HomeMy Public PortalAboutFox Point Lake Water Quality Monitoring Report 2021
Fox Point Lake
2021 Water Quality Monitoring Report
March 2022
Prepared for:
Municipality of Chester
Fox Point Lake Water Quality Monitoring Committee
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 2
Fox Point Lake 2021 Water Quality Monitoring Report
Contributing Authors
Blake McNeely, Watersheds & Water Quality Team Lead (Coastal Action)
March 2022
Coastal Action
45 School Street, Suite 403
Mahone Bay, N.S., B0J 2E0
Ph: (902) 634-9977
Email: info@coastalaction.org
This work was supported by:
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 3
Contents
List of Figures .................................................................................................................................. 4
List of Tables ................................................................................................................................... 6
1. Introduction ............................................................................................................................. 7
1.1. Fox Point Lake Background .............................................................................................. 7
1.2. Program Background ........................................................................................................ 8
1.3. Review of the 2020 Fox Point Lake Water Quality Monitoring Report ........................... 8
2. 2021 Water Quality Monitoring Results ................................................................................ 10
2.1. Water Sampling .............................................................................................................. 10
2.1.1. Physical Water Quality Parameters ........................................................................ 10
2.1.2. Chemical Water Quality Parameters ...................................................................... 20
2.1.3. Biological Water Quality Parameters ...................................................................... 23
2.2. Sediment Sampling ......................................................................................................... 25
2.2.1. Metals ..................................................................................................................... 26
2.2.2. Sediment Phosphorus and Orthophosphate .......................................................... 29
2.3. Additional Monitoring Parameters ................................................................................ 30
2.3.1. Rainfall .................................................................................................................... 30
2.3.2. Lake Level ................................................................................................................ 30
2.3.3. Stream Discharge Rates .......................................................................................... 31
3. Discussion .............................................................................................................................. 33
3.1. Algae Blooms in Fox Point Lake ...................................................................................... 33
3.2. Trophic State of Fox Point Lake ...................................................................................... 33
3.3. Potential for Nutrient Enrichment of Fox Point Lake ..................................................... 36
4. Review of FPL Water Quality from 2015 to 2021 .................................................................. 37
4.1 Trends in Water Quality Parameters .................................................................................. 37
4.2 Trends by Site ...................................................................................................................... 39
5. Recommendations ................................................................................................................. 40
6. References ............................................................................................................................. 41
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 4
List of Figures
Figure 1 Drainage basin and sampling sites of Fox Point Lake. ...................................................... 7
Figure 2. Phycocyanin (RFU) levels from the 2021 monthly YSI readings. ................................... 10
Figure 3. Chlorophyll-α (RFU) levels from the 2021 monthly YSI readings. ................................. 11
Figure 4. Cyanobacteria cells per mL from the 2021 monthly YSI readings. ................................ 11
Figure 5. Cyanobacteria cells per mL from the 2021 monthly depth profiles at Lake site........... 12
Figure 6. Chlorophyll-a (RFU) levels from the 2021 monthly depth profiles at the Lake site. ..... 12
Figure 7. Annual average water temperatures at all sites from 2015-2021. Red line indicates 20-
degree threshold for cold-water fish species. .............................................................................. 13
Figure 8. July and August average water temperatures at all sites from 2015 -2021. Red line
indicates 20-degree threshold for cold-water fish species. ......................................................... 13
Figure 9. Monthly water temperature depth profiles at the Lake site from 2015 -2021. ............ 15
Figure 10. Annual average dissolved oxygen (mg/L) at all sites from 2015-2021. Red line
indicates 6.5 mg/L minimum for aquatic species set by CCME. ................................................... 16
Figure 11. Dissolved oxygen (mg/L) depth profiles at Lake site from 2015-2021. ....................... 18
Figure 12. Annual average pH at all sites from 2015-2021. Red line indicates 6.5 pH minimum
for aquatic species set by CCME. .................................................................................................. 19
Figure 13. Annual average Total Dissolved Solids (mg/L) at all sites from 2015-2021................. 20
Figure 14. Annual average Total Suspended Solids (mg/L) at all sites from 2015-2021. ............. 21
Figure 15. Annual Average Phosphorus (mg/L) at all sites from 2015-2021. The solid red line
indicates the ≤ 0.03 mg/L MOECC guideline for streams and rivers, and the dotted red line
indicates ≤ 0.02 mg/L MOECC guideline for lakes. ....................................................................... 22
Figure 16. Annual average total nitrogen (mg/L) at all sites from 2015 -2021. Red line indicates
0.9 mg/L guideline from Dodds and Welch (2000). ...................................................................... 22
Figure 17. Annual average Fecal Coliform at all sites from 2015-2018. ....................................... 23
Figure 18. Annual average E. coli at all sites from 2019-2021. Red line indicates the Health
Canada primary contact guideline. ............................................................................................... 24
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 5
Figure 19. Microcystin-LR concentrations in water samples collected during observed algal
blooms in FPL. ............................................................................................................................... 25
Figure 20. Phosphorus and orthophosphate concentrations in benthic sediment at Southwest
Cove in FPL from 2018-2021. ........................................................................................................ 29
Figure 21. Phosphorus and orthophosphate concentrations in benthic sediment at the South
Inlet site from 2018-2021. ............................................................................................................ 29
Figure 22. Rainfall amounts at FPL from 2015 to 2021. ............................................................... 30
Figure 23. Stream discharge rates at FPL from 2015 to 2021. ..................................................... 32
Figure 24. Carlson TSI for FPL in 2021 using the mean Secchi disk depth (transparency), mean
chlorophyll α concentration, and mean total phosphorus concentration. (Carlson, 1977) ........ 34
Figure 25. Comparison of FPL TSI scores from 2015 to 2021 and trophic states, using the Carlson
(1977) trophic equations for total phosphorus, chlorophyll α, and Secchi disk. ......................... 35
Figure 26. Trophic State Index of FPL from 2015-2021. ............................................................... 36
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 6
List of Tables
Table 1. Concentrations of metals within site sediment samples. Light yellow indicates
parameters approaching one of the guidelines, orange indicates an exceedance of ISQG, red
indicates an exceedance of either the PEL or NSEQS guidelines.................................................. 26
Table 2. Summary of guideline exceedances of metals in sediment samples from SW Cove and
South Inlet sampling locations. Light yellow indicates parameters approaching one of the
guidelines, orange indicates an exceedance of the ISQG, and red indicates an exceedance of
either the PEL or NSEQS guidelines. ............................................................................................. 28
Table 3. TSI values for the FPL Lake site in 2021 for three parameters. ...................................... 34
Table 4: Nutrient concentrations from surface and depth (below the thermocline) water at the
Lake sample site. ........................................................................................................................... 37
Table 5: Nutrient concentrations from the two South Inlet sites following rainfall events in 2019,
2020, and 2021. ............................................................................................................................ 37
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 7
1. Introduction
The following report summarizes the results of the 2021 monitoring period at Fox Point Lake as
well as a review of water quality changes at the lake from 2015 to 2021.
1.1. Fox Point Lake Background
Fox Point Lake (FPL) is a 1.4 km2 lake located on the Aspotogan Peninsula, within the Municipality
of Chester, Nova Scotia (Figure 1). FPL contains 11 small islands and has an average depth of 4.9
m (Beanlands, 1980). The lake drains an area of 8 km2, with two inlet streams – the north and
south - and one outlet draining into St. Margaret’s Bay. The northern inlet drains a forested
region, crossing a wetland before reaching the lake, while the southern inlet flows through the
Aspotogan Golf Course. Residential properties, both year-round and seasonal, line the lake
perimeter.
Figure 1 Drainage basin and sampling sites of Fox Point Lake.
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 8
1.2. Program Background
In 2014, due to concerns from residents about the water quality of FPL, the Municipality of
Chester created the Fox Point Lake Water Quality Monitoring Committee (WQMC). The southern
end of FPL began suffering significant sedimentation pollution after heavy rainfall events. This
sedimentation coincided with the beginning of development at Aspotogan Ridge, a 550-acre
community with original development plans for 344 residential units and an 18-hole golf course.
The sedimentation events, occurring near the southern inlet which drains from the golf course,
raised the concern of citizens for the health of FPL.
