Site Prioritization Tool For Potentially POPs Contaminated Sites

All Site Prioritization Tool Questions

pre-screening tool questions | site prioritization tool questions

This page shows all the questions asked in the Site Prioritization Tool and how that answer impacts the score given by the tool.

Contaminant Characteristics

Q1: Over what period of time were chemical contaminants used at the site?

Why is this question important? The longer that contaminants were used at the site, the greater the likelihood that the site is contaminated.

for over 10 years score: 5 --> go to next question

1 - 10 years score: 3 --> go to next question

for less than 1 year score: 1 --> go to next question

Do Not Know score: 3 --> go to next question; Considered in the sufficient information calculation.

Q2: Are the activities resulting in chemical contamination ongoing?

Why is this question important? If activities resulting in chemical contamination are ongoing, then there is a greater likelihood that people or the environment is being exposed, than if the activities had ended.

Yes score: 5 --> go to next question

No score: 0 --> go to next question

Do Not Know score: 2 --> go to next question; Considered in the sufficient information calculation.

Q3: Are the contaminant concentrations in soil known or strongly suspected to exceed environmental quality guidelines?

For soils, select appropriate guidelines based on current (or proposed future) land use (i.e, agricultural, residential/parkland, commercial, or industrial), and soil texture if applicable (i.e., coarse or fine).

Why is this question important? Measured concentrations of contaminants exceeding environmental guidelines indicate a potential chemical hazard.

Yes score: 2 --> go to next question

No score: 0 --> go to next question

Do Not Know score: 1 --> go to next question; Considered in the sufficient information calculation.

References to use when answering this question:

  • Canadian Soil Quality Guidelines for the Protection of Environmental and Human Health ( view PDF file )
  • Risk Based Environmental Guidelines Provided by US EPA ( view XLS file )

Q4: Are there contaminant concentrations in sediment known or strongly suspected to exceed environmental quality guidelines?

Why is this question important? Measured concentrations of contaminants exceeding environmental guidelines indicate a chemical hazard.

Yes score: 2 --> go to next question

No score: 0 --> go to next question

Do Not Know score: 1 --> go to next question; Considered in the sufficient information calculation.

References to use when answering this question:

  • Canadian Sediment Quality Guidelines for the Protection of Aquatic Life ( view PDF file )
  • Risk Based Environmental Guidelines Provided by US EPA ( view XLS file )

Q5: Are the contaminant concentrations in surface water known or strongly suspected to exceed environmental quality guidelines?

Surface water is considered contaminated for site classification purposes if a contaminant in the surface water exceeds the Canadian CCME environmental quality guidelines for water.

For surface water used for drinking water, use the guidelines for Canadian Drinking Water Quality.

Why is this question important? Measured concentrations of contaminants exceeding environmental guidelines indicate a potential chemical hazard.

Yes score: 2 --> go to next question

No score: 0 --> go to next question

Do Not Know score: 1 --> go to next question; Considered in the sufficient information calculation.

References to use when answering this question:

  • Canadian Water Quality Guidelines for the Protection of Agricultural Water Uses ( view PDF file )
  • Canadian Water Quality Guidelines for the Protection of Aquatic Life ( view PDF file )
  • Canadian Recreational Water Quality Guidelines and Aesthetics ( view PDF file )
  • Risk Based Environmental Guidelines Provided by US EPA ( view XLS file )

Q6: Are the contaminant concentrations in groundwater known or strongly suspected to exceed environmental quality guidelines?

Groundwater is considered contaminated for ranking purposes if a contaminant level exceeds the Health Canada guidelines for groundwater used for drinking.

Why is this question important? Measured concentrations of contaminants exceeding environmental guidelines indicate a potential chemical hazard.

Yes score: 2 --> go to next question

No score: 0 --> go to next question

Do Not Know score: 1 --> go to next question; Considered in the sufficient information calculation.

References to use when answering this question:

  • Canadian Guidelines for groundwater used for drinking ( view DOC file )
  • Canadian Water Quality Guidelines for the Protection of Agricultural Water Uses ( view PDF file )
  • Canadian Water Quality Guidelines for the Protection of Aquatic Life ( view PDF file )
  • Canadian Recreational Water Quality Guidelines and Aesthetics ( view PDF file )

Q7: For contaminants known to be at the site (or strongly suspected to be at the site), were there any contaminants in a pure liquid state? If not, what was the largest Exceedance Factor calculated?

