Water Quality Monitoring Instruments and Methods

MEASURING WATER QUALITY
Methods and Instruments
Raymond RaLonde
University of Alaska Fairbanks
Alaska Sea Grant Marine Advisory
Program

WHAT TO MEASURE?
• Weather
– Often measured with water quality
• Air Temp
• Cloud cover
– Weather station data
• Precipitation
• Air Pressure
• Snow
– Conductivity
• Photography
– Of monitoring locations
– Habitat evaluation

WATER COLLECTION
vANdORN$125.00

TEMPERATURE MONITORING
Thermometers
•Calibration thermometer
•Nothing replaces a
good thermometer
– Accuracy ± 0.1 o
• Max/Min
– Always handy
• Electronic recording
– YSI temperature probe
– Require calibration

TEMPERATURE RECORDERS
Electronic thermometers
Suppliers
Radio shack, Hannah,
Aquatic Ecosystems
• Waterproof
• Record Max/Min
• Extension cords for outside
• Cost $15.00-60.00
• Accuracy 1 o C
• Calibrate with thermometer

TEMPERATURE RECORDERS
Temperature data loggers
• Hanna
• Hobo logger
– Set timing period (sec-days)
• Set for every 6 hours
• Deploy at top of lantern net to
account for tide and solar influences
– 21,580 measurements
– Accuracy 0.02 o
– Logger cost $110.00 each
– Infrared base station $60.00
• Boxcar Pro for Readout
– One-timer purchase $95.00
– Export data to Excel

HOBO DATA LOGGER
DEPLOYMENT

HOBO DATA LOGGER
Readout

TYPES OF SUSPENDED SOLIDS
• Organic – Volatile (burn to ash)
– Organic material was once living (e.g. plants)
– Closer to the surface
• Inorganic – (Does not burn to ash)
– Example (finely ground rock)
– Deeper in the water (heavier than organics)
– Colloidal – Stays in suspension – May need a flocculent
to settle the solids
– Settleable – Settles with time

TURBIDITY IS NOT AS SIMPLE
AS IT MAY SEEM
• Need to consider the objectives of the
measurement
• Difference in particle composition
– Organic or inorganic
– Setteable or suspended
• Degree of precision required for the monitoring
project
– Monitoring or litigation requirement

TURBIDITY TESTING METHODS
• Turbidity measures the actual quality and
quantity of suspended solids in the water
– JTU (Jackson Turbidity Units)
• Measurement of transmission of light
– NTU (Nephelometric Turbidity Units)
• Measurement of dispersal of light
– Secchi Disk
• Measurement of light penetration
– Settling cones
• Heavy inorganic solids

JTU and NTU
Transmission vs. Dispersion
JTU
Light
receiver
NTU
Light
receiver
Light
Light
Water sample
Water sample

TURBIDITY METERS
• Required for accurate
measurement
• Required for
regulatory purpose $700.00
$2,775.00

SETTLEABLE SOLIDS AND
THE SECCHI DISK
SIMPLICITY AT ITS BEST
Settling Cones
One hour
Measure
the volume
Secchi disk
Water surface
Lower the secchi
into the water until
it disappears
Record apparent color
Yellow
Gray
Blue
Green

CONDUCTIVITY
• Ionic content of water – Charged particles
–Ca + , Cu + , Hg + , Mg +
• Measured by ability of water to carry an electrical
current
• The reverse of resistance
• Higher ionic content the better the conductance
• Expressed as microhms/cm of conductance
• Related to pH - Generally high conductivity
means higher pH

CONDUCTIVITY
• Directly related to (TDS)
total dissolved solids
–Ca, , Mg, Na, K, CO 3 ,
SO 4 , Cl
• Moderate levels
improve productivity
• Ease osmoregulatory
stress at higher
conductivity
TDS mg/L
160
140
120
100
80
60
40
20
0
0 100 200 300
Conductivity

CONDUCTIVITY
• Hannah conductivity, PH, TDS meter, Redox
• Conductivity in relation to total dissolved solids
– Coastal S.E. Alaska low
– Interior streams relatively high
– Seawater very high
• Dissolved solids and salinity
$129.00
– Less then 1000 mg/L - Freshwater
– 1,000-3,000 mg/L - Slightly saline
– 3,000-10,000 mg/L - Moderately saline
– 10,000-35,000 mg/l - Very saline (Ocean concentrations)

SALINITY
• Ocean concentration ~ 36 ppt
– Affected by temperature and pressure
– Warmer and deeper water more saline
• Salinity nearshore affected by freshwater,
• Estuaries vary from 0-360
ppt
• Measure salinity to aid in locating source of
pollution
• Tolerance to high and low salinities vary by
species

SALINITY RECORDERS
Hydrometers
• Least expensive
– $30.00 to 100.00
– Compensate for
temperature
• Accuracy ± 1.5 ppt