To monitor the water quality conditions and track changes within the lake, Coastal Action was
contracted in 2015 by the Municipality of Chester to join the WQMC and develop and implement
a water quality monitoring program. The program involves four sample sites to monitor the water
quality incoming, within and exiting the lake (Figure 1). Monitoring activities are conducted by a
small group of trained volunteers, with the support of Coastal Action staff.
Further details on the program can be found in the Fox Point Lake Water Quality Monitoring
Program (2015), and program results are found in the Fox Point Lake Water Quality Monitoring
Reports from 2015 to 2020; all are available on request from the Municipality of Chester.
1.3. Review of the 2020 Fox Point Lake Water Quality Monitoring Report
From 2015 to 2019, the trophic state of FPL has been oligotrophic - approaching mesotrophic,
indicating that the biological productivity of the lake has not changed during this period.
However, in 2020 the lake displayed a shift in trophic state and was determined to be
mesotrophic.
Thermal stratification was observed at the Lake sample site leading to a depletion of oxygen at
depth, with concentrations of less than 3 mg/L recorded in the bottom waters of the lake.
A water sample was collected during a potential algal bloom in 2020; however, the sample was
lost by UPS in transit from BV Labs to their contracted lab. The suspected bloom was associated
with a large flock of Canada geese (Branta canadensis); therefore, it is difficult to determine if
the water was discoloured due to an algal bloom or geese.
Three of the four FPL sites did not exceed phosphorus guidelines in 2020; however, the South
Inlet site exceeded the 0.03 mg/L MOECC stream guideline, as it has done from 2015 to 2019.
The annual average total phosphorus in 2020 was the lowest of any previous year, at 0.073 mg/L
with a low of 0.065 mg/L. It is worth noting that the July sample was lost, and the data was
excluded from the annual average.
Sediment was sampled at the Southwest Cove and South Inlet sites to test for metal
concentrations. At the Southwest Cove site, arsenic, lead, mercury, and selenium were elevated;
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 9
with arsenic, lead, and mercury exceeding ISQG (Interim Sediment Quality Guidelines), and
selenium exceeding NS Environment (NSE) guidelines. At the South Inlet sample site, arsenic
decreased, exceeding the ISQG guidelines, but not the NSE guidelines. Lead levels decreased and
were no longer approaching the ISQG guidelines, while mercury maintained the same
concentration as in 2019, exceeding the ISQG guidelines.
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 10
2. 2021 Water Quality Monitoring Results
2.1. Water Sampling
2.1.1. Physical Water Quality Parameters
2.1.1.1. Chlorophyll-a, and Phycocyanin
In 2021, a ProDSS Total Algae PC Sensor was purchased by the Municipality of the District of
Lunenburg (MODL) to use on the ProDSS YSI unit owned jointly by MOC and MODL. This probe
measures concentrations of chlorophyll-α and phycocyanin present in water. Phycocyanin is a
pigment found in cyanobacteria, or blue-green algae, and provides an estimate of total
cyanobacteria production. Chlorophyll-α is a pigment produced by all types of algae and provides
an estimate of total algae production.
Collecting this data over multiple seasons will help determine the baseline concentrations of
phycocyanin in FPL, which can vary across waterbodies. Long-term monitoring with this probe,
paired with the collection of microcystin-LR water samples during blooms, will help to identify
spikes in phycocyanin concentrations and build a predictive curve for the relationship between
the concentrations of these algal pigments and the occurrence of algal blooms in FPL.
Algal concentrations are measured as Relative Fluorescence Units (RFU). These units were
converted to the total number of cells (Genzolia and Kann 2016). World Health Organization
(WHO) provides two guideline levels, ‘alert level 1’ is reached when 20,000 cells/mL are observed,
and ‘alert level 2’ is reached when 100,000 cells/mL are observed. At no point were the WHO
guidelines exceeded, nor were they approached. The data was not collected before, during, or
immediately after any known algae blooms.
Figure 2. Phycocyanin (RFU) levels from the 2021 monthly YSI readings.
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 11
Figure 3. Chlorophyll-α (RFU) levels from the 2021 monthly YSI readings.
Figure 4. Cyanobacteria cells per mL from the 2021 monthly YSI readings.
Depth profiles display an increase in cyanobacteria cells with depth, except for in October when
the lake turned over (Figure 5). This is indicative of algal cells dropping out of the photic zone and
getting trapped in the thermocline. Over the years, FPL has displayed microbial decomposition in
the thermocline zone with a significant decrease in dissolved oxygen in this part of the water
column.
Chlorophyll-α concentrations throughout the water column differ from the pattern displayed by
cyanobacteria cells, remaining fairly consistent from the top to the bottom. More data is needed
in subsequent monitoring years to better understand these changes in algal concentrations
during thermal stratification at FPL.
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
June July August September OctoberChlorophyll-α (RFU)Month
North Inlet South Inlet Lake Outlet South culvert
-500.00
0.00
500.00
1000.00
1500.00
2000.00
2500.00
June July August September OctoberCyanobacteria Cells/mlNorth Inlet South Inlet Lake Outlet South culvert
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 12
Figure 5. Cyanobacteria cells per mL from the 2021 monthly depth profiles at Lake site.
Figure 6. Chlorophyll-a (RFU) levels from the 2021 monthly depth profiles at the Lake site.
2.1.1.2. Surface and Depth Profile Water Temperatures
Water temperatures are recorded monthly. Average annual temperatures ranged from 9.4°C to
19.5°C (Figure 7). The South Inlet and South Culvert sites are consistently cooler due to the dense
forest canopy along this sampling zone. The highest average annual temperature recorded was
at the Lake site in 2018. At no point did any of the annual averages exceed the 20oC temperature
threshold for cold-water fish species (Nova Scotia Salmon Association [NSSA], 2014).
-500.00
0.00
500.00
1000.00
1500.00
2000.00
2500.00
0 2 4 6 8 10 12 14 16 18Cyanobacteria Cells/mlDepth (m)
June July August September October
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16Chlorophyll-α(RFU)Depth (m)
June July August September October
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 13
Figure 7. Annual average water temperatures at all sites from 2015-2021. Red line indicates 20-degree threshold for cold-water
fish species.
Average surface water temperatures for July and August exceeded the 20oC threshold for cold-
water fish from 2015 to 2021 at the Lake and Outlet sites. The North Inlet site exceeded the same
threshold only once in 2020, and the South Inlet did not exceed this threshold. The deeper waters
of the lake and deep cold-water pools in the Outlet can provide refuge during the warmest part
of the summer. However, in previous years the North Inlet was also a source of cooler water
refuge, which might not continue to be the case during the summer months (Figure 8).
Figure 8. July and August average water temperatures at all sites from 2015-2021. Red line indicates 20-degree threshold for cold-
water fish species.
0.0
5.0
10.0
15.0
20.0
25.0
2014 2015 2016 2017 2018 2019 2020 2021 2022Average Temperature (°C)Year
North Inlet South Inlet Lake Outlet South Culvert
0.0
5.0
10.0
15.0
20.0
25.0
2014 2015 2016 2017 2018 2019 2020 2021 2022
Average Temperature(°C) July & AugYear
North Inlet South Inlet Lake Outlet
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 14
Depth profiles have been conducted monthly at the Lake site from 2015 to 2021 (Figure 9).
Thermal stratification establishes in the lake between June to July, with warmer waters remaining
at the surface (epilimnion) and the cooler, more-dense waters settling to the lake bottom
(hypolimnion). The thermocline, the depth at which the water temperature rapidly changes, has
been consistent each year. The thermocline in June is between 9-10 m depth. The temperature
of the top 3 m of the water column in 2021 stayed above the 20°C threshold, while none of the
other years saw temperatures above 20°C in June.
The top 4 meters of the lake exceeded the 20°C threshold required for cold-water species, in all
years of the project. This is problematic given the trend across all years of low dissolved oxygen
concentrations available for cold-water fish at depth.
September brought some much-needed cooler water temperatures in most years, but surface
temperatures in 2015, 2016, and 2018 exceeded the 20°C threshold for cold-water species.
