|
|
 |
|
 |
 |
|
|
|
|
|
|
|
| Air |
|
|
Land |
|
|
Water |
|
|
Climate Change |
|
|
Waste |
|
|
About Us |
|
|
 Quick Links
|
Advisories
|
Online Reporting
|
| Last Review/Updated: September 4, 2002 |
|
NRBS - HomeTable of Contents |
Northern River Basins Study Final Report
3.0 Major Findings
|
|||||||
| Related NRBS Question: | |
|---|---|
| 8. |
Recognizing that people drink water and eat fish from these
River systems, what is the current concentration of contaminants in water
and edible fish tissue and how are these levels changing through time and
by location?
|
| 9. | Are fish tainted in these waters, and if so, what is the source of the tainting compounds (i.e., compounds affecting how fish and water taste and smell to humans)? |
| Table 3.10.1 | Guidelines for Canadian Drinking Water Quality: Selected Parameters |
Good quality drinking water is essential to life. But what are the characteristics that comprise good water quality? Most would agree that public health is the primary consideration in drinking water quality. In the northern River basins, these concerns are related to levels of chemical and microbial contaminants that stem from a variety of natural and non-natural sources. Based on an average water consumption of 1.5 L a day, a 75 year-old person will have consumed over 40,000 L of water in his or her lifetime. Evidently, water can be an important vehicle for contaminants to enter the body and can significantly impact public health.
Public perception is also a factor in water quality. Aesthetic considerations, such as taste, odour, and appearance are influenced by the substances in water and strongly affect our view of water quality and health. They may also be the first indications of a health hazard. As such, aesthetic considerations must also be considered in any evaluation of water quality.
In Canada, the federal Guidelines for Canadian Drinking Water Quality (GCDWQ) are the basis for evaluating the safety of drinking water. In most Canadian provinces and territories, the guidelines serve as recommendations, but in Alberta they are enforced under provincial legislation. The guidelines define minimum quality standards, based on an acceptable level of risk to the population at large. What constitutes an acceptable health risk is a judgement that weighs societal costs against the relative benefit to public health. One could move beyond the GCDWQ to legislate the elimination of all detectable contaminants, but the additional benefits to public health may be negligible. This does not mean, however, that we should not constantly strive for better water quality.
The GCDWQ outline three different water quality standards. Maximum acceptable concentrations (MACs) are set for those substances that pose a known or suspected health threat. MACs represent the concentrations of constituents that will not result in a significant risk to consumer health over a lifetime of consumption. Interim maximum acceptable concentrations (IMACs) are set for those substances that are assumed to have an adverse effect on health, but for which there is insufficient information to form a reliable MAC. Aesthetic objectives (AOs) are given to substances or conditions that contribute to the consumers' perceptions of drinking water quality but do not constitute a health threat. The guidelines are frequently revised in light of new scientific knowledge. Table 3.10.1 describes a few substances or conditions that appear in the GCDWQ that may be of concern to northern residents.
Ordinarily, the guidelines would be used to assess the quality of drinking water that has been processed by a treatment facility, assuming that a great majority of residents receive treated water. This is not necessarily the case in the northern River basins, where many residents (especially those in remote areas) rely on natural water bodies for their water supply. Using information from new studies, historic databases and literature, the NRBS Drinking Water Component has compiled a picture of the use and quality of both treated and untreated drinking water in the Alberta portion of the Study area.
| Figure 3.10.1 | Population Served by Conventional Drinking Water Treatment Plants |
Conventional drinking water refers to a community water supply that is obtained from a drinking water treatment facility. According to statistics from Alberta Environmental Protection, there are currently 180 such facilities operating in the Peace and Athabasca basins, supplying water to 55 - 75 per cent of basin residents (Figure 3.10.1). Of these facilities, 105 rely upon surface water sources, while 75 draw upon groundwater supplies.
The remaining basin residents obtain water from non-conventional sources that may require treatment by individual consumers prior to consumption. The NRBS household survey reveals that the most common sources of non-conventional water are (in order of importance), wells, dugouts, bottled water, river water, lake water and spring water. Other minor sources include rain, snow, ice, muskeg water and water that is tapped from birch trees. Non-conventional drinking water use is more prevalent among those that "live off the land" and is most common in remote northern areas where treatment facilities are often unavailable.
Did You Know:
Results from the Traditional Knowledge Component reveal that 95 per cent of those that "live off the land" rely on non-conventional water sources.
