Disclaimer & Copyright Notices; Optimized for the MS Edge

Background lakes and comparisons in Nova Scotia, Guidelines

Updated: July 01, 2021

Select data is available in the OneDrive's public folder:-
Freshwaters & Marine= https://1drv.ms/f/s!Au0xeIA-MCofgT6hH_HmNC5EW7Oe

Primary Index:

Archival comparative data mostly from older Government reports with some exceptions
Reference lake types used as indicator thresholds for anthropogenic stressors
Phosphorus comparisons of 80 representative lakes within HRM

Reference lake types used as indicator thresholds of anthropogenic stressors (Mandell, 1994)

The data of the three following protected lakes within Atlantic Canada's National Parks can be used as a baseline comparison with lakes across Nova Scotia, perhaps all across Atlantic Canada. The fecal coliform counts relate to other drinking water lakes obtained from the Nova Scotia Health Authority by Mandell.

Phosphorus comparisons of 80 representative lakes within HRM

Download the MS Excel file: This file includes our modelled hindcast values, the pre-industrial diatom inference and modelled values of other lead researchers, historical field data as well as HRM's synoptic data, and HRM's thresholds along with the CCME guidelines.

We had modelled approximately one thousand lakes/ponds over 1 ha in size for phosphorus, mostly within HRM: all the models are available in the aforementioned OneDrive.

Secondary Index:

(Note: Due to issues with the HTML composer, ug/l means micro gm/l, and SD is for plusminus standard deviation)
(Also see lake morphology)

Introduction

Surface area

Maximum depth

Mean depth

Total Phosphorus, TP in lake water

Environment Canada, 2004: Canadian Guidance Framework
OECD (Organisation for Economic Cooperation and Development): Management Model

TP in bottom sediments

PO₄-P

Mean Chlorophyll-a

Environment Canada, 2004: Canadian Guidance Framework
OECD (Organisation for Economic Cooperation and Development): Management Model

Maximum Chlorophyll-a

Environment Canada, 2004: Canadian Guidance Framework

Total Nitrogen (TN)

Nitrate-N

Nitrite-N

Ammonia (NH₄-N)

Clarity as Secchi depth, SD

Environment Canada, 2004: Canadian Guidance Framework

Turbidity

TSS

TDS

Colour

TOC

DOC

SO₄

Dissolved Oxygen (DO)

E. coli and fecal coli

Enterococci

Microorganisms

References

Introduction

This web page has been prepared with historical data on several variables, both for overall provincial and Halifax Metro averages as well as for pristine and relatively undisturbed lakes. With some exceptions, these may be used for comparing any field data. The relevant guidelines from Environment Canada, 2004, the CCME (Canadian Ministers of the Environment), OME (Ontario Ministry of the Environment), Health and Welfare Canada, and the NRCC (National Research Council of Canada), have also been included.

Parameters

Surface Area (ha)
Lake Means & Guidelines	Lake & Specifics	References & Notes
85 SD 192	175 Halifax Co. lakes	Alexander et al, 1986
89 SD 279	781 Nova Scotia lakes	Alexander et al, 1986

Maximum Depth (m)

Lake Means & Guidelines Lake & Specifics References & Notes

10.6 SD 8.4 175 Halifax Co. lakes Alexander et al, 1986

8.2 SD 6.8 772 Nova Scotia lakes Alexander et al, 1986

Maximum Depth (m)
Lake Means & Guidelines	Lake & Specifics	References & Notes
10.6 SD 8.4	175 Halifax Co. lakes	Alexander et al, 1986
8.2 SD 6.8	772 Nova Scotia lakes	Alexander et al, 1986

Mean Depth (m)

Lake Means & Guidelines Lake & Specifics References & Notes

3.1 SD 2.4 118 Halifax Co. lakes Alexander et al, 1986

2.8 SD 2.1 660 Nova Scotia lakes Alexander et al, 1986

Mean Depth (m)
Lake Means & Guidelines	Lake & Specifics	References & Notes
3.1 SD 2.4	118 Halifax Co. lakes	Alexander et al, 1986
2.8 SD 2.1	660 Nova Scotia lakes	Alexander et al, 1986

Total Phosphorus, ug/l TP (as Phosphorus ug/l)

Lake Means & Guidelines Lake & Specifics References & Notes

mean=2.7
(<1 - 5) 22 pristine Halifax Co. clear-water lakes (Dec. 1984) Data from John Underwood (pers. comm. Feb. 1994); Lakes Jack, Bayers, Susies, Bell, Paces, Kearney, Grand [Preston], Eagle, Long [Preston], Horseshoe, Uniacke, Cochran, Lewis [Kearney watershed], McQuade, Anderson, Spruce Hill, Ragged, Cooper, Otter, Land of Laziness, Coxs, and Long

4 Clear-water Pockwock Lake (1991-92; 4 events; TSI[TP]=24, TSI[Cha]=24]) Clear-water, water supply lake in Hammonds Plains, Mandell (1994)

5 Clear-water Bell Lake (1991-92; 30 events; TSI[TP]=27, TSI[Cha]=34) Clear-water, urban lake in Dartmouth, Mandell (1994)

6 Clear-water Bell Lake (1990; 3 events; TSI[TP]=30, TSI[Cha]=26) Clear-water, urban lake in Dartmouth, SWCS (1991)

2 Clear-water Chocolate Lake (1991-92; 4 events; TSI[TP]=14, TSI[Cha]=11]) Clear-water, urban lake in Halifax, Mandell (1994)

3.8 Clear-water Beaverskin Lake (near surf. yearly means; TSI[TP]=23, TSI[Cha]=34]) Undisturbed clear-water lake in a National Park, Kerekes (1975)

6.6, 6.0 Clear-water Beaverskin Lake (May-April 1979-80: TSI[TP]=31, TSI[Cha]=32]; May-April 1980-81: TSI[TP]=30, TSI[Cha]=31]; wtd. means) Undisturbed clear-water lake in a National Park, Beauchamp and Kerekes (1989)

mean= 7.1
(3- 17) 14 Halifax County Coloured-water lakes (Dec. 1984) Data from John Underwood (pers, comm. Feb. 1994), Lakes Spectacle, Howe, O'Brien, Kidston, Hubley's Big, Peters [Eastern Shore], Big Bridge Bog Pond, Welsh, Long Canal, Purcell's Pond, Duncan's Pond, Fink Pond, Black, and Silver

9.1 Coloured-water Kejimkujik Lake (near surf. yearly means) Undisturbed, colored-water lake in a National Park, Kerekes (1975)

10.4, 10.4 Coloured-water Kejimkujik Lake (May-April 1979-80, May-April 1980-81, wtd. means) Undisturbed, colored-water lake in a National Park, Beauchamp and Kerekes (1989)

5 to 10 17 Keji Park lakes Kerekes. 1975

Environment Canada, 2004: Canadian Guidance Framework

< 4 Ultra-oligotrophic Almost nil impairment of multi-purpose use of lake

4-10 Oligo-mesotrophic Little impairment of multi-purpose use of lake

10-35 Meso-eutrophic Variable impairment of multi-purpose use of lake

35-100 Eutrophic Great impairment of multi-purpose use of lake

> 100 Hypereutrophic Extreme impairment of multi-purpose use of lake

OECD Management Model: There is no possibility of defining strict boundary values between trophic categories. This model incorporates the class midpoints for mean TP and mean Ch-a

