Water Security Agency - CONFIDENTIAL REPORT and Comparison...CONFIDENTIAL REPORT Review and...

CONFIDENTIAL REPORT

Review and Comparison of Regional Groundwater Quality Data in

Saskatchewan

by

H. Maathuis

Environment Branch

SRC Publication No. 10417-4C00

October 2000

CONFIDENTIAL REPORT

Review and Comparison of Regional Groundwater Quality Data in

Saskatchewan

by

H. Maathuis

Environment Branch

Saskatchewan Research Council SRC Publication No. 10417-4C0015 Innovation Blvd.Saskatoon, SK S7N 2X8Tel: 306-933-5400Fax: 306-933-7299 October 2000

Review and Comparison of Regional Groundwater Quality Data in Saskatchewan

SRC Publication No. 10417-4C00 page i

TABLE OF CONTENTS

page

LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

LIST OF FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2. OBJECTIVES AND LIMITATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

3. WATER QUALITY GUIDELINES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

4. GROUNDWATER QUALITY DATABASES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5. GROUNDWATER QUALITY DISTRIBUTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75.1 Aesthetic Groundwater Quality Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75.2 Dissolved Organic Carbon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115.3 Health Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

5.3.1 Nitrate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125.3.2 Arsenic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135.3.3 Selenium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145.3.4 Total and Faecal Coliforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

6. CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

7. REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17


SRC Publication No. 10417-4C00 page ii

LIST OF TABLES

Table 1 Selected Saskatchewan municipal drinking water quality objectives . . . . . . . . . 2Table 2 Selected guidelines for Canadian drinking water quality (Canada Health, 1996)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Table 3 Bacteriological guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Table 4 Saskatchewan chemical water quality guidelines for private water supplies

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Table 5 Digital groundwater databases used in study . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Table 6 Total number of wells and number of wells with water exceeding the Saskatchewan

drinking water quality objectives for sulfate . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Table 7 Total number of wells and number of wells with water exceeding the Saskatchewan

drinking water quality objectives for sodium . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Table 8 Total number of wells and number of wells with water exceeding the Saskatchewan

drinking water quality objectives for chloride . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Table 9 Total number of wells and number of wells with water exceeding the Saskatchewan

drinking water quality objectives for total hardness . . . . . . . . . . . . . . . . . . . . . . 9Table 10 Total number of wells and number of wells with water exceeding the Saskatchewan

drinking water quality objectives for iron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Table 11 Total number of wells and number of wells with water exceeding the Saskatchewan

drinking water quality objectives for manganese . . . . . . . . . . . . . . . . . . . . . . . . 10Table 12 Total number of wells and number of wells with water exceeding the Saskatchewan

drinking water quality objectives for total dissolved solids . . . . . . . . . . . . . . . . 10Table 13 Comparison of percentages of wells which exceed Saskatchewan aesthetic water

quality objectives for Saskatchewan, RWQAP and Alberta (CASE) groundwaterquality surveys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Table 14 Total number of wells and number of wells with water exceeding a dissolved organic carbon concentration greater than 5 mg/L . . . . . . . . . . . . . . . . . . . . . . . 12

Table 15 Total number of wells and number of wells with water exceeding the Saskatchewandrinking water quality objectives for nitrates . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Table 16 Total number of wells and number of wells with water exceeding the Saskatchewandrinking water quality objectives for arsenic . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Table 17 Total number of wells and number of wells with water exceeding the Saskatchewan drinking water quality objectives for selenium . . . . . . . . . . . . . . . . . . . . . . . . . 14

Table 18 Total number of wells and number of wells with water exceeding the Saskatchewandrinking water quality objectives for total coliforms . . . . . . . . . . . . . . . . . . . . . 15

Table 19 Total number of wells and number of wells with water exceeding the Saskatchewandrinking water quality objectives for faecal coliforms . . . . . . . . . . . . . . . . . . . . 15