Lake turnover in FPL typically occurs between late September to early October. This is a relatively
brief window of time when the surface layer becomes colder than the bottom layer and begins
to descend, causing a mixing of the entire lake. During this period, parameters are observed to
be uniform at all depths.
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 15
Figure 9. Monthly water temperature depth profiles at the Lake site from 2015-2021.
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 16
2.1.1.3. Surface and Depth Profile Dissolved Oxygen
Dissolved oxygen (DO) was recorded bi-monthly at all four sites, from 2015 to 2017, and monthly
from 2018 to 2021 (Figure 10). The average annual DO ranges from 3.77 mg/L to 9.32 mg/L.
Average DO levels were generally lower in the summer months of July and August, which ranged
from 0.9 mg/L to 8.81 mg/L. The North Inlet consistently had the lowest DO concentrations, while
the highest concentrations were recorded at the Lake site. The low velocity, minimal incline, and
wetland drainage conditions of the North Inlet stream are likely factors in the low DO
measurements, as these factors limit the water’s ability to engulf oxygen from the air due to the
lack of turbulence of the water.
DO is a requirement for the survival of aquatic organisms, with a minimum threshold of 6.5 mg/L
set by the Canadian Council of Ministers of the Environment (CCME) for cold-water species
(CCME, 1999). Surface DO concentrations are not concerning at the Lake and Outlet sites. Low
DO concentrations were observed at the South Inlet site in 2016 and 2018.
Figure 10. Annual average dissolved oxygen (mg/L) at all sites from 2015-2021. Red line indicates 6.5 mg/L minimum for aquatic
species set by CCME.
DO was also measured at the Lake site from the surface to the bottom at each meter depth, from
2015 to 2021 (Figure 11). Annual averages were calculated month by month to compare DO levels
through the water column.
The DO levels below the thermocline in 2021 were outliers from previous years. The DO of all
surface readings ranged from 9.04 mg/L to 7.31 mg/L. The DO levels each year, except 2021,
followed the same pattern of declining at 3-5 m depth, slightly increasing at 6-8 m depth, then
decreasing gradually to the bottom. The DO levels in 2017 followed a similar pattern but
decreased more rapidly at 10 m depth, and ended at a lower concentration.
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
2014 2015 2016 2017 2018 2019 2020 2021 2022Average Dissolved Oxygen (mg/L)Year
North Inlet South Inlet Lake Outlet South Culvert
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 17
The 6.5 mg/L threshold is crossed every year in August but the depth at which it decreased varied
considerably. There is a noticeable trend in the last two years, where DO levels remain high until
8 m depth in 2021, and 10 m depth in 2020. In previous years, DO began to decline at shallower
depths.
The DO annual averages in September were much less varied than in August. Surface DO levels
in August from all years ranged from 7.54 mg/L in 2015 to 9.91 mg/L in 2020. Bottom DO levels
for all years ranged from 0.89 mg/L in 2015 and 8.32 mg/L in 2017.
The depth at which the thermocline is reached differs year to year. The temperature profiles
mirror this sentiment; however, the temperature change vs the DO change is much less drastic.
The annual averages in October show data that is to be expected of a lake headed for turnover.
The DO levels in 2016, and 2021 remain consistent, top to bottom, with very little change. The
lake had yet to turn over in the other years, with the thermocline still being present between 13-
16-m depth.
The August profiles display the most challenging conditions that fish in the lake will experience,
given the high temperatures throughout the water column coupled with the steep drop in DO
at depth.
In 2018, water temperature remained above the 20-degree threshold until 6-m depth, but
below that depth, DO concentrations are far below the 6.5 mg/L threshold. This leaves no part
of the water column that remains above either threshold; however, DO levels return to ~ 5
mg/L at 10-12 m depth. In 2019, water temperatures exceed the 20°C threshold until 4-m depth
and DO levels decrease below 6.5 mg/L at that depth. In 2020, the temperature stayed at
22.6°C until 11 m depth, at which point the DO levels had dropped to 4.52 mg/L. In 2021, the
temperature hovered around 20°C until 9-m depth. There was a sharp drop in DO from 7.41
mg/L to 4.52 mg/L at this depth. While not ideal conditions, the top layers of the lake would
have been easier on the local fish species than in previous years.
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 18
Figure 11. Dissolved oxygen (mg/L) depth profiles at Lake site from 2015-2021.
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 19
2.1.1.4. pH
pH, a measurement of the acidity of a liquid, was measured monthly at all sites from 2015 to
2021. Although the pH measurements for most annual averages fell below the 6.5-pH threshold
set by the CCME (CCME, 2002), the acidity of the FPL waters is not a significant concern. As Nova
Scotia has experienced high amounts of acid precipitation in the past, an d its geology limits the
replenishment of base cations to soils (NSSA, 2015), surface waters in southwest Nova Scotia are
generally lower than the 6.5-pH threshold. In addition, though the FPL sites’ pH values are lower
than 6.5 pH, many fish species can survive in waters >5.0-pH (NSSA, 2014) and therefore it
appears that most of the time the acidity of the waters at FPL pose minimal threat to organisms.
Figure 12. Annual average pH at all sites from 2015-2021. Red line indicates 6.5 pH minimum for aquatic species set by CCME.
Before 2021, the year-to-year annual average pH trends demonstrated that they were rising at
all the stream sites and slightly decreasing in the lake (Figure 12). The last year of the project saw
the opposite trend as the annual average pH in the lake was higher than in previous years at 6.88,
and the stream sites were lower, ranging from 5.42 to 4.88.
The pH at the South Culvert site has been measured only twice, in 2019 and 2021. There was very
little difference between the two years, but these readings were one-time samples, not annual
averages.
2.1.1.5. Total Dissolved Solids
The annual average of total dissolved solids (TDS) from the four FPL sites sampled monthly from
June-October ranged from 24.6 mg/L to 50 mg/L (Figure 13). The North Inlet displays the highest
TDS concentrations, while the remaining sites never exceeded 35 mg/L.
Annual average TDS at the Lake and Outlet sites were nearly identical for the duration of the
program. There is no guideline for TDS set by the CCME for the protection of aquatic health;
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
2014 2015 2016 2017 2018 2019 2020 2021 2022Average pHYear
North Inlet South Inlet Lake Outlet South Culvert
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 20
however, Hinch and Underwood (1985) found that pristine Nova Scotian lakes had an average of
20 mg/L. The Lake site displays an overall average of 30 mg/L, with a low of 27.5 in 2015, and a
high of 33.2 in 2018. This suggests that the lake is not pristine and to some extent is affected by
sedimentation. The presence of high TDS is not necessarily harmful as dissolved materials can be
from both anthropogenic and natural sources. As TDS does not have a guideline for the
protection of aquatic organisms, TDS concentrations do not appear to be detrimental to FPL.
Figure 13. Annual average Total Dissolved Solids (mg/L) at all sites from 2015-2021.
2.1.2. Chemical Water Quality Parameters
2.1.2.1. Total Suspended Solids
Total suspended solids (TSS) were measured as the value of solids suspended in a water column
that do not pass through a 45 µm glass fibre filter. Annual averages ranged from 1.0 mg/L to 7.58
mg/L (Figure 14). The South Inlet site displays the highest concentrations of TSS across all years,
spiking significantly in 2017 and 2020. As the CCME has a guideline of a 10 mg/L allowable
increase from baseline in waterbodies with TSS ≤ 100 mg/L (CCME, 2002), the increases observed
in FPL do not appear to be a threat to aquatic organisms.
0.0
10.0
20.0
30.0
40.0
50.0
60.0
2014 2015 2016 2017 2018 2019 2020 2021 2022Average Total Dissolved Solids (mg/L)Year
North Inlet South Inlet Lake Outlet South Culvert
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 21
Figure 14. Annual average Total Suspended Solids (mg/L) at all sites from 2015-2021.
2.1.2.2. Total Phosphorus
Annual averages for total phosphorus ranged from 0.006 mg/L at the Lake site in 2018, to 0.164
mg/L at the South Inlet site in 2015 (Figure 15). The highest phosphorus concentrations were
consistently measured at the South Inlet and were different from the North Inlet, Outlet, and
Lake sites.
