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ENVIRONMENTAL
MEASUREMENT
1 Engr. Yvonne Ligaya F. Musico
Concentration in Environment
• Chemical concentration is one of the
most important determinants in almost all
aspects of chemical fate, transport, and
treatment in both natural and engineered
system.
2 Engr. Yvonne Ligaya F. Musico
Concentration in Environment
• Concentration is the driving force that controls
the movement of chemicals within and between
environmental media, as well as the rate of may
chemical reaction.
• Concentration often determines the severity of
adverse effects, such as toxicity,
bioconcentration, and climate change.
3 Engr. Yvonne Ligaya F. Musico
1. Mass Concentration Units
• Concentration often
determines the
severity of adverse
effects, such as
toxicity,
bioconcentration, and
climate change.
4 Engr. Yvonne Ligaya F. Musico
Mass concentration units
5 Engr. Yvonne Ligaya F. Musico
Mass/Mass Units
Parts per million by
mass (referred to as
ppm or ppmm) is
defined as the number
of units of mass of
chemical per million
units of total mass.
totalgiofgppmm610
610xm
mppm
total
im
6 Engr. Yvonne Ligaya F. Musico
Mass/Mass Units
Parts per billion by
mass (ppb or ppbm) 910x
m
mppb
total
im
Parts per trillion by
mass (ppt or pptm) 1210x
m
mppt
total
im
7 Engr. Yvonne Ligaya F. Musico
Sample Problem 1
Concentration in Soil
A 1 kg sample of soil is analyzed for the
chemical solvent trichloroethylene (TCE).
The analysis indicates that the sample
contains 5.0 mg of TCE. What is the TCE
concentration in ppmm and ppbm?
8 Engr. Yvonne Ligaya F. Musico
Solution
Note that in soil and sediments,
mg/kg equals ppmm, and g/kg
equals ppbm
𝑇𝐶𝐸 = 5.0 𝑚𝑔 𝑇𝐶𝐸
1.0 𝑘𝑔 𝑠𝑜𝑖𝑙=
0.005 𝑔 𝑇𝐶𝐸
103𝑔 𝑠𝑜𝑖𝑙
= 5 𝑥 10−6𝑔 𝑇𝐶𝐸
𝑔 𝑠𝑜𝑖𝑙 𝑥 106 = 5 𝑝𝑝𝑚𝑚 = 5, 000 𝑝𝑝𝑏𝑚
9 Engr. Yvonne Ligaya F. Musico
Mass/Volume Units
mg/m3 and g/m3 – it is
commonly used unit for
concentration of mass
per volume of air in the
atmosphere
mg/L and g/L –
commonly used for
concentration unit for
water.
In most aqueous
system, ppmm is
equivalent to mg/L.
10 Engr. Yvonne Ligaya F. Musico
Sample Problem 2
Concentration in Water
One liter of water is analyzed and found to
contain 5.0 mg of TCE. What is the TCE
concentration in mg/L and ppmm?
11 Engr. Yvonne Ligaya F. Musico
Solution
𝑇𝐶𝐸 = 5.0 𝑚𝑔 𝑇𝐶𝐸
1.0 𝐿 𝐻2𝑂=
5.0 𝑚𝑔
𝐿
𝑇𝐶𝐸 = 5.0 𝑚𝑔 𝑇𝐶𝐸
1.0 𝐿 𝐻2𝑂𝑥
1.0 𝐿 𝐻2𝑂
1,000 𝑔 𝐻2𝑂
= 5.0 𝑚𝑔 𝑇𝐶𝐸
1.0 𝐿 𝐻2𝑂=
5.0 𝑥 10−6 𝑔 𝑇𝐶𝐸
𝑔 𝑡𝑜𝑡𝑎𝑙𝑥
106𝑝𝑝𝑚𝑚𝑚𝑎𝑠𝑠 𝑓𝑟𝑎𝑐𝑡𝑖𝑜𝑛
𝑇𝐶𝐸 = 5.0 𝑝𝑝𝑚𝑚
12 Engr. Yvonne Ligaya F. Musico
Sample Problem 3
Concentration in Air
What is the carbon monoxide (CO)
concentration expressed in g/m3 of 10 L
gas mixture that contains 10-6 mole of CO?