Exceedance Factor =
Measured concentration
Environmental Guideline

Why is this question important? The larger the Exceedance Factor, the greater the probability that there will be risks to Human Health of the Environment. For chemicals in the pure liquid state, the pure liquid state is generally the highest possible concentration which an organic contaminant can be found. In the liquid state, contaminants have a greater potential to migrate and thus may increase the size of the contaminated area.
Chemicals that can be in a pure liquid state includes PCB oils, petroleum products, pesticide formulations etc.

the primary contaminant of concern is in a pure liquid state score: 8 --> go to next question

the Exceedance Factor is High (contaminantion is more than 100 times the guideline) score: 6 --> go to next question

the Exceedance Factor is Medium (contamination is 10 - 100 times the guideline) score: 4 --> go to next question

the Exceedance Factor is Low (contamination is 1 - 10 times the guideline) score: 2 --> go to next question

Do Not Know score: 4 --> go to next question; Considered in the sufficient information calculation.

References to use when answering this question:

  • Canadian Soil Quality Guidelines for the Protection of Environmental and Human Health ( view PDF file )
  • Canadian Tissue Residue Guidelines for the Protection of Wildlife Consumers of Aquatic Biota ( view PDF file )
  • Canadian Water Quality Guidelines for the Protection of Agricultural Water Uses ( view PDF file )
  • Canadian Water Quality Guidelines for the Protection of Aquatic Life ( view PDF file )
  • Canadian Recreational Water Quality Guidelines and Aesthetics ( view PDF file )
  • Canadian Guidelines for groundwater used for drinking ( view DOC file )
  • Risk Based Environmental Guidelines Provided by US EPA ( view XLS file )

Q8: Are any of the contaminants at the site Persistent Organic Pollutants (POPs) or persistent chlorinated chemicals?

POPs include eight pesticides (aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, mirex, and toxaphene); two industrial chemicals (polychlorinated biphenyls and hexachlorobenzene); and two unintended by-products, dioxins and furans.

Why is this question important? Due to their large toxic potency, ability to bioaccumulate and persistence, POPs chemicals pose a unique hazard to human health and the environment. (read more about POP chemicals)

Yes (or likely) score: 2 --> go to next question

No (or unlikely) score: 0 --> go to next question

Do Not Know score: 1 --> go to next question; Considered in the sufficient information calculation.

Q9: How many seperate contaminant classes pose a chemical hazard at the site?

Contaminant classes are defined as:

  • POPs – i.e., aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, mirex, toxaphene, polychlorinated biphenyls, hexachlorobenzene, and dioxins and furans.
  • Other persistent toxic substances (PTS)
  • Inorganic substances - e.g., metals, salts etc.
  • Petroleum hydrocarbons - e.g., BTEX, gasoline, lubricating oils, diesel etc..
  • PAHs (polycyclic aromatic hydrocarbons) – e.g., benzo(a)pyrene, anthracene, fluoranthene etc..
  • Phthalate esters – e.g. di-2-ethyl hexyl phthalate (DEHP), diisodecyl phthalate (DIDP) and diisononyl phthalate (DINP) etc..
  • Non-halogenated pesticides - e.g. malathion, carbamate, dinoseb etc..
  • Other organic contaminants – e.g., nitrophenols, glycols, organic solvents etc..

Why is this question important? Different contaminant classes generally have different modes of toxicity. The exposure to more than one contaminant class simultaneously, may pose an additional hazard to human health or the environment.

Five or more different contaminant classes are present score: 3 --> go to next question

2 - 4 different contaminant classes are present score: 2 --> go to next question

One contaminant class is present score: 1 --> go to next question

Do Not Know score: 2 --> go to next question; Considered in the sufficient information calculation.

References to use when answering this question:

Q10: What is the known size of the contaminated area or estimated quantity of all contaminants at the site?

