PUBLISHED: 04 December 2017


Icon showing a green, cartoon representation of algae

Also known as phytoplankton, pond scum, watermelon snow. 

What is it?

Algae is a general term for microscopic plants that live in the water. There are many different types of algae and they can grow and multiply very quickly. Like land plants, they photosynthesize (they absorb carbon dioxide and release oxygen) and they absorb nutrients from the water. 

There is a wide variety of algae in Alberta. Their appearance in water can range from murkiness; to green pea soup; to mats of green, brown or reddish material. Some types of algae float in the water, while others attach to something. Sometimes, the same type of algae can appear differently if the environmental conditions change. 

Blue green algae/cyanobacteria

Blue green algae are not algae at all. They are a group of many different bacteria that have similar traits to algae. Cyanobacteria usually form long strands of single bacteria cells all linked together and living cooperatively. They have unique pigments and some (but not all) look blue green in colour. 

Cyanobacteria are often referred to as algae because they photosynthesize, form blooms, absorb nutrients, and look similar to algae.

Are algae in the water regulated in Alberta?

Yes, there are guidelines for quantities of algae in surface water for purposes of environmental protection, human health and recreation. There are also regulations on some activities that can indirectly cause algae blooms (e.g., fertilization of crops).  

The toxins produced by algae are regulated by federal guidelines. The Canadian guideline for the cyanobacterial toxin microcystin is 1.5 micro-grams per litre. More information can be found here

Are algae in my water?

Source Water

Algae are in surface water across Alberta. In addition to lakes, ponds and rivers, algae are also found on snow and ice, in the soil, and paired up with fungi to make lichens. Natural algae in surface water are an essential part of the ecosystem, despite their reputation as problematic for water quality. See our page on concerns about blue-green algae for more information.

Tap Water

There are no algae in tap water because they are easily filtered out. Certain toxins released by algae can end up in tap water, but the health authority will have issued a health advisory for any residents whose source water may be contaminated with these toxins.

When there are any health risks from a toxic algae bloom, Alberta Health Services posts public health advisories on signs at the water itself, over the media, and online

What are the impacts on human health?

When there is an abundance of all the things algae need to grow (e.g. nutrients, sunlight, and carbon dioxide) they can multiply so quickly that they form a bloom. 

Some types of algae produce strong toxins that are released into the water. When these types of algae form blooms, they are called toxic algal blooms and are damaging for the environment and people. During a toxic algal bloom, people and their pets are warned to avoid drinking the water or playing in or near it. People are advised not to fish and farmers are advised not to let their livestock drink it.

Water treatment plants can have a difficult time removing algal toxins from drinking water, so in some cases people are advised to drink bottled water rather than tap water if their source water has an algae bloom.

Although they are not true algae, cyanobacteria are the most common cause of toxic algal blooms.

What are the impacts on the environment?

Algae are an essential part of aquatic ecosystems. They provide food for many other organisms, help recycle nutrients, and help absorb some contaminants from water.

An algae bloom can damage an ecosystem because it can smother other plants and, when all the algae die and start to decompose, oxygen is depleted. Without enough oxygen in the water fish and other animals can die. Toxic algal blooms also lead to fish and other animals dying from the toxicity of the water.

How do algae get into the water?

Algae are naturally occurring. Algal blooms are triggered when there are more nutrients than typical for a certain body of water. The more relevant question is, “How do extra nutrients enter surface water?”

What can we do about algae in the water?

The Bow River Basin the Phosphorus Management Plan has been put in place to reduce the amount of phosphorus getting into the water. This is a positive step to preventing algae blooms.

Restricting the use of non-essential fertilizers can help prevent nutrients from entering the water.

Where can I find more information?

Public Health Advisories in Alberta

Quick facts about blue green algae in Alberta

Cyanobacteria blooms and toxicity

Environment and Climate Change Canada – Phosphorus and excess algal growth



Also known as watering down, decreasing the concentration, a component of assimilative capacity. 

Icon showing a beaker tipping and adding water, representing dilution

What is it?

For decades, the approach to pollution management was to increase dilution. There was even a saying: “The solution to pollution is dilution.” Adding water (diluting) and decreasing the concentration of a pollutant was thought to reduce negative impacts on the environment.  

The principal of dilution is true in that the natural environment, specifically aquatic ecosystems, have capacity to absorb and degrade a certain amount of pollutants. For a river or lake this is referred to as the assimilative capacity; but it takes much more than simple dilution of the pollutant stream to decrease its concentration. The water body’s capacity to receive pollutants depends on many other processes (e.g., sedimentation, volatilization, chemical breakdown, microbial breakdown/transformation, and uptake by aquatic plants).  

However, not all contaminants can be degraded quickly through natural processes and humans are now producing more waste in concentrated areas than can be adequately diluted and assimilated by the environment. Wastewater from communities and homes needs to go through a treatment process before it is released to the environment. Additionally, treating wastewater can produce by-products from heat and electricity.

Although dilution is an important factor in wastewater management, dilution is not the solution to pollution.

Is dilution regulated in Alberta?

Yes, there are regulations for the necessary dilution ratio of effluent released into surface waters. The type of treatment process and level of treatment used to treat the wastewater also changes the required dilution. However, in general, the ratio of effluent volume to surface water volume is 1:10.

Why is dilution important?