SRC Publication No. 10417-4C00 page iii

LIST OF FIGURES

Figure 1 Locations of wells sampled in SaskatchewanFigure 2 Locations of wells sampled in AlbertaFigure 3 Histogram of well depths for the RWQAP, SRC and Rutherford groundwater quality

databasesFigure 4 Histogram of well depths for the Rosetown/ADDD, Estevan and Lanigan

groundwater quality databasesFigure 5 Histogram of well depths for the CAESA groundwater quality databaseFigure 6 Well depth versus sulfate concentration for RWQAP and other Saskatchewan

groundwater quality databasesFigure 7 Well depth versus sodium concentration for RWQAP and other Saskatchewan

groundwater quality databasesFigure 8 Well depth versus chloride concentration for RWQAP and other Saskatchewan

groundwater quality databasesFigure 9 Well depth versus total hardness for RWQAP and other Saskatchewan groundwater

quality databasesFigure 10 Well depth versus iron concentration for RWQAP and other Saskatchewan

groundwater quality databasesFigure 11 Well depth versus manganese concentration for RWQAP and other Saskatchewan

groundwater quality databasesFigure 12 Well depth versus total dissolved solids for RWQAP and other Saskatchewan

groundwater quality databasesFigure 13 Well depth versus DOC concentration for RWQAP and Rosetown/ADDD

groundwater quality databasesFigure 14 Well depth versus nitrate concentration for RWQAP and other Saskatchewan

groundwater quality databases


SRC Publication No. 10417-4C00 page 1

1. INTRODUCTION

Since 1993, SaskWater continues to operate a program referred to as the Rural Water QualityAdvisory Program (RWQAP). The RWQAP is a voluntary program in which rural residents contactSaskWater if they want to have the quality of the water from their well tested. The samples are takenby SaskWater staff and the water is analysed for major ions, nutrients, bacteria and a suite of metals.To date, water from over 738 wells has been collected and analysed, including 63 wells from whichwater was sampled as part of a 1996 pilot project. A review of the water quality data from 535 wellswas conducted by Sketchell and Shaheen (1999). The review indicated that in water from 99.6% ofthe wells one or more provincial municipal drinking water quality objectives was exceeded.Concentrations of nitrates, total coliform bacteria, selenium and arsenic were found to exceed theobjectives in a significant number of wells.

The Saskatchewan Research Council was requested to review and compare the results of the datacollected under the Rural Water Quality Advisory Program with other groundwater quality surveysin Saskatchewan and beyond.

2. OBJECTIVES AND LIMITATIONS

The objective of the study is:

– to review the results of the Rural Water Quality Advisory Program and to compare theresults with findings of other studies within Saskatchewan and other jurisdictions

Both within Saskatchewan and elsewhere there are a large number of groundwater quality databaseswhich could have been used in the present study. However, due time constraints only selecteddatabases could be used in the present study (see section 4). A detailed review of the spatial andvertical distribution of the water quality data from the various surveys was beyond the scope of thecurrent study. Any review and comparison of water quality data would ideally be conducted on anaquifer basis and also include considerations as the geochemical evolution and land use practices.

3. WATER QUALITY GUIDELINES

Water quality objectives are divided into two main groups: those related to health and those relatedto aesthetics. Maximum Acceptable Concentrations (MACs) have been established for chemicalconstituents know or suspected to cause adverse effects on health. Interim Maximum AcceptableConcentrations (IMACs) are used for those constituents for which there are insufficient toxicologicaldata to derive a MAC. Aesthetic objectives (AOs) are for constituents or characteristics that canaffect acceptance by consumers or interfere with practices for supplying good quality water.

The Saskatchewan objectives for municipal drinking water quality (Table 1) are derived from theCanadian standards for public and private water supplies (Table 2). There are only minor differencesbetween the Saskatchewan objectives and the Canadian guidelines. The Saskatchewan objectivesfor total dissolved solids and sodium are higher than the Canadian guidelines. Saskatchewan also



continues to have objectives for alkalinity, hardness and magnesium. The objectives forbacteriological characteristics are similar (Table 3)

In the present study, the groundwater quality data are being compared to the Saskatchewan municipalobjectives. However, it is noted that Saskatchewan also has guidelines for private water supplies(Table 4).

Table 1 Selected Saskatchewan municipal drinking water quality objectives

Constituent MACmg/L

IMACmg/L

AOmg/L

Alkalinity, mg/L as CaCO3 500

Hardness, mg/L as CaCO3 800

Total dissolved solids, as mg/L 1500

pH, units 6.5 - 9.0

Magnesium, as mg/L 200

Sodium, as mg/L 300

Sulfate, as mg/L 500

Sulfide, mg/L as H2S 0.05

Chloride, as mg/L 250

Nitrate, mg/L as NO3

Fluoride, as mg/L 1.5

Manganese, as mg/L 0.05

Iron, as mg/L 0.3

Arsenic, as mg/L 0.025

Barium, as mg/L 1.0

Boron, as mg/L 5.0

Cadmium, as mg/L 0.005

Chromium, as mg/L 0.05

Copper, as mg/L 1.0

Lead, as mg/L 0.01

Selenium, as mg/L 0.01

Zinc, as mg/L 5.00

Uranium, as mg/L 0.1



Table 2 Selected guidelines for Canadian drinking water quality (Canada Health, 1996)