>10 ha in size or contains > 5000 m3 of contaminants score: 9 --> go to next question

2 to 10 ha in size or 1000 to 5000 m3 of contaminants score: 6 --> go to next question

< 2 ha in size or < 1000 m3 of contaminants score: 2 --> go to next question

Do Not Know score: 4 --> go to next question; Considered in the sufficient information calculation.

Q11: Are the contaminants capable of damaging infrastructure?

Infrastructure can include underground utilities (electricity, gas, water pipes, telephone lines, etc). Some contaminants may react or absorb into underground utilities and infrastructure. For example, organic solvents may degrade some plastics, and salts could cause corrosion of metal.

Yes score: 2 --> go to next question

No score: 0 --> go to next question

Do Not Know score: 1 --> go to next question; Considered in the sufficient information calculation.

Groundwater Migration Potential

Q12: Are contaminants known or strongly suspected to migrate off-site in groundwater?

Yes score: 12 --> jump to Q16

Migration through groundwater is possible score: 8 --> jump to Q16

Migration through groundwater is unlikely score: 0 --> jump to Q16

Do Not Know score: n/a --> go to next question; Considered in the sufficient information calculation.

Q13: For the contaminants of concern found on the site, select the relative mobility classification corresponding to the most mobile contaminant

Why is this question important? Highly mobile contaminants will be washed out of soils and into groundwater more readily than chemicals with low mobility.

High relative mobility score: 4 --> go to next question

Moderate relative mobility score: 2 --> go to next question

Low relative mobility score: 1 --> go to next question

Insignificant relative mobility score: 0 --> go to next question

Do Not Know score: 2 --> go to next question; NOT considered in the sufficient information calculation.

References to use when answering this question:

Q14: What is the estimated annual rainfall at the site?

Why is this question important? The greater the rainfall and greater the permeability of soils, the greater the probability that contaminants will be washed out of soils and into groundwater.

estimated annual rainfall: meters (if amount is unknown, enter 0)

Q15: What type of soil is at the site?

Why is this question important? The greater the rainfall and greater the permeability of soils, the greater the probability that contaminants will be washed out of soils and into groundwater.

Gravel score: 1 x rainfall from Q14 --> go to next question

Sand score: 0.6 x rainfall from Q14 --> go to next question

Loam score: 0.3 x rainfall from Q14 --> go to next question

Pavement or clay score: 0 x rainfall from Q14 --> go to next question

Do Not Know score: n/a --> go to next question; NOT considered in the sufficient information calculation.

Surface Water Migration Potential

Q16: Are contaminants known or strongly suspected to migrate off-site in surface water? (i.e. dissolved in water or attached to particles)

Yes score: 12 --> jump to Q24

Migration of contaminants off-site with surface water is known or strongly suspected score: 8 --> jump to Q24

Migration of contaminants off-site with surface water is unlikely score: 0 --> jump to Q24

Contaminants in surface water do not exceed guidelines score: 0 --> jump to Q24

Do Not Know score: n/a --> go to next question; Considered in the sufficient information calculation.

Q17: Is surface water on the site contained?

  • Fully contained: berms and dikes or contaminated soils are capped
  • Partially contained: water movement offsite is delayed (i.e. in a sediment pond)
  • Not contained: no barriers between the site and nearby surface water

Water on site is fully contained score: 0.5 --> go to next question

Water on site is partially contained score: 3 --> go to next question

Water on site is not contained score: 5 --> go to next question

Do Not Know score: 3 --> go to next question; NOT considered in the sufficient information calculation.

Q18: What is the distance from the site to the nearest surface water stream or bodies?

more than 300m score: 0.5 --> go to next question

100 - 300m score: 2 --> go to next question

0 - 100m score: 4 --> go to next question

Do Not Know score: 2 --> go to next question; NOT considered in the sufficient information calculation.

Q19: How far below the soil surface were contaminants found?

At the soil surface score: 2 --> go to next question

Below the soil surface score: 0 --> go to next question

Do Not Know score: 1 --> jump to Q26; NOT considered in the sufficient information calculation.

Q20: How steep is the site?

More information: Grade (land steepness) is measured against the horizontal. For example, a 50% grade indicates land increasing 0.5 m vertically for every horizontal meter.

Why is this question important? The steeper the grade, the greater the potential for erosion and therefore surface water transporting contaminants which were originally in soils.