Even though wastewater treatment plants remove many contaminant materials, there are usually remaining organic matter, microorganisms, and other contaminants in the water being returned to the environment. 

Downstream water users and downstream environments can be protected through dilution or additional water treatment. Additional water treatment can be expensive, so having adequate dilution in a receiving water body reduces water treatment costs for communities. 

What are the impacts on human health?

Many contaminants are not harmful when they are present in low concentrations, so even when there may be a source of pollution upstream, downstream water quality will be improved through the process of dilution. 

Conversely, in a lake or pond that evaporates over time, some types of contaminants will become more concentrated, making it unsafe for swimming. 

What are the impacts on the environment?

Dilution is an important factor in effectively protecting aquatic ecosystems. 

If there is not enough dilution (e.g., if the river level is too low in late summer), aquatic organisms can be overwhelmed by the concentration of contaminants. 

In Alberta during the winter, dilution is a particularly important factor when rivers and streams freeze over. Because ice prevents most of the oxygen from passing into the water, the decomposition of organic matter in the water can use all the remaining oxygen, leading to fish and other organisms dying.

How does dilution happen?

When tributary streams join a river, or two rivers join (confluence), the water mixes and dilutes. Similarly, when adding treated wastewater from a community into a large river, the wastewater is diluted into the full volume of the river.

What can we do about dilution?

Think about what goes down the drain in your home, garden or property.

As the population grows, human communities produce more waste (including emerging contaminants), which dilution may not be able to deal with.

Where can I find more information?

Wastewater system standards for performance and design

Links to websites for wastewater service providers in Alberta

Protecting surface water quality from wastewater discharges through assimilative capacity studies  

Sources: PUBLISHED: 18 DECEMBER 2017

Disinfection By-products

Also known as chlorination by-products, trihalomethanes, DBPs. 

Icon showing bubbles and a container of chlorine disinfectant

What are they?

Disinfection by-products (DBPs) are specific molecules that form when a chemical is used to disinfect water for drinking or for release into the environment. The disinfecting chemical reacts with naturally occurring organic matter in the raw water. 

Chlorine is the most commonly used disinfectant in the world (and possibly also the greatest public health achievement of the 20th century). However, using chlorine as a disinfectant produces trihalomethanes, including chloroform and bromoform.

Other examples of DBPs from disinfection include:

  • DBPs resulting from chlorine dioxide disinfection: chlorate, chlorite.
  • DBPs resulting from ozone disinfection: bromate, formaldehyde. 
  • DBPs resulting from chloramine disinfection: N-nitrosodimethylamine (NDMA).

Are DBPs regulated in Alberta?

Yes, the most frequently detected DBPs are regulated with specific detection limits for the individual compounds and the total for the group. For example, the total allowable quantity of trihalomethanes is 100 parts per billion, but each trihalomethane has a specific limit as well.

Are disinfection by-products in my water?

Source water

No, there is no evidence of disinfection by-products present before the water has gone through the disinfection process.

Tap Water

Yes, there are DBPs in tap water. The amount and type of DBPs depends on what trace substances are in the source water and what process is used for disinfection.   

Many technologies exist to help limit DBP formation and remove DBPs from tap water. These are often employed at treatment plants, which have a higher likelihood of producing DBPs. The Guidelines for Canadian Drinking Water have thresholds for DBPs, requiring water service providers to monitor for their presence and ensure they remain below certain thresholds.

What are the impacts on human health?

People are exposed to DBPs through drinking water, showering, and swimming in chlorinated swimming pools. 

When people are exposed to high concentrations, many of the chemicals that are formed as DBPs have been shown to have serious human health effects. Trihalomethanes are considered carcinogens, suspected of causing kidney and liver cancer. However, it is very rare for high concentrations to be found in water. An example for reference is that NDMA is found in much higher concentrations in bacon and beer than is detected in drinking water.

What are the impacts on the environment?

DBPs do not generally have a significant impact on the environment because they are formed from disinfection of drinking water. This means the DBPs have usually evaporated or degraded by the time the wastewater is released back to the environment. 

How do disinfection by-products get into the water?

DBPs are formed in the water when disinfection substances react with natural organic matter and other chemicals. DBPs themselves are not added to water but they form, under specific circumstances, when certain chemicals are added to water.

What can we do about disinfection by-products in the water?

DBPs cannot be avoided as they are a part of the disinfecting process.

Water treatment professionals are trained in practices and processes that help limit the production of DBPs.

Where can I find more information?

Disinfection by-products information from the centre for Disease Control

Chlorination by-products in Canada, general information

Guidelines for Canadian Drinking Water


Alberta Environment and Parks (2017). Glossary – Regulated Drinking Water.  

Charrois, J., Graham, D., Hrudey, S. and Froese, K. (2004). Disinfection By-products in Small Alberta Community Drinking-water Supplies. Journal of Toxicology and Environmental Health, Part A, 67(20-22), pp.1797-1803.  

Hrudey, S. (2004). Chlroination Disinfection By-products (DBPs) in Drinking Water and Public Health in Canada, a primer for public health practitioners reviewing evidence from obver 30 years.  

World Health Organization (2005). Trihalomethanes in Drinking-water: background document for development of WHP guidelines for drinking-water quality.  

