Download measurement of pollutants in water

MEASUREMENT OF POLLUTANTS IN WATER
There are 3 kinds of water:
-drinking water
-waste water
-surface water
Drinking water or potable water is water of sufficiently high quality that can be
consumed or used without risk of immediate or long term harm. It is provided by water
supply networks or may be found in deep wells or springs.
Waste water or sewage comprises liquid waste discharged by domestic residences,
commercial properties, industry, and/or agriculture and can encompass a wide range of
potential contaminants and concentrations. In the most common usage, it refers to the
municipal wastewater that contains a broad spectrum of contaminants resulting from
the mixing of wastewaters from different sources.
Surface water is water collecting on the ground or in a stream, river, lake, wetland, or
ocean; it is related to water collecting as groundwater or atmospheric water.
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Environmental monitoring
Environment Monitor Water Quality
(video clip)
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Regulations
Environmental Protection Law 137/1995 updated by
Ordonance 195/2005
Waste water
Law: HG 352/2005, completion of HG 188/2002 refers to 2 types of waste water:
- industrial and urban waste waters overflowed into natural receivers (lakes, rivers)
(NTPA 001)
- waste waters overflowed into sewerage networks (NTPA 002)
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MEASUREMENT OF POLLUTANTS IN WATER
Waste water quality standard NTPA 001 (several chemical indicators)
No.
Quality indicator
Unit
Limit values
Analysis method
1.
pH
pH units
6,5-8,5
SR ISO 10523-97
2.
Suspended materials
mg/dm3
35,0 (60,0)
STAS 6953-81
3.
Biochemical Oxygen Demand at 5
days
mg O2/dm3
25,0
SR EN 1899-2/2002
4.
Chemical Oxygen Demand (CCOCr)
mg O2/dm3
125,0
SR ISO 6060-96
5.
Ammonia (NH4+)6)
mg/dm3
2,0(3,0)
SR ISO 5664:2001
SR ISO 7150-1/2001
6.
Nitrates (NO3-)6)
mg/dm3
25,0(37,0)
SR ISO 7890-2:2000;
SR ISO 7890-3:2000
7.
Sulphide (S2-)
mg/dm3
0,5
8.
Phenols (C6H5OH)
mg/dm3
0,3
9.
Oil products
mg/dm3
5,0
SR 7877/1-95
10.
Total phosphorus (P)6)
mg/dm3
1,0(2,0)
SR EN 1189-2000
11.
Synthetic detergents
mg/dm3
0,5
SR EN 903:2003
12.
Aluminium (Al3+)
mg/dm3
5,0
STAS 9411-83
13.
Calcium (Ca2+)
mg/dm3
300,0
14.
Lead (Pb2+)3)
mg/dm3
0,2
STAS 8637-79;
15.
Nickel (Ni2+)3)
mg/dm3
0,5
SR ISO 8288:2001
16.
Zinc (Zn2+)3)
mg/dm3
0,5
STAS 8314-87
SR ISO 10530-97
SR ISO 6439:2001;
SR ISO 8165/1/00
STAS 3662-90
SR ISO 7980-97
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MEASUREMENT OF POLLUTANTS IN WATER
Waste water quality standard NTPA 002 (several chemical indicators)
No.
Quality indicator
Unit
Limit values
Analysis method
1.
pH
pH units
6,5-8,5
SR ISO 10523-97
2.
Suspended materials
mg/dm3
350,0 (60,0)
STAS 6953-81
3.
Biochemical Oxygen Demand at 5
days
mg O2/dm3
300,0
SR EN 1899-2/2002
4.
Chemical Oxygen Demand (CCOCr)
mg O2/dm3
500,0
SR ISO 6060-96
5.
Ammonia (NH4+)6)
mg/dm3
30,0
6.
Cyanide total (CN)
mg/dm3
1,0
SR ISO 6703/1-98-2/00
7.
Sulphide (S2-)
mg/dm3
1,0
SR ISO 10530-97
8.
Phenols (C6H5OH)
mg/dm3
30,0
9.
Oil products
mg/dm3
5,0
SR 7877/1-95
10.
Total phosphorus (P)6)
mg/dm3
5,0
SR EN 1189-2000
11.
Synthetic detergents
mg/dm3
25
SR EN 903:2003
12.
Cadmium (Cd-)
mg/dm3
0,3
SR EN ISO 5961:2002
13.
Zinc (Zn2+)
mg/dm3
1,0
STAS 8314-87;
SR ISO 8288:2001
14.