Steep slope (more than 50% grade) score: 3 --> go to next question

Intermediate slope (5 - 50% grade) score: 2 --> go to next question

Flat slope (less than 5% grade) score: 1 --> go to next question

Do Not Know score: 0 --> go to next question; NOT considered in the sufficient information calculation.

Q21: What is the estimated annual rainfall at the site?

estimated annual rainfall: meters (if amount is unknown, enter 0)

Q22: What type of soil is at the site?

Why is this question important? Coarser soils allow for more infiltration of water and therefore less runoff.

Gravel score: 0 x rainfall from Q21 --> go to next question

Sand score: 0.3 x rainfall from Q21 --> go to next question

Loam score: 0.6 x rainfall from Q21 --> go to next question

Pavement or clay score: 1 x rainfall from Q21 --> go to next question

Do Not Know score: n/a --> go to next question; NOT considered in the sufficient information calculation.

Q23: What is the flood potential for the site?

A flood is defined as water covering at least 25% of the site and on average about 10 cm deep.

Why is this question important? Due to the large mass of water involved, flooding can result in significant migration of soils.

1 flood every 1-2 years, and potentially contaminated soils can become flooded score: 1 --> go to next question

1 flood every 3-10 years, and potentially contaminated soils can become flooded score: 0.5 --> go to next question

1 flood every 11-50 years, and potentially contaminated soils can become flooded score: 0.2 --> go to next question

Potentiall contaminated soils on the site are unlikely to be flooded score: 0 --> go to next question

Do Not Know score: 0.5 --> go to next question; NOT considered in the sufficient information calculation.

Surface Soil Migration Potential

Q24: Are contaminates known or strongly suspected to migrate off-site with soils? (i.e. through blowing dust)

Yes (or likely) score: 12 --> jump to Q27

Migration of contaminants with surface soils is possible score: 9 --> jump to Q27

Migration of contaminants with surface soils is unlikely score: 0 --> jump to Q27

Surface soil contamination does not exceed guidelines score: 0 --> jump to Q27

Do Not Know score: n/a --> go to next question; Considered in the sufficient information calculation.

Q25: What covers contaminated soils on site?

Why is this question important? The type and depth of covering over contaminated soils can reduce or eliminate the migration of soils.

Contaminated soils are mostly exposed (not covered) score: 6 --> go to next question

Contaminated soils are mostly covered with plants score: 4 --> go to next question

Contaminated soils are mostly covered with clean soils score: 2 --> go to next question

Contaminated soils are mostly covered by hard surface (i.e., road or building) score: 0 --> go to next question

Do Not Know score: 4 --> go to next question; NOT considered in the sufficient information calculation.

Q26: How many months of the year are contaminated soils covered?

On some sites, vegetation may die back for some periods of the year.

Why is this question important? Plants growing over soils can reduce or eliminate erosion of soils either by wind or surface water run-off

Soils are always covered score: 0 --> go to next question

Soils are covered for 4-12 months of the year score: 3 --> go to next question

Soils are covered for less than 4 months of the year score: 6 --> go to next question

Do Not Know score: 3 --> go to next question; NOT considered in the sufficient information calculation.

Other Potential Migrations

Q27: Are there buried pipes/wires which may create a preferential pathway for the migration of soil contaminants?

Pipes and wires buried in soils may have been backfilled with gravel or lie in concrete trenches. These gravel channels or trenches may serve as a preferential pathway for the migration of soil contaminants.

Yes score: 4 --> go to next question

No score: 0 --> go to next question

Do Not Know score: 2 --> go to next question; Considered in the sufficient information calculation.

Q28: Are human activities likely to transport contamination off-site?

More information: Examples of this can include people bringing PCB containing transformer oil home for domestic use or contaminated soils being carried off-site attached to vehicle tires.

Yes (or likely) score: 4 --> go to next question

No (or unlikely) score: 0 --> go to next question

Do Not Know score: 2 --> go to next question; Considered in the sufficient information calculation.

