APPENDIX A. Provincial Water Quality Objectives (PWQO) for selected PWQMN parameters. Other sources of information are provided where appropriate
(e.g. Canadian Water Quality Guidelines, US EPA Water Quality Criteria). √ - Denotes recommended indicator parameters.
PWQMN Parameter
PWQO 1
Alkalinity, total
(ALKT)
narrative
Aluminum, unfiltered
total (ALUT)
N/A
CWQG 2
EPA Criteria
Notes
Toxicity of metals can vary as a function of alkalinity (CaCO3).
Alkalinity buffers aquatic ecosystems from fluctuations in pH
and serves as a reservoir of carbon for photosynthesis.
5-100 µg/L 3
750 µg/L
(acute). 4
Total aluminum concentration, as measured in the PWQMN,
should not be evaluated against the PWQO for clay-free samples.
Sources include weathering of rocks and clays, industrial wastes,
treatment plants that use alum as a flocculent.
Ammonia (un-ionized)
Calculated from
Ammonium, total
unfiltered reactive
(NNHTUR) using
Field (FWPH) or
Laboratory pH and
Water Temperature
(FWTEMP).
20 µg/L NH3
19 µg/L NH3 5,
approximately equaling
15 µg/L ammonia-N
See also EPA
(1999). 6
Unfiltered ammonia nitrogen (NNHTUR) includes ammonia
(NH3) and ammonium (NH4+). Un-ionized ammonia refers to all
forms of ammonia with the exception of the ammonium ion.
Un-ionized ammonia (NH3) concentration varies with pH and
water temperature. See OMOE (1994)1 for a helpful summary
table and equations.
PWQMN ammonia concentrations are expressed as mg/L total
ammonia-N. Others report as mg/L NH3. To convert mg/L NH3
to mg/L total ammonia-N multiply by 0.8.
Ammonia is highly soluble in water. Sources include sewage
treatment plants, steel mills, fertilizer plants, petroleum
industries, intensive farming, natural decomposition of organic
wastes, gas exchange with the atmosphere.
Ammonia in surface water is naturally converted to nitrate. This
conversion, in addition to increasing nitrate concentration,
removes oxygen from the water, which also can adversely affect
fish and invertebrates.
Barium, unfiltered
total (BAUT)
Beryllium, unfiltered
total (BEUT)
Common element in earth’s crust. Trace amounts usually found
in surface water.
11 µg/L
(< 75 mg/L CaCO3)
Sources include combustion of fossil fuels, manufacture of alloys
and organic chemicals. Some beryllium compounds are readily
soluble in water (e.g. chloride and nitrate salts).
1100 µg/L
(> 75 mg/L CaCO3)
Biochemical Oxygen
Demand, 5-day
(BOD5)
Cadmium, unfiltered
total (CDUT)
BOD is the amount of oxygen that is consumed by bacteria and
other microorganisms while they decompose organic matter
under aerobic conditions at a specified temperature. Five-day
BOD (BOD5) is a measure of the amount of oxygen consumed in
a sample incubated for five days at 20 °C.
0.1 µg/L
(< 100 mg/L CaCO3)
Guideline varies with
hardness, see equation. 7
See also EPA
(2002). 4
0.5 µg/L
(> 100 mg/L CaCO3)
Calcium, unfiltered
total (CAUT)
Calcium is a cation dissolved from rocks and soils. The highest
concentrations are usually found in waters that have been in
contact with limestone, dolomite, or gypsum.
√ Chloride, unfiltered
reactive (CLIDUR)
860 mg/L
acute (one
hour). 8
230 mg/L
chronic (4 day
average). 8
Chromium, unfiltered
total (CRUT)
Present in trace amounts as a result of natural weathering
processes. Anthropogenic sources include mining (particularly
zinc processing), agriculture, burning of fossil fuels, nickel
cadmium batteries.
N/A
N/A
Road salts have been designated a ‘toxic’ substance under the
Canadian Environment Protection Act. Assessment report
documents toxicity for sensitive species at 210 mg/L
(Environment Canada/Health Canada, 2001).9
Total chromium concentration, as measured in the PWQMN,
should not be evaluated against the PWQO or CWQG for
hexavalent or trivalent chromium. Different forms of chromium
have different degrees of toxicity.