Government of Canada (2013). Guidelines for Canadian Drinking Water Quality: Guideline Technical Document – Trihalomethanes.  PUBLISHED: 18 DECEMBER 2017

Emerging Contaminants

Also known as contaminants of emerging concern (CECs), contaminants of concern, emerging contaminants, incidental contaminants, pharmaceuticals in the environment, pharmaceuticals and personal care products (PPCPs), endocrine disrupting compounds (EDCs), poly-aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs).

Icon showing medications representing pharmaceuticals and emerging contaminants

Because there are a wide variety of harmful contaminants that can be found in water they are grouped in various ways and referred to by many different names. Some terms are interchangeable and may cover broad categories, while other terms are more specific. 

What are harmful and emerging contaminants?

There are hundreds of thousands of industrial and other fabricated chemicals used today for many different purposes and in many products. Many of these have been released to the environment on an ongoing basis. For some of these compounds, there is conclusive evidence that they are harmful to humans and other biota. Others are suspected (but not proven) to be harmful. Some are everyday products like gasoline.

Contaminants are generally grouped into categories based on their chemical properties. These categories include petroleum hydrocarbon compounds, chlorinated solvents, and polybrominated diphenyl ethers (PBDEs). Sometimes they are grouped based according to their original purpose, such as pharmaceuticals, wood preservatives, plasticizers, and degreasers. Pesticides are also often categorized as harmful and emerging contaminants.

Pharmaceuticals and personal care products are some of the emerging contaminants receiving the most attention. Over-the-counter and prescription medication and some ingredients in toiletries, cosmetics, perfumes, cleansers, and hair products wash down the drain and are not fully removed in the wastewater treatment process. Some of the ingredients are being traced to problems in the environment.

Flame retardants are also harmful contaminants. These are used in many types of textiles (e.g., clothing, bedding, furniture, etc.) and building materials. They are important for slowing down or preventing fires, however the compounds can wash off in the laundry or be released into the atmosphere when building materials burn.   

Are harmful and emerging contaminants regulated in Alberta?

Some contaminants are regulated, but many are not. Some harmful contaminants are not yet regulated because scientific data is not yet conclusive about the concentrations at which they cause harm to humans or other organisms. In many cases, the contaminant has been released to the environment for some time but there has been no way to measure the presence or effect in the natural environment until now (thanks to new testing technologies).

Contaminants are difficult to study, and many of them have not been studied thoroughly in a laboratory for impacts on the environment. Further studies will help policy makers determine how to regulate them and what guidelines to set.

Are contaminants in my water?

Source Water

Yes, around the world, emerging contaminants are found in all surface water and some groundwater.

Simple, rapid tools for assessing concentrations and different forms of emerging contaminants do not yet exist, and resources are limited for doing research to determine how these compounds and combinations of different compounds impact aquatic life.

Tap Water

Public water treatment systems in Alberta are designed to maintain tap water at a standard that is safe to drink. It is possible that there are very low concentrations of some contaminants in your tap water, but in these cases, there is no conclusive evidence that they have any health impacts. 

What are the impacts on human health?

Part of the concern about emerging contaminants is that the impacts on human health are not clearly known. 

Pharmaceutical products pose an interesting challenge because they are designed to have an impact on human health so, when they are found in drinking water, we can assume the human body will be impacted. However, they are usually found in such small amounts in water that they do not come close to the dosage amount required for them to act. 

What are the impacts on the environment?

Some emerging contaminants have gained significant attention due to observed impacts on wildlife or the natural receiving environment.  

Synthetic estrogens from birth control pills and hormone replacement therapy drugs have been found in Alberta rivers downstream of municipal effluent.

Runoff from agricultural and cattle operations are another potential source of natural steroids and compounds that exhibit estrogen-like activity, which in extreme cases may cause unnatural proportions of male and female fish populations, and fish with multiple sex organs or that are infertile.

How do contaminants get into the water?

Contaminants mostly come from everyday products, and get washed, flushed, or discarded, and end up in soil and water. Wastewater treatment plants may not be able to remove the contaminants from the wastewater so they end up being released into the river. Some emerging contaminants are removed by ultraviolet light, some are removed in settling ponds, some can be filtered out with very fine filters, and some degrade over time.

What can we do about contaminants in the water?

Dispose of motor oil, paint, vehicle fluids, electronics, and all hazardous wastes in designated disposal areas.

Do not put extra medication or expired medication down the drain. Take them to a pharmacy for safe disposal. 

Use environmentally-friendly cleaning products.

Do not dispose cosmetics, or skin and hair products down the drain. 

Where can I find more information?

Contaminants of Emerging Concern including Pharmaceuticals and Personal Care Products – US Environmental Protection Agency

Water Quality Indicators – Hydrocarbons

Links to webpage information and technical reports – Environment and Climate Change Canada


Raghav, M., Eden, S., Mitchell, K., and Witte, B. (2013). Contaminants of Emerging Concern in Water. The Arroyo. Water Resources Research Center College of Agriculture and Life Sciences, University of Arizona.

U.S. Geological Survey (2017). Contamints of Emerging Concern in the Environment. U.S. Department of the Interior.

Sauvé, S., & Desrosiers, M. (2014). A review of what is an emerging contaminant. Chemistry Central Journal, 8(1), 15.

Herman, R. (2014, May 7). Emerging Contaminants Taint Drinking Water Supply. Scientific American.