Constituent MACmg/L

IMACmg/L

AOmg/L

Alkalinity, mg/L as CaCO3 not mentioned as a parameter in the guidelines

Hardness, mg/L as CaCO3 parameter identified as not requiring a numerical guideline

Total dissolved solids, as mg/L

pH, units 6.5 - 8.5

Magnesium, as mg/L parameter identified as not requiring a numerical guideline

Sodium, as mg/L � 200

Sulfate, as mg/L � 500

Sulfide, mg/L as H2S � 0.05

Chloride, as mg/L � 250

Nitrate, mg/L as NO3 45

Fluoride, as mg/L 1.5

Manganese, as mg/L � 0.05

Iron, as mg/L � 0.3

Arsenic, as mg/L 0.025

Barium, as mg/L 1.0

Boron, as mg/L 5

Cadmium, as mg/L 0.005

Chromium, as mg/L 0.05

Copper, as mg/L � 1.0

Lead, as mg/L 0.010

Selenium, as mg/L 0.01

Zinc, as mg/L � 5.0

Uranium, as mg/L 0.1



Table 3 Bacteriological guidelines

Bacteria Saskatchewan Canada

Total coliforms no organism per 100 ml of sample no organism per 100 ml of sample

Faecal coliform no organism per 100 ml of sample none to be present

Background bacteria not more than 200 colonies per 100ml of sample

not more than 200 colonies on acoliform membrane filter

Heterotrophic bacteria not more than 50,000 plate countsper 100 ml of sample

not more than 500 plate counts perml of sample

Table 4 Saskatchewan chemical water quality guidelines for private water supplies

Constituent SatisfactoryQuality

PoorQuality

NotRecommended

forConsumption

Unsuitable for Use

Total dissolved solids, mg/L 100 - 1500 1500 - 3000 3000 -4000 over 4000

Total hardness, mg/l as CaCO3 50 - 500 500 - 1000 1000 - 2000 over 2000

Total alkalinity, mg/l as CaCO3 50 - 500 500 - 1000 1000 - 1500 over 1500

Chloride, mg/L up to 250 250 - 500 500 - 1000 over 1000

Sodium, as mg/L up to 300 300 - 500 500 -1000 over 1000

Sulfate, as mg/L up to 400 400 - 800 800 - 1200 over 1200

Nitrate (NO3), mg/L up to 40 40 - 300

Iron up to 0.3 0.3 - 1.0

Manganese, as mg/L up to 0.05 0.05 - 0.5

pH, units 7.0 - 9.5 6 - 7 and 9.5 - 10

less than 5.5more than 10.5

Source: Saskatchewan Environment, 1977



4. GROUNDWATER QUALITY DATABASES

There are a large number of groundwater databases within Saskatchewan, adjacent provinces, andelsewhere, which contain information relevant to the objectives of the present study. However, timeconstraints prevented incorporating all available information. Regarding Saskatchewan, for example,the groundwater quality database maintained by Saskatchewan Environment and ResourcesManagement (SERM), was not included in the present study. The main reason for this was the timeconstraint, but the SERM database also contains little information regarding the quality of the waterfrom rural domestic wells. The digital databases used are listed in Table 5.

Table 5 Digital groundwater databases used in study

Area Database Period

Number ofwells withchemicalanalyses

Range ofwell depths

(m)

Saskatchewan SaskWater Rural Water Quality Program(RWQAP) and Pilot survey

1996 - 2000 7383851 4 - 424

Saskatchewan Research Council (SRC) 1962 - 1986 2297 1.5 - 562

Rutherford (1967) 1963 - 1964 1971 1.8 - 350

Rosetown (72-O) and AgriculturalDevelopment and DiversificationDistricts (ADDD)

1995 - 1996 258 3.4 - 18.3

Estevan 1981 - 1993 458 1.8 - 177

Lanigan area 2000 34 4 - 121

Alberta CAESA farmstead water quality survey 1995 -1996 733 0.3 - 284Note 1: only for 385 of the 738 sample site the well depth was readily available

The locations of the wells for the surveys done in Saskatchewan are shown in Figure 1 and for theAlberta survey in Figure 2. Figure 1 shows that the RWQAP well sites have a similar coverage ofsouthern Saskatchewan as the combined other Saskatchewan groundwater quality databases. Thecoverage of the latter databases are considered to provide a good representation of the water qualityin rural wells.