According to the NRBS household survey, many northern residents are not content with the quality of their drinking water. Thirty-one per cent of surveyed conventional water users report a problem with their drinking water. These concerns are predominantly attributed to high levels of chlorine or a general bad taste or smell (see Figure 3.3.2 in Section 3.3). Several individuals interviewed by the Drinking Water Component associate a health risk with the consumption of chlorinated drinking water. The reported health effects included "vein-clogging", allergic reactions, onset of cancer and general gastrointestinal illnesses.
Approximately 28 per cent of non-conventional water users report quality problems. Bad tastes or odours are a common concern, but other problems are directly related to the raw water source. Dugout users, for instance, reported problems with algae or bacteria, while groundwater wells were often high in minerals. Surprisingly, a large proportion of those that use river water report a perceived taste or odour problem with chlorine.
| Figure 3.10.2 | Frequency of Coliform Positive Samples in the NRBS Area (1988-1994) |
| Table 3.10.2 | Percentage of Samples Exceeding Trihalomethanes Guideline 00.1 mg/L |
Generally speaking, conventional drinking water within the northern river basins is of good quality. The majority of basin residents receiving conventional drinking water are served by larger facilities that produce high quality water. However, NRBS studies reveal that high quality drinking water may be a challenge for some smaller facilities within the Study area.
Historical records from 1988-1994 reveal that smaller treatment facilities in the Study area have difficulty meeting microbial standards for drinking water. All of the facilities that exceeded GCDWQ guidelines were smaller facilities serving populations less than 500 (Figure 3.10.2). Of the smallest sites (watering points serving less than 150 people) approximately 30 per cent have difficulty meeting GCDWQ standards for coliform bacteria. This proportion swells to 45 per cent if "poor" samples (those eliminated because the coliforms were too numerous to count) are included. A few of the communities in question may have been exposed to excessive microbial contaminants for seven years in a row.
Smaller communities also tend to have higher turbidity levels in their conventional water supplies, and several sites may have difficulty in meeting GCDWQ guidelines for turbidity. Turbidity does not necessarily constitute a health threat, but it can indicate the effectiveness of the treatment process in filtering out harmful chemicals and disease-causing bacteria. The combination of high turbidity and poor microbiological performance indicates a potential health risk to small northern communities. The NRBS Study Board has notified Alberta authorities of this problem.
A few facilities exceeded GCDWQ guidelines for chemical contaminants. Most of the poor samples from these facilities exceeded aesthetic objectives for particular parameters (1,2 dichlorobenzene, iron, sodium and total dissolved solids), but in these cases the contaminants were more of a nuisance than a health threat. A small number of surface water facilities, however, exceeded the maximum acceptable concentration for trihalomethanes—a by-product of chlorine disinfection that has been linked to cancer. Three sites exceeded the older GCDWQ guideline for trihalomethanes (0.35 mg/L) that was in effect when the samples were collected. If trihalomethane levels remain unchanged, a significant proportion of the surface water facilities included in this study will likely exceed the more stringent 1993 guideline of 0.1 mg/L (Table 3.10.2).
Generally speaking, smaller facilities serving populations less than 500 and relying on surface water sources have greater difficulty in meeting water quality guidelines. Visits to several small treatment plants reveal that these difficulties may be related to financial and operational difficulties. Small facilities generally have fewer employees. This translates into greater responsibilities for individual operators and less time allotted for separate tasks. The training incentives and opportunities for small facility operators are also fewer than in large facilities where employees receive advanced training for their specific duty. This situation is by no means unique to the Study area. Across the province of Alberta, small treatment facilities are a continual challenge in terms of available finances and technical expertise. In contrast to these findings, an overwhelming majority (96 per cent) of operators responding to the NRBS survey believe that their facilities produce water that meets drinking water standards.
With regard to microbial contaminants, untreated surface water within the Study area is generally undrinkable. All surface water samples from the Study area exceeded microbial guidelines. As a consequence, drinking untreated water could pose a serious health risk to consumers.
The same holds true for surface waters that may be considered safe by virtue of their remoteness from human activities. Many microorganisms, such as Giardia (the group of bacteria responsible for "beaver fever"), are carried by animals and can infect drinking water despite the absence of human contamination. Snow, for example, is often contaminated by animal feces. Fresh rain water contains very low contaminant levels but can become contaminated with bacteria if collected or stored improperly. Dugout and muskeg waters are also susceptible to bacterial contamination.
Manganese was also found to be a problem in several surface water sources in the Study area, particularly those from the Wapiti / Smoky River system. There are no health risks associated with manganese, but it produces a strong taste and odour that consumers often find objectionable.