Proctor, A. (2009). Emerging Contaminants, Assessing Pennsylvania’s Watersheds and Drinking Water Supplies. Presentation online, retrieved from

Government of Alberta (2005). Aquatic Ecosystems review of Issues and Monitoring.

Conestoga-Rovers & Associates (2014). Final Report: Drinking Water Survey for New Parameters of Interest/Concern. Alberta Environment and Sustainable Resources Development. PUBLISHED: 18 DECEMBER 2017

Heavy Metals

Also known as trace elements,and toxic metals. 

Icon showing nuts and bolts, representing metals

What are they?

Heavy metals are metallic elements and metalloids with high density relative to water and can be toxic or poisonous at low concentrations. 

Low-level exposure to heavy metals through consumption or contact can induce organ damage, and some are known or suspected human carcinogens. Certain metals, including copper and chromium, are essential for body function at certain concentrations but quickly become toxic beyond a biological threshold.  

Examples of heavy metals that can be found in water are: lead, arsenic, mercury, thallium, cadmium, and chromium. 

Are heavy metals in water regulated in Alberta?

Yes, heavy metals are regulated in Alberta in several ways. The Environmental Quality Guidelines for Alberta Surface Waters identify threshold levels of heavy metals for protection of aquatic life and for agricultural uses.  

There are provincial and federal regulations concerning the correct disposal and management of industrial wastes, electronic waste, and mine tailings because these can contribute heavy metals to the water system. Regulations for reclamation of decommissioned mine sites also relate to heavy metals as these sites can be significant sources of heavy metal contamination in groundwater and surface water over the long term.

Are heavy metals in my water?

Source Water

Heavy metals can be dissolved in water. However, in the Bow River Basin, heavy metals (if present) are found in low concentrations.

Tap Water

Water treatment generally removes metals from drinking water, but some risks can exist from old pipe networks. Read more about lead in drinking water on the page “Do you feel mis-LEAD by your water?” 

What are the impacts on human health?

Heavy metals can be highly toxic. When they are present in water at higher concentrations they can cause serious damage to human health. For example, high levels of arsenic are found in groundwater in some areas of British Columbia, China, and the United States. In Bangladesh, the amount of arsenic in the drinking water has resulted in a long-standing health crisis.

Lead is one example of a heavy metal that occurs naturally in rocks and soil, but is much more common in human-made materials. Lead is found in various products including paint, dinnerware and food items (almost all food has some traces of lead). In the past, water pipes were made with lead – and lead was also added to gasoline. We are exposed to lead every day and almost none of that exposure comes from the water we drink (drinking water quality regulations require less than 0.01 mg/litre of lead). 

In higher quantities, lead is toxic to humans. It can accumulate in the body, including in developing bones. In children, high levels of lead in drinking water leading to blood lead levels between 11 and 30 micro-grams per decalitre have resulted in slower cognitive abilities and learning, and altered behaviour. Higher lead levels in water can also cause skin disorders and hair loss.

What are the impacts on the environment?

Heavy metals can also be toxic for animals. Where there are higher concentrations of heavy metals in water, aquatic life can experience biological difficulties. In Canada there is a federal standard of thresholds for acceptable concentrations of various heavy metals, specific limits can be found in Table 1 of The Environmental Quality Guidelines for Alberta Surface Waters (Pg. 25 to 38). 

How do heavy metals get into the water?

Although heavy metals occur naturally in rocks and soil, very few enter the water system from natural sources. Human use of heavy metals, and mining and refining processes, are the main sources of heavy metals in water. 

Increased human exposure to heavy metals in water comes from activities such as mining, smelting, metal corrosion, and use of metal-containing compounds in domestic and agricultural applications. Heavy metals get into the air through various ways, and when they fall with rain or snow they frequently end up in waterways. This is a particularly common route for mercury entering the water system.  

In 2016, the U.S. City of Flint, Michigan, gained global attention due to lead entering the drinking water via lead water pipes. Lead has not been used in new Canadian water service lines since 1975, however there are lead water pipe systems in use around the world that were installed before the risks to human health were fully understood. Lead pipes can corrode when water has a certain temperature, standing time, pH and hardness. Lead dissolves most easily in water that is soft and acidic.   

What can we do about heavy metals in the water?

If you are concerned about lead in your tap water you can have it tested by a lab.

Treatment plants may use processes to remove heavy metals before the treated water is returned to the river. You can check treatment process information by taking the virtual tour of the Calgary wastewater treatment plants or by exploring the website of the Alberta Capital Region Wastewater Commission

Today the practice of adding lead to gasoline, paint, toys, and utensils has been reduced or eliminated around the world.

Although heavy metals cannot be degraded or destroyed, they can be absorbed or trapped and become less harmful to animals and people. Certain plants have been scientifically shown to remove heavy metals from water and soils. By ensuring we protect wetlands and riparian areas we can help keep heavy metal contamination out of our water systems.

Where can I find more information?

The City of Calgary Drinking Water – Lead service connections information

WHO Guidelines for Drinking Water

US Environmental Protection Agency – National Primary Drinking Water Regulations

Arsenic and Manganese in Well Water – Alberta Health Services FAQ


Ali, H., Khan, E., & Sajad, M. (2013). Phytoremediation of heavy metals—Concepts and applications. Chemosphere, 91(7), 869-881.