The distributions of the depths of the wells for the surveys listed in Table 5 are shown in Figures 3,4 and 5, respectively. These figures show that a relative large percentage of the wells sampled areless than 30.5 m (100 ft) deep. The percentage varies from 100% for the Rosetown/ADDD survey,to 64% and 68% for the Rutherford and Lanigan surveys, about 38% for the Estevan and SRCinventories and 52% for the RWQAP. The variability reflects both the hydrogeological setting ofSaskatchewan, the size of the area covered by the inventories and the purpose of the survey.

Data from the RWQAP were combined with the data presented by Shaheen and Sketchell (1998).Since the RWQAP is a voluntary program, there is no control on the spatial distribution of the



sample locations nor on the type and depth of well sampled. Water is analysed for major ions,nutrients, DOC, trace metals and total and faecal coliforms.

The Saskatchewan Research Council (SRC) started collecting groundwater samples for chemicalanalyses in the mid 1960s. This program was initiated to obtain information on the quality ofgroundwater in aquifers in Saskatchewan. Water was taken from wells in part randomly and in partconcentrated in areas of SRC projects. The total number of chemical analyses done is estimated tobe over 5,000 but the readily available digital database only includes data for the period 1963 - 1986.For the purpose of this report, surface water and repeat analyses, and analyses without well depthinformation were eliminated from the original digital database. Typically, samples were analysed formajor ions. The concentrations of F, NO3, PO4, Fe and Mn were analysed for most of the samplescollected.

In 1964 and 1965, the Saskatchewan Research Council conducted a regional groundwater qualitysurvey throughout southern Saskatchewan (Rutherford, 1967). The province was subdivided intoareas of 3 by 3 townships and samples for chemical analyses where obtained in the middle of thisarea. Samples were analysed for major ions. Determination of the nitrate concentration was onlydone if the error in the ionic balance was not within ±3%. The iron concentration was also notsystematically determined and manganese was not determined at all. The Rutherford databasecontains chemical analyses for 2,848 wells but includes the data for the surveys of the GeologicalSurvey of Canada. The latter data were eliminated from the database.

As part of the Canada - Saskatchewan Agricultural Greenplan agreement, Clifton Associatesconducted a survey of shallow wells in the Rosetown (72O) mapsheet area (Clifton Associates,1996), and in several Agricultural Development and Diversification Board Districts throughoutsouthern Saskatchewan (Clifton Associates 1997a,b,c,d,e,f,g,h,i,l,k,l,m). Well selection criteriaincluded that the well had to be completed in a shallow unconfined aquifer and that it was locatedin a crop production area. Samples were analysed for major ions, DOC and selected pesticides.

As part of the SE-region aquifer management plan, van Stempvoort and Simpson (1994) developeda water quality inventory for the Estevan area. The original data set included all data available at thetime, including those contained in the Rutherford and SRC databases. For the purpose of this reportthe database was revised since the Rutherford and SRC databases are discussed separately. Therevised database represents the more recent data (1981 - 1993) and mainly contains data fromregional surveys conducted by Beckie Hydrogeologists Ltd. (1988a-c, 1989a-c, 1990), and data fromconsultant reports. Samples were analysed for major ions, NO3, Fe and Mn.

A regional groundwater survey conducted in 2000 in the Lanigan area included analysis for majorion and Fe, Mn, and nitrate concentrations for 34 farm wells (Maathuis and Zlipko, 2000).

In 1995 and 1996, a rural groundwater quality survey was conducted in Alberta to determine thesuitability and safety of groundwater used at farmsteads and to establish baseline data for futurereference. The survey was conducted by the Prairie Farm Rehabilitation Administration (PFRA) aspart of the Canada - Alberta Environmentally Sustainable Agriculture Agreement (Fitzgerald et al.,1997, CASEA, 1998). Over 800 sites were sampled, including some surface waters, and sampleswere analysed for major ions, trace metals, nutrients, coliforms and selected herbicides.



A rural groundwater quality sampling program was initiated in Manitoba in 1999. About one sampleper 36 square mile township was collected from randomly selected private rural wells and analysedfor major ions, nutrients and bacteria (personal communication Manitoba Conservation). TheManitoba database is not available at the present time because the results from this survey arecurrently processed.

In Ontario, a groundwater quality survey of private rural wells was conducted in 1991 and 1992.Four wells per township were sampled in each township where greater than 50% of the land wasused for agricultural production and one well per township in other areas. A total of 1262 wells weresampled for nutrients and bacteria. The results of the survey have been summarized by Goss et al.(1998).