13 Engr. Yvonne Ligaya F. Musico
Solution
𝐶𝑂 = 1.0 𝑥10−6 𝑚𝑜𝑙𝑒 𝐶𝑂
10 𝐿 𝑡𝑜𝑡𝑎𝑙𝑥
28 𝑔𝐶𝑂
𝑚𝑜𝑙𝑒 𝐶𝑂
𝐶𝑂 = 28 𝑥 10−6 𝑔 𝐶𝑂
10 𝐿 𝑡𝑜𝑡𝑎𝑙𝑥
106𝜇𝑔
𝑔 𝑥
103𝐿
𝑚3
= 2,800 𝜇𝑔
𝑚3
14 Engr. Yvonne Ligaya F. Musico
2. Volume/Volume and Mole/Mole Units
Parts per million by
volume (referred to as
ppm or ppmv) is
defined as the number
of units of volume of
chemical per million
units of total volume.
610xV
Vppm
total
iv
15 Engr. Yvonne Ligaya F. Musico
2. Volume/Volume and Mole/Mole Units
Ideal Gas Law states that the volume occupied by
a given number of molecules of any gas is the
same, no matter what the molecular weight or
composition of the gas, as long as the pressure
and temperature are constant
nRTPV
16 Engr. Yvonne Ligaya F. Musico
2. Volume/Volume and Mole/Mole Units
Universal Gas Constant
• 0.08205 L-atm/mol-K
• 8.205 x 10-5 m3-atm/mole-K
• 82.05 cm3-atm/mole-K
• 1.99 x 10-3 kcal/mole-K
• 8.314 J/mole-K
• 1.987 cal/mole-K
• 62,358 cm3-torr/mole-K
• 62,358 cm3-mm Hg/mole-K
At standard conditions
(P=1 atm and
T=273.15K), 1 mole of
any pure gas will
occupy a volume of
22.4 L.
17 Engr. Yvonne Ligaya F. Musico
2. Volume/Volume and Mole/Mole Units
For gases, volume ratios and mole ratios are equivalent
610xmole
moleppm
total
iv
18 Engr. Yvonne Ligaya F. Musico
Sample Problem 4 Gas Concentration in Volume Fraction
A gas mixture contains 0.001 mole of sulfur
dioxide (SO2) AND 0.999 mole of air. What
is the SO2 concentration, expressed in units
of ppmv?
19 Engr. Yvonne Ligaya F. Musico
Solution
𝑆𝑂2 = 𝑉𝑆𝑂2
𝑉𝑇𝑜𝑡𝑎𝑙 𝑥106
But,
𝑉𝑆𝑂2 =𝑛𝑅𝑇
𝑃= 0.001 𝑚𝑜𝑙𝑒 𝑆𝑂2
𝑅𝑇
𝑃
And,
𝑉𝑡𝑜𝑡𝑎𝑙 = (0.999 + 0.001) 𝑚𝑜𝑙𝑒 𝑇𝑜𝑡𝑎𝑙𝑅𝑇
𝑃
The concentration in ppmv is:
20 Engr. Yvonne Ligaya F. Musico
Solution
𝑝𝑝𝑚𝑣 =0.001 𝑚𝑜𝑙𝑒 𝑆𝑂2
𝑅𝑇𝑃
1.000 𝑚𝑜𝑙𝑒 𝑡𝑜𝑡𝑎𝑙 𝑅𝑇𝑃
𝑥 106
𝑝𝑝𝑚𝑣 =0.001𝐿 𝑆𝑂2
1.000 𝐿 𝑡𝑜𝑡𝑎𝑙 𝑥 106 = 1,000 𝑝𝑝𝑚𝑣
21 Engr. Yvonne Ligaya F. Musico
2. Volume/Volume and Mole/Mole Units
Mole ratio (moles i/moles total) is sometimes
referred to as mole fraction, X.