SALINITY RECORDERS
• Conductivity meters
– Expensive
– Hundreds to thousands
– Adjust for temperature
• YSI Meter salinity meters
– Expensive ($800.00 +)
– Easy to use
– Record temperature also
– Record at different depths

SALINITY RECORDERS
Refractometers
• Very simple to use
• Portable
• Ask for temperature
compensation model
• $45.00-$205.00
$205.00

CHLORIDE
• Generally very low is
freshwater (ave 8.3
ppm)
• Primarily component in
salt water (19.3 ppt)
– 19,300 ppm
• Test strips (30-600
ppm)
• Titration (drop by drop
5-200 ppm)
• Colorimeter (0 to 20
ppm)
$900.00
$33.00/40 tests
$74.00/100 tests

pH
• Measure of “hydrogen
power”
• Often referred to as
– Acidic or Alkaline
• Living organisms must
function with narrow
range of pH
– 6.5-8.5
pH = -log H +
pH scale 1-14
Lemon juice -2
Orange juice-3
Sodium
bicarbonate-8
Ammonia-10

WHAT DOES PH MEAN
WITH THE NORMAL RANGE MEAN?
• Higher pH makes ammonia compounds
more toxic
• Lower pH enable dissolving of heavy metals
if present in the water
• Higher pH increase respiratory efficiency
• Lower pH generally indicated lower mineral
concentrations (TDS)
• Ph affects rates of biochemical reactions

• High pH
• High particulate organic
matter concentration
• High suspended
SUSPENDED
sediment load
SEDIMENT
• Water circulation high
PHASE
PARITIONING
TRIANGLE
DISSOLVED
IN WATER
• Low pH
• Low particulate organic
matter concentration
• Low suspended
sediment load
• High dissolved organic
matter concentration
BOTTOM
SEDIMENT
• High pH
• High particulate organic
matter concentration

WHAT ARE THE METALS?
• Abundant metals – e.g. aluminum, iron
• Rare metals – mercury, cadmium, silver
• Trace metals – “micronutients” – copper,
zinc, chromium

SOURCES
• Chemical weathering
• Runoff sediments
• Atmospheric deposition
• Chemicals – antifouling agents, metal from
pipes
• Oxidation of acid sulfate soils
• Mining and land disturbance
• Waste discharge

• Low pH
DISSOLVED METALS
PREDOMINATE WITH
– Solubility of metal hydroxides (Ca(OH)2, Mg(OH)2,
Fe(OH)2, Al(OH)3) increase as pH drops
– Adsorption capacity on solid surfaces
–H + from the acid competes with metals for attachment
sites on organic molecules
• Low particulate matter
• High levels of dissolved organic matter

METAL PARTITIONING
• Partitioning refers to the transfer of metal
(including contaminants such as heavy
metals) between different phases and
biological components (benthos and
plankton) in natural waters.
•Soluble – Most bioavailable
•Suspended – Bonded in some form
•Settlable – In the sediment

TYPES OF METAL
PARTITIONING
• Adsorption – Adherence of a substance to
another in which is contacts
– Most common process since metals have an
attraction for iron, particulate organic matter and clays
• Complexation – Complex bonding process
where ions or molecules bond to a central
charged particle, usually a metal.
– Remain in solution
• Precipitation - A chemical reaction where a
soluble substance become heavy enough to
settle out (precipitate)

ORGANIC ADSORPTION
• Metal adheres directly to a
clay or organic particle
– Heavy it sinks
– May stay in solution
Cu Zn
Clay particle
Zn
Cu Cu
Zn

ORGANIC MATERIAL EFFECT
% Copper attached
120
100
80
60
40
20
0
Deep
Surface
0 1 2 3 4 5 6 7
% Carbon (Organic material)

Mercury
ALASKAN TESTING
RESULTS
(Alaska Dept Environmental Conservation)
Some concern about bioaccumulation
in spawning and rearing streams
over time.

SUMMARY
• Testing of heavy metals requires
laboratory services
• Proper sampling is essential
• The affects of pH and salinity cause by
freshwater influences are profound
• Heavy metals are cumulative, must look at
the long term
• Organism tolerance and bioaccumulation
are extremely variable by species

NITROGENOUS COMPOUNDS
• Ammonia (NH 3 ) – Byproduct of protein digestion
with deamination of amino acids in the protein
– Directly lethal to aquatic organisms
• Nitrite (NO 3 ) – Nitrosomonas bacteria and oxygen
– Generally in small quantitie
• Nitrate (NO 4 )- Nitrobacter and oxygen more
abundant than nitrite or ammonia if oxygen is
available

THE END
• The end of this program is the beginning of
planning
• You project may encompass part, all, or
other measurements that presented here
• We are here to provide personal advice and
additional information in the presentations to
follow
• Do not expect to get a QAPP finished here,
but you will have the basics to followup