Human Exposure

Q29: How many people are potentially exposed to contaminants from the site?

more than 100,000 score: 20 --> go to next question

10,000 - 100,000 score: 10 --> go to next question

1,000 - 10,000 score: 5 --> go to next question

less than 1,000 score: 2 --> go to next question

Do Not Know score: 10 --> go to next question; Considered in the sufficient information calculation.

Q30: Are there documented or strongly suspected impacts to human health at the site?

More information: Impacts to human health are defined here as two or more people sick from what appears to be contaminant-related exposure.

Yes score: 22 --> jump to Q39

Strongly suspected score: 10 --> jump to Q39

No score: 0 --> jump to Q39

Do Not Know score: n/a --> go to next question; Considered in the sufficient information calculation.

Q31: Is there a sensitive land use within 1 km of the site?

Why is this question important? A sensitive land use may mean one of two things either a) there are a large number of people exposed for long periods of time and/or b) the people exposed may be more sensitive to the effects of contaminants (i.e., babies, children, elderly or people who are sick).

schools, agriculture, hospital, temple, or residential area score: 3 --> go to next question

parkland score: 2 --> go to next question

Commercial area score: 1 --> go to next question

Industrial area score: 0.5 --> go to next question

Q32: How many people live within 1km of the site?

Why is this question important? People living within 1km of a contaminated site are more likely exposed to contaminants from that site than those people living further away.

More than 500 score: 3 --> go to next question

50 - 500 score: 2 --> go to next question

5 - 50 score: 1 --> go to next question

Do Not Know score: 2 --> go to next question; NOT considered in the sufficient information calculation.

Q33: Is the contamination in soils accessible to humans?

Soils may not be accessible to humans if there is a fence or wall around the site preventing people from entering, or if contaminated soils are covered with asphalt or concrete.

Yes score: 2 --> go to next question

Somewhat score: 1 --> go to next question

No score: 0 --> go to next question

Do Not Know score: 1 --> go to next question; NOT considered in the sufficient information calculation.

Q34: Is there a direct exposure pathway to humans via Dermal contact (i.e. skin contact)?

More information: Exposure via the skin is generally believed to be a minor exposure route. However, for some organic contaminants, skin exposure is an important component of overall exposure. Dermal exposure can occur while swimming in contaminated waters, bathing with contaminated surface water/groundwater and digging in contaminated dirt, and during chemical handling.

Yes score: 3 --> go to next question

No score: 0 --> go to next question

Do Not Know score: 1.5 --> go to next question; NOT considered in the sufficient information calculation.

Q35: Is there a direct exposure pathway to humans via Inhalation (i.e. breathing)?

More information:

Inhalation can be via both particulates (dust) and gas (vapours).

Dust - Soils are more likely to generate dust if they consist primarily of fine material (i.e., having a median grain size of 75 microns, as defined by CCME (2006)).

Vapours can be a problem where buildings have been built on former industrial sites or where volatile contaminants have migrated below buildings, resulting in the potential for vapours entering indoor air. The closer a person is to a source of volatile chemicals in soil, the greater the potential of exposure. In addition, coarser-grained soil will convey vapour much more efficiently in the soil than finer grained material such as clays and silts.

Yes score: 3 --> go to next question

No score: 0 --> go to next question

Do Not Know score: 1.5 --> go to next question; NOT considered in the sufficient information calculation.

Q36: Is there a direct exposure pathway to humans via Ingestion?

Contaminants can be ingested through drinking water, food items and by accidental ingestion of contaminated soils.

Yes score: 3 --> jump to Q38

No score: 0 --> jump to Q38

Do Not Know score: 1.5 --> go to next question; NOT considered in the sufficient information calculation.

Q37: How close is the nearest drinking water supply?

A drinking water supply can be a groundwater well or surface water reservoir.

Why is this question important? The closer a source of drinking water to a contaminated site, the greater probability that the drinking water can become contaminated.

0 to 100 m score: 3 --> go to next question

100 to 300 m score: 2.5 --> go to next question

300 m to 1 km score: 2 --> go to next question

1 to 5 km score: 1.5 --> go to next question

More than 5km or No drinking water present score: 0 --> go to next question

Do Not Know score: 2 --> go to next question; NOT considered in the sufficient information calculation.

Q38: Do people rely on food items gathered within a 1km radius of the contaminated site, especially meat?