Cobalt, unfiltered total
(COUT)
Sources include weathering of cobalt-rich ores and from
anthropogenic sources such as emission from coal burning
industries.
Conductivity, 25 °C
Field (CONDAM) or
Laboratory (COND25)
Conductivity varies with water temperature and is corrected to a
standard temperature of 25 °C.
√ Copper, unfiltered
total (CUUT)
Indicates water's ability to conduct an electrical current and
provides an indication of the amount of dissolved ions.
1 µg/L
(< 20 mg/L CaCO3)
2 µg/L
(< 120 mg/L CaCO3)
5 µg/L
(> 20 mg/L CaCO3)
3 µg/L
(120-180 mg/L CaCO3)
See also EPA
(2002). 4
Sources include the weathering of copper minerals and numerous
sources from human activities (e.g. copper pipe, metal alloys,
wiring, fungicides and insecticides).
4 µg/L
(> 180 mg/L CaCO3)
Dissolved Solids or
Residue, Filtered
(RSF)
Dissolved Oxygen
(DO)
Refers to minerals, salts, metals, cations or anions dissolved in
water. In many streams there is a direct linear relationship
between dissolved solids concentration and conductivity.
>5 - 8
(warm water biota)
> 5.5 - 6.5
(warm water biota)
>4-7
(cold water biota)
> 6.5 - 9.5
(cold water biota)
Guidelines are designed to protect cold water biota (e.g. salmonid
fish communities) and warm water biota (e.g. centrarchid fish
communities).
Decomposition of organic matter may deplete dissolved oxygen
below concentrations required by aquatic life.
Hardness, total
(HARDT)
Iron, unfiltered total
(FEUT)
A measure of cations in water, primarily calcium and
magnesium. Influences the form and toxicity of metals.
300 µg/L
300 µg/L
1 000 µg/L 4
Sources include weathering of rocks and soils, mining and
processing of iron ores, steel making and metal fabricating,
burning of fossil fuels, corrosion of iron or steel products.
Kjeldahl Nitrogen,
unfiltered reactive total
(NNKTUR)
√ Lead, - unfiltered
total (PBUT)
Total Kjeldahl nitrogen is a measure of the total nitrogenous
matter present, excluding nitrate and nitrite. The total Kjeldahl
nitrogen concentration less the ammonia nitrogen concentration
gives a measure of the organic nitrogen present.
1 µg/L
(< 30 mg/L CaCO3)
1 µg/L
(< 60 mg/L CaCO3)
3 µg/L
(30-80 mg/L CaCO3)
2 µg/L
(60-120 mg/L CaCO3)
5 µg/L
(> 80 mg/L CaCO3)
4 µg/L
(120-180 mg/L CaCO3)
7 µg/L
(> 180 mg/L CaCO3)
Magnesium, unfiltered
total (MGUT)
Manganese, unfiltered
total (MNUT)
Molybdenum,
unfiltered total
(MOUT)
40 µg/L
73 µg/L
Nickel, unfiltered total
(NIUT)
25 µg/L
25 µg/L
(< 60 mg/L CaCO3)
65 µg/L
(60-120 mg/L CaCO3)
110 µg/L
(120-180 mg/L CaCO3)
150 µg/L
(> 180 mg/L CaCO3)
Sources include weathering of rocks and soils, the burning of
fossil fuels, processing of nickel ores, smelting and electroplating
industries.
13 mg/L NO3-
√ Nitrate
Calculated by
subtracting Nitrite,
unfiltered reactive
(NNO2UR) from
Nitrates, total
unfiltered reactive
(NNOTUR)
PWQMN nitrate concentrations are expressed as mg/L NO3--N.
Others report concentration as nitrate ion (i.e. mg/L NO3-). To
convert mg NO3--N/L to mg/L NO3- multiply by 4.43.
The EPA (1996) maximum contaminant level (MCL) for nitrate
(as nitrogen) is 10 mg NO3--N/L.
60 µg/L
Nitrite, unfiltered
reactive (NNO2UR)
pH, Field (FWPH) or
Laboratory (pH)
10 mg/L NO3-N
Acceptable range of
6.5-8.5.
Acceptable range of
6.5-9.
pH is reported as the logarithm of the reciprocal of the hydrogen
ion concentration. pH represents a measure of the acidity (pH
less than 7) or alkalinity (pH greater than 7) of a solution; a pH of
7 is neutral.