Ontario’s Ministry of Environment and Climate Change (MOECC) has established two guidelines
for phosphorus in water bodies: ≤ 0.02 mg/L for lakes, and ≤ 0.03 mg/L for rivers and streams
(Ontario’s Ministry of Environment [MOE], 1979). The rivers and streams guideline was exceeded
every year in the South Inlet and South Culvert sites. The North Inlet site only exceeded the river
and streams guideline once in 2019, at 0.031 mg/L. The Outlet site never exceeded the guidelines
for rivers and streams, and the Lake site never exceeded the lake guidelines.
While the phosphorus levels at the South Inlet site have been consistently high each year, there
is a noticeable downward trend since the start of the program, with a small average increase in
2021. The reduction in phosphorus concentrations suggests that the stream may be slowly
recovering from nutrient enrichment and that the control measures placed along any
developments feeding the South Inlet are helping. The South Culvert site only consists of three
total samples, but there may be an upward trend occurring at this site. As there are few natural
phosphorus inputs into the environment, elevated concentrations indicate an anthropogenic
source.
0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
8.000
2014 2015 2016 2017 2018 2019 2020 2021 2022Average Total Suspended Solids (mg/L)Year
North Inlet South Inlet Lake Outlet South Culvert
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 22
Figure 15. Annual Average Phosphorus (mg/L) at all sites from 2015-2021. The solid red line indicates the ≤ 0.03 mg/L MOECC
guideline for streams and rivers, and the dotted red line indicates ≤ 0.02 mg/L MOECC guideline for lakes.
2.1.2.3. Total Nitrogen
Annual averages for total nitrogen ranged from 0.214 mg/L at the Lake site in 2016, to 1.221 mg/L
at the South Inlet site in 2015 (Figure 16). The highest concentrations of total nitrogen were
observed at the South Inlet site. Annual averages at the North Inlet site seem to be on an upward
trend since 2018. The three samples collected at the South Culvert site are not annual averages;
these samples were taken after rainfall events. Total nitrogen concentrations have remained
stable at the Lake and Outlet sites from 2015 to 2021.
Figure 16. Annual average total nitrogen (mg/L) at all sites from 2015-2021. Red line indicates 0.9 mg/L guideline from Dodds
and Welch (2000).
0.000
0.020
0.040
0.060
0.080
0.100
0.120
0.140
0.160
0.180
2014 2015 2016 2017 2018 2019 2020 2021 2022Average Phosphorus (mg/L)Year
North Inlet South Inlet Lake Outlet South Culvert
0.000
0.200
0.400
0.600
0.800
1.000
1.200
1.400
2014 2015 2016 2017 2018 2019 2020 2021 2022Average Nitrogen (mg/L)Year
North Inlet South Inlet Lake Outlet South Culvert
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 23
2.1.3. Biological Water Quality Parameters
2.1.3.1. Fecal Bacteria
In 2019, the FPL Monitoring Program switched from monitoring fecal coliforms to monitoring
Escherichia coli (E. coli) to align with Health Canada’s recommended use of E. coli as the primary
indicator of bacteria contamination in freshwaters. Health Canada has set primary and secondary
recreational contact guidelines for E. coli in freshwaters, ≤400 CFU/100 mL and ≤1000 CFU/100
mL, respectively (Health Canada, 2012).
Bacteria samples were collected monthly from all sites. Annual averages were calculated and split
into two categories: fecal coliform before 2019 (Figure 17), and E. coli levels from 2019 to 2021
(Figure 18).
E. coli samples can be compared against Health Canada’s primary recreational contact guideline.
Annual average E. coli levels ranged from 9 CFU/100 mL at the Lake site in 2021 to 154 CFU/100
mL at the North Inlet site in 2019. None of the annual averages or individual sample results
exceeded the 400 CFU/100 mL guideline.
Three bacteria samples were collected from the South Culvert site after rainfall events. Only one
of them recorded the presence of E. coli at a concentration of 250 CFU/100 mL. A residential
property with livestock was built in 2018 next to the south inlet stream, downstream of the South
Inlet sample site but upstream of FPL. This site is monitored for nutrients and bacteria due to the
potential for pollution entering the stream from the livestock and manure on this property.
Figure 17. Annual average Fecal Coliform at all sites from 2015-2018.
0
100
200
300
400
500
600
700
800
900
2014 2015 2016 2017 2018 2019
Average Fecal Coliform / 100 mL Year
North Inlet South Inlet Lake Outlet South Culvert
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 24
Figure 18. Annual average E. coli at all sites from 2019-2021. Red line indicates the Health Canada primary contact guideline.
2.1.3.2. Microcystin-LR & Algal Blooms
The recreational guideline for cyanobacterial toxins – microcystin-LR is 10 µg/L (Health Canada,
2012). This guideline is meant to protect against exposure to microcystins and other toxins that
may be present in an algal bloom. Microcystin-LR can persist in aquatic environments after a
visible bloom has dissipated (Federal-Provincial-Territorial Committee on Drinking Water, 2002).
Not all algal blooms are toxic cyanobacteria blooms, and Microcystin-LR is only one of the
possible toxins in a cyanobacteria bloom. For this reason, every algal bloom should be treated
with caution and reported to Nova Scotia Environment (NSE).
Algal blooms were observed in the lake during several years of the program (Figure 19). In 2016,
an algal bloom was detected on June 22 and a grab sample was collected and submitted to
Maxxam Analytics Laboratory to be analyzed for Microcystin-LR. The results showed Microcystin-
LR levels of 1.25 µg/L, confirming the presence of cyanobacterial toxins in the bloom. This was
the only recorded bloom in 2016.
A bloom was observed and tested on June 17th, 2017, displaying a Microcystin-LR concentration
of 0.71 µg/L, again lower than the Health Canada guidelines.
A sample collected in 2018 displayed a Microcystin-LR concentration of 0.16 µg/L, much lower
than the previous two years.
No blooms were sampled in 2019; however, NSE was contacted regarding a bloom. An NSE
inspector made a site visit and obtained a grab sample; it was determined that no bloom was
present.
A possible algal bloom was reported in 2020 on July 27th. A sample was collected and sent for
analysis; however, it was lost in transit by UPS. The toxicity of this bloom remains unconfirmed.
0
50
100
150
200
250
300
350
400
450
2018 2019 2020 2021 2022Average E. Coli /100 mLYear
North Inlet South Inlet Lake Outlet South Culvert
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 25
In 2021 there were two blooms observed in the lake by volunteers. The first bloom occurred on
July 17th, 2021. Results showed no Microcystin-LR present in the sample. The second bloom was
detected by volunteers on August 29, 2021. Results showed a Microcystin-LR concentration of
0.13 µg/L.
Figure 19. Microcystin-LR concentrations in water samples collected during observed algal blooms in FPL.
2.2. Sediment Sampling
Sediment sampling in the Southwest side of the lake (known as ‘SW Cove’) and at the South Inlet
site has occurred each year since 2017. The bottom substrate from both sites was analyzed for
metals, phosphorus, and orthophosphate, to assess the risk of internal nutrient loading within
the lake and potential risk from the accumulation of metals within the sediments (Tables 1 & 2).
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
2015 2016 2017 2018 2019 2020 2021 2022microcystin-LR (µg/L)Year
Fox Point Lake
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 26
2.2.1. Metals
Table 1. Concentrations of metals within site sediment samples. Light yellow indicates parameters approaching one of the
guidelines, orange indicates an exceedance of ISQG, red indicates an exceedance of either the PEL or NSEQS guidelines.