mean < 2.5 Ultra-oligotrophic Almost nil impairment of multi-purpose use of lake

mean = 2.5-8 Oligotrophic Little impairment of multi-purpose use of lake

mean = 8-25 Mesotrophic Variable impairment of multi-purpose use of lake

mean= 25-80 Eutrophic Great impairment of multi-purpose use of lake

mean > 80 Hypertrophic Extreme impairment of multi-purpose use of lake

Total Phosphorus, ug/l TP (as Phosphorus ug/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
mean=2.7 (<1 - 5)	22 pristine Halifax Co. clear-water lakes (Dec. 1984)	Data from John Underwood (pers. comm. Feb. 1994); Lakes Jack, Bayers, Susies, Bell, Paces, Kearney, Grand [Preston], Eagle, Long [Preston], Horseshoe, Uniacke, Cochran, Lewis [Kearney watershed], McQuade, Anderson, Spruce Hill, Ragged, Cooper, Otter, Land of Laziness, Coxs, and Long
4	Clear-water Pockwock Lake (1991-92; 4 events; TSI[TP]=24, TSI[Cha]=24])	Clear-water, water supply lake in Hammonds Plains, Mandell (1994)
5	Clear-water Bell Lake (1991-92; 30 events; TSI[TP]=27, TSI[Cha]=34)	Clear-water, urban lake in Dartmouth, Mandell (1994)
6	Clear-water Bell Lake (1990; 3 events; TSI[TP]=30, TSI[Cha]=26)	Clear-water, urban lake in Dartmouth, SWCS (1991)
2	Clear-water Chocolate Lake (1991-92; 4 events; TSI[TP]=14, TSI[Cha]=11])	Clear-water, urban lake in Halifax, Mandell (1994)
3.8	Clear-water Beaverskin Lake (near surf. yearly means; TSI[TP]=23, TSI[Cha]=34])	Undisturbed clear-water lake in a National Park, Kerekes (1975)
6.6, 6.0	Clear-water Beaverskin Lake (May-April 1979-80: TSI[TP]=31, TSI[Cha]=32]; May-April 1980-81: TSI[TP]=30, TSI[Cha]=31]; wtd. means)	Undisturbed clear-water lake in a National Park, Beauchamp and Kerekes (1989)
mean= 7.1 (3- 17)	14 Halifax County Coloured-water lakes (Dec. 1984)	Data from John Underwood (pers, comm. Feb. 1994), Lakes Spectacle, Howe, O'Brien, Kidston, Hubley's Big, Peters [Eastern Shore], Big Bridge Bog Pond, Welsh, Long Canal, Purcell's Pond, Duncan's Pond, Fink Pond, Black, and Silver
9.1	Coloured-water Kejimkujik Lake (near surf. yearly means)	Undisturbed, colored-water lake in a National Park, Kerekes (1975)
10.4, 10.4	Coloured-water Kejimkujik Lake (May-April 1979-80, May-April 1980-81, wtd. means)	Undisturbed, colored-water lake in a National Park, Beauchamp and Kerekes (1989)
5 to 10	17 Keji Park lakes	Kerekes. 1975




Environment Canada, 2004: Canadian Guidance Framework
< 4	Ultra-oligotrophic	Almost nil impairment of multi-purpose use of lake
4-10	Oligo-mesotrophic	Little impairment of multi-purpose use of lake
10-35	Meso-eutrophic	Variable impairment of multi-purpose use of lake
35-100	Eutrophic	Great impairment of multi-purpose use of lake
> 100	Hypereutrophic	Extreme impairment of multi-purpose use of lake




OECD Management Model: There is no possibility of defining strict boundary values between trophic categories. This model incorporates the class midpoints for mean TP and mean Ch-a
mean < 2.5	Ultra-oligotrophic	Almost nil impairment of multi-purpose use of lake
mean = 2.5-8	Oligotrophic	Little impairment of multi-purpose use of lake
mean = 8-25	Mesotrophic	Variable impairment of multi-purpose use of lake
mean= 25-80	Eutrophic	Great impairment of multi-purpose use of lake
mean > 80	Hypertrophic	Extreme impairment of multi-purpose use of lake

TP (mg/l) in sediments

Lake Means & Guidelines Lake & Specifics References & Notes

1.2 Natural lakes of Nova Scotia Underwood and Josselyn, 1979

TP (mg/l) in sediments
Lake Means & Guidelines	Lake & Specifics	References & Notes
1.2	Natural lakes of Nova Scotia	Underwood and Josselyn, 1979

PO₄-P (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

0.001 SD 0.001 234 N.S. lakes Underwood et al, 1986

PO₄-P (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
0.001 SD 0.001	234 N.S. lakes	Underwood et al, 1986

Mean Chlorophyll-a (ug/l)

Lake Means & Guidelines Lake & Specifics References & Notes

0.53 Clear-water Pockwock Lake (1991-92; 4 events; TSI[TP]=24, TSI[Cha]=24) Clear-water, water supply lake in Hammonds Plains, Mandell (1994)

1.41 Clear-water Bell Lake (1991-92; 30 events; TSI[TP]=27, TSI[Cha]=34) Clear-water, urban lake in Dartmouth, Mandell (1994)

0.6 Clear-water Bell Lake (1990; 3 events; TSI[TP]=30, TSI[Cha]=26) Clear-water, urban lake in Dartmouth, SWCS (1991)

0.14 Clear-water Chocolate Lake (1991-92; 4 events; TSI[TP]=14, TSI[Cha]=11]) Clear-water, urban lake in Halifax, Mandell (1994)

1.4 Clear-water Beaverskin Lake (near surf. yearly means; TSI[TP]=23, TSI[Cha]=34]) Undisturbed clear-water lake in a National Park, Kerekes (1975)

1.20, 1.03 Clear-water Beaverskin Lake (May-April 1979-80: TSI[TP]=31, TSI[Cha]=32; May-April 1980-81: TSI[TP]=30, TSI[Cha]=31) Undisturbed, clear-water lake in a National Park, Beauchamp and Kerekes (1989)

2.1 Coloured-water Kejimkujik Lake (near surf. yearly means) Undisturbed, colored-water lake in a National Park, Kerekes (1975)

1.16, 0.93 Coloured-water Kejimkujik Lake (May-April 1979-80, May-April 1980-81, wtd. means) Undisturbed, colored-water lake in a National Park, Beauchamp and Kerekes (1989)

1.8 (1 to 3) 17 Keji Park lakes Kerekes, 1975

1.3 5 Terra Nova Park lakes, NFLD Kerekes, 1975

3 Lakes in the Canadian Shield in NW Ontario Kerekes, 1975

Environment Canada, 2004: Canadian Guidance Framework

< 1 Ultra-oligotrophic Almost nil impairment of multi-purpose use of lake

< 2.5 Oligo-mesotrophic Little impairment of multi-purpose use of lake

2.5-8 Meso-eutrophic Variable impairment of multi-purpose use of lake

8-25 Eutrophic Great impairment of multi-purpose use of lake

> 25 Hypereutrophic Extreme impairment of multi-purpose use of lake

OECD Management Model: There is no possibility of defining strict boundary values between trophic categories. This model incorporates the class midpoints for mean TP and mean Ch-a

mean < 0.7 Ultra-oligotrophic Almost nil impairment of multi-purpose use of lake

mean = 0.7-2.1 Oligotrophic Little impairment of multi-purpose use of lake

mean = 2.1-6.25 Mesotrophic Variable impairment of multi-purpose use of lake

mean= 6.25-19.2 Eutrophic Great impairment of multi-purpose use of lake

mean > 19.2 Hypertrophic Extreme impairment of multi-purpose use of lake

Mean Chlorophyll-a (ug/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
0.53	Clear-water Pockwock Lake (1991-92; 4 events; TSI[TP]=24, TSI[Cha]=24)	Clear-water, water supply lake in Hammonds Plains, Mandell (1994)
1.41	Clear-water Bell Lake (1991-92; 30 events; TSI[TP]=27, TSI[Cha]=34)	Clear-water, urban lake in Dartmouth, Mandell (1994)
0.6	Clear-water Bell Lake (1990; 3 events; TSI[TP]=30, TSI[Cha]=26)	Clear-water, urban lake in Dartmouth, SWCS (1991)
0.14	Clear-water Chocolate Lake (1991-92; 4 events; TSI[TP]=14, TSI[Cha]=11])	Clear-water, urban lake in Halifax, Mandell (1994)
1.4	Clear-water Beaverskin Lake (near surf. yearly means; TSI[TP]=23, TSI[Cha]=34])	Undisturbed clear-water lake in a National Park, Kerekes (1975)
1.20, 1.03	Clear-water Beaverskin Lake (May-April 1979-80: TSI[TP]=31, TSI[Cha]=32; May-April 1980-81: TSI[TP]=30, TSI[Cha]=31)	Undisturbed, clear-water lake in a National Park, Beauchamp and Kerekes (1989)
2.1	Coloured-water Kejimkujik Lake (near surf. yearly means)	Undisturbed, colored-water lake in a National Park, Kerekes (1975)
1.16, 0.93	Coloured-water Kejimkujik Lake (May-April 1979-80, May-April 1980-81, wtd. means)	Undisturbed, colored-water lake in a National Park, Beauchamp and Kerekes (1989)
1.8 (1 to 3)	17 Keji Park lakes	Kerekes, 1975
1.3	5 Terra Nova Park lakes, NFLD	Kerekes, 1975
3	Lakes in the Canadian Shield in NW Ontario	Kerekes, 1975




Environment Canada, 2004: Canadian Guidance Framework
< 1	Ultra-oligotrophic	Almost nil impairment of multi-purpose use of lake
< 2.5	Oligo-mesotrophic	Little impairment of multi-purpose use of lake
2.5-8	Meso-eutrophic	Variable impairment of multi-purpose use of lake
8-25	Eutrophic	Great impairment of multi-purpose use of lake
> 25	Hypereutrophic	Extreme impairment of multi-purpose use of lake




OECD Management Model: There is no possibility of defining strict boundary values between trophic categories. This model incorporates the class midpoints for mean TP and mean Ch-a
mean < 0.7	Ultra-oligotrophic	Almost nil impairment of multi-purpose use of lake
mean = 0.7-2.1	Oligotrophic	Little impairment of multi-purpose use of lake
mean = 2.1-6.25	Mesotrophic	Variable impairment of multi-purpose use of lake
mean= 6.25-19.2	Eutrophic	Great impairment of multi-purpose use of lake
mean > 19.2	Hypertrophic	Extreme impairment of multi-purpose use of lake