Tchounwou, P. B., Yedjou, C. G., Patlolla, A. K., & Sutton, D. J. (2012). Heavy Metals Toxicity and the Environment. EXS, 101, 133–164.

Solomon, F. (2008, April). Impacts of metals on aquatic ecosystems and human health. Retrieved from:

Government of Canada (1992). Canadian Drinking Water Quality: Guideline technical Document – Lead. PUBLISHED: 18 DECEMBER 2017


Also known as microbial contaminants, microbes, pathogens, water-borne illness, fecal coliforms. 

Icon showing various types of microorganisms

What are they?

Microorganisms are microscopic organisms transmitted via water from one host to another. They include: bacteria, viruses, protozoans and other parasites. Many microorganisms in water do not harm humans or animals, but there are a number that can cause serious illness. Examples of illnesses caused by microorganisms in drinking water are: Escherichia coli (E. coli), cholera, beaver fever (giardiasis), typhoid fever, swimmer’s itch and salmonella. 

Are microorganism in water regulated in Alberta?

Yes, microorganisms are monitored and regulations are in place to limit the microorganisms in source water and effluent water. Municipal water in North America is treated and tested specifically for microorganisms. Regulations limit the number of microorganisms released in effluent from wastewater treatment plants, and the concentration of microorganisms that are in wastewater or runoff water from industry and agriculture.

Are micro-organisms in my water?

Source water

Yes, there are microorganisms in surface water in Alberta. If you are recreating in and around a natural water source, or if you are hiking in the mountains, it is important to be aware that there can be microorganisms, even in clean-looking water. See our tips on what you can do about microorganisms in the water.

Tap Water

No, there should be no microorganisms in your tap water. 

A public drinking-water advisory will be in place if your water supply is not safe to drink. If you have a private well or live in an area without a water treatment plant (e.g., in an on-reserve Indigenous community or a rural private property), the tap water may need to be disinfected with chlorine, UV light, or another method to kill the microorganisms. 

Many rural residents source their drinking water from a well on their property. Water wells in Alberta are sealed and protected against microorganism contamination and the Alberta Government provides suggestions and some testing support to keep private well water safe for drinking. 

What are the impacts on human health?

Every year, people in Alberta get illnesses caused by microorganisms in the water. The health system treats around 400 people for giardiasis (an intestinal infection caused by Giardia, a protozoan parasite) and around 100 people for cryptosporidiosis (an infection caused by Cryptosporidium). In most cases the illness is not life threatening and requires standard medical treatment. See our misconceptions page on Pristine Headwaters to learn more about these organisms and ways to avoid infection.

What are the impacts on the environment?

Microorganisms are a natural part of ecosystems, and do not typically have negative impacts on the environment. Microorganisms, while unseen, are an essential element of biodiversity. They are critical for nutrient cycling, among other things. 

How do micro-organisms get into the water?

Unsafe microorganisms can enter rivers or lakes when sewage leaks from a septic system, or rain washes animal feces into the water. Also, if animals or people defecate on top of snow or ice in the winter, by springtime the snowmelt carries the faeces into the water.

Confined Feeding Operations (CFOs), especially of cattle, result in large amounts of manure with very high concentrations of microorganisms. If the manure is not managed properly, nearby waterways can become contaminated by these microorganisms as well as nutrients. 

What can we do about micro-organisms in the water?

Because microorganisms are potentially dangerous, there are many protocols already in place to keep them out of the tap water. That said you can also:

  • Keep microorganisms out of the waterways by cleaning up after dogs.
  • Ensure septic tanks and sewage lines are operating properly and are not leaking.
  • Use public restrooms or follow instructions in parks for burial of feces away from watercourses.
  • Filter or boil your water if you are collecting it from a river, stream or lake.
  • Avoid swallowing water when swimming in a lake or river, and be aware of posted warnings regarding swimmer’s itch or fecal coliforms. Alberta Health Services posts public health advisories on signs at the water site itself, online, or through other media.

Where can I find more information?

Alberta Health Services active advisories

Understanding your Drinking Water test Results

Guidelines for microorganisms in recreational water. Table 3 Pg. 46

Federal government – Guidelines for Canadian Recreational Water Quality

The City of Calgary Drinking Water

The State of the Watershed


World Health Organisation (2011) Guidelines for Drinking-water Quality, fourth edition. 

Government of Alberta (2015) Alberta Notifiable Disease Incidence: a historical record 1919–2014. 

Government of Alberta (2004). Notifiable Diseases in Alberta, 2004 annual report.

Government of Canada (2017). Guidelines for Canadian Drinking Water Quality – Summary table. 

Government of Alberta (2013) Part 3 Wastewater Systems Standards for Performance and Design of a total of 5 Parts. Microorganism limits in effluent water. Tables 3.1 and 3.2. In Standards and Guidelines for Municipal Waterworks, wastewater and Storm Drainage Systems.

Alberta Agriculture and Forestry (2017, May 3). Protecting Your Well From Contamination.$department/deptdocs.nsf/all/wwg413 

Alberta Environment and Parks (2017. March 28). Surface Water Quality Data. 