UNITS SW Cove South Inlet
Sediment
Concentration
Guidelines
Metals 2018 2019 2020 2021 2017 2018 2019 2020 2021 ISQG PEL NS
Acid Extractable
Aluminum (Al) mg/kg 1700 10000 14000 12000 4400 6100 6200 6600 6400
Acid Extractable
Antimony (Sb) mg/kg ND ND ND ND ND ND ND ND ND 25
Acid Extractable
Arsenic (As) mg/kg 6 6.1 9.1 20 7.9 10 22 9.8 35 5.9 17 17
Acid Extractable
Barium (Ba) mg/kg 14 37 69 73 30 50 54 46 50
Acid Extractable
Beryllium (Be) mg/kg ND 2.4 2.2 3.3 ND ND ND ND ND
Acid Extractable
Bismuth (Bi) mg/kg ND ND ND ND ND ND ND ND ND
Acid Extractable Boron
(B) mg/kg ND ND ND ND ND ND ND ND ND
Acid Extractable
Cadmium (Cd) mg/kg ND 0.8 0.48 1.6 ND 0.4 0.37 ND ND 0.6 3.5 3.5
Acid Extractable
Chromium (Cr) mg/kg ND 6.4 12 7 3.2 4.5 4.4 5.4 5 37.3 90 90
Acid Extractable Cobalt
(Co) mg/kg 1.2 1.1 3.3 3.2 1.9 2 3.3 2.9 4.6
Acid Extractable
Copper (Cu) mg/kg 2.2 11 18 10 7.4 8.5 8.3 7.3 7.3 35.7 197 197
Acid Extractable Iron
(Fe) mg/kg 4000 3200 11000 7200 5900 7000 12000 11000 16000 47,766
Acid Extractable Lead
(Pb) mg/kg 2.6 50 61 21 17 33 31 21 21 35 91.3 91.3
Acid Extractable
Lithium (Li) mg/kg 6.6 7.6 20 11 6.8 7.8 9.3 13 11
Acid Extractable
Manganese (Mn) mg/kg 230 150 420 430 330 270 550 420 1800 1,100
Acid Extractable
Mercury (Hg) mg/kg ND 0.16 0.23 0.13 0.12 0.21 0.17 0.17 0.19 0.17 0.486 0.486
Acid Extractable
Molybdenum (Mo) mg/kg ND ND ND 4.2 ND ND ND ND ND
Acid Extractable Nickel
(Ni) mg/kg ND 4.6 8.1 4 2.7 3.8 3.8 4.2 3.6 75
Acid Extractable
Phosphorus (P) mg/kg 110 1,100.00 1200 460 640 920 660
Acid Extractable
Rubidium (Rb) mg/kg 4.3 6.2 16 9.3 7.1 7.9 9 13 11
Acid Extractable
Selenium (Se) mg/kg ND 2.7 2.1 3.3 ND 1.1 1 0.71 0.9 2
Acid Extractable Silver
(Ag) mg/kg ND ND ND ND ND ND ND ND ND 1
Acid Extractable
Strontium (Sr) mg/kg ND 11 16 9.8 12 24 24 17 15
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 27
ND = Not Detected
Three guidelines are used for comparison for the sediment analysis; the CCME’s recommended
interim sediment quality guideline (ISQG), the CCME’s probable effect levels (PEL), and the Nova
Scotia Environmental Quality Standards (NSEQS) contamination threshold. Sediment samples
were collected at two sites in Fox Point Lake, starting in 2017. One of these sites, Southwest Cove,
was sampled for only phosphorus in 2017, and then a full metals suite in 2018, 2019, 2020, and
2021. The South Inlet was sampled for a full metals suite from 2017 to 2022.
Arsenic levels were noticeably high at both sites, in all years. At Southwest Cove, the ISQG
guidelines were exceeded from 2018 to 2020, and all three guidelines were exceeded in 2021.
There is a noticeable increase in arsenic at this site. The levels in 2018 showed 6 mg/kg, and a
jump to 20 mg/kg in 2021. A similar trend is present in the South Inlet site, where ISQG guidelines
were exceeded in 2017, 2018, and 2020. All three guidelines were exceeded in 2019 and 2021 .
There was an increase from 7.9 mg/kg in 2017, to 35 mg/kg in 2021. This suggests that there is
an active input of arsenic into the system that is gradually increasing concentrations in the
sediment at both sites. Increased arsenic levels reduce the abundance of benthic invertebrates,
the main food source for many aquatic species (CCME, 2002). Given the increasing levels of
arsenic at both sites, the presence of food for freshwater species may be actively decreasing.
Organisms living within the stream should be considered at-risk for bioaccumulation. Any
fisheries should be limited to the lake, where the inputs from the South Inlet are diluted and do
not appear to affect the overall sediment quality within the lake .
Cadmium levels in the Southwest Cove site exceeded the ISQG guidelines in 2019 and 2021 but
were never exceeded in the South Inlet. The highest cadmium level recorded was 1.6 mg/kg in
the Southwest Cove in 2021. Like arsenic, cadmium reduces the abundance of benthic
invertebrates and damages aquatic species. However, cadmium levels are generally low at both
sites, often going undetected in the metal suite analysis. The highest level recorded only
exceeded is ISQG guidelines by 0.7 mg/kg.
Lead levels were also relatively low in both sites, with only the ISQG guidelines being exceeded
in 2019, and 2020, at the Southwest Cove site. In 2019, lead was recorded at 50 mg/kg, and 61
mg/kg in 2020. These levels exceeded the ISQG guidelines by 15 mg/kg, and 31 mg/kg,
Acid Extractable
Thallium (Tl) mg/kg ND 0.13 0.18 0.52 ND ND 0.1 0.15 0.13
Acid Extractable Tin
(Sn) mg/kg ND 3.2 3.7 1.4 ND ND 1.1 1.3 1.1
Acid Extractable
Uranium (U) mg/kg 1.5 14 11 18 6.9 11 10 7.5 8.9
Acid Extractable
Vanadium (V) mg/kg 2.8 15 25 18 6.1 8.4 10 9.4 9.9
Acid Extractable Zinc
(Zn) mg/kg 16 50 48 78 30 43 35 35 31 123 315 315
Orthophosphate (P) mg/kg 0.64 0.24 0.30 0.16 0.51 1.30 0.55 0.33 0.33
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 28
respectively. Lead levels at the South Inlet approached the ISQG guidelines in 2018, and 2019,
but did not exceed them. Lead can reduce the abundance of benthic invertebrates, and
depending on the physicochemical conditions, can be harmful to other aquatic organisms (CCME,
2002). The levels of lead at both sites appear to be decreasing and do not approach the threshold
of the PEL or NSEQS guidelines.
Mercury levels observed at both sites appear to consistently exceed or approach the ISQG
guidelines. At the Southwest Cove, mercury levels exceeded the ISQG guidelines once in 2020,
but only approached them in 2019, and 202 1. At the South Inlet site, the ISQG guidelines were
either met or exceeded from 2018 to 2021 and were approached in 2017. The highest levels of
mercury observed were 0.23 mg/kg at the Southwest Cove and 0.21 mg/kg at the South Inlet.
While these levels exceeded the ISQG guidelines, they did not come close to approaching the PEL
or NSEQS guidelines. There doesn’t appear to be an increasing trend at either site.
Selenium is another metal that was found to exceed at least one of the three guidelines. In 2019,
2020, and 2021, the selenium levels at the Southwest Cove were found to exceed the 2 mg/kg
guideline from the NSEQS. The selenium levels in the South Inlet never exceeded or approached
these guidelines.
The development of the residential property near the south inlet stream may pose issues with
water quality within the remaining stretch of the stream before it flows into the lake. Continued
development and disturbance of bedrock upstream of this area also pose a risk. As the South
Inlet’s sediment has been contaminated with heavy metals previously, disturbance of the
sediment and additions of more pollutants to the sediment can result in the release of metals
into the water, thereby affecting water quality and organisms. Overall, metals appear to be
increasing at both sites since 2018.
Table 2. Summary of guideline exceedances of metals in sediment samples from SW Cove and South Inlet sampling locations.
Light yellow indicates parameters approaching one of the guidelines, orange indicates an exceedance of the ISQG, and red
indicates an exceedance of either the PEL or NSEQS guidelines.
SW Cove South Inlet
UNITS 2018 2019 2020 2021 2017 2018 2019 2020 2021
Acid Extractable Arsenic
(As) mg/kg 6 6.1 9.1 20 7.9 10 22 9.8 35
Acid Extractable
Cadmium (Cd) mg/kg ND 0.8 0.48 1.6 ND 0.4 0.37 ND ND
Acid Extractable Lead
(Pb) mg/kg 2.6 50 61 21 17 33 31 21 21
Acid Extractable
Mercury (Hg) mg/kg ND 0.16 0.23 0.13 0.12 0.21 0.17 0.17 0.19
Acid Extractable
Selenium (Se) mg/kg ND 2.7 2.1 3.3 ND 1.1 1 0.71 0.9
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 29
2.2.2. Sediment Phosphorus and Orthophosphate
Concentrations of both acid extractable (total) phosphorus and bioavailable orthophosphate in
sediment were analyzed from 2018 to 2021, with total phosphorus being excluded from the 2021
sample (Figures 20 and 21). Within the SW Cove, the concentration of orthophosphate dropped
to 0.16 mg/kg in 2021. Within the South Inlet, orthophosphate concentration was 0.33 mg/kg,
the same as 2020.