Maximum Chlorophyll-a (ug/l)

Lake Means & Guidelines Lake & Specifics References & Notes

0.73 Clear-water Pockwock Lake (1991-92; 4 events; TSI[TP]=24, TSI[Cha]=24) Clear-water, water supply lake in Hammonds Plains, Mandell (1994)

3.33 Clear-water Bell Lake (1991-92; 30 events; TSI[TP]=27; TSI[Cha]=34) Clear-water, urban lake in Dartmouth, Mandell (1994)

0.74 Clear-water Bell Lake (1990; 3 events; TSI[TP]=30, TSI[Cha]=26) Clear-water, urban lake in Dartmouth, SWCS (1991)

0.23 Clear-water Chocolate Lake (1991-92; 4 events; TSI[TP]=14, TSI[Cha]=11]) Clear-water, urban lake in Halifax, Mandell (1994)

3.27, 2.24 Beaverskin Lake (May-April 1979-80: TSI[TP]=31, TSI[Cha]=32; May-April 1980-81: TSI[TP]=30, TSI[Cha]=31) Undisturbed, clear-water lake in a National Park, Beauchamp and Kerekes (1989)

2.80, 1.92 Coloured-water Kejimkujik Lake (May-April 1979-80, May-April 1980-81) Undisturbed, colored-water lake in a National Park, Beauchamp and Kerekes (1989)

Environment Canada, 2004: Canadian Guidance Framework

< 2.5 Ultra-oligotrophic Almost nil impairment of multi-purpose use of lake

< 8 Oligo-mesotrophic Little impairment of multi-purpose use of lake

8-25 Meso-eutrophic Variable impairment of multi-purpose use of lake

25-75 Eutrophic Great impairment of multi-purpose use of lake

> 75 Hypereutrophic Extreme impairment of multi-purpose use of lake

Maximum Chlorophyll-a (ug/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
0.73	Clear-water Pockwock Lake (1991-92; 4 events; TSI[TP]=24, TSI[Cha]=24)	Clear-water, water supply lake in Hammonds Plains, Mandell (1994)
3.33	Clear-water Bell Lake (1991-92; 30 events; TSI[TP]=27; TSI[Cha]=34)	Clear-water, urban lake in Dartmouth, Mandell (1994)
0.74	Clear-water Bell Lake (1990; 3 events; TSI[TP]=30, TSI[Cha]=26)	Clear-water, urban lake in Dartmouth, SWCS (1991)
0.23	Clear-water Chocolate Lake (1991-92; 4 events; TSI[TP]=14, TSI[Cha]=11])	Clear-water, urban lake in Halifax, Mandell (1994)
3.27, 2.24	Beaverskin Lake (May-April 1979-80: TSI[TP]=31, TSI[Cha]=32; May-April 1980-81: TSI[TP]=30, TSI[Cha]=31)	Undisturbed, clear-water lake in a National Park, Beauchamp and Kerekes (1989)
2.80, 1.92	Coloured-water Kejimkujik Lake (May-April 1979-80, May-April 1980-81)	Undisturbed, colored-water lake in a National Park, Beauchamp and Kerekes (1989)
Environment Canada, 2004: Canadian Guidance Framework
< 2.5	Ultra-oligotrophic	Almost nil impairment of multi-purpose use of lake
< 8	Oligo-mesotrophic	Little impairment of multi-purpose use of lake
8-25	Meso-eutrophic	Variable impairment of multi-purpose use of lake
25-75	Eutrophic	Great impairment of multi-purpose use of lake
> 75	Hypereutrophic	Extreme impairment of multi-purpose use of lake

Total Nitrogen, TN (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

0.19 SD 0.09 37 pristine Halifax Co. lakes (Dec. 1984) John Underwood (pers. comm.), Jan. 1994

0.09 Clear-water Pockwock Lake (1991-92; 4 events) Clear-water, water supply lake in Hammonds Plains, Mandell (1994)

0.06 Bell Lake (1991-92; 30 events) Clear-water, urban lake in Dartmouth. Mandell (1994)

0.2 Clear-water Chocolate Lake (1991-92; 4 events) Clear-water, urban lake in Halifax, Mandell (1994)

0.145, 0.152 Beaverskin Lake (May-April 1979-80, May-April 1980-81, wtd. means) Undisturbed, clear-water lake in a National Park, Beauchamp and Kerekes (1989)

0.17, 0.17 Coloured-water Kejimkujik Lake (May-April 1979-80, May-April 1980-81, wtd. means) Undisturbed, colored-water lake in a National Park, Beauchamp and Kerekes (1989)

≤0.3 Oligotrophic systems Underwood & Josselyn, 1979

Total Nitrogen, TN (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
0.19 SD 0.09	37 pristine Halifax Co. lakes (Dec. 1984)	John Underwood (pers. comm.), Jan. 1994
0.09	Clear-water Pockwock Lake (1991-92; 4 events)	Clear-water, water supply lake in Hammonds Plains, Mandell (1994)
0.06	Bell Lake (1991-92; 30 events)	Clear-water, urban lake in Dartmouth. Mandell (1994)
0.2	Clear-water Chocolate Lake (1991-92; 4 events)	Clear-water, urban lake in Halifax, Mandell (1994)
0.145, 0.152	Beaverskin Lake (May-April 1979-80, May-April 1980-81, wtd. means)	Undisturbed, clear-water lake in a National Park, Beauchamp and Kerekes (1989)
0.17, 0.17	Coloured-water Kejimkujik Lake (May-April 1979-80, May-April 1980-81, wtd. means)	Undisturbed, colored-water lake in a National Park, Beauchamp and Kerekes (1989)
≤0.3	Oligotrophic systems	Underwood & Josselyn, 1979

Nitrate-N (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

0.02 SD 0.03 37 pristine Halifax County lakes (Dec. 1984) John Underwood (pers. comm.) Jan, 1994

<0.19 Susies Lake (1980-83) Undisturbed lake in Halifax Metro, Kerekes et al, 1986

10.0 as N Drinking Water- Maximum Acceptable Concentration CCME- Where both nitrate and nitrite are present the total nitrate- plus nitrite-nitrogen should not exceed 10

Nitrate-N (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
0.02 SD 0.03	37 pristine Halifax County lakes (Dec. 1984)	John Underwood (pers. comm.) Jan, 1994
<0.19	Susies Lake (1980-83)	Undisturbed lake in Halifax Metro, Kerekes et al, 1986
10.0 as N	Drinking Water- Maximum Acceptable Concentration	CCME- Where both nitrate and nitrite are present the total nitrate- plus nitrite-nitrogen should not exceed 10

Nitrite-N (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

0.06 Freshwater Aquatic Life CCME guidelines

1.0 as N Drinking Water- Maximum Acceptable Concentration CCME- Where both nitrate and nitrite are present the total nitrate- plus nitrite-nitrogen should not exceed 10

Nitrite-N (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
0.06	Freshwater Aquatic Life	CCME guidelines
1.0 as N	Drinking Water- Maximum Acceptable Concentration	CCME- Where both nitrate and nitrite are present the total nitrate- plus nitrite-nitrogen should not exceed 10

Ammonia, NH₄-N (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

0.007 SD 0.019 37 pristine Halifax Co. lakes (Dec. 1984) John Underwood (pers. comm.). Jan, 1994

Ammonia, NH₄-N (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
0.007 SD 0.019	37 pristine Halifax Co. lakes (Dec. 1984)	John Underwood (pers. comm.). Jan, 1994

Clarity (as Secchi disk depth in m)

Lake Means & Guidelines Lake & Specifics References & Notes

2.9 N.S. Average Underwood & Josselyn, 1979

Minimum visibility at 1.2 Recreational Water Quality CCME guidelines

Environment Canada, 2004: Canadian Guidance Framework

mean > 12
min. > 6 Ultra-oligotrophic Almost nil impairment of multi-purpose use of lake

mean > 6
min. > 3 Oligo-mesotrophic Little impairment of multi-purpose use of lake

mean = 6-3
min. = 3-1.5 Meso-eutrophic Variable impairment of multi-purpose use of lake

mean= 3-1.5
min. = 1.5-0.7 Eutrophic Great impairment of multi-purpose use of lake

mean < 1.5
min. < 0.7 Hypereutrophic Extreme impairment of multi-purpose use of lake