Lead (Pb2+)3)
mg/dm3
0,5
STAS 8637-79;
15.
Nickel (Ni2+)3)
mg/dm3
1,0
SR ISO 8288:2001
Manganese (Mn)
mg/dm3
2,0
SR 8662/1-96
16.
SR ISO 5664:2001
SR ISO 7150-1/2001
SR ISO 6439:2001;
SR ISO 8165/1/00
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MEASUREMENT OF POLLUTANTS IN WATER
Regulations
Drinking water
Law 311/2004, completion of Law 458/2002
Microbiological parameters
Parameter
Limit value
(number/100 ml)
Escherichia coli (E.coli)
0
Enterococi
0
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MEASUREMENT OF POLLUTANTS IN WATER
Drinking water
Law 311/2004, completion of Law 458/2002
Chemical parameters
Parameter
Limit value
Unit
Ammonia
0,50
mg/l
Chlorine
250
mg/l
2.500
S cm-1 la 200C
Nitrate
50
mg/l
Nitrite
0.5
mg/l
> 6,5; < 9,5
unităţi de pH
Sulphate
250
mg/l
Sulphyde
100
g/l
Turbidity
<5
UNT
Chromium total
50
g/l
Zinc
5.000
g/l
Iron
200
g/l
Manganese
50
g/l
Copper
0.1
mg/l
Alpha global activity
0,1
Bq/l
1
Bq/l
Conductivity
pH
Beta global activity
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Drinking water – USA National Primary D.W. regulations
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Drinking water – USA National Primary D.W. regulations
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MEASUREMENT OF POLLUTANTS IN WATER
Surface water
Law Order 1146/10.12.2002
Chemical parameters
Parameter
Unit
Limit values
I
II
III
IV
pH
pH units
6,5 < pH < 8,5
Dissolved oxygen
mg/l O2
7
6
5
4
BOD5
mg/l O2
3
5
10
25
CODCr
mg/l O2
10
25
50
125
Nitrate
mg N/l
1
3
6
15
Nitrite
mg N/l
0.01
0.06
0.12
0.3
Total phosphorus
mg/l
0.1
0.2
0.4
1
Zinc total
g/l
background
100
200
500
Chromium total
g/l
background
2
4
10
Nickel total
g/l
background
50
100
250
Lead total
g/l
background
5
10
25
Copper total
g/l
background
20
40
100
Anionic detergents
g/l
background
500
750
1000
Oil hydrocarbures
g/l
background
100
200
500
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
How to measure all of these parameters?
There are various methods, techniques and equipments
devoted to measure water quality parameters.
They are divided in:
- in-situ methods
- laboratory methods
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Water sampling
(video clip)
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Environmental monitoring
Measurement of water pollutants using ion selective
electrodes (ISE)
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Environmental monitoring
Measurement of water pollutants using ion selective
electrodes (ISE)
Ion selective electrodes
(video clip)
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Environmental monitoring
Measurement of water pollutants using ion selective
electrodes (ISE)
Ions to be measured using ISE
Cations
Ammonium (NH4+)
Barium (Ba2+)
Calcium (Ca2+)
Copper (Cu2+)
Lead (Pb2+)
Mercury (Hg2+)
Potassium (K+)
Sodium (Na+)
Silver (Ag+)
Anions
Bromide (Br-)
Chloride (Cl-)
Cyanide (CN-),
Fluoride (F-)
Iodide (I-)
Nitrate (NO3-)
Nitrite (NO2)
Perchlorate (ClO4-)
Sulphide (S-)
Thiocyanate (SCN).
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Environmental monitoring
Measurement of water pollutants using ion selective
electrodes (ISE)
Advantages of measuring using ISE
•
•
•
•
•
very fast and easy measurements
the possibility of implementation of continuous monitoring
relatively inexpensive
wide range of concentration for a large variety of ions
by fulfilling the imposed conditions of maintenance and calibration, one
can achieve accuracy and precision levels of 2 – 3 %, sometimes
comparable with analytical techniques.
• unaffected by sample colour and turbidity.