Figure 20. Phosphorus and orthophosphate concentrations in benthic sediment at Southwest Cove in FPL from 2018 -2021.
Figure 21. Phosphorus and orthophosphate concentrations in benthic sediment at the South Inlet site from 2018-2021.
Although there is a decrease in the fraction of orthophosphate in the sediment of the South Inlet
and only a slight increase in SW Cove, the overall continued increase in total phosphorus
concentrations could result in nutrient enrichment during fall turnover if the available
orthophosphate stores increase and are not assimilated.
0
200
400
600
800
1000
1200
1400
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
2018 2019 2020 2021
Total Phosphorous (mg/kg).Orthophosphate (mg/kg)SW Cove
Total Phosphorus (P)Orthophosphate (P)
0
200
400
600
800
1000
1200
1400
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
2018 2019 2020 2021 Total Phosphorous (mg/kg)Orthophosphate (mg/kg)South Inlet
Total Phosphorus (P)Orthophosphate (P)
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 30
The total phosphorus concentrations within the sediment of both sites suggest marginally
polluted sediment. According to Ontario’s provincial sediment quality guidelines, pollution can
range from clean/marginally polluted (‘lowest ef fect level’) at 600 mg/kg of phosphorus to
heavily contaminated (‘severe effect level’) at >2000 mg/kg of phosphorus in sediment (Ontario
MOE, 2008). Both the South Inlet and SW Cove have marginally polluted sediment, exceeding the
600 mg/kg boundary by 60 mg/kg and 600 mg/kg, respectively in 2020. The decrease in total
phosphorus at the South Inlet site is promising as it is close to achieving the 600 mg/L boundary;
however, the continued increase in total phosphorus in the SW Cove indicates an increase of
pollution over the past year into the lake.
2.3. Additional Monitoring Parameters
2.3.1. Rainfall
Rainfall was monitored during all years of the project (except in 2019). Data were collected daily
by a volunteer using a rain gauge until 2021 when a weather station was installed at the lake.
In 2021 the weather station was used to remotely collect 107 readings, totally in 607 mm of rain.
Readings were not collected in June, or the first half of July.
Figure 22. Rainfall amounts at FPL from 2015 to 2021.
2.3.2. Lake Level
The water level of FPL was measured daily by a volunteer using a staff gauge from 2015 to 2021,
except for 2016 and 2019. The staff gauge was attached to the volunteer's dock and the lake level
was recorded by visual observation. Lake level monitoring was included in the original design of
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 31
this monitoring program to identify any significant changes in lake level as a result of upstream
water usage (i.e., irrigation activities at the Aspotogan Ridge Golf Course).
In 2015, the average water level for all months was 0.69 m. In 2017, the average water level
across all months was 0.68 m. In 2018, the average across all months was 0.68 m, however, a
large data gap in this year means the average is less reliable. In 2020, the overall average of the
lake level was 0.69 m; however, volunteer data collection was sporadic.
In 2021, sporadic data collection displayed lake levels of 0.61 m in June, 0.59 m in July, and 0.65
m in August. Attempts to contact the volunteer to retrieve data from the remaining two months
were unsuccessful.
Water levels remained consistent from 2015 to 2021, with a slight decrease in 2021; however,
considering the limited and sporadic data collection, this data is not considered useful.
2.3.3. Stream Discharge Rates
Stream discharge rates were monitored at the two inlet sites – North and South – and the Outlet
site monthly from June to October from 2015 to 2021. Stream discharge (m³) was calculated
using a Global Water Flow Probe along with measurements of wetted width and water depth.
Similar to lake levels, discharge rates were included in this program as a way to identify significant
changes caused by water usage within the lake’s drainage basin.
The North Inlet and Outlet sites had the highest discharge, but the North Inlet site did experience
periods of negative results. The negative directions recorded at the North Inlet are associated
with the strong influence from wind and the lake’s waves, causing the stream to appear to be
moving backward. Trendlines show that the total discharge of the North Inlet is decreasing
slightly, but the South Inlet and Outlet are slightly increasing.
The average annual total stream discharge at the North Inlet was highest in 2019 at a rate of 0.67
m³ and was at its lowest in 2016 with a total stream discharge of 0.178 m³. The annual average
stream discharge at the South Inlet was highest in 2019 at a rate of 0.105 m³ and was at its lowest
in 2016 with a total stream discharge of 0.027 m³. The highest readings at the Outlet were 0.67
m³ in 2019, and the lowest readings were 0.178 m³ in 2016.
Stream discharge rates were highest in 2019 and lowest in 2016. This corresponds with the
rainfall amounts observed in 2016 during a significant drought period.
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 32
Figure 23. Stream discharge rates at FPL from 2015 to 2021.
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 33
3. Discussion
3.1. Algae Blooms in Fox Point Lake
In 2021, a weather station was installed to capture long-term weather data. This station collected
air temperature, dew point, heat index, wind chill, pressure, accumulated rainfall, windspeeds,
wind speed averages, and wind direction data in 5-minute intervals. With continued data
collection, this weather data can be used in conjunction with the algal probe (see section 2.1.1.1)
to better understand conditions at the lake leading up to and during an algal bloom.
NS Environment’s current system of notifying lake residents of potentially harmful algae blooms
is reactive and can be ineffective. NSE responds to reports of suspected blooms but inspectors
are not always able to respond in time to witness the bloom. NSE rarely collects water samples
for analysis and often has to post precautionary advisories based on the appearance of a bloom
in photographs submitted by residents. Lake closure advisories are posted via Twitter and other
online locations. Many residents of FPL do not have internet access at the lake. An NSE advisory
posted via Twitter in the summer of 2021 did not reach the majority of lake residents.
Microcystin-LR is not the only toxin produced by cyanobacteria. Anatoxins, Cylindrospermopsins,
Nodularins, Saxitoxins, Dermatoxtoxins, and other irritant toxins are also produced by
cyanobacteria (Health Canada, 2012). The majority of commercia l labs in Canada do not test for
these toxins. This means that the absence of Microcystin-LR in a water sample does not mean
that a bloom does not contain other toxins. Because of this, lake residents should be made aware
of all blooms and treat all blooms with the same level of caution.
As algal blooms can be induced and intensified by increases in nutrients to ecosystems (whether
naturally from mixing of waters or anthropogenically from pollution), trends in algal blooms are
hard to predict and can vary spatially. Increases in total nitrogen and phosphorus concentrations
in FPL increase the potential for blooms to occur. The literature predicts increases in both size
and frequency of blooms, globally, in the future (Michalak et al., 2013). Algal blooms should
continue to be monitored and tested within FPL, with residents made aware of algal bloom
causes, health effects, precautions to take, and the reporting procedure if a bloom occurs.
3.2. Trophic State of Fox Point Lake
The biological productivity of FPL has been assessed and monitored for changes over time by
identifying its trophic state annually. Based on the mean depth of transparency (Secchi disk), and
mean concentrations of chlorophyll-α and phosphorus, a Trophic State Index (TSI) score can be
calculated using the Carlson (1977) equations (Equations 1, 2, and 3). Trophic states range from
oligotrophic (low productivity and minimal biomass) to hypereutrophic (high productivity and
maximum biomass).