RT
PxMWxppm
m
gV
000,13
22 Engr. Yvonne Ligaya F. Musico
Sample Problem 5 Conversion of Gas Concentration
The concentration of SO2 is measured in air
to be 100 ppbv. What is this concentration in
units of g/m3? Assume the temperature is
28oC and pressure is 1 atm.
23 Engr. Yvonne Ligaya F. Musico
3. Partial Pressure Units
24 Engr. Yvonne Ligaya F. Musico
3. Partial Pressure Units
])[(
][
totaliv
totaliii
Pxppm
PxfractionmoleorfractionvolumeP
610xP
Pppm
total
iV
25 Engr. Yvonne Ligaya F. Musico
Sample Problem 6 Concentration as Partial Pressure
The concentration of gas-phase polychlorinated
biphenyls (PCBs) in the air above Lake Superior
was measured to be 450 picogram per cubic meter
(pg/m3). What is the partial pressure (in atm) of
PCBs? Assume the temperature is 0oC, the
atmospheric pressure is 1 atm and the average
molecular weight of PCBs is 325.
26 Engr. Yvonne Ligaya F. Musico
Polychlorinated Biphenyl (PCBs)
27 Engr. Yvonne Ligaya F. Musico
Sample Problem 7 Concentration as Partial Pressure
What would be the partial pressure (in atm) of
carbon dioxide (CO2) when barometer reads 29.0
inches of Hg, the relative humidity is 80 percent,
and the temperature is 70oF? Use Table 2.2 to
obtain the concentration of CO2 in dry air. The
vapor pressure of water at 70oF is 0.36 lb/in2.
28 Engr. Yvonne Ligaya F. Musico
4. Mole/Volume Units
Molarity (M)
solutionofliter
soluteofmolesMMolarity )(
29 Engr. Yvonne Ligaya F. Musico
Sample Problem 8 Concentration as Molarity
The concentration of trichloroethylene (TCE)
is 5 ppm. Convert this units of molarity. The
molecular weight of TCE is 131.5 g/mole.
30 Engr. Yvonne Ligaya F. Musico
Sample Problem 9 Concentration as Molarity
The concentration of alachlor, a common
herbicide, in the Mississippi River was found to
range from 0.04 to 0.1 g/L. What is the
concentration range in nanomoles/L? The
molecular formula for the alachlor is C14H20NCl,
and its molecular weight is 270.
31 Engr. Yvonne Ligaya F. Musico
4. Mole/Volume Units
soluteofweightequivalent
soluteofweightsoluteofequivalent
solutionofLiter
soluteofequivalentNNormality
)(
Normality (N)
32 Engr. Yvonne Ligaya F. Musico
Equivalent Weight
• Weight of substances that are equivalent
to one another in chemical reaction.
• The equivalent of an oxidizing agent or
reducing agent is the weight of the
substance required to gain or lose 1 mole
of electron.
33 Engr. Yvonne Ligaya F. Musico
Equivalent Weight
Equivalent Weight = molecular weight (MW)
f (factor)
34 Engr. Yvonne Ligaya F. Musico
Reacting Capacity of Solute
ACID BASE SALT
f
Total number
of H+
replaceable
Total number
of replaceable
OH-
Total (+/-)
charge
35 Engr. Yvonne Ligaya F. Musico
Sample Problem 10 Calculations of Equivalent Weights
What are the equivalent weights of HCl,
H2SO4, NaOH, CaCO3, and aqueous CO2?
36 Engr. Yvonne Ligaya F. Musico
Relationship between Normality
and Molarity
N = n solute x f
liter of solution
N = molarity (M) x f
37 Engr. Yvonne Ligaya F. Musico
Sample Problem 11 Calculation of Normality
What is the normality of 1 M of HCl and
H2SO4?
38 Engr. Yvonne Ligaya F. Musico
Sample Problem 12 Use of Equivalents in Determining the
Accuracy of a Water Analysis
The label on a bottle of New Zealand mineral water
purchased in the city of Dunedin states that a chemical
analysis of the mineral water resulted in the following
cations and anions being identified with corresponding
concentrations (in mg/L):
[Ca2+] = 2.9 [Mg2+] = 2.0 [Na+] = 11.5 [K+] = 3.3
[SO42-] = 4.7 [F-] = 0.09 [Cl-] = 7.7
Is the analysis correct?
