, to the concentration, C of a species in solution:
A 5 γC
The activity coefficient is dependent on the ionic strength of the solution. Ions of similar size and charge have similar activ-
ity coefficients. D4127
activity standard, n—standardizing solution whose value is reported in terms of ionic activity. If the electrode is calibrated
using activity standards, the activity of the free, unbound ion in the sample is determined. D4127
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adenosine triphosphate—see ATP. D6161
adsorption, n—holding of a substance onto the surface of a solid by chemical surface forces, without forming new chemical
bonds. D6161
aerobic bacteria, n—bacteria that require oxygen for growth. See bacteria, aerobes. D6161
aerosol, n—any solid or liquid particles, with a nominal size range from 10 nm to 100 μm, suspended in a gas (usually air).
D5544
agglomeration or flocculation, n—coalescence of dispersed suspended matter into large flocs or particles that settle rapidly.
D4410
aggradation, n—geologic process by which stream beds, flood plains, and the bottoms of other water bodies are raised in
elevation by the deposition of material eroded and transported by water from other areas. D4410
aggregate, n—granular material such as sand, gravel, or crushed stone. D6161
air header, n—pipe running within a cassette that distributes the air to the individual modules or aerators. D6161
air scour, v—distributing air over the entire area at the bottom of a filter media flowing upward or immersed membrane to
improve the effectiveness of filtration or backwashing or to permit the use of lower backwash water flow rate, or both. D6161
air stripping, v—removal of volatile substances from a water solution by passing a gas through the solution. D6161
algae, n—major group of lower plants, generally aquatic, photosynthetic of extremely varied morphology and physiology,
monocellular plants with chlorophyll often masked by a brown or red pigment. D6161
alkaline error, n—in alkaline solutions, where hydrogen ion activity becomes very small, some glass electrodes respond to other
cations, such as sodium. A negative error in the pH reading results. By changing the composition of the glass, the affinity of the
glass for sodium ion can be reduced. Such electrodes are known as lithium glass, high-pH, or full-range electrodes. D4127
alkalinity, n—the quantitative capacity of aqueous media to react with hydrogen ions.
alkalinity, n—quantitative capacity of aqueous media to react with hydrogen ions. “M” alkalinity is that which will react with
acid as the pH of the sample is reduced to the methylorange endpoint of about 4.5. “P” alkalinity is that which reacts with acid
as the pH of the sample is reduced to the phenolphthalein end point of 8.3. “M” is the total alkalinity which is the sum of
hydroxide, carbonate, and bicarbonate contents, “P” includes all the hydroxyl and half the carbonate content. D6161
alkyl benzene sulfonate (ABS)—generic name applied to the neutralized product resulting from the sulfonation of a
branched-chain alkylated benzene. See also Terminology D459. D2330
alluvial channel—see alluvial stream. D4410
alluvial deposit—sediment deposited by the action of moving water. D4410
For a more complete discussion of terms relating to synthetic detergents and their significance, refer to McKinney, R. E., “Syndets and Waste Disposal,” Sewage and
Industrial Wastes, Vol 29, Part 6, June 1957, pp. 654–666.
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alluvial fans—sediment deposited in the shape of a segment of a cone formed because of a sudden flattening of a stream gradient
especially at debouchures of tributaries on main stream flood plains. D4410
alluvial stream, n—stream whose boundary is composed of appreciable quantities of the sediments transported by the flow and
which generally changes its bed forms as the rate of flow changes. D4410
alleviation, n—process of accumulating sediment deposits at places where the flow is retarded. D4410
alluvium, n—general term for all fluvial deposits resulting directly or indirectly from the sediment transport of (modern)
streams, thus including the sediments laid down in riverbeds, flood plains, lakes, fans, and estuaries. D4410
alpha (α), n—velocity-head coefficient that adjusts the velocity head computed on basis of the mean velocity to the true velocity
head. D5129
alpha (α), n—velocity-head coefficient that adjusts the velocity head computed on basis of the mean velocity to the true velocity
head. It is assumed equal to 1.0 if the cross section is not subdivided. D5243
alpha (α), n—velocity-head coefficient that represents the ratio of the true velocity head to the velocity head computed on the
basis of the mean velocity. It is assumed equal to 1.0 if the cross section is not subdivided. For subdivided sections, a is computed
as follows: D5130
k
i
S 2D
(
A
i
α5
K
T
A
T
where:
K and A = the conveyance and area of the subsection indicated by the subscript i, and
K and A = the conveyance and area of the entire cross section.
T T
alpha (α), n—dimensionless velocity-head coefficient that represents the ratio of the true velocity head to the velocity head
computed on the basis of the mean velocity. It is assumed equal to unity if the cross section is not subdivided. For subdivided
sections, a is computed as follows: D5388
k
i
S D
( 2
a
i
α5
K
T
A
T
where:
k and a = the conveyance and area of the subsection indicated by the subscript i, and
K and A = the conveyance and area of the total cross section indicated by the subscript T.
T T
alpha particle (α), n—particle consisting of two protons and two neutrons emitted from the nucleus of an atom during
radioactive decay. D7316
alpha particle detection efficiency, n—in the measurement of radioactivity, that fraction of alpha particles emitted by a source
which are identified as alpha particles by the counter. D7283
alpha-to-beta spillover, n—in the measurement of radioactivity, that fraction of alpha particles emitted by a source which are
misclassified as beta particles. D7283
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alum, n—aluminum sulfate, AL (SO ) XH O (X = 14-18), a coagulant. D6161
2 4 3 2
ambient temperature, n—temperature of the surroundings, generally assumed to be 20–25°C. D6161
American Water Works Association—see AWWA. D6161
American Water Works Association Research Foundation—see AWWARF. D6161
amorphous, adj—noncrystalline, devoid of regular cohesive structure. D6161
amperometric systems, n—those instrumental probes that involve the generation of an electrical current from which the final
measurement is derived. D888
amphoteric, adv—capable of acting as an acid or a base. D6161
anaerobic bacteria, n—bacteria that do not use oxygen. Oxygen is toxic to them. See bacteria, anaerobes. D6161
analate addition, n—variation of the known addition measurement technique in which the sample (analate) is added to a reagent
containing the ion being measured. The electrode is placed in the reagent, and the sample concentration is calculated from the
change in electrode potential after the addition of the sample. D4127
analate subtraction, n—variation of the known subtraction measurement technique in which the sample (analate) is added to
a reagent containing an ion that reacts with the species being determined. The electrode is placed in the reagent, the change in
electrode potential is observed when the sample is added, and the sample concentration calculated. D4127
analyte, n—a possible sample component whose presence and concentration is of interest.
analyte, n—chemical or constituent being determined. D5463
analytical column, n—chromatography column that contains the stationary phase for separation by ion exchange. The column
is packed with anion exchange resin that separates the analytes of interest based on their retention characteristics before
detection. D6994
analytical column, n—column used to separate the anions of interest. D5996
analytical column, n—ion exchange column used to separate the ions of interest according to their retention characteristics prior
to detection. D6581
analytical column set, n—combination of one or more guard columns, followed by one or more analytical columns used to
separate the ions of interest. All of the columns in series then contribute to the overall capacity and resolution of the analytical
column set. D6581
analytical column set, n—combination of one or more guard columns followed by one or more analytical columns. D5996
analytical columns, n—combination of one or more guard columns followed by one or more separator columns used to separate
the ions of interest. It should be remembered that all of the columns in series contribute to the overall capacity of the analytical
column set. D4327
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analytical columns, n—combination of one or more guard columns followed by one or more separator columns used to separate
the ions of int
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