Clarity (as Secchi disk depth in m)
Lake Means & Guidelines	Lake & Specifics	References & Notes
2.9	N.S. Average	Underwood & Josselyn, 1979
Minimum visibility at 1.2	Recreational Water Quality	CCME guidelines
Environment Canada, 2004: Canadian Guidance Framework
mean > 12 min. > 6	Ultra-oligotrophic	Almost nil impairment of multi-purpose use of lake
mean > 6 min. > 3	Oligo-mesotrophic	Little impairment of multi-purpose use of lake
mean = 6-3 min. = 3-1.5	Meso-eutrophic	Variable impairment of multi-purpose use of lake
mean= 3-1.5 min. = 1.5-0.7	Eutrophic	Great impairment of multi-purpose use of lake
mean < 1.5 min. < 0.7	Hypereutrophic	Extreme impairment of multi-purpose use of lake

Turbidity

Lake Means & Guidelines Lake & Specifics References & Notes

0.92 SD 0.45 NTU 37 pristine Halifax Co. lakes (Dec. 1984) John Underwood (pers. comm.). Jan, 1994

1.05 SD 0.60 NTU 234 N.S. lakes Underwood et al, 1986

1 Clear-water Pockwock Lake (1991-92; 4 events) Clear-water, water supply lake in Hammonds Plains, Mandell (1994)

1 Clear-water Bell Lake (1991-92; 30 events) Clear-water, urban lake in Dartmouth, Mandell (1994)

0 Clear-water Chocolate Lake (1991-92; 4 events) Clear-water, urban lake in Halifax, Mandell (1994)

5.0 NTU maximum increase Recreational Water Quality CCME guidelines- Maximum allowable increase over natural turbidity when turbidity is low (<50 NTU)

Turbidity
Lake Means & Guidelines	Lake & Specifics	References & Notes
0.92 SD 0.45 NTU	37 pristine Halifax Co. lakes (Dec. 1984)	John Underwood (pers. comm.). Jan, 1994
1.05 SD 0.60 NTU	234 N.S. lakes	Underwood et al, 1986
1	Clear-water Pockwock Lake (1991-92; 4 events)	Clear-water, water supply lake in Hammonds Plains, Mandell (1994)
1	Clear-water Bell Lake (1991-92; 30 events)	Clear-water, urban lake in Dartmouth, Mandell (1994)
0	Clear-water Chocolate Lake (1991-92; 4 events)	Clear-water, urban lake in Halifax, Mandell (1994)
5.0 NTU maximum increase	Recreational Water Quality	CCME guidelines- Maximum allowable increase over natural turbidity when turbidity is low (<50 NTU)

TSS (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

3 Average background conc. of N.S. lakes Hinch & Underwood, 1985 (SS is the component of total residue retained by a 0.45 �m filter and may consist of clay, silt, finely divided organics and inorganics, planktonic and microscopic organisms)

Maximum increase of 10.0 Freshwater Aquatic Life CCME guidelines- when background suspended solids ≤100.0

Maximum increase of 10% above background Freshwater Aquatic Life CCME guidelines- when background suspended solids >100.0

TSS (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
3	Average background conc. of N.S. lakes	Hinch & Underwood, 1985 (SS is the component of total residue retained by a 0.45 �m filter and may consist of clay, silt, finely divided organics and inorganics, planktonic and microscopic organisms)
Maximum increase of 10.0	Freshwater Aquatic Life	CCME guidelines- when background suspended solids ≤100.0
Maximum increase of 10% above background	Freshwater Aquatic Life	CCME guidelines- when background suspended solids >100.0

TDS (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

<30 Natural background levels as a result of land drainage from natural sources such as weathering of rock, `waters in contact with granite`, siliceous sand, well-baked soil, or other relatively soluble material Hinch & Underwood, 1985 (TDS is the component of total residue that passes through a 0.45 �m filter and refers primarily to inorganic salts and organic matter dissolved in water. Principal ions that contribute to TDS include: CO₃, HCO₃, Cl, SO₄, NO₃, Na, K, Ca, and Mg)

20
(12.45-86.14) Average for pristine N.S. lakes Hinch & Underwood, 1985

500 Maximum Canadian objective drinking water standard Hinch & Underwood, 1985

TDS (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
<30	Natural background levels as a result of land drainage from natural sources such as weathering of rock, `waters in contact with granite`, siliceous sand, well-baked soil, or other relatively soluble material	Hinch & Underwood, 1985 (TDS is the component of total residue that passes through a 0.45 �m filter and refers primarily to inorganic salts and organic matter dissolved in water. Principal ions that contribute to TDS include: CO₃, HCO₃, Cl, SO₄, NO₃, Na, K, Ca, and Mg)
20 (12.45-86.14)	Average for pristine N.S. lakes	Hinch & Underwood, 1985
500	Maximum Canadian objective drinking water standard	Hinch & Underwood, 1985

Colour

Lake Means & Guidelines Lake & Specifics References & Notes

45 SD 48 TCU 37 pristine Halifax County lakes (Dec. 1984) John Underwood (pers. comm.). Jan. 1994 (True color [TCU] results from dissolved substances in solution. One source, the humic substances [resulting from decay or aqueous extraction of natural vegetation] are of environmental significance since they tend to absorb a variety of organic substances as well as bind aluminum, many of which have toxic properties. Apparent color [Hazen U] results from suspended or colloidal matter [Health & Welfare Canada, 1980 per Hinch & Underwood, 1985])

5 Susies Lake (1980-83) Undisturbed lake in Halifax Metro. Kerekes et al, 1986

5 Clear-water Pockwock Lake (1991-92; 4 events) Clear-water, water supply lake in Hammonds Plains, Mandell (1994)

2 Bell Lake (1991-92; 30 events) Clear-water, urban lake in Dartmouth. Mandell (1994)

4 Clear-water Chocolate Lake (1991-92; 4 events) Clear-water, urban lake in Halifax, Mandell (1994)

44.5 SD 54.6 TCU 234 N.S. lakes Underwood et al, 1986

15 TCU Drinking Water- Maximum Acceptable Concentration CCME guidelines

Colour
Lake Means & Guidelines	Lake & Specifics	References & Notes
45 SD 48 TCU	37 pristine Halifax County lakes (Dec. 1984)	John Underwood (pers. comm.). Jan. 1994 (True color [TCU] results from dissolved substances in solution. One source, the humic substances [resulting from decay or aqueous extraction of natural vegetation] are of environmental significance since they tend to absorb a variety of organic substances as well as bind aluminum, many of which have toxic properties. Apparent color [Hazen U] results from suspended or colloidal matter [Health & Welfare Canada, 1980 per Hinch & Underwood, 1985])
5	Susies Lake (1980-83)	Undisturbed lake in Halifax Metro. Kerekes et al, 1986
5	Clear-water Pockwock Lake (1991-92; 4 events)	Clear-water, water supply lake in Hammonds Plains, Mandell (1994)
2	Bell Lake (1991-92; 30 events)	Clear-water, urban lake in Dartmouth. Mandell (1994)
4	Clear-water Chocolate Lake (1991-92; 4 events)	Clear-water, urban lake in Halifax, Mandell (1994)
44.5 SD 54.6 TCU	234 N.S. lakes	Underwood et al, 1986
15 TCU	Drinking Water- Maximum Acceptable Concentration	CCME guidelines

TOC (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

8 (0.7 - 20) Pristine N.S. lakes Hinch & Underwood, 1985 (TOC= suspended + dissolved organic constituents. High TOC values are commonly due to humic substances. Although not in itself a hazard, organic material may provide precursors of potentially harmful contaminants since humic acids tend to firmly adsorb or complex organic and inorganic pollutants and metals)

TOC (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
8 (0.7 - 20)	Pristine N.S. lakes	Hinch & Underwood, 1985 (TOC= suspended + dissolved organic constituents. High TOC values are commonly due to humic substances. Although not in itself a hazard, organic material may provide precursors of potentially harmful contaminants since humic acids tend to firmly adsorb or complex organic and inorganic pollutants and metals)

DOC (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

6.5 SD 6.4 37 pristine Halifax County lakes (Dec. 1984) John Underwood (pers. comm. Jan, 1994)

2.7 Susies Lake (Dec, 1985) Undisturbed lake in Halifax Metro. Urban et al, 1990

1.8 Clear-water Pockwock Lake (1991-92; 4 events) Clear-water, water supply lake in Hammonds Plains, Mandell (1994)

0.3 Clear-water Bell Lake (1991-92; 30 events) Clear-water, urban lake in Dartmouth, Mandell (1994)

0.45 Clear-water Chocolate Lake (1991-92; 4 events) Clear-water, urban lake in Halifax, Mandell (1994)

5.73 SD 3.57 234 N.S. lakes Underwood et al, 1986

5.0 Drinking Water OME- Aesthetic Objective

DOC (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
6.5 SD 6.4	37 pristine Halifax County lakes (Dec. 1984)	John Underwood (pers. comm. Jan, 1994)
2.7	Susies Lake (Dec, 1985)	Undisturbed lake in Halifax Metro. Urban et al, 1990
1.8	Clear-water Pockwock Lake (1991-92; 4 events)	Clear-water, water supply lake in Hammonds Plains, Mandell (1994)
0.3	Clear-water Bell Lake (1991-92; 30 events)	Clear-water, urban lake in Dartmouth, Mandell (1994)
0.45	Clear-water Chocolate Lake (1991-92; 4 events)	Clear-water, urban lake in Halifax, Mandell (1994)
5.73 SD 3.57	234 N.S. lakes	Underwood et al, 1986
5.0	Drinking Water	OME- Aesthetic Objective