5. GROUNDWATER QUALITY DISTRIBUTION

5.1 Aesthetic Groundwater Quality Parameters

Aesthetic groundwater quality parameters include: SO4, Na, Cl, total hardness, Fe, Mn and TDS

The percentage of wells in the various surveys that yielded water with a sulfate concentration greaterthan 500 mg/L is shown in Table 6.

Table 6 Total number of wells and number of wells with water exceeding the Saskatchewandrinking water quality objectives for sulfate

Data Source Total number of wellssampled

Number of wells withwater with SO4��500

mg/L

Percentage of wellswith SO4��500

mg/L

RWQAP 738 325 44

SRC 2279 1167 51

Rutherford 1948 1013 52

Rosetown & ADDDs 257 91 35

Estevan 458 221 48

Lanigan 43 21 62

For the RWQAP, SRC, Rutherford and Estevan surveys the percentage is in a similar range (44%to 52%). The lower percentage for the Rosetown/ADDD inventory (35%) is due to the fact that thesurvey was limited to shallow wells (wells less than 20 m deep). The higher percentage for theLanigan area likely is related to the hydrogeological setting of the survey area.

In Table 7, the percentages of wells are shown which yield sodium concentrations greater than 300mg/L.



Table 7 Total number of wells and number of wells with water exceeding the Saskatchewandrinking water quality objectives for sodium


Number of wells withwater with Na��300 mg/L

Percentage of wellswith Na��300 mg/L

RWQAP 738 185 25

SRC 2279 1167 36



Estevan 458 273 60

Lanigan 34 12 35

The percentages (25% - 36%) are similar for the RWQAP, SRC and Lanigan surveys. The relativelyhigh percentage (60%) of wells in the Estevan area with water with sodium concentrations greaterthan 300 mg/L is indicative of a different evolution of the groundwater quality in this area. The 9%for the Rosetown/ADDD survey again reflects that only shallow wells were sampled.

The various surveys show that the groundwater quality objective for chloride of 250 mg/L isexceeded in 7 to 15% of the wells (Table 8). This range is relatively narrow, but likely reflects somehydrogeological based regional differences.

Table 8 Total number of wells and number of wells with water exceeding the Saskatchewandrinking water quality objectives for chloride


Number of wells withwater with Cl��250

mg/L

Percentage of wells withwater with Cl��250

mg/L

RWQAP 737 49 7.0

SRC 2247 267 11.9

Rutherford 1964 129 6.6

Rosetown & ADDDs 257 15 5.8

Estevan 457 68 14.9

Lanigan 34 5 14.7

Total hardness reflects both the concentrations of calcium and magnesium. In turn, theconcentrations of calcium and magnesium are a reflection of the geochemical evolution ofgroundwater. The percentage of wells with water having a total hardness greater than 800 mg/L asCaCO3 ranges from 26% to 71%. The percentages for the RWQAP, SRC, Rutherford andRosetown/ADDD surveys are close, in the 33 to 42% range. The somewhat lower percentage (26%)in the Estevan area is likely due to the fact that water in the area often is sodium dominated, as



reflected by the number of wells yielding water with a sodium concentration exceeding the objective(see Table 7). The high percentage of wells in the Lanigan area exceeding the objective for totalhardness is considered to be due to the hydrogeological setting of the area.

Table 9 Total number of wells and number of wells with water exceeding the Saskatchewandrinking water quality objectives for total hardness


Number of wells withwater with TH��800 mg/L

Percentage of wells withwater with TH��800 mg/L

RWQAP 738 246 33

SRC 2294 768 33



Estevan 458 119 26

Lanigan 34 24 71

From an aesthetic point of view it is well know that iron and manganese concentrations are one ofthe greatest “problems” in Saskatchewan. This is evident from Table 10 and 11, which show thatthe iron concentration in well water is exceeded in 35% to 88% of the wells, depending on thesurvey. For manganese the range is between 59% and 84%. The significance of the relatively largespread in percentages between the various surveys is not known. Not only is there little informationavailable on regional differences, the sampling method may have had an impact on reportedconcentration values. The reported data for some of the surveys may represent a mixture of samplessome which were filtered in the field and samples which were not.