Alberta Agriculture and Forestry (2017). Benficial Management Practices: Environmental Manual for Crop Producers in Alberta – Water Quality.$department/deptdocs.nsf/all/agdex9317  PUBLISHED: 18 DECEMBER 2017

Naturally Occurring Substances in Water

Also known as materials, matter, constituents, chemicals, compounds. 

An icon demonstrating some naturally occurring substances

What naturally occurring substances are in Alberta’s water?

Naturally occurring substances in source water

Source water is water that is in its natural state, such as water in a mountain stream.  

Source water in Alberta has a variety of naturally occurring substances, including metals, minerals, nutrients, organic matter and microorganisms.  Sulfur and iron, for example, are naturally occurring in source water (they also give water a distinct colour and smell!).

In the Bow River and its tributaries, naturally occurring substances include fluoride, iron, calcium, magnesium, sulphate and bicarbonate. Also, in addition to material from rocks, Bow River water can contain naturally occurring constituents like parasites, bacteria, and viruses from animals upstream. See Microorganisms for more information.

Naturally occurring substances in water that are less common include hydrocarbons and radioactive elements. Some places in Alberta, including around the Athabasca River and Lake Athabasca, have radioactive material and crude oil in the rocks or sand, which naturally seep into water sources. 

Naturally occurring substances in tap water

Besides the water molecules themselves (i.e., hydrogen and oxygen), there are many other things in tap water. Small amounts of naturally occurring substances are not removed by treatment processes. Tap water likely contains small amounts of minerals like calcium, fluoride and magnesium, some salts, and some dissolved organic matter. 

Communities that use groundwater as a source for drinking water may find different materials in their water than communities who use river or lake water. Different minerals, metals, and substances are added depending on the type of rock or ground the water travels through.

Are naturally occurring substances in water regulated in Alberta? 

While the natural processes that lead to substances in the water cannot be regulated, human activities that cause more natural substances to be released into water are regulated for water quality protection. Additionally, surface water quality guidelines include parameters like total dissolved solids, total suspended solids, various naturally occurring metals, and turbidity. 

Do naturally occurring substances impact human health?

Source Water

In the Bow River Basin, most naturally occurring materials are not found in high enough concentrations to negatively impact human health. However, some microorganisms are potentially harmful at any concentration. Read more about these organisms and how to avoid them in our article about Pristine Headwaters and the Microorganisms Factpage.

Tap Water

Water treatment plants, water filters and disinfection systems are all used to remove harmful constituents, both natural and introduced. If you have a private water supply system (like many rural area residents, on-reserve Indigenous communities, and homes not connected to public or municipal treatment systems), there may be more naturally occurring substances in your water. To determine if the water source is safe to drink it is advisable to have a sample of the water tested at an accredited testing laboratory.

Do naturally occurring substances impact the environment?

Yes, but not in a negative way. Because they are natural, these substances are often consistently present in the water and therefore plants and animals have adapted to them. The natural chemistry of water is part of what makes an ecosystem unique and functional. For example, the Banff Mineral Hot Springs have high concentrations of naturally occurring materials including sulphur, calcium, and magnesium, and the plants and animals living around the springs are different compared to species in other areas of the Bow River headwaters. 

Natural substances in water can be important for an ecosystem to flourish. Wetland ecosystems that receive minerals and nutrients flowing from upstream have abundant vegetation, whereas wetlands that receive only rainwater (which has almost no minerals) grow very slowly and the plant species do not need many nutrients. 

How do naturally occurring substances get into the water?

As water flows over the ground and through rock, it picks up minerals, metals, bacteria, and many other materials. These substances flow in the water until they are removed by biological or physical processes. Examples include bacteria and organic matter being trapped in the sediment, and heavy metal ions being absorbed by aquatic plants. 

Many substances travel through the air. These can be natural in origin (e.g., smoke from a wildfire) or human-made (e.g., exhaust from a car). Many substances in the air end up in the water system by falling with rain or snow.

What can we do about naturally occurring substances in the water?

For more tips on how you can help water quality visit the page “What can I do”

You should not drink water directly from streams or rivers in Alberta without suitable treatment first.

Where can I find more information?

Canadian Drinking Water Guidelines Total Dissolved Solids

The City of Calgary Drinking Water – Natural Fluoride

Contaminants in Groundwater

Natural sources of contamination of private wells – US Environmental Protection: AgencyAgency 


United States Environmental Protection Agency (2013). Rivers & Streams.

City of Calgary (2017). Water quality and water hardness reports.

Joanna Skrajny (2107, Dec 1). Alberta “tackles” Fish Recovery in North-central Eastern Slopes. Alberta Wilderness Association

Alberta Environment and Parks (2017). Alberta River Water Quality Index.

Government of Nova Scotia (2017). Natural Water Contaminants.

United States Environmental Protection Agency (2016). Contaminant Candidate List (CCL) and Regulatory Determination.

Government of Canada (2017). Canadian Drinking Water Quality Guideline: Total Dissolved Solids.

Water Logic (2017). Why Does My Water Have a Bad Taste or Smell?

Government of British Columbia and the British Columbia Groundwater Association (2007). Water Stewardship Information Series: Arsenic in Groundwater. PUBLISHED: 18 DECEMBER 2017


Also known as nitrogen/nitrate/nitrite/ammonia, phosphorus/phosphate.  

Icon showing manure, a nitrogen molecule, and a sac of fertiliser

What is it?