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Environmental monitoring
Measurement of water pollutants using ion selective
electrodes (ISE)
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Environmental monitoring
Measurement of water pollutants using ion selective
electrodes (ISE)
Measurement principle of ISE (example pH measurement)
Measurement
electrode
Reference
electrode
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Environmental monitoring
Measurement of water pollutants using ion selective
electrodes (ISE)
Measurement and reference electrodes
Wire connection
Wire connection
Measurement
electrode
Bulb filled with
potassium chloride
buffer solution
Voltage
Voltageproduced
produced
across
acrossthickness
thicknessof
of
glass
membrane
glass membrane
Reference
electrode
Glass body
Glass or plastic
body
Filled with
potassium chloride
buffer solution
Very
Verythin
thinglass
glassbulb
bulb
chemically
chemicallydoped
dopedwith
with
lithium
ions
lithium ions
Porous junction
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Environmental monitoring
Measurement of water pollutants using ion selective
electrodes (ISE)
Nernst equation
E  E0 
2,303RT
lg a
nF
a  C
pH   lg a
a = activity of ions (for pH, a is the activity of hydrogen ions)
C = ion concentration
γ = activity coefficient
E = measured potential
E0 = standard electrode potential (E for a = 1)
R = gas constant
T = absolute temperature [K]
F = Faraday constant
n = ion charge (n = 1 for pH)
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Environmental monitoring
Measurement of water pollutants using ion selective
electrodes (ISE)
50 oC
25 oC
2,303RT
slope 
nF
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Environmental monitoring
Measurement of water pollutants using ion selective
electrodes (ISE)
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Environmental monitoring
Measurement of water pollutants using ion selective
electrodes (ISE)
Combined (double junction) electrode
shielded
cable
reference
filling hole
filling hole
reference electode
(Ag/AgCl)
reference junction
KCl
junction glass frit
measurement
electode (Ag/AgCl)
membrane
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Environmental monitoring
Measurement of water pollutants using ion selective field
effect transistors (ISFET)
Principle of operation of an ISFET
Gate
Drain
Sensitive layer
p-type Si
Insulator
Source
Substrate
D
G
VGS
VDS
S ID
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Environmental monitoring
Measurement of water pollutants using ion selective field
effect transistors (ISFET)
Some ISFET Characteristics
Analyte
Sensing structure
Comments
Ammoni
um
PVC treated with HMDS for
adhesion
Sensitivity: 30mV/part NH4
Detection limit: 2x10-6
Both sensor and reference fabricated FET
Cd2+,
Pb2+
Polysiloxane + cyclodextrin
Sensitivity: 29 mV/decade for Cd2+
Sensitivity: 15 mV/decade for Pb2+
Lifetime: 3 months
Cu2+
Etched chalcogenide glass with
aluminium adhesion layer
Sensitivity: 28 mV/part Cu
Response time: 5 s
Lifetime: several weeks
Cyanide
PVP (poly-(4-vinylpyridine-costyrene) with horseradish
peroxidase as sensitive layer
Sensitivity: 10-7 to 10-5 molar solution
Reproducibility: 20 % (pH dependent)
K+
Polysiloxane with poly-HEMA
adhesion layer as sensitive layer
Sensitivity: 59 mV/decade
Lifetime: 75 days
Na+
Polysiloxane
Sensitivity: 56.7 mV/decade
pH
Tin oxide
Sensitivity: 58 mV/pH
Linear between pH 2 to 10
Response time: 1 s
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Optical methods
-
E = hc/λ = hν
They are based on:
reflection
colorimetry
absorbtion of light
fluorescence
Planck equation
h = Planck’s constant (6.626 ·10-34 J·s)
C = velocity of light in vacuum
λ = wave length
Fluorescence
ν = light frequency
This method utilizes the fluorescence, either natural or induced, of a compound.
Fluorescent chemicals absorb radiation of a specific wavelength and emit at
another.