Conductivity (�S/cm)

Lake Means & Guidelines Lake & Specifics References & Notes

62.5 SD 32.0 37 pristine Halifax County lakes (Dec. 1984) John Underwood (pers. comm.). Jan, 1994. (Conductivity is the ability of a substance to conduct an electric current [per Hinch & Underwood, 1985])

45.6 Susies Lake (Dec. 1985) Undisturbed lake in Halifax Metro. Urban et al, 1990

58.0 SD 74.8 159 Halifax County lakes Alexander et al, 1986

33 Clear-water Pockwock Lake (1991-92; 4 events) Clear-water, water supply lake in Hammonds Plains, Mandell (1994)

49 Clear-water Bell Lake (1991-92; 30 events) Clear-water, urban lake in Dartmouth, Mandell (1994)

500 Clear-water Chocolate Lake (1991-92; 4 events) Clear-water, urban lake in Halifax, Mandell (1994)

69.5 SD 493.0 638 N.S. lakes Alexander et al, 1986

46.9 SD 23.8 234 N.S. lakes Underwood et al, 1986

<5 Distilled water

20 to 40 Keji Park lakes Tordon (Environment Canada)

70 to 90 Halifax City tapwater McCarthy

30,000 + Seawater

Conductivity (�S/cm)
Lake Means & Guidelines	Lake & Specifics	References & Notes
62.5 SD 32.0	37 pristine Halifax County lakes (Dec. 1984)	John Underwood (pers. comm.). Jan, 1994. (Conductivity is the ability of a substance to conduct an electric current [per Hinch & Underwood, 1985])
45.6	Susies Lake (Dec. 1985)	Undisturbed lake in Halifax Metro. Urban et al, 1990
58.0 SD 74.8	159 Halifax County lakes	Alexander et al, 1986
33	Clear-water Pockwock Lake (1991-92; 4 events)	Clear-water, water supply lake in Hammonds Plains, Mandell (1994)
49	Clear-water Bell Lake (1991-92; 30 events)	Clear-water, urban lake in Dartmouth, Mandell (1994)
500	Clear-water Chocolate Lake (1991-92; 4 events)	Clear-water, urban lake in Halifax, Mandell (1994)
69.5 SD 493.0	638 N.S. lakes	Alexander et al, 1986
46.9 SD 23.8	234 N.S. lakes	Underwood et al, 1986
<5	Distilled water
20 to 40	Keji Park lakes	Tordon (Environment Canada)
70 to 90	Halifax City tapwater	McCarthy
30,000 +	Seawater

pH

Lake Means & Guidelines Lake & Specifics References & Notes

4.9 SD 0.56 37 pristine Halifax County lakes (Dec. 1984) John Underwood (pers. comm.). Jan, 1994

4.8 (calculated from ueq/l) Susies Lake (1980-83) Undisturbed lake in Halifax Metro. Kerekes et al, 1986

5.32 Clear-water Pockwock Lake (1991-92; 4 events) Clear-water, water supply lake in Hammonds Plains, Mandell (1994)

5.67 Bell Lake (1991-92; 30 events) Clear-water, urban lake in Dartmouth. Mandell (1994)

5.21 Clear-water Chocolate Lake (1991-92; 4 events) Clear-water, urban lake in Halifax, Mandell (1994)

5.7 SD 0.57 234 N.S. lakes Underwood et al, 1986

6.2 SD 0.6 167 Halifax County lakes Alexander et al, 1986

6.2 SD 0.8 730 N.S. lakes Alexander et al, 1986

5.0 to 9.0 Recreational Water Quality CCME guidelines

6.5 to 9.0 Freshwater Aquatic Life CCME guidelines

6.5 to 8.5 Drinking Water- Maximum Acceptable Concentration CCME guidelines

pH
Lake Means & Guidelines	Lake & Specifics	References & Notes
4.9 SD 0.56	37 pristine Halifax County lakes (Dec. 1984)	John Underwood (pers. comm.). Jan, 1994
4.8 (calculated from ueq/l)	Susies Lake (1980-83)	Undisturbed lake in Halifax Metro. Kerekes et al, 1986
5.32	Clear-water Pockwock Lake (1991-92; 4 events)	Clear-water, water supply lake in Hammonds Plains, Mandell (1994)
5.67	Bell Lake (1991-92; 30 events)	Clear-water, urban lake in Dartmouth. Mandell (1994)
5.21	Clear-water Chocolate Lake (1991-92; 4 events)	Clear-water, urban lake in Halifax, Mandell (1994)
5.7 SD 0.57	234 N.S. lakes	Underwood et al, 1986
6.2 SD 0.6	167 Halifax County lakes	Alexander et al, 1986
6.2 SD 0.8	730 N.S. lakes	Alexander et al, 1986
5.0 to 9.0	Recreational Water Quality	CCME guidelines
6.5 to 9.0	Freshwater Aquatic Life	CCME guidelines
6.5 to 8.5	Drinking Water- Maximum Acceptable Concentration	CCME guidelines

SO₄ (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

5.9 SD 2.2 37 pristine Halifax County lakes (Dec. 1984) John Underwood (pers. comm.). Jan, 1994

4.79 (calculated from ueq/l) Susies Lake (1980-83) Undisturbed lake in Halifax Metro. Kerekes et al, 1986

6 Clear-water Pockwock Lake (1991-92; 4 events) Clear-water, water supply lake in Hammonds Plains, Mandell (1994)

9.6 Bell Lake (1991-92; 30 events) Clear-water, urban lake in Dartmouth. Mandell (1984)

39 Clear-water Chocolate Lake (1991-92; 4 events) Clear-water, urban lake in Halifax, Mandell (1994)

500 Drinking Water- Maximum Acceptable Concentration CCME guidelines

SO₄ (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
5.9 SD 2.2	37 pristine Halifax County lakes (Dec. 1984)	John Underwood (pers. comm.). Jan, 1994
4.79 (calculated from ueq/l)	Susies Lake (1980-83)	Undisturbed lake in Halifax Metro. Kerekes et al, 1986
6	Clear-water Pockwock Lake (1991-92; 4 events)	Clear-water, water supply lake in Hammonds Plains, Mandell (1994)
9.6	Bell Lake (1991-92; 30 events)	Clear-water, urban lake in Dartmouth. Mandell (1984)
39	Clear-water Chocolate Lake (1991-92; 4 events)	Clear-water, urban lake in Halifax, Mandell (1994)
500	Drinking Water- Maximum Acceptable Concentration	CCME guidelines

Alkalinity (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

0.19 SD 0.38 37 pristine Halifax County lakes (Dec. 1984) John Underwood (pers. comm.). Jan, 1994 (Alk. is the capacity of a solution to neutralize acid to a designated pH [per Hinch & Underwood, 1985])

0 Clear-water Pockwock Lake (1991-92; 4 events) Clear-water, water supply lake in Hammonds Plains, Mandell (1994)

0.09 Clear-water Bell Lake (1991-92; 30 events) Clear-water, urban lake in Dartmouth, Mandell (1994)

0 Clear-water Chocolate Lake (1991-92; 4 events) Clear-water, urban lake in Halifax, Mandell (1994)

No decrease >25% Water Quality Objectives OME- should not be decreased by more than 25% of the natural concentration

Alkalinity (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
0.19 SD 0.38	37 pristine Halifax County lakes (Dec. 1984)	John Underwood (pers. comm.). Jan, 1994 (Alk. is the capacity of a solution to neutralize acid to a designated pH [per Hinch & Underwood, 1985])
0	Clear-water Pockwock Lake (1991-92; 4 events)	Clear-water, water supply lake in Hammonds Plains, Mandell (1994)
0.09	Clear-water Bell Lake (1991-92; 30 events)	Clear-water, urban lake in Dartmouth, Mandell (1994)
0	Clear-water Chocolate Lake (1991-92; 4 events)	Clear-water, urban lake in Halifax, Mandell (1994)
No decrease >25%	Water Quality Objectives	OME- should not be decreased by more than 25% of the natural concentration

Hardness as CaCO₃ (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

80-100 Acceptable balance between corrosion and incrustration Hinch & Underwood, 1985 (Hardness is a traditional measure of the capacity of water to react with soap. In freshwaters, the principal hardness-causing ions are Ca and Mg neither of which are considered concerns to health)

0-60 Soft water Health & Welfare Canada, 1980 (per Hinch & Underwood, 1985)

60-120 Medium hard Water Health & Welfare Canada, 1980 (per Hinch & Underwood, 1985)