Table 10 Total number of wells and number of wells with water exceeding the Saskatchewandrinking water quality objectives for iron


Number of wells withwater with Fe��0.3 mg/L

Percentage of wells withwater with Fe��0.3 mg/L

RWQAP 729 346 48

SRC 2159 1866 86


Estevan 438 304 69

Lanigan 34 12 35



Table 11 Total number of wells and number of wells with water exceeding the Saskatchewandrinking water quality objectives for manganese

Data Source Total number of wells sampled

Number of wells withwith Mn��0.05 mg/L

Percentage of wells withwater with Mn��0.05 mg/L

RWQAP 728 525 72

SRC 1270 1071 84

Estevan 450 304 68

Lanigan 34 20 59

The total dissolved solids (sum of ions) is a measure of the total concentration of dissolvedconstituents in water. Table 12 highlights that the quality of groundwater in Saskatchewan is poor.Depending on the survey, between 33% and 71% of the wells yield water exceeding the objectiveof 1,500 mg/L. The percentages for the RWQAP, SRC and Rutherford databases are close (49%to 59%). These databases each are broad based, providing a realistic representation of ruralgroundwater quality. However, the results also reflect regional differences, as is evident by the largepercentage of wells exceeding the objective in the Estevan and Lanigan areas.

Table 12 Total number of wells and number of wells with water exceeding the Saskatchewandrinking water quality objectives for total dissolved solids

Data Source Total number of wells sampled

Number of wells withwater with TDS��1500

mg/L

Percentage of wells waterwith TDS��1500 mg/L

RWQAP 738 366 50

SRC 2293 1350 59



Estevan 458 312 68

Lanigan 34 24 71

Tables 6 to 12, and the discussion of these tables, show that there are both similarities anddifferences between the various groundwater quality databases for Saskatchewan. The percentageof wells exceeding a particular objective are both a function of the design of the survey and regionaldifferences in groundwater quality. In turn, regional difference in groundwater quality can be theresult of regional differences in hydrogeological setting and/or geochemical evolution of thegroundwater.

In Figures 6 to 12, plots are provided of the well depths and concentrations of aesthetic parametersfor the RWQAP database and the combined SRC, Rutherford, Rosetown/ADDD, Estevan andLanigan databases. It is noted that not all data from the RWQAP database could be plotted as only



for 385 site well depth information was readily available. However, as is evident from these figures,the RWQAP data fall well within the variability of the ground water quality in Saskatchewan.

For the Saskatchewan (SRC, Rutherford, Rosetown/ADDD, Estevan and Lanigan), RWQAP, andAlberta (CAESA) rural groundwater quality databases, the percentage of wells exceedingSaskatchewan’s objectives for aesthetic parameters are shown on Table 13.

Table 13 Comparison of percentages of wells which exceed Saskatchewan aesthetic waterquality objectives for Saskatchewan, RWQAP and Alberta (CASE) groundwaterquality surveys

Constituent Saskatchewan RWQAP Alberta

Na 33% 25% 51

SO4 50 44 20

Cl 11 7 7

TDS 55 50 7

Total hardness 36 33 23

Fe 84 47.5 33

Mn 80 72 32

Considering the differences in objectives, size of the areas surveyed, data density, known regionalvariations in groundwater quality, Table 13 indicates that there is little difference between theSaskatchewan and RWQAP databases in term of percentage of wells exceeding a given aestheticground water quality objective. The exception is for the percentage of wells exceeding the objectivefor iron. There is no obvious explanation for the much lower percentage of wells in the RWQAPdatabase exceeding this objective.

As indicated in Table 13, comparison of Saskatchewan groundwater quality data with those regionalsurveys outside the Province (i.e. Alberta) show that there are significant differences. Thesedifferences are related to differences in hydrogeological settings and geochemical evolutions.Therefore, with respect to major ions data, inter-provincial comparison of regional groundwaterquality databases is of little value.

5.2 Dissolved Organic Carbon

Dissolved Organic Carbon (DOC) is neither listed in the Saskatchewan or the Canadian water qualityguidelines as a substance for which a health or aesthetic guideline has been established. In industrialareas or in vicinities of, for example, landfills, elevated DOC levels in groundwater may indicatecontamination of compounds for which objectives have been established. However, in rural areas,DOC in groundwater is natural and related to organic matter. DOC may play an important role in thegeochemical evolution of groundwaters. Elevated naturally occurring DOC concentrations mayimpact water treatment.



To date little is known about both the concentrations and distribution of DOC in groundwater inSaskatchewan as determination of its concentration is usually not included in routine chemicalanalyses of groundwaters. Taking an arbitrary concentration of 5 mg/L, Table 14 shows that between57 and 70% of wells in Saskatchewan yield water with elevated DOC concentrations.