Monochrome
light
ν0
Light detector
ν1
Sample
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Optical methods
Nephelometry
Light detectors
White light or
infrared light
White light or
infrared light
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Optical methods
Colorimetry
A = log(I/Io) = knC Beer’s law
Visual tests
Photometer
Monochrome
light
I0
Light detector
I
Sample
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Colorimetry
Water Quality Colorimeter
(video clip)
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Environmental monitoring
Measurement of water parameters using UV-VIS
spectrophotometer method
The measurements may be performed in laboratory or in the field
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Environmental monitoring
Measurement of water parameters using UV-VIS
spectrophotometer method
Spectrophotometer DR 2800
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Environmental monitoring
Measurement of water parameters using UV-VIS
spectrophotometer method
Spectrophotometer DR 5000
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Environmental monitoring
Measurement of water parameters using UV-VIS
spectrophotometer method
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Environmental monitoring
Measurement of water parameters using UV-VIS
spectrophotometer method
Cuvette tests method
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Environmental monitoring
Measurement of water parameters using UV-VIS
spectrophotometer method
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Environmental monitoring
Measurement of water parameters using UV-VIS
spectrophotometer method
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Environmental monitoring
Measurement of water parameters using UV-VIS
spectrophotometer method
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Environmental monitoring
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Measurement of water parameters using UV-VIS
spectrophotometer method
Parameters to be measured
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Environmental monitoring
Measurement of water parameters using UV-VIS
spectrophotometer method
Hach robot for spectrophotometric measurements
(video clip)
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Measurement of metals using Atomic Absorption Spectrophotometry (AAS)
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Measurement of metals using Atomic Absorption Spectrophotometry
Beer – Lambert’s law
I
T
 10 l  10 lc
I0
T = transmission (transmissivity)
α = absorbtion coefficient
l = pass length (distance the light travels through the material
ε = molar absorptivity of the absorber
c = concentration of the absorber in the material
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Measurement of metals using Atomic Absorption Spectrophotometry
Difference between atomic and molecular spectroscopy
Atomic spectroscopy
Molecular spectroscopy
- concerns only the properties of atoms
- concerns the molecules, which are
infinitely more numerous
- concerns all the interaction of
electromagnetic waves
- we can found the nature and the
amounts of a given element in the
sample
- gives us more advice than atomic
spectroscopy especially about chemical
functions and structure of matter
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Measurement of metals using Atomic Absorption Spectrophotometry
Analytik Jena Zeenit A700 AAS spectrophotometer
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Measurement of metals using Atomic Absorption Spectrophotometry
AAS Block Diagram
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Measurement of metals using Atomic Absorption Spectrophotometry
Flames used in AAS
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Measurement of metals using Atomic Absorption Spectrophotometry
Light source
Hollow cathode
lamp
Xenon lamp
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Measurement of metals using Atomic Absorption Spectrophotometry
Detection limits for some elements (μg/l)
Element
Flame
Electrothermal (furnace)
Ag
3
0.02
Al
30
0.2
Ca
1
0.5
Cd
1
0.02
Cr
4
0.06
Cu
2
0.1
Fe
6
0.5
Mn
2
0.02
Ni
3
1
Pb
5
0.2
Sn
15
10
Zn
1
0.04
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MEASUREMENT OF POLLUTANTS IN WATER
Dissolved Oxygen (DO) Measurement
Dissolved oxygen analysis can be used to determine:
• the health or cleanliness of a lake or stream,
• the amount and type of biomass a freshwater system can support,
• the amount of decomposition occurring in the lake or stream.
There are three methods:
• Azide-Winkler method
• Metering with DO probe
• Field kits
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MEASUREMENT OF POLLUTANTS IN WATER
Dissolved Oxygen (DO) Measurement (Winkler method)
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Dissolved Oxygen (DO) Measurement with Clark electrodes
Clark type electrode
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Dissolved Oxygen (DO) Measurement
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Influence of the temperature upon Dissolved Oxygen
curve A – fresh water
curve B – salted water
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Biochemical Oxygen Demand (BOD)
• BOD is a measure of the oxygen used by microorganisms to
decompose the organic waste dissolved in water.
• BOD is affected by temperature.
• BOD is influenced by the content of nitrates and phosphates
dissolved in the water.
• BOD is an indicator of the organic quality of water.
• It is most commonly expressed in milligrams of oxygen
consumed per litre of sample during 5 days of incubation at
20 C.
Two methods of measurement:
- Dilution method
- Manometric method
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Biochemical Oxygen Demand (BOD)
BOD Level
(in ppm)
Water Quality
1-2
Very Good
There will not be much organic waste
present in the water supply.
3-5
Fair: Moderately Clean
6-9
Poor: Somewhat Polluted
Usually indicates organic matter is
present and bacteria are decomposing
this waste.
100 or
greater
Very Poor: Very Polluted
Contains organic waste.
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Biochemical Oxygen Demand (BOD)
Dilution method
A very small amount of micro-organism seed is added
to each sample being tested
BOD can be calculated by:
Undiluted: Initial DO - Final DO = BOD
Diluted: (Initial DO  Final DO) x Dilution Factor
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Biochemical Oxygen Demand (BOD)
Manometric method
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Biochemical Oxygen Demand (BOD)
Working procedure
Required apparatus:
BOD bottles
Spatula scoop
BOD incubator
Seal cup, stir bar
Reagents
2 potassium hydroxide pellets
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Environmental monitoring
MEASUREMENT OF POLLUTANTS IN WATER
Biochemical Oxygen Demand (BOD)
Working procedure
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Environmental monitoring