120-180 Hard water Health & Welfare Canada, 1980 (per Hinch & Underwood, 1985)

180 and above Very hard water Health & Welfare Canada, 1980 (per Hinch & Underwood, 1985)

7.1 SD 4.1 37 pristine Halifax County lakes (Dec. 1984) John Underwood (pers. comm.). Jan, 1994

Hardness as CaCO₃ (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
80-100	Acceptable balance between corrosion and incrustration	Hinch & Underwood, 1985 (Hardness is a traditional measure of the capacity of water to react with soap. In freshwaters, the principal hardness-causing ions are Ca and Mg neither of which are considered concerns to health)
0-60	Soft water	Health & Welfare Canada, 1980 (per Hinch & Underwood, 1985)
60-120	Medium hard Water	Health & Welfare Canada, 1980 (per Hinch & Underwood, 1985)
120-180	Hard water	Health & Welfare Canada, 1980 (per Hinch & Underwood, 1985)
180 and above	Very hard water	Health & Welfare Canada, 1980 (per Hinch & Underwood, 1985)
7.1 SD 4.1	37 pristine Halifax County lakes (Dec. 1984)	John Underwood (pers. comm.). Jan, 1994

Cl (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

10.3 SD 6.7 37 pristine Halifax County lakes (Dec. 1984) John Underwood (pers. comm.). Jan, 1994 (At 250 mg/l, salty taste may occur when the cation is Na. A high Cl content is known to harm metallic pipes as well as agricultural plants. Environmentally, Cl is a useful indicator of the effectiveness of lake mixing and dilution [per Hinch & Underwood, 1985])

4.08 (calculated from ueq/l) Susies Lake (1980-83) Undisturbed lake in Halifax Metro. Kerekes et al, 1986

6.2 Clear-water Pockwock Lake (1991-92; 4 events) Clear-water, water supply lake in Hammonds Plains, Mandell (1994)

9 Bell Lake (1991-92; 30 events) Clear-water, urban lake in Dartmouth. Mandell (1994)

148 Clear-water Chocolate Lake (1991-92; 4 events) Clear-water, urban lake in Halifax, Mandell (1994)

250 Drinking Water- Maximum Acceptable Concentration CCME

Cl (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
10.3 SD 6.7	37 pristine Halifax County lakes (Dec. 1984)	John Underwood (pers. comm.). Jan, 1994 (At 250 mg/l, salty taste may occur when the cation is Na. A high Cl content is known to harm metallic pipes as well as agricultural plants. Environmentally, Cl is a useful indicator of the effectiveness of lake mixing and dilution [per Hinch & Underwood, 1985])
4.08 (calculated from ueq/l)	Susies Lake (1980-83)	Undisturbed lake in Halifax Metro. Kerekes et al, 1986
6.2	Clear-water Pockwock Lake (1991-92; 4 events)	Clear-water, water supply lake in Hammonds Plains, Mandell (1994)
9	Bell Lake (1991-92; 30 events)	Clear-water, urban lake in Dartmouth. Mandell (1994)
148	Clear-water Chocolate Lake (1991-92; 4 events)	Clear-water, urban lake in Halifax, Mandell (1994)
250	Drinking Water- Maximum Acceptable Concentration	CCME

Na (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

6.3 SD 4.1 37 pristine Halifax County lakes (Dec. 1984) John Underwood (pers. comm.). Jan, 1994

3.6 (calculated from ueq/l) Susies Lake (1980-83) Undisturbed lake in Halifax Metro. Kerekes et al, 1986

3.8 Clear-water Pockwock Lake (1991-92; 4 events) Clear-water, water supply lake in Hammonds Plains, Mandell (1994)

4.9 Bell Lake (1991-92; 30 events) Clear-water, urban lake in Dartmouth. Mandell (1994)

88 Clear-water Chocolate Lake (1991-92; 4 events) Clear-water, urban lake in Halifax, Mandell (1994)

Na (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
6.3 SD 4.1	37 pristine Halifax County lakes (Dec. 1984)	John Underwood (pers. comm.). Jan, 1994
3.6 (calculated from ueq/l)	Susies Lake (1980-83)	Undisturbed lake in Halifax Metro. Kerekes et al, 1986
3.8	Clear-water Pockwock Lake (1991-92; 4 events)	Clear-water, water supply lake in Hammonds Plains, Mandell (1994)
4.9	Bell Lake (1991-92; 30 events)	Clear-water, urban lake in Dartmouth. Mandell (1994)
88	Clear-water Chocolate Lake (1991-92; 4 events)	Clear-water, urban lake in Halifax, Mandell (1994)

K (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

0.41 SD 0.15 37 pristine Halifax County lakes (Dec. 1984) John Underwood (pers. comm.). Jan, 1994

0.14 (calculated from ueq/l) Susies Lake (1980-83) Undisturbed lake in Halifax Metro. Kerekes et al, 1986

0.39 Clear-water Pockwock Lake (1991-92; 4 events) Clear-water, water supply lake in Hammonds Plains, Mandell (1994)

0.73 Bell Lake (1991-92; 30 events) Clear-water, urban lake in Dartmouth. Mandell (1994)

4.5 Clear-water Chocolate Lake (1991-92; 4 events) Clear-water, urban lake in Halifax, Mandell (1994)

K (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
0.41 SD 0.15	37 pristine Halifax County lakes (Dec. 1984)	John Underwood (pers. comm.). Jan, 1994
0.14 (calculated from ueq/l)	Susies Lake (1980-83)	Undisturbed lake in Halifax Metro. Kerekes et al, 1986
0.39	Clear-water Pockwock Lake (1991-92; 4 events)	Clear-water, water supply lake in Hammonds Plains, Mandell (1994)
0.73	Bell Lake (1991-92; 30 events)	Clear-water, urban lake in Dartmouth. Mandell (1994)
4.5	Clear-water Chocolate Lake (1991-92; 4 events)	Clear-water, urban lake in Halifax, Mandell (1994)

Ca (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

1.6 SD 0.95 37 pristine Halifax County lakes (Dec. 1984) John Underwood (pers. comm.). Jan, 1994

0.88 (calculated from ueq/l) Susies Lake (1980-83) Undisturbed lake in Halifax Metro. Kerekes et al, 1986

1.4 Clear-water Pockwock Lake (1991-92; 4 events) Clear-water, water supply lake in Hammonds Plains, Mandell (1994)

2.6 Bell Lake (1991-92; 30 events) Clear-water, urban lake in Dartmouth.Mandell (1994)

13 Clear-water Chocolate Lake (1991-92; 4 events) Clear-water, urban lake in Halifax, Mandell (1994)

Ca (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
1.6 SD 0.95	37 pristine Halifax County lakes (Dec. 1984)	John Underwood (pers. comm.). Jan, 1994
0.88 (calculated from ueq/l)	Susies Lake (1980-83)	Undisturbed lake in Halifax Metro. Kerekes et al, 1986
1.4	Clear-water Pockwock Lake (1991-92; 4 events)	Clear-water, water supply lake in Hammonds Plains, Mandell (1994)
2.6	Bell Lake (1991-92; 30 events)	Clear-water, urban lake in Dartmouth.Mandell (1994)
13	Clear-water Chocolate Lake (1991-92; 4 events)	Clear-water, urban lake in Halifax, Mandell (1994)

Mg (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

0.78 SD 0.41 37 pristine Halifax County lakes (Dec. 1984) John Underwood (pers. comm.). Jan, 1994

0.44 (calculated from ueq/l) Susies Lake (1980-83) Undisturbed lake in Halifax Metro. Kerekes et al, 1986

1 Clear-water Pockwock Lake (1991-92; 4 events) Clear-water, water supply lake in Hammonds Plains, Mandell (1994)

1 Bell Lake (1991-92; 30 events) Relatively undisturbed, clear-water, urban lake in Dartmouth. Mandell (1994)

2 Clear-water Chocolate Lake (1991-92; 4 events) Clear-water, urban lake in Halifax, Mandell (1994)

Mg (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
0.78 SD 0.41	37 pristine Halifax County lakes (Dec. 1984)	John Underwood (pers. comm.). Jan, 1994
0.44 (calculated from ueq/l)	Susies Lake (1980-83)	Undisturbed lake in Halifax Metro. Kerekes et al, 1986
1	Clear-water Pockwock Lake (1991-92; 4 events)	Clear-water, water supply lake in Hammonds Plains, Mandell (1994)
1	Bell Lake (1991-92; 30 events)	Relatively undisturbed, clear-water, urban lake in Dartmouth. Mandell (1994)
2	Clear-water Chocolate Lake (1991-92; 4 events)	Clear-water, urban lake in Halifax, Mandell (1994)

Fe (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

0.073 (calculated from ueq/l) Susies Lake (1980-83) Undisturbed lake in Halifax Metro. Kerekes et al, 1986