Phosphate, filtered
reactive (PPO4FR)
√ Phosphorus,
unfiltered total (PPUT)
30 µg/L (streams)
20 µg/L (lakes)
Phosphorus is associated with eutrophication—the enrichment of
a body of water with nutrients resulting in accelerated algal or
plant production.
PWQO for TP is intended to prevent the nuisance growth of
algae. TP is not toxic to aquatic life but excess concentrations
can lead to undesirable changes in aquatic ecosystems (e.g.
reduced biodiversity, reduced oxygen conditions, toxic algae
blooms, impaired aesthetics and recreational opportunities).
The EPA recommends that total phosphorus concentration (as
phosphorus) not exceed 0.10 milligram per liter in streams not
discharging directly into reservoirs and not exceed 0.05
milligram per liter in streams discharging directly into reservoirs.
milligram per liter in streams discharging directly into reservoirs.
Potassium, unfiltered
total (KKUT)
√ Suspended Solids or
Residue, particulate
(RSP)
narrative
narrative
narrative
narrative
Sodium, unfiltered
total (NAUT)
Strontium, unfiltered
total (SRUT)
Temperature, Field
(FWTEMP)
Water temperature data are sensitive to time of measurement.
Temperature is influenced by season, weather conditions, time of
day and streamflow velocity. Typically, peak daily temperatures
occur in late afternoon, and daily minima occur just before dawn.
Temperature should be measured continuously to examine daily
fluctuations.
Thermal pollution is the result of using water for cooling
purposes.
Temperature controls the rate of many chemical reactions (e.g.
the equilibrium between unionized ammonia and ammonium is
temperature-dependent).
Titanium, unfiltered
total (TIUT)
Turbidity (TURB)
narrative
Turbidity is a measure of the cloudiness of water resulting from
suspended particles such as clay, silt, organic matter and
microorganisms. Turbidity is measured by quantifying the
degree to which light traveling through a water column is
scattered by the suspended particles.
High turbidity may reduce light transmission and therefore
reduce photosynthesis of aquatic plants. High turbidity may also
interfere with disinfection.
Vanadium, unfiltered
total (VNUT)
6 µg/L
√ Zinc, unfiltered total
(ZNUT)
20 µg/L
30 µg/L
1
Ontario Ministry of the Environment, 1994. Water management: policies, guidelines, provincial water quality objectives of the Ministry of the Environment.
This document is available on the OMOE Internet site (http://www.ene.gov.on.ca/envision/gp/3303e.pdf) and is commonly referred to as the ‘Blue Book’. Also
see: Ontario Ministry of the Environment, 1979. Rationale for the establishment of Ontario’s provincial water quality objectives.
2
Canadian Council of Ministers of the Environment, 2002. Canadian water quality guidelines for the protection of aquatic life. This document is available on
the CCME Internet site (http://www.ccme.ca/assets/pdf/e5_002.pdf).
3
CWQG for aluminum:
5 µg/L where pH > 6.5; [Ca2+] < 4mg/L; DOC < 2mg/L
100µg/L where pH ≥ 6.5; [Ca2+] ≥ 4mg/L; DOC ≥ 2mg/L.
4
United States Environmental Protection Agency (EPA), 2002. National recommended water quality criteria. This document is available on the EPA Internet
site (http://www.epa.gov/waterscience/pc/revcom.pdf).
5
See ammonia fact sheet in Canadian environmental quality guidelines (CCME, 1999) for more information.
6
EPA, 1999. Update of ambient water quality criteria for ammonia (http://www.epa.gov/waterscience/standards/nh3_rpt.pdf). Acute criterion for ammonia is
dependent on fish species and pH.
7
CWQG for cadmium:
10{0.86[log(hardness)] - 3.2)
where the WQG is in µg/L and hardness is mg/L CaCO3. See cadmium fact sheet in Canadian environmental quality guidelines (CCME, 1999) for more
information.
8
EPA, 1988. Ambient aquatic life water quality criteria for chloride (http://www.epa.gov/ost/pc/ambientwqc/chloride1988.pdf).
9
Environment Canada and Health Canada, 2001. Canadian Environment Protection Act priority substances list assessment report: road salts
(http://www.ec.gc.ca/substances/ese/eng/psap/final/roadsalts.cfm).