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 34
Equation 1: 𝑆𝑆𝐼 (𝑆𝑐𝑐𝑐𝑖ℎ 𝑐�ℎ𝑟𝑘)=60 −14.41 × ln(𝑀𝑐𝑎𝑘 𝑆𝑐𝑐𝑐𝑖ℎ 𝑐�ℎ𝑟𝑘 [𝑘])
Equation 2: 𝑆𝑆𝐼 (𝑐�𝑘𝑘𝑟𝑘𝑘�𝑦𝑘𝑘 𝐴)=30.6 +9.81 × ln(𝑀𝑐𝑎𝑘 𝑐�𝑘𝑘𝑟𝑘𝑘�𝑦𝑘𝑘 𝑎 [𝜇𝑔
𝐿])
Equation 3: 𝑆𝑆𝐼 (𝑟𝑘𝑟𝑎𝑘 𝑘�𝑘𝑟𝑘�𝑘𝑟𝑟𝑟)=4.15 +14.42 × ln(𝑀𝑐𝑎𝑘 𝑟𝑘𝑟𝑎𝑘 𝑘�𝑘𝑟𝑘�𝑘𝑟𝑟𝑟 [𝜇𝑔
𝐿])
Table 3. TSI values for the FPL Lake site in 2021 for three parameters.
Figure 24. Carlson TSI for FPL in 2021 using the mean Secchi disk depth (transparency), mean chlorophyll α concentration, and
mean total phosphorus concentration. (Carlson, 1977)
The trophic state of FPL has consistently been recorded as oligotrophic-approaching mesotrophic
from 2015-2019, however, the TSI results for 2020 put FPL into the mesotrophic category. In
Parameter Calculated TSI Value
Secchi (Transparency) 46.26
Chl α 42.53
Phosphorus 31.50
TSI Result 40.10
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 35
2021, the trophic state returned to oligotrophic (Figure 25). Phosphorus remains in the
oligotrophic range and chlorophyll-α decreased from a TSI of 48.9 in 2020 to 42.53 in 2021
keeping it in the mesotrophic-approaching oligotrophic range.
The continued increase in chlorophyll-α concentrations over several years, suggests the lake may
return to the mesotrophic range in the coming years. Chlorophyll-α dropped considerably since
2020, but it remains higher than any other year. The eutrophication process is driven initially by
catchment processes that contribute excess nutrients, particularly phosphorus, to a waterbody
and increase the probability of the occurrence of cyanobacterial blooms (Necombe et al., 2010).
Trend lines show that the trophic state of FPL is on an upward trend (Figure 26).
Figure 25. Comparison of FPL TSI scores from 2015 to 2021 and trophic states, using the Carlson (1977) trophic equations for total
phosphorus, chlorophyll α, and Secchi disk.
20
25
30
35
40
45
50
55
2015 2016 2017 2018 2019 2020 2021TSI ValueTSI Secchi Chla TP
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 36
Figure 26. Trophic State Index of FPL from 2015-2021.
3.3. Potential for Nutrient Enrichment of Fox Point Lake
Excessive nutrients entering FPL can be detrimental and contribute to a shift in the lake’s trophic
status. Nutrient enrichment can be from both external and internal loading sources. External
sources can be natural (wildlife waste, plant decomposition, etc.) or anthropogenic (septic tank
malfunction, fertilizer application, livestock waste, composter leachate, etc.) (Sereda et al., 2008;
Wetzel, 1990; Dion et al., 1983). Internal sources come from within the lake, whether nutrients
trapped within the lake substrate (i.e., orthophosphate) or nutrients trapped in the water below
the thermocline until lake turnover occurs (Kennedy and Walker, 1990).
In FPL, external loading appears to affect the inlet streams more than the lake. Both inlet streams
had greater nitrogen and phosphorus concentrations compared to the lake, which is able to
dilute and assimilate some excess nutrients. The elevated nutrient concentrations of these two
inlet streams suggest a level of pollution related to nutrients, particularly phosphorus entering
the South Inlet from its catchment area. Nutrient loading within the two inlets is further
increased during rainstorms via overland flow. Further increases in nutrients in the inlet streams
or along the perimeter of FPL may affect the delicate balance within the lake and speed up the
process of eutrophication.
Internal loading poses a risk to nutrient enrichment and eutrophication in FPL. In 2021, nitrogen
and phosphorus in the water column below the thermocline displayed slightly higher
concentrations than those measured at the surface (Table 4). When fall turnover occurs, the
redistribution of these elevated levels of nutrients can lead to algal blooms or increase the
eutrophication of the lake.
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 37
The low dissolved oxygen conditions of the bottom waters during lake stratification increase this
risk of internal nutrient loading. Anoxic conditions can lead to the release of sediment-bound
phosphorus from complexes with metals.
Table 4: Nutrient concentrations from surface and depth (below the thermocline) water at the Lake sample site.
Surface Waters At-Depth Waters
2019 2020 2021 2019 2020 2021
Phosphorus Concentrations (mg/L) 0.007 0.261 0.007 0.012 0.246 0.010
Nitrogen Concentrations (mg/L) 0.007 0.304 0.267 0.014 0.288 0.572
The South Inlet continues to display the highest nutrient concentrations within the FPL system
and suffers from a significant buildup of sedimentation. The residential property with livestock
located near the South Inlet poses further risk to this stream during overland runoff events.
In addition, increases in both phosphorus and orthophosphate concentrations at the SW Cove in
the lake indicate enrichment within the lake.
The water samples from the South Inlet and South Culvert sites showed no difference in
phosphorous or nitrogen in 2021 (Table 5).
Table 5: Nutrient concentrations from the two South Inlet sites following rainfall events in 2019, 2020, and 2021.
South Inlet South Culvert Site Difference
2019 2020 2021 2019 2020 2021 2019 2020 2021
Phosphorus
Concentrations
(mg/L) 0.049 0.645 0.063 0.049 0.056 0.063 0.000 -0.589 0.000
Nitrogen
Concentrations
(mg/L) 0.065 0.714 0.461 0.661 0.691 0.461 0.596 -0.023 0.000
4. Review of FPL Water Quality from 2015 to 2021
4.1 Trends in Water Quality Parameters
Water Temperature
Average monthly water temperatures across all sites are on a slight downward trend; however,
in the summer months of July and August, each site is on a slight upward trend, except for the
Lake site, which shows a slight downward trend. During the summer months of July and August,
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 38
trendlines show that the water temperatures of the North Inlet have increased by ~2.5 oC, and
~1oC at the South Inlet and the Outlet over the course of the program. Trendlines show that the
temperature at the Lake site has slightly decreased by ~0.3oC over the course of the program.
Dissolved Oxygen
Average monthly dissolved oxygen levels (mg/L) across all sites are on an upward trend;
trendlines show that the DO levels have increased by ~1 mg/L in the North Inlet, ~0.70 mg/L in
the Lake, ~0.50 mg/L in the South Inlet, and ~0.20 mg/L in the Outlet. During the summer months
of July and August, trendlines show that the average monthly dissolved oxygen levels have
increased in the North Inlet by ~1.40 mg/L, ~0.2 mg/L in the Lake, and have remained unchanged
in the South Inlet, and Outlet.
pH
Average monthly pH levels across all sites are on an upward trend. Throughout the program,
trendlines show that the pH levels have increased by ~0.30 in the Lake, and the North Inlet, ~0.25
in the Outlet, and ~0.10 in the South Inlet.
Total Dissolved Solids
Average monthly TDS levels across all sites have increased at each site, except the North Inlet.
Throughout the program, trendlines show that the TDS levels have decreased at the North Inlet
site by ~7 mg/L, increased by ~2 mg/L in the Lake, and ~1 mg/L at the South Inlet, and Outlet.
Total Suspended Solids
Average monthly TSS levels across all sites have increased at each site, except in the Lake.
Throughout the project, trendlines show that TSS levels have increased at the South Inlet by ~3.8
mg/L, ~1 mg/L at the North Inlet, ~0.20 mg/L at the Outlet, and decreased by ~0.70 mg/L in the
Lake.
Total Phosphorous
Average monthly total phosphorous levels have increased at the North Inlet, and the Outlet, but
have decreased at the South Inlet, and the Lake. Throughout the program, trendlines show that
TP levels have increased by ~0.05 mg/L at the North Inlet, and ~0.01 mg/L at the Outlet, while
levels have decreased by ~0.08 mg/L at the Lake, and ~0.01 mg/L at the South Inlet.
Total Nitrogen
Average monthly total nitrogen levels have increased at the North Inlet, and the Lake, but have
decreased at the South Inlet and Outlet. Throughout the program, trendlines show that TN levels
have increased by ~0.10 mg/L at the North Inlet, ~0.05 mg/L in the Lake, and decreased by ~0.40
mg/L at the South Inlet, and ~0.02 mg/L at the Outlet.