0.06 Clear-water Pockwock Lake (1991-92; 4 events) Clear-water, water supply lake in Hammonds Plains, Mandell (1994)

0.04 Clear-water Bell Lake (1991-92; 30 events) Clear-water, urban lake in Dartmouth, Mandell (1994)

0.1 Clear-water Chocolate Lake (1991-92; 4 events) Clear-water, urban lake in Halifax, Mandell (1994)

0.3 Freshwater Aquatic Life CCME

0.3 Drinking Water- Maximum Acceptable Concentration CCME

Fe (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
0.073 (calculated from ueq/l)	Susies Lake (1980-83)	Undisturbed lake in Halifax Metro. Kerekes et al, 1986
0.06	Clear-water Pockwock Lake (1991-92; 4 events)	Clear-water, water supply lake in Hammonds Plains, Mandell (1994)
0.04	Clear-water Bell Lake (1991-92; 30 events)	Clear-water, urban lake in Dartmouth, Mandell (1994)
0.1	Clear-water Chocolate Lake (1991-92; 4 events)	Clear-water, urban lake in Halifax, Mandell (1994)
0.3	Freshwater Aquatic Life	CCME
0.3	Drinking Water- Maximum Acceptable Concentration	CCME

Mn (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

0.06 (<0.01-1.2) Average in N.S. lakes Hinch & Underwood, 1985 (Mn does not occur naturally as a metal but is present in over 100 common salts and minerals in rocks, soils, and on the floors of lakes and oceans. In natural waters, generally <0.05. Higher levels are either associated with industrial pollution or with reducing conditions such as exist underground and in some lakes and reservoirs [per Health & Welfare Canada, 1980])

0.0715 Susies Lake (Dec. 1985) Undisturbed lake in Halifax Metro. Urban et al, 1990

0.05 Drinking Water- Maximum Acceptable Concentration CCME (Mn is one of the elements least toxic to mammals. At levels exceeding 0.15, Mn stains plumbing fixtures and laundry and causes undesirable tastes in beverages. It is difficult to remove Mn at conc.<0.05 [Health & Welfare Canada, 1980 per Hinch & Underwood, 1985])

<0.01 Objective conc. (because of potential deposition and staining even at the max. acceptable level) Health & Welfare Canada, 1980 (per Hinch & Underwood, 1985)

Mn (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
0.06 (<0.01-1.2)	Average in N.S. lakes	Hinch & Underwood, 1985 (Mn does not occur naturally as a metal but is present in over 100 common salts and minerals in rocks, soils, and on the floors of lakes and oceans. In natural waters, generally <0.05. Higher levels are either associated with industrial pollution or with reducing conditions such as exist underground and in some lakes and reservoirs [per Health & Welfare Canada, 1980])
0.0715	Susies Lake (Dec. 1985)	Undisturbed lake in Halifax Metro. Urban et al, 1990
0.05	Drinking Water- Maximum Acceptable Concentration	CCME (Mn is one of the elements least toxic to mammals. At levels exceeding 0.15, Mn stains plumbing fixtures and laundry and causes undesirable tastes in beverages. It is difficult to remove Mn at conc.<0.05 [Health & Welfare Canada, 1980 per Hinch & Underwood, 1985])
<0.01	Objective conc. (because of potential deposition and staining even at the max. acceptable level)	Health & Welfare Canada, 1980 (per Hinch & Underwood, 1985)

Al (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

0.145 (0.008-0.55) Average background level for N.S. lakes Hinch & Underwood, 1985 (Al- the third most abundant of elements in the earth's crust)

0.230 (calculated from ueq/l) Susies Lake (1980-83) Undisturbed lake in Halifax Metro. Kerekes et al, 1986

0.005 Freshwater Aquatic Life CCME (pH<6.5; Ca²⁺<4.0 mg/l; DOC<2.0 mg/l)

0.1 Freshwater Aquatic Life CCME (pH≥6.5; Ca²⁺≥4.0 mg/l; DOC≥2.0 mg/l)

Al (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
0.145 (0.008-0.55)	Average background level for N.S. lakes	Hinch & Underwood, 1985 (Al- the third most abundant of elements in the earth's crust)
0.230 (calculated from ueq/l)	Susies Lake (1980-83)	Undisturbed lake in Halifax Metro. Kerekes et al, 1986
0.005	Freshwater Aquatic Life	CCME (pH<6.5; Ca²⁺<4.0 mg/l; DOC<2.0 mg/l)
0.1	Freshwater Aquatic Life	CCME (pH≥6.5; Ca²⁺≥4.0 mg/l; DOC≥2.0 mg/l)

As (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

<0.002 37 pristine Halifax County lakes (Dec. 1984) John Underwood (pers. comm.). Jan, 1994

≤0.005 Objective conc. in drinking water Hinch & Underwood, 1985

0.05 Maximum acceptable conc. in drinking water Hinch & Underwood, 1985

As (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
<0.002	37 pristine Halifax County lakes (Dec. 1984)	John Underwood (pers. comm.). Jan, 1994
≤0.005	Objective conc. in drinking water	Hinch & Underwood, 1985
0.05	Maximum acceptable conc. in drinking water	Hinch & Underwood, 1985

Ba (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

0.017 Average conc. in N.S. lakes Hinch & Underwood, 1985 (Ca and SO₄ are commonly associated with Ba as CO₃ and sandstones)

1.0 Maximum acceptable conc. in drinking water Hinch & Underwood, 1985

≤0.1 Objective conc. in drinking water Hinch & Underwood, 1985

Ba (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
0.017	Average conc. in N.S. lakes	Hinch & Underwood, 1985 (Ca and SO₄ are commonly associated with Ba as CO₃ and sandstones)
1.0	Maximum acceptable conc. in drinking water	Hinch & Underwood, 1985
≤0.1	Objective conc. in drinking water	Hinch & Underwood, 1985

Cd (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

0.005 - 0.008 Average value in natural waters is less than the detection limit Hinch & Underwood, 1985. (Cd is a relatively rare element and is nonetheless commonly found in association with Cu, Pb, and Zn. Surface waters having more than a few �gCd/l have probably been contaminated by industrial wastes [from metallurgical plants, plating works, plants manufacturing cadmium pigments, textile operations, cadmium-stabilized plastics or nickel cadmium batteries], or by effluents from sewage treatment plants)

0.7 Average value in N.S. lake sediments Hinch & Underwood, 1985

0.005 Maximum acceptable conc. in drinking water Hinch & Underwood, 1985

≤0.001 Objective conc. in drinking water Hinch & Underwood, 1985

Cd (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
0.005 - 0.008	Average value in natural waters is less than the detection limit	Hinch & Underwood, 1985. (Cd is a relatively rare element and is nonetheless commonly found in association with Cu, Pb, and Zn. Surface waters having more than a few �gCd/l have probably been contaminated by industrial wastes [from metallurgical plants, plating works, plants manufacturing cadmium pigments, textile operations, cadmium-stabilized plastics or nickel cadmium batteries], or by effluents from sewage treatment plants)
0.7	Average value in N.S. lake sediments	Hinch & Underwood, 1985
0.005	Maximum acceptable conc. in drinking water	Hinch & Underwood, 1985
≤0.001	Objective conc. in drinking water	Hinch & Underwood, 1985

Co (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

<0.01 - 0.08 N.S. lake averages Hinch & Underwood, 1985 (majority of Co readings in N.S. lakes are below the detection limit of 0.01)

Co (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
<0.01 - 0.08	N.S. lake averages	Hinch & Underwood, 1985 (majority of Co readings in N.S. lakes are below the detection limit of 0.01)

Cu (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

0.011
(<0.005 - 0.17) Average conc. in N.S. lakes Hinch & Underwood, 1985 (Cu is ubiquitous [found everywhere] in the environment)

1.0 Maximum acceptable conc. in drinking water Hinch & Underwood, 1985 (At higher concentrations Cu stains laundry and plumbing fixtures, and may also impart an undesirable taste to the water and enhance corrosion of Al and Zn)

<1.0 Objective conc. in drinking water Hinch & Underwood, 1985

Cu (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
0.011 (<0.005 - 0.17)	Average conc. in N.S. lakes	Hinch & Underwood, 1985 (Cu is ubiquitous [found everywhere] in the environment)
1.0	Maximum acceptable conc. in drinking water	Hinch & Underwood, 1985 (At higher concentrations Cu stains laundry and plumbing fixtures, and may also impart an undesirable taste to the water and enhance corrosion of Al and Zn)
<1.0	Objective conc. in drinking water	Hinch & Underwood, 1985

Pb (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

0.008 (<0.05-0.03) N.S. lake averages Hinch & Underwood, 1985 (Lead is considered a ubiquitous element in the environment)