Table 14 Total number of wells and number of wells with water exceeding a dissolved organic carbon concentration greater than 5 mg/L

Data Source Total number ofwells sampled

Number of wells with waterwith DOC�� 5 mg/L

Percentage of wells withwater with DOC�� 5 mg/L

RWQAP 735 413 56


A plot of well depth verus DOC concentration (Figure13 ) shows little correlation between depth andDOC.

5.3 Health Parameters

Health related groundwater quality parameters include: nitrate, total and faecal coliforms, arsenicselenium, barium, boron, cadmium, chromium, lead, uranium.

5.3.1 Nitrate

Nitrate in concentrations greater than 45 mg/L as NO3 (10 mg/L as N) is considered dangerous forinfants because of methemoglobinemia. General reviews of nitrate concentrations in groundwaterin western Canada have been provided by Henry and Meneley (1993), and Henry (1995). Goss et al.reviewed surveys of well contamination with NO3 in regions similar to Ontario. These surveysindicated that between 2% and 22% of wells yielded water with a NO3 concentration greater than 45mg/L. Coote and Gregorich (2000) provided a Canada wide review of nitrate in groundwater. Theirreview indicated that between 1% to 44% of well in Canada yield water with a nitrate concentrationgreater than 45 mg/L.

The first survey of nitrate concentrations in water from rural wells in Saskatchewan was reported byRobertson and Ridell (1949). Nearly 19% of the more than 2,000 wells sampled in 1948 had anitrate concentration greater than 50 mg/L.

Table 15 shows the percentage of wells which yield water exceeding the objective of 45 mg/L.



Table 15 Total number of wells and number of wells with water exceeding the Saskatchewandrinking water quality objectives for nitrates

Data Source Total number ofwells

Number of wells with waterwith NO3 �� 45 mg/L

Percentage of wells withwater with NO3 �� 45 mg/L

RWQAP 738 97 13

SRC 1756 129 7



Estevan 458 47 10

Lanigan 34 13 38

Alberta (CAESA) 733 42 6

Manitoba1 1005 161 16

Ontario2 1292 14Notes: 1 Manitoba Conservation, 2 Goss et al. (1998)

As is evident from Table 15, the percentage may vary significantly, depending on the survey, andranges from 7% to 42%. The percentage of wells with water having a nitrate concentration greaterthan 45 mg/L is affected by the type of survey, the area of the survey, the number of wells sampledand their depth distribution. For example, the percentage (42%) for the Rutherford survey likelywould have been lower if the nitrate concentration was determined on all the samples and not onlyon samples which had an initial error in the ionic balance greater than ± 3%. The relatively highpercentage for the Rosetown/ADDD data (36%) is considered related to the design of the survey asonly wells less than 20 m deep were sampled. Also, in the Lanigan area a large percentage of wellsyield water with a nitrate concentration greater than 45 mg/L (38%). This reflects the distributionof the depth of the wells sampled.

Combining the nitrate data for the SRC, Rutherford, Estevan, Rosetown/ADDD and Lanigansurveys, the overall percentage of wells with a nitrate concentration greater than 45 mg/L is about18%. Using all the RWQAP data, the percentage is about 13%. These percentages are not onlyclose considering the objectives of the various databases, they also compare well with results foundin Manitoba and Ontario.

In Figure 14, well depths and nitrate concentrations for the RWQAP database and the combinedother water quality databases for Saskatchewan are shown. This Figure shows that the RWQAP datafall within the variability of the nitrate concentrations found in water from wells in Saskatchewan.

5.3.2 Arsenic

To date little is known about arsenic concentrations in groundwater in western Canada. Only twosurveys have been conducted in which arsenic concentrations were reported, the RWQAP and Albertasurveys. The percentage of wells with arsenic concentrations greater than 0.025 mg/L varies between



10% in Saskatchewan and 3% in Alberta Table (16). There is no obvious explanation for thedifference in percentage.

Table 16 Total number of wells and number of wells with water exceeding the Saskatchewandrinking water quality objectives for arsenic

Data Source Total number of wells

Number of wells withwater with As��0.025 mg/L

Percentage of wells with waterwith As��0.025 mg/L

RWQAP 735 55 7.5

Alberta 718 20 2.8

5.3.3 Selenium

To date little is known about selenium concentrations in groundwater in western Canada. Only twosurveys have been conducted in which selenium concentrations were reported, the RWQAP andAlberta surveys. The percentage of wells with selenium concentrations greater than 0.025 mg/Lvaries between 10% in Saskatchewan and 4% in Alberta (Table 17). There is no obvious explanationfor the difference in percentage.