Examples of animals providing local meats could include both wild animals (snakes, lizards, snails, frogs, fish etc.), or farmed animals (chickens, pigs, fish etc..).

Why is this question important? Some chemical contaminants (i.e., POPs and PTS) have the ability of accumulating in food items, especially fish and meats. Food items collected close to a contaminated site have a greater probability of having some level of contamination. When a person eats the contaminated food item, some of the contaminants are taken up.

Yes score: 3 --> go to next question

No score: 0 --> go to next question

Do Not Know score: 1.5 --> go to next question; NOT considered in the sufficient information calculation.

Ecological Exposure

Q39: Do animals or plants appear to be negatively affected due to exposure to chemical contaminants?

Some low levels of impact to ecological receptors are considered acceptable, particularly on commercial and industrial land uses. However, if ecological effects appear to be severe, the site would be a priority for risk management. For this tool, effects that would be considered severe include observed effects to a population or community of ecological receptors at the site.

More information: Ecological effects should be evaluated at a population or community level, as opposed to at the level of individuals, which was what was done for humans. For example, population-level effects could include reduced reproduction, growth or survival in a species. Community-level effects could include reduced species diversity or relative abundances. Further discussion of ecological assessment endpoints is provided in A Framework for Ecological Risk Assessment: General Guidance (CCME 1996).

Yes score: 18 --> jump to Q45

Strongly suspected score: 12 --> jump to Q45

No score: 0 --> jump to Q45

Do Not Know score: n/a --> go to next question; Considered in the sufficient information calculation.

Q40: Is there a nature preserve or wetland in the immediate area?

Yes score: 3 --> go to next question

No score: 0 --> go to next question

Do Not Know score: 1.5 --> go to next question; NOT considered in the sufficient information calculation.

Q41: Are plants and soil invertebrates likely exposed?

Invertebrates, for example, can include ants, earthworms, centipedes etc.

If contaminated soils are located within the top 1.5 m, it is assumed that plants and soil invertebrates may be exposed. Exposure to soils deeper than 1.5 m is possible, but less likely.

Why is this question important? Plants and soil invertebrates generally exposed to a small area of soil, therefore they can be a sensitive indicator of potential environmental effects. In addition, plants and soil invertebrates can be important dietary components to animals. Consequently, they can contribute to the bioaccumulation of POPs and PTS chemicals in animals and humans.

Yes score: 3 --> go to next question

No score: 0 --> go to next question

Do Not Know score: 1.5 --> go to next question; NOT considered in the sufficient information calculation.

Q42: Have animals been seen ingesting contaminants at the site?

Ingested contaminated material can include food or soil. Most animals will ingest some soil while eating plant matter or soil invertebrates.

Yes score: 3 --> go to next question

No score: 0 --> go to next question

Do Not Know score: 1.5 --> go to next question; NOT considered in the sufficient information calculation.

Q43: What is the distance to a sensitive terrestrial ecological area?

Examples of terrestial ecological areas include, a ecological reserve, and an area known to contain endangered species

less than 1 km score: 3 --> go to next question

Between 1 and 5km away score: 2 --> go to next question

Between 5 and 20km away score: 1 --> go to next question

More than 20km away score: 0 --> go to next question

Do Not Know score: 1.5 --> go to next question; NOT considered in the sufficient information calculation.

Q44: Does contaminated groundwater flow to the surface, or does surface water from the site enter an aquatic habitat?

Yes score: 3 --> go to next question

No score: 0 --> go to next question

Do Not Know score: 1.5 --> go to next question; NOT considered in the sufficient information calculation.

Q45: Are rare or protected species likely to be affected by site contamination?

Yes score: 3 --> go to next question

No score: 0 --> go to next question

Do Not Know score: 1.5 --> go to next question; Considered in the sufficient information calculation.

Q46: Does food taste strange or different within 5 km of site?

Difference in taste is usually most apparent in fish or meats.

Yes score: 3 --> go to summary display

No score: 0 --> go to summary display

Do Not Know score: 1.5 --> go to summary display; Considered in the sufficient information calculation.

Hatfield Consultants The World Bank funded by the Canadian POPs Trust Fund through the      
Canadian International Development Agency