0.05 Maximum acceptable drinking water standard Hinch & Underwood, 1985

≤0.001 Objective conc. in drinking water

Pb (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
0.008 (<0.05-0.03)	N.S. lake averages	Hinch & Underwood, 1985 (Lead is considered a ubiquitous element in the environment)
0.05	Maximum acceptable drinking water standard	Hinch & Underwood, 1985
≤0.001	Objective conc. in drinking water

Zn (mg/l)

Lake Means & Guidelines Lake & Specifics References & Notes

0.014 (<0.01-0.22) Average in N.S. lakes Hinch & Underwood, 1985 (Zn is an abundant element in the earth. In addition, various industrial and domestic emissions contribute considerable amounts to the air and water environment [primary iron and steel production, primary copper and nickel production, fuel combustion of coal and heavy oils, solid waste incineration, transportation, and pesticide application are all potential contributors])

5.0 Maximum acceptable conc. in drinking water Hinch & Underwood, 1985 (In excess of 5 mg/l, water has an undesirable taste, and may develop a greasy film when boiled)

<5.0 Objective conc. in drinking water Hinch & Underwood, 1985

Zn (mg/l)
Lake Means & Guidelines	Lake & Specifics	References & Notes
0.014 (<0.01-0.22)	Average in N.S. lakes	Hinch & Underwood, 1985 (Zn is an abundant element in the earth. In addition, various industrial and domestic emissions contribute considerable amounts to the air and water environment [primary iron and steel production, primary copper and nickel production, fuel combustion of coal and heavy oils, solid waste incineration, transportation, and pesticide application are all potential contributors])
5.0	Maximum acceptable conc. in drinking water	Hinch & Underwood, 1985 (In excess of 5 mg/l, water has an undesirable taste, and may develop a greasy film when boiled)
<5.0	Objective conc. in drinking water	Hinch & Underwood, 1985

Dissolved Oxygen (DO) (mg/l)

Freshwater Aquatic Life
DO conc. in mg/l (CCME)

Categories of biota Early life stages Other life stages

Warm-water 6 5

Cold-water 9.5 (6.5) 6.5

(6.5- interstitial water of the gravel)

Freshwater Aquatic Life
DO limits (Davis, NRCC in CCME)

Temperature Warm-water biota Cold-water biota Primarily salmonids

^oC % Sat. mg/l % Sat. mg/l % Sat. mg/l

0 47 7 54 8 57 8

5 47 6 54 7 57 7

10 47 5 54 6 57 6

15 47 5 54 6 59 6

20 47 4 57 5 65 6

25 48 4 63 5 72 6

Dissolved Oxygen (DO) (mg/l)
Freshwater Aquatic Life DO conc. in mg/l (CCME)
Categories of biota	Early life stages	Other life stages
Warm-water	6	5
Cold-water	9.5 (6.5)	6.5
(6.5- interstitial water of the gravel)






Freshwater Aquatic Life DO limits (Davis, NRCC in CCME)
Temperature	Warm-water biota	Cold-water biota	Primarily salmonids
^oC	% Sat.	mg/l	% Sat.	mg/l	% Sat.	mg/l
0	47	7	54	8	57	8
5	47	6	54	7	57	7
10	47	5	54	6	57	6
15	47	5	54	6	59	6
20	47	4	57	5	65	6
25	48	4	63	5	72	6

E. coli and fecal coli

Guidelines Specifics Reference

The geometric mean of at least 5 samples taken during a period of 30 days should not exceed 2000 E. coli per litre Recreational Water Quality CCME

E. coli and fecal coli
Guidelines	Specifics	Reference
The geometric mean of at least 5 samples taken during a period of 30 days should not exceed 2000 E. coli per litre	Recreational Water Quality	CCME

Enterococci

Guidelines Specifics Reference

The geometric mean of at least 5 samples taken during a period of 30 days should not exceed 350 enterococci per litre Recreational Water Quality CCME

Enterococci
Guidelines	Specifics	Reference
The geometric mean of at least 5 samples taken during a period of 30 days should not exceed 350 enterococci per litre	Recreational Water Quality	CCME

Microorganisms

Guidelines Specifics References

a) No sample should contain more than 10 total coliform organisms per 100 ml;
b) not more than 10% of the samples taken in a 30 day period should show the presence of coliforms;
c) not more than two consecutive samples from the same site should show the presence of coliforms; and
d) none of the coliform organisms detected should be fecal coliforms Drinking Water- Maximum Acceptable Concentration CCME

Microorganisms
Guidelines	Specifics	References
a) No sample should contain more than 10 total coliform organisms per 100 ml; b) not more than 10% of the samples taken in a 30 day period should show the presence of coliforms; c) not more than two consecutive samples from the same site should show the presence of coliforms; and d) none of the coliform organisms detected should be fecal coliforms	Drinking Water- Maximum Acceptable Concentration	CCME

References

Alexander, D.R., Kerekes, L.J., and Sabean, B.C. 1986. Description of selected lake characteristics and occurrence of fish species in 781 Nova Scotia Lakes. In Proc. N.S. Inst. Sci., vol. 36/2. 106p.

Beauchamp, S.T., and Kerekes, J. 1989. Effects of acidity and DOC on phytoplankton community structure and production in three acid lakes (Nova Scotia). In Water, Air, and Soil Pollution. 46:323-333.

Canadian Council of Ministers of Environment (CCME). Canadian Water Quality Guidelines. September 1989, Revised to April 1993.

Carlson, R.E. 1977. A trophic state index for lakes. Limnol. and Oceanog. 22(2):361-369.

Environment Canada. 2004. Canadian Guidance Framework for the Management of Phosphorus in Freshwater Systems. Ecosystem Health: Science-based Solutions Report No. 1-8. National Guidelines and Standards Office, Water Policy and Coordination Directorate, Environment Canada. 114 pp.

Gorham, E., Underwood, J.K., Martin, F.B., and Ogden III, J.G. 1986. Natural and anthropogenic causes of lake acidification in Nova Scotia. In Nature. 324(6096):451-453.

Hinch, P.R., and Underwood, J.K. 1985. A study of aquatic conditions in Lake Echo during 1984. N.S. Dept. Env. Lib. L192.1 85/00 C2. 38p,Appendix.

Hutchinson, N.J., Neary, B.P. and Dillon, P.J. 1991. Validation and use of Ontario's Trophic Status Model for establishing lake development guidelines. Lake and Reserv. Manage. 7(1):13-23.

Janus, L.L., and Vollenweider R.A. 1981. The OECD Cooperative Programme On Eutrophication. Summary Report. Canadian Contribution. Canada Center for Inland Waters, Burlington. 392p.

Kerekes, J. 1975. Phosphorus supply in undisturbed lakes in Kejimkujik National Park, Nova Scotia (Canada). In Verh. Internat. Verein. Limnol. 19:349-357.

Kerekes, J., Beauchamp, S., Tordon, R., and Pollock,T. 1986. Sources of Sulphate and Acidity in Wetlands and Lakes in Nova Scotia. In Water, Air, and Soil Pollution. 31:207-214.

Kratzer, C.R., and P.L. Brezonik. 1981. A Carlson-type trophic state index for nitrogen in Florida lakes. Water Res. Bull., Am. Water Res. Assn. 17(4):713-715,1057-1060.

Mandell, P.R. 1994. The Effects of Land Use Changes on Water Quality of Urban Lakes in the Halifax/Dartmouth Region. M. Sc. Thesis, Dalhousie Univ., Halifax. xii, 171p.

Ontario Ministry of the Environment (OME). Water Management- Goals, Policies, Objectives and Implementation Procedures. July 1994, Reprinted February 1999.

Organization for Economic Co-operation and Development (OECD). 1982. Eutrophication Of Waters. Monitoring, Assessment And Control. Organization for Economic Co-operation and Development, Paris. 154p.

Soil & Water Conservation Society of Metro Halifax. 1991. Limnological study of twenty seven Halifax Metro lakes. 136p.

Underwood, J.K., and Josselyn, D.M. 1979. The extent of road salt and nutrient stressing of Williams Lake, Halifax, Nova Scotia. N.S. Dept. Env. Lib.# W724 79/08. 88p.

Underwood, J.K., Ogden III, J.G., and Smith,D.L. 1986. Contemporary chemistry of Nova Scotian lakes. In Water, Air, and Soil Pollution. 30:991-999.

Underwood, J.K. (pers. comm. February, 1994). Unpublished data on 37 pristine Halifax County lakes, (N.S. Dept. of Environment single event sampling @ 0.5m-1m depth during 07-18 December, 1984).

Urban, N.R., Gorham, E., Underwood, J.K., Martin, F.B. and F.B. Ogden III, F.B. 1990. Geochemical processes controlling concentrations of Al, Fe, and Mn in Nova Scotia lakes. In Limnol. Oceanogr. 35(7):1516-1534.

We salute the Chebucto Community Net (CCN) of Halifax, Nova Scotia, Canada for hosting our web site, and we applaud its volunteers for their devotion in making `CCN' the best community net in the world