In contrast to surface waters, groundwater within the Study area is generally of good quality. Protected aquifers are usually free from pathogenic microorganisms and many wells may achieve acceptable water quality without any treatment. However, groundwater is susceptible to contaminants in the soil as well as any substances dropped into the mouth of a well. As a result, care should be taken in the choice and maintenance of groundwater wells.
There are a number of chemical and mechanical methods to disinfect or remove contaminants from drinking water, ranging from simple techniques (e.g., boiling or chlorinating) to highly complex mechanical systems (e.g., ultra-violet disinfection or reverse osmosis). Among basin households that rely on non-conventional water sources, only 34 per cent report using some form of treatment. The most common methods are filtering, distilling, boiling and chlorinating. Ultimately, the choice of treatment is up to the individual and depends upon the particular problems associated with the raw water source. A few points for consideration are given below.
Heat remains one of the oldest and most effective methods for eliminating unwanted microorganisms, although there is some dispute over the required boiling time to ensure disinfection. Chlorine is also an effective disinfectant, but many residents have expressed concern regarding its taste and perceived effects on health. A number of individuals interviewed by the Drinking Water Component had access to chlorinated water from a treatment plant, but refused to use it for these reasons.
A number of portable drinking water filters designed for wilderness use are available through camping stores. Basin residents are cautioned that the effectiveness of these devices is not guaranteed. None of the commercially available drinking water filters analyzed in NRBS studies could meet manufacturers' claims as to their abilities. Only one unit could achieve GCDWQ turbidity guidelines and efficiently remove particles as small as Giardia cysts.
Basin residents should also exercise caution in their choice of bottled waters. NRBS studies revealed that most bottled waters are of good quality, but a few contain higher than average levels of bacteria, organic contaminants (e.g., chloroform) and minerals (e.g., sodium, arsenic and fluoride).
Guidelines are useful as a ruler to measure water quality, but it is also important to understand the relative risk of individual contaminants so as to better focus treatment efforts.
Microbial contaminants pose by far the greatest health risk to northern residents. A large reservoir of disease-causing microbes occurs throughout northern waters and while treatment may eliminate the immediate health hazard, it cannot eradicate the source of the problem. Moreover, NRBS studies suggest that several water treatment facilities may not be effective in removing disease-causing microbes from drinking water.
However, northern residents are far more concerned about health risks arising from chemical contaminants, particularly those related to chlorine and its by-products. Chemical contaminants are much more difficult to link to disease because an individual can be exposed for months or years before symptoms can be observed. Within the northern river basins, trihalomethanes (a group of chlorine by-products) may be the largest health risk related to chemical contaminants. The chance of contracting cancer from trihalomethanes is extremely small in comparison to catching a bacterial disease associated with inadequate disinfection, but the health consequences are much more serious. Consequently, both of these issues require attention.
| Figure 3.10.3 | Cases of Giardiasis in the NRBS Area |
It is difficult to ascertain whether residents suffer a greater risk from waterborne disease than people elsewhere. Health records reveal a slightly higher incidence of giardiasis (Figure 3.10.3), salmonellosis and shigellosis in the Study area in comparison to the provincial average, but the difference is not great enough to indicate a substantially higher risk of waterborne disease. Furthermore, it is impossible to ascertain from health records whether the disease was contracted from drinking water or some other means.
Another difficulty arises from the methods for measuring microbial water quality. Traditionally, routine monitoring efforts have relied on specific organisms (e.g., coliform bacteria) to indicate the presence of disease-causing microorganisms. These indicators have served us well in the past, as shown by the dramatic decline in outbreaks of typhoid fever and cholera. Yet the absence of these indicators does not mean that water is free of disease-causing bacteria. Giardia, for instance, is fairly resistant to disinfection and may pose a health risk even when coliform bacteria are not detected. As it is both technically and financially impossible to monitor each of the thousands of microorganisms in nature, authorities such as the U.S. Environmental Protection Agency now rely on turbidity as a better measure of microbial water quality.
At the beginning of the Study, bad tastes and odours were reported in fish and water from the Athabasca River downstream of the pulp mill in Hinton. Early studies confirmed that these problems persisted downstream as far as Fort McMurray and consumers feared that the new AlPac pulp mill, once on-line, would cause the situation to worsen.
Recent studies reveal that new technologies greatly reduce bad odours associated with pulp mill effluent. Odour problems downstream of the Hinton mill were significantly reduced following environmental upgrades that included full chloride substitution. Effluent from AlPac and other pulp mills in the basin had a characteristic odour, but the effect on the smell of the river was negligible. Suncor effluent had a strong hydrocarbon smell, but its impact on the Athabasca River could not be distinguished from that arising from natural sources.