39 Engr. Yvonne Ligaya F. Musico
5. Concentration as a Common Constituent
• Greenhouse gases, nitrogen, and phosphorus are
chemicals that have their concentration typically reported
as a common constituent.
• Phosphorus may be present as orthophosphates
(H3PO4, H2PO4-, HPO42-, PO4
3, HPO42- complexes)
polyphosphate (for example, H4P2O7 AND H3P3O102-),
metaphosphates (for example, HP3O92-), and/or organic
phosphates (mg P/L, mg/L as P, or mg/L P)
40 Engr. Yvonne Ligaya F. Musico
Sample Problem 13 Nitrogen Concentration as a Common
Constituent
A water contains two nitrogen species. The
concentration of NH3 is 30 mg/L NH3, and
the concentration of NO3- is 5 mg/L NO3
-.
What is the total nitrogen concentration in
units of mg N/L?
41 Engr. Yvonne Ligaya F. Musico
5. Concentration as a Common Constituent
• Hardness of water is caused by the presence of divalent
cations in water, which Ca2+ and Mg2+ are by far the
most abundant (mg CaCO3/L).
32
2
/
50CaCOas
L
mg
eqvginMofwteqvL
mginM
42 Engr. Yvonne Ligaya F. Musico
5. Concentration as a Common Constituent
• Global warming potential (GWP) is a multiplier used to
compare the emissions of different greenhouse gases to
a common constituent.
• Carbon dioxide equivalent are metric measurement
used to compare the mass emissions of greenhouse
gases to a common constituents, based on the specific
gas’ global warming potential.
43 Engr. Yvonne Ligaya F. Musico
44 Engr. Yvonne Ligaya F. Musico
Sample Problem 14 Determination of a Water Hardness
Water has the following chemical
composition: [Ca2+] = 15 mg/L; [Mg2+] = 10
mg/L; [SO42-] = 30 mg/L. What is the total
hardness in units of mg/L as CaCO3?
45 Engr. Yvonne Ligaya F. Musico
46 Engr. Yvonne Ligaya F. Musico
6. Reporting Particle Concentration in Air
and Water
• Total suspended particulate (TSP) – the
increase in weight of the filter due to
collection of particulate divided by the
volume of air passed through the filter,
g/m3 or g/m3.
47 Engr. Yvonne Ligaya F. Musico
Sample Problem 15 Carbon Equivalent as a Common
Constituents
The US greenhouse gas emissions reported
in 2004 were 5,988 teragrams (Tg) CO2e OF
N2O. How many gigagrams (Gg) of CH4 and
N2O were emitted in 2004?
48 Engr. Yvonne Ligaya F. Musico
6. Reporting Particle Concentration in Air
and Water
49 Engr. Yvonne Ligaya F. Musico
6. Reporting Particle Concentration in Air
and Water
50 Engr. Yvonne Ligaya F. Musico
7. Representation by Effect
• Biological oxygen demand (BOD)
• Chemical oxygen demand (COD)
51 Engr. Yvonne Ligaya F. Musico
Sample Problem 16 Determining Concentration of Solids in a
Water Sample
A laboratory provides the following analysis obtained from a 50 mL
sample of wastewater: total solids = 200 mg/L, total suspended solids =
160 mg/L, fixed suspended solids = 40 mg/L, and volatile suspended
solids = 120 mg/L.
1. What is the concentration of total dissolved solids of this sample?
2. Suppose this sample was filtered through a glass-fiber filter, and
the filter was then placed in a muffle furnace at 550oC overnight.
What would be the weight of the solids (in mg) remaining on the
filter after the night in the furnace.
3. Is this sample turbid? Estimate the percent of the solids that are
organic matter.
52 Engr. Yvonne Ligaya F. Musico
THANK YOU
53 Engr. Yvonne Ligaya F. Musico
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