“Nutrients” is a general term describing chemical elements and compounds (composed of several elements) that are essential to the growth and survival of living organisms. Nutrients are the core ingredient of fertilizers used in agriculture to help crops grow. Nutrients are an essential part of a healthy ecosystem, but too many nutrients can cause unwanted growth and may not be a good thing for an ecosystem. 

In the context of surface water quality, the two most important nutrients are nitrogen (N) and phosphorus (P). Because these elements occur in inorganic and organic forms, they are often expressed as total nitrogen (TN) and total phosphorus (TP) to capture all the forms that affect plant growth. Although an excess amount of either of these key nutrients can have water quality implications, phosphorus usually receives more attention because it is typically a limiting factor for growth of aquatic plants and algae. Unnaturally large inputs of phosphorus typically initiate a series of processes that often lead to problematic water quality. To learn more about the effects of algal blooms on water quality and their relationship to phosphorus, read our fact page on algae

Are nutrients in the water regulated in Alberta?

Some nutrients are regulated regarding their discharge into rivers and lakes in Alberta. Human activities, such as wastewater and sludge discharge into water, are often regulated. For example, The City of Calgary’s Total Loading Management Plan (TLMP) is a requirement of their wastewater approval from Alberta Environment and Parks’ (AEP) Environmental Protection and Enhancement Act (EPEA). The TLMP manages total loading of substances like total phosphorus as per their wastewater operating approval requirements by AEP. The Canadian federal government has Phosphorus Concentration Regulations that limit the amount of phosphorus in detergents, soaps and other cleaning products.

Canadian Drinking Water Guidelines have threshold limits for those nutrients that are dangerous in high concentrations.

The Environmental Quality Guidelines for Alberta Surface Waters has specific thresholds of several different nutrients, as does Alberta’s groundwater quality guidelines. These thresholds are designed to protect drinking water sources, aquatic life and livestock.

The Bow River Basin Phosphorus Management Plan is not a regulation, but it is a collaborative initiative among various basin stakeholders to reduce phosphorus inputs to the Bow River from non-point sources. This plan is a demonstration of the success that can be achieved through collaborative efforts to improve water quality.

Are nutrients in my water?

Source Water

There are some nutrients in source water and they help plants and animals to thrive. Natural sources of phosphorus, nitrogen, and other nutrients are rocks and soil, decomposing organic matter, and animal wastes. 

Nutrients, including nitrate, are also found in groundwater and come from natural or human sources. 

Nitrate, nitrite, ammonia and phosphate are common water testing metrics, so it is usually easy to find out which nutrients are present in a water source. Provincial government information and reports, or local lake management groups, can provide information.

Tap Water

Nutrients are present in tap water and are part of the standard water testing for drinking water. Where concentrations of nutrients are above acceptable thresholds, filters that use ion-exchange, reverse osmosis, or distillation technology can be used to remove some of the nutrients. 

Nutrients are also present in well water because the groundwater pumped from wells naturally contains nutrients from weathering of rock.  Human activity, such as fertilizer application, manure spreading, or improper maintenance of septic systems, may lead to additional nutrients entering groundwater.

What are the impacts on human health?

High concentrations of nitrate in drinking water can cause a rare but severe disease called methemoglobinemia, a potentially fatal disease in infants (also known as blue baby syndrome). If you are expecting a baby and you use well water, or are generally concerned about the level of nutrients or any constituents in your water, it is recommended to have your well water tested for nitrate and nitrite.

What are the impacts on the environment?

Because nutrients are essential for living things to grow, it is important that they are available in the environment. As they grow, aquatic plants and algae absorb nutrients. If nutrients are added to the aquatic ecosystem suddenly or in large quantities, the algae can grow very quickly and cause a bloom. Over-enrichment of any ecosystem with nutrients is called eutrophication, and in water bodies it can often lead to problematic water quality.

Algal blooms degrade water quality by decreasing dissolved oxygen. As aerobic microbes decompose dead plant material in the sediment, dissolved oxygen in the water is depleted. Oxygen depletion can cause fish kills and loss of other aquatic animal life. Algae also blocks light to aquatic plants, and sometimes releases compounds that smell or taste badly, or are even toxic. 

How do nutrients get into the water?

Nutrients in water come from natural sources like plant and animal matter, and soil, as well as from human sources including manure, fertilizers, wastewater treatment plants, septic fields, and landfills.

What can we do about nutrients in the water?

Composting your food scraps instead of putting them in a garburator or the garbage ensures that more nutrients are returned to the soil instead of ending up downstream in the water.

Participate in municipal ‘green bin’ composting programs where available. 

Follow instructions and quantities carefully when applying fertilizers on your property. 

Generally, nutrient additions should be placed as close to the growing plant as possible without damaging the crop. The greater the distance between the plant and the fertilizer, the greater the chance that it will be lost before it can be taken up.

Ensure septic tanks and septic fields are working properly and not leaking.  

Where can I find more information?

Is there Nitrate/nitrite in my Drinking Water? 

Nutrient Management Planning

Bow River Phosphorus Management Plan

Alberta Lake Management Society


Rissman, A., & Carpenter, S. (2015). Progress on Nonpoint Pollution: Barriers & Opportunities. Daedalus, 144(3), 35-47. 