Less is known on the topic of fish tainting. A wealth of anecdotal information suggests that fish are tainted immediately downstream of pulp mills and in the oil sands region near Fort McMurray on the Athabasca River. To date, science has not been able to identify the specific compounds that cause these problems.
| Figure 3.10.4 | Spill Response Model for the Athabasca River: Simulated Output |
During the course of the Study, public consultations revealed the need for a system that would assist communities along the Athabasca River to respond to potentially hazardous contaminant spills in a timely and effective manner. In response, researchers developed a Spill Response Model for the Athabasca River.
The Spill Response Model is an easy-to-use computer program that can be employed by local authorities to estimate the arrival time of a contaminant spill at a water intake, the time it will take the spill to pass, the peak concentration of the contaminant and a list of downstream community contacts (Figure 3.10.4). This information will empower communities to develop plans that mitigate the immediate impacts of a contaminant spill. The program runs on almost any personal computer.
NRBS Synthesis Reports
Armstrong, T.F., Prince, D.S., Stanley, S.J. and D.W. Smith. 1995. Assessment of Drinking Water Quality in the Northern River Basins Study Area. Northern River Basins Study Synthesis Report No. 9.
NRBS Technical ReportsAitken, B. 1996. Spill Response Model. Northern River Basins Study Technical Report No. 126.
Armstrong, T.F., Stanley, S.J. and D.W. Smith. 1995. Assessment of Non-Conventional Drinking Water in the Northern River Basins. Northern River Basins Study Technical Report No. 116.
Emde, K.M.E., Smith, D.W. and S.J. Stanley. 1994. An Analysis of Alberta Health Records for the Occurrence of Waterborne Disease for the Northern River Basins Study. Northern River Basins Study Technical Report No. 54.
Kenefick, S.L., Brownlee, B., Hrudey, E., Gammie, L. and S.E. Hrudey. 1994. Water Odour, Athabasca River, February and March 1993. Northern River Basins Study Technical Report No. 42.
Kenefick, S.L., Brownlee, B., Hrudey, S.E., MacInnis, G. and S.E. Hrudey. 1996. Water Taste and Odour, Athabasca River, 1994 (Post AlPac). Northern River Basins Study Technical Report No. 114.
Kenefick, S.L. and S.E. Hrudey. 1995. A Review and Annotated Bibliography of Water and Fish Tainting in the Peace, Athabasca and Slave River Basins. Northern River Basins Study Project Report No. 52.
Kenefick, S.L. and S.E. Hrudey. 1994. A Review and Annotated Bibliography of Water and Fish Tainting in the Peace, Athabasca and Slave River Basins. Northern River Basins Study Project Report No. 52.
Liem, E., Smith, D.W. and S.J. Stanley. 1995. Inorganic Contaminants Removals - A Literature Review. Northern River Basins Study Technical Report No. 88.
Oke, N.J., Smith, D.W. and S.J. Stanley. 1995. Literature Review on the Removal of Organic Chemicals from Drinking Water. Northern River Basins Study Technical Report No. 87.
Prince, D.S., Smith, D.W. and S.J. Stanley. 1994. A Review and Analysis of Existing Alberta Data on Drinking Water Quality and Treatment Facilities for the Northern River Basins Study. Northern River Basins Study Project Report No. 55.
Prince, D.S., Smith, D.W. and S.J. Stanley. 1995. Independent Assessment of Drinking Water Quality in the Northern River Basins. Northern River Basins Study Project Report No. 115.
Stanley, S. et al. 1996. Critical Review of Bacterial Treatment Efficiencies. Northern River Basins Study Technical Report No. 139.
Other Relevant DocumentsAitken, B. 1995. User's Manual for NRBS Spill Response Model. Environment Canada. 15 pp.
Alberta Environmental Protection. 1988. Standards and Guidelines for Municipal Water Supply, Wastewater and Storm Drainage Facilities. Standards and Approvals Division, Edmonton, Alberta.
Federal-Provincial Subcommittee on Drinking Water of the Federal-Provincial Advisory Committee on Environmental and Occupational Health. 1993. Guidelines for Canadian Drinking Water Quality. 5th ed. Ottawa, Ontario. 24 pp.
World Health Organization. 1993. Guidelines for Drinking Water Quality. Volume 1: Recommendations. 2nd ed. Geneva. 188 pp.
|
...PREVIOUS |
NEXT... |
| Environment
Home | Search
| Contact
Us | Privacy
Statement |
Minister's Office Expenses Emergency Numbers The user agrees to the terms and conditions set out in the Copyright and Disclaimer statement. © 2009 Government of Alberta |
|
|