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 39
4.2 Trends by Site
Outlet
The water quality data from the Outlet shows all parameters are slightly on the rise except
nitrogen which has been on a slight downward trend throughout the project. Bacteria have also
been on the rise since the start of the program. Similar to the North Inlet, this increase in
nutrients is consistent with the results of the trophic state index.
North Inlet
The water quality data from the North Inlet shows that almost every parameter is on the rise,
except total suspended solids, which are on a slight decline. This change in water quality is
consistent with the results of the shifting trophic state in the lake. The stream is becoming more
nutrient-rich, and both the temperature and pH are increasing. Bacteria in the stream are on the
decline. Chlorophyll-α levels have been on the rise since 2015 but there was a large drop in 2021.
Lake
The water quality data from the Lake display varied changes in every parameter. Dissolved
oxygen, pH, total dissolved solids, total nitrogen, and chlorophyll-α are on the rise. Temperature,
total suspended solids, total phosphorous, and bacteria are declining. The trophic state has
shifted slightly; however, additional monitoring years would be needed to determine if this is a
long-term trend.
South Inlet
The South Inlet site has experienced some minor changes in parameters throughout the program.
Trendlines show that the temperature is on the rise and has increased by ~0.9°C. DO (mg/L) and
pH do not show any notable changes. Annual average DO levels are either slightly above or below
6 mg/L each year, and the annual average pH, which shows even less variability, is near 5.4 each
year. TDS is varied each year, but trendlines show that it has increased by ~1 mg/L since the start
of the program. TSS shows a clearer upward trend of ~3 mg/L since the start of the program.
Trendlines show that total phosphorous and nitrogen have decreased since the start of the
program, which started with very high concentrations of both parameters in 2015. Since 2016,
average annual nitrogen levels have been between 0.7 mg/L and 0.5 mg/L, on a slight downward
trend. Since 2017 the average annual phosphorus levels have been between 0.1 mg/L and 0.7
mg/L, also on a slight downward trend.
Fecal Coliform and E. Coli levels have been declining since the start of the pro gram. Three very
high outliers exist in 2015, 2016 and 2018, but the overall results show fewer instances of
elevated bacteria.
Trendlines show that the level of Chlorophyll-α is on a slight upward trend since the start of the
project, increasing by ~0.30 mg/L, however, the annual average in 2021 was the lowest of any
year at 2.21 mg/L.
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 40
5. Recommendations
It is recommended that the Fox Point Lake Water Quality Monitoring Program be continued. The
lake has shown a shift in its trophic state in recent years, algal blooms continue to occur, the
water quality of the North Inlet appears to be declining, and the South Inlet continues to su ffer
from poor water and sediment quality as well as significant sedimentation .
Coastal Action recommends a continuation of all current program components as well as the
consideration of additional rainfall-dependent sampling, homeowner education initiatives, and
the removal of sediment from the South Inlet stream.
Continued use of the ProDSS Algal Probe, along with data collected by the weather station and
the collection of water samples, will improve the understanding of lake conditions leading up to
and during algal bloom events. While algal bloom advisories are the responsibility of NS
Environment, this program could seek to improve the notification process for FPL to ensure that
all lake residents are immediately made aware of potentially dangerous algal blooms.
Homeowner education initiatives are recommended for the continued protection of the lake.
This could include the distribution of fact sheets and informational booklets, as done in past years
of the program, informing residents of best management practices for protecting water quality.
An investigation of the land-use activities within the catchment area of the North Inlet is
warranted, given the declining water quality observed in this stream in recent years.
Finally, we recommend the consideration of a sediment removal project in the South Inlet
stream. The severe sedimentation events that occurred in this stream in the early years of the
development project have left a legacy of contamination that will remain for many years to come.
The sediment left in this stream and the bottom waters of the south end of FPL display elevated
and increasing concentrations of metals. Coastal Action is recommending an investigation into
the feasibility of sediment removal using a device called a Sand Wand. There may be an
opportunity to have this activity partially funded from outside sources.
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 41
6. References
Beanlands, D.I. 1980. Surveys of Ten Lakes in Guysborough, Halifax, Hants, and Lunenburg
Counties, Nova Scotia, 1978. Freshwater and Anadromous Division Resource Branch.
Canadian Data Report of Fisheries and Aquatic Sciences No. 192.
Canadian Council of Ministers of the Environment (CCME). (1999). Canadian water quality
guidelines for the protection of aquatic life: Dissolved oxygen (Freshwater). In: Canadi an
environmental quality guidelines, 1999, Canadian Council of Ministers of the Environment,
Winnipeg.
Canadian Council of Ministers of the Environment (CCME). (2001). Canadian sediment quality
guidelines for the protection of aquatic life: Introduction. U pdated. In: Canadian
environmental quality guidelines, 1999, Canadian Council of Ministers of the Environment,
Winnipeg.
Canadian Council of Ministers of the Environment (CCME). 2002. Canadian water quality
guidelines for the protection of aquatic life: Total particulate matter. In: Canadian
environmental quality guidelines, 1999, Canadian Council of Ministers of the Environment,
Winnipeg.
Carlson, R. E. (1977). A trophic state index for lakes. Limnology and oceanography, 22(2), 361-
369.
Dion, N. P., Sumioka, S. S., and Winter, T. C. (1983). General hydrology and external sources of
nutrients affecting Pine Lake, King County, Washington. US Department of the Interior, US
Geological Survey.
Dodds, W.K. and Welch, E.B. (2000). Establishing nutrient criteria in streams.
J.N.Am.Benthol.Soc.19(1), 186-196.
Health Canada. (2012). Guidelines for Canadian Recreational Water Quality, Third Edition. Water
Air, and Climate Change Bureau, Healthy Environments and Consumer Safety Branch, Health
Canada, Ottawa, Ontario. (Catalogue No H129-15/2012E).
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. 38 p.
Kennedy, R. H., and Walker, W. W. (1990). Reservoir nutrient dynamics. Reservoir limnology:
ecological perspectives, 109-131.
Michalak, A.M., Anderson, E.J., Beletsky, D., Boland, S., Bosch, N.S., Bridgeman, T.B., Chaffin, J.D.,
Cho, K., Confesor, R., Daloğlu, I. and DePinto, J.V. (2013). Record-setting algal bloom in Lake
Erie caused by agricultural and meteorological trends con sistent with expected future
conditions. Proceedings of the National Academy of Sciences, 201216006.
Necombe, G., House, J., House, Ho, L., Baker P. and Burch M. (2010). Management Strategies for
Cyanobacteria (Blue-Green Algae): A Guide for Water Utilities. Research Report No. 74. Water
Quality Research Australia.
Nova Scotia Environment (NSE). (2014). Environmental Quality Standards for Contaminated Sites,
Rationale and Guidance Document. Version 1.0, April 2014. 57 p.
Fox Point Lake Final Report | Municipality of Chester | Coastal Action | 2022
Page | 42
Nova Scotia Salmon Association (NSSA) NSLC Adopt-A-Stream Program. (2014). Walking the
River: A Citizen’s Guide to Interpreting Water Quality Data. 43 p.
Nova Scotia Salmon Association (NSSA) NSLC Adopt-a-Stream Program. (2015). Acid Rain.
[http://www.nssalmon.ca/issues/acid-rain].
Ontario Ministry of the Environment (MOE). (1979). Rationale for the establishment of Ontario’s
Provincial Water Quality Objectives. Queen’s Printer for Ontario. 236 p.
Ontario Ministry of the Environment (MOE). (2008). Guidelines for Identifying, Assessing and
Managing Contaminated Sediments in Ontario. Queen’s Printer for Ontario. 112 p.
Sereda, J. M., Hudson, J. J., Taylor, W. D., and Demers, E. (2008). Fish as sources and sinks of
nutrients in lakes. Freshwater Biology, 53(2), 278-289.
Wetzel, R. G. (1990). Land-water interfaces: metabolic and limnological regulators. Internationale
Vereinigung für theoretische und angewandte Limnologie: Verhandlungen, 24(1), 6-24.