Table 17 Total number of wells and number of wells with water exceeding the Saskatchewan drinking water quality objectives for selenium


Number of wells withwater with Se��0.01 mg/L

Percentage of wells with waterwith Se��0.01 mg/L

RWQAP 737 76 10

Alberta (CAESA) 718 31 4.3

5.3.4 Total and Faecal Coliforms

Total and faecal coliform counts provide an indication of the bacteriological quality of the water.

The results of available surveys for total coliforms are shown in Table 18.



Table 18 Total number of wells and number of wells with water exceeding the Saskatchewandrinking water quality objectives for total coliforms


Number of wells with water withtotal coliforms�� 1 per 100 ml

Percentage of wells with water withtotal coliforms�� 1 per 100 ml

RWQAP 717 224 31

Alberta 729 106 14.5

Manitoba1 997 428 43

Note: 1 source - Manitoba Conservation

Goss et al. (1998) reported that 34% of the wells sampled in Ontario exceeded the Ontario provincialguidelines for total coliforms. However, Ontario uses a MAC of 5 colonies per 100 ml rather thanthe objective used in the Prairie provinces of no colonies per 100 ml. In the recent Manitoba survey,the sample points were not sterilized before sampling and consequently, the percentage of wells withwith a total coliform count �1 per 100 ml might be misleadingly high.

The available surveys for faecal coliforms is even less than those for total coliforms and are shownin Table 19.

Table 19 Total number of wells and number of wells with water exceeding the Saskatchewandrinking water quality objectives for faecal coliforms

Data Source Total number ofsamples

Number of sampleswith faecal coliforms �� 1

Percentage of wellswith faecal coliforms �� 1

RWQAP 711 18 2.5

Alberta (CAESA) 729 29 4.0

Both with respect to total and faecal coliforms, the data obtained from the RWQAP survey must beconsidered as baseline/reference data.



6. CONCLUSIONS

The groundwater quality databases considered in this report are diverse in many ways, ranging fromtheir objective, size of the area of the surveys, distribution of the depth of wells sampled, and thetype of chemical analyses conducted. Also taking into account the differences in the geochemicalevolution of groundwaters in Saskatchewan, the following can be concluded:

• When considering the Saskatchewan databases (SRC, Rutherford, Rosetown/ADDD,Estevan and Lanigan) and the Rural Water Quality Advisory Program (RWQAP) data,there is little difference between Saskatchewan and RWQAP databases in the percentagesof wells yielding water exceeding a certain aesthetic water quality objective. Plots ofwell depths versus concentrations of aesthetic water quality parameters show also thatthe results of the RWQAP survey are consistent with the variability of the groundwaterquality in Saskatchewan. Therefore, in terms of major ions (aesthetic parameters), theresults of the RWQAP survey can be considered representative for the variability of thequality of groundwaters in Saskatchewan.

• The percentage of wells which yield water with a nitrate concentration greater than 45mg/L varies from survey to survey, as it is dependent on the size of the area covered bythe survey (which results in a greater diversity of hydrogeological settings), the objectiveof the survey and the distribution of the depth of the wells sampled. The overallpercentage of wells with a nitrate concentration greater than 45 mg/L is 18% for thecombined nitrate data from the SRC, Rutherford, Estevan, Rosetown/ADDD andLanigan surveys. The percentage is about 13% for all the RWQAP data. Thesepercentages are not only close considering the objectives of the various databases, theyalso compare well with results found in Manitoba and Ontario.

• The arsenic and selenium data generated by the Rural Water Quality Advisory Programmust be considered as baseline/reference data since determination of the concentrationof these constituents was not part of other groundwater quality surveys conducted inSaskatchewan.

• Both with respect to total and faecal coliforms, the data obtained from the RWQAPsurvey must be considered as baseline data as the results can not be directly comparedto other surveys because of either differences in sampling technique (e.g. Manitoba) anddefinition of the MAC (e.g. Ontario).



7. REFERENCES

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Beckie Hydrogeologists Ltd. 1989a Estevan Valley and Tableland aquifers. Monthly water qualityand water levels for January 1989. Beckie Hydrogeologists Ltd., Regina.

Beckie Hydrogeologists Ltd. 1989b Estevan Valley and Tableland aquifers. Monthly water qualityand water levels for February 1989. Beckie Hydrogeologists Ltd., Regina.

Beckie Hydrogeologists Ltd. 1989b Estevan Valley and Tableland aquifers. Monthly water qualityand water levels for February 1989. Beckie Hydrogeologists Ltd., Regina.

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