Milk River Watershed Council Canada: Water Quality Monitoring  

Water Quality – Regional Aquatics Monitoring Program (RAMP)$department/deptdocs.nsf/all/sag11864  PUBLISHED: 18 DECEMBER 2017


Also known as insecticides, herbicides, fungicides, weed killer, crop protection products. 

Icon showing six different spray bottles and cans of pesticides

What are they?

Pesticides are chemicals or biological agents that deter, incapacitate, kill, or otherwise discourage pests. Pests can be plants, animals, insects and fungi. Substances that target microorganisms (including wood preservatives and laundry additives) can also be considered pesticides. Some pesticides take many years to degrade naturally and can therefore move through the environment, including into the food chain.

The Stockholm Convention on Persistent Organic Pollutants (2004) is an international agreement signed by many countries (including Canada) to restrict the use of a list of chemicals that are damaging and long lasting in the environment. Most substances on the list are pesticides. 

Are pesticides in water regulated in Alberta?

Some of them are, yes. The Environment Protection and Enhancement Act regulates pesticide use, handling and storage in Alberta. The Government of Alberta has four levels of restrictions for pesticides, with certain regulations for purchase and use. An information overview can be found here.

The Alberta Surface Water Protection Guidelines have identified threshold levels for many specific pesticides in water. There is a separate guideline for protection of aquatic life and for water used in agriculture. 

Are pesticides in my water?

Source Water

Pesticides are relatively prominent in surface water in Alberta and have been detected in the Bow River Basin. The most recent study performed by Alberta Environment and Parks found that pesticides were detected in over half of the surface water samples taken from all over Alberta. In most cases, the amount of pesticide found in the water was below the maximum allowable concentration as set out in the applicable Surface Water Quality Guidelines. The guidelines, such as those for the protection of aquatic life, irrigation, and drinking water, were exceeded in less than a third of the samples. Out of 30 sites and 406 samples on the Bow River, 192 samples contained pesticide measurements that exceeded Alberta Surface Water Quality Guidelines.

Pesticides are moderately common in groundwater. A study in the USA from 1997-2001 shows that only about 50% of groundwater wells contained one or more pesticide compound. (U.S. Geological Survey) 

Tap Water

With hundreds of pesticides in use today, and water treatment processes unable to remove all of them, there are small amounts of pesticides in tap water. 

What are the impacts on human health?

The Guidelines for Canadian Drinking Water Quality include thresholds for maximum acceptable concentrations of several pesticides. These are set because negative human health impacts have been proven to result from some pesticides. Some pesticides have an impact on neurological function or development, and the functioning of certain organs.

What are the impacts on the environment?

Pesticides can be toxic to birds, fish, beneficial insects and non-target plants. Insecticides are generally the most acutely toxic class of pesticides, but herbicides can also pose risks to non-target organisms. Overuse of pesticides affects soil organisms (similar to how the overuse of antibiotics affects humans). Indiscriminate use of pesticides might be effective for a few years, but over time, there are a reduced number of beneficial soil organisms (those that hold onto the nutrients).

How do pesticides get into the water?

Pesticides are applied to crops, gardens, homes, and other situations where certain weeds, fungi, animals, or insects are considered a problem. Pesticides are often sprayed onto the crops from the air, which means particles can be blown by wind and deposited on surface water. 

After being applied, pesticides can also be carried by rain into irrigation ditches, streams and rivers. For households, pesticides used in gardens and parks can also be carried by rainwater into the storm drain system.  

What can we do about pesticides in the water?

Use alternatives to pesticides in your garden and home.

Encourage local school and municipal landscapers to reduce or eliminate pesticide use.

Choose food items that have been grown where pesticide use is well regulated, or choose foods that were grown without the use of pesticides.

Speak with members of your community and local government about changing land management practices to safeguard local water supplies.

Where can I find more information?

Pesticides in Alberta’s Agricultural Watersheds

National Pesticide Telecommunications Network Factsheet

Canadian Drinking Water Quality Guidelines:


Rissman, A., & Carpenter, S. (2015). Progress on Nonpoint Pollution: Barriers & Opportunities. Daedalus, 144(3), 35-47.

Alberta Environment and Parks (2017). Surface Water Quality Program 

Byrtus, G., Pongar, K., Browning, C., Burland, R., McGuinness, E., & Humphries, D. (2004). A Summary of Pesticide Residue Data from the Alberta Treated Water Survey, 1995-2003. Alberta Environment.

Anderson, A. (1995). Overview Of Pesticide Data In Alberta Surface Waters Since 1995. Alberta Environment.

Knauer, K. (2016). Pesticides in surface waters: a comparison with regulatory acceptable concentrations (RACs) determined in the authorization process and consideration for regulation. Environmental Sciences Europe, 28(1), 13. 

Phelan, C. and Lorenz, K. (2012). Pesticides in Alberta’s Agricultural Watersheds, Irrigation and farm Water Division.$Department/deptdocs.nsf/all/irr14259/$FILE/pestinabagwatersheds_factsheet.pdf 

U.S. Geological Survey (2006). Pesticides in the Nations Streams and Groundwater, 1992-2001 – A Summary. U.S. Department of the Interior. 

Aktar, M. W., Sengupta, D., & Chowdhury, A. (2009). Impact of pesticides use in agriculture: their benefits and hazards. Interdisciplinary Toxicology, 2(1), 1–12.