Freshwater SO 4 pH 2- Al 3+ Al 3+ Research Research O O 2 4 4 - - PowerPoint PPT Presentation

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Freshwater SO 4 pH 2- Al 3+ Al 3+ Research Research O O 2 4 4 - - PowerPoint PPT Presentation

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Freshwater SO 4 pH 2- Al 3+ Al 3+ Research Research O O 2 4 4 Ca 2+ 2 Nutrients PO 4 3- - S 2- - e 2+ + Fe Importance of sample timing, handling p p g g and other methods to low-level analysis of phosphorus in lake water p p

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SLIDE 1

Freshwater

Research

Al3+ pH O SO4

2-

Research

PO4

3-

  • Al3+

Ca2+ S2-

  • O2

2

Fe e2+

+ 4 4

Nutrients

Importance of sample timing, handling p p g g and other methods to low-level analysis

  • f phosphorus in lake water

p p

Gertrud Nürnberg, Ph.D.

Freshwater Research, Baysville, Ontario

1

www.fwr.ca

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SLIDE 2

Thank you y

  • Invitation by Session Chairs

T l t b NEMC

  • Travel grant by NEMC

Conference Coordinator, Jerry Parr of the NELAC Institute NELAC Institute Charlie Patton Charlie Patton

  • 1. Reasons NOT to use low-level analysis

2 What may be more important instead

  • 2. What may be more important instead

2

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SLIDE 3

Problems with low level analysis y

– Contamination – Need a lot of replicates (high analytical effort) – Few comparative data from other studies/ systems available – High cost, effort, specialization, etc. “Trade off” – Transient “Snapshot”: not reproducible (high sampling effort) – example “Blooms”

3

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SLIDE 4
  • Urban, larger Metro Toronto area
  • Well-buffered, hardwater

,

  • Area: 56 ha; Max Depth: 16 m
  • Dimictic kettle lake
  • Dimictic kettle lake
  • Meso- to eutrophic: summer TP 25 - 30 µg/L

I t l h h l d i 65% f t t l l d

  • Internal phosphorus load is 65% of total load
  • Anoxic hypolimnion

Urban Lake Wilcox

4

Urban Lake Wilcox, Southern Ontario, Canada

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SLIDE 5

Cyanobacteria vs SRP

(dissolved reactive P, detection limit 0.5 µg/L) ( , µg )

5

R2= 0.25, p<0.0001, n=123

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SLIDE 6

Cyanobacteria vs Ammonium

Detection limit: 0 002 0 005 mg/L Detection limit: 0.002 – 0.005 mg/L

6

R2= 0.22, p<0.0001, n=124

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SLIDE 7

Cyanobacteria vs Nitrate&Nitrite

Detection limit 0 005 mg/L Detection limit 0.005 mg/L

7

R2= 0.17, p<0.0001, n=181

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SLIDE 8

Bluegreen algal bloom in Fanshawe Lake on August 26, 2005

8

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SLIDE 9

Fanshawe Lake Nitrate and Chlorophyll Nitrate and Chlorophyll

Nitrate Chlorophyll

12 14 140 160

Nitrate Chlorophyll

8 10

e (mg/L)

80 100 120

(ug/L)

2 4 6

Nitrate

20 40 60 80

Chl

2 20

1989 1991 1990 1988

9

1989 1991 1990 1988

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SLIDE 10

Bloom Indicator: Low-Nitrate-Days

The period of time during summer and early fall, when p g y , nitrate concentration is below 1-2 mg/L

2 0 0 ays 1 0 0 1 5 0 ate-Da 5 0 1 0 0 w-Nitra 5 0 Low

10

1 9 6 5 1 9 7 5 1 9 8 5 1 9 9 5 2 0 0 5 Y E A R

Nürnberg 2007

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SLIDE 11

The quest for adequate phosphorus measurements in lakes Wh t i th l i f ? What is the analysis for?

  • Assessment for nutrients by routine
  • Assessment for nutrients by routine

monitoring, trophic state definition (Country, State, County) ( y, , y)

  • Remediation of eutrophication problems

(Specific lake or watershed) ( )

  • Modelling (Scenarios, TMDLs)
  • Specific scientific questions

p q

11

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SLIDE 12

What may be more important than LLA O tli

  • Outline -
  • Background knowledge

g g

– Limnological characteristics – Historic data (“blooms”, fish kill) – Knowledge from other studies/systems

  • Adequate sampling & handling, w/o contamination
  • Determine related variables (instead or in addition)
  • Adequate monitoring plan

– Spatial and temporal sampling – Specific fractions to be determined

12

  • Use a model instead
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SLIDE 13

(MOST) Important background ( ) g knowledge

  • Surface water

– Eutrophication – Cyanobacterial blooms

What is limiting algal growth?

  • Hypolimnia in lakes and reservoirs

A i ? Anoxic or not?

13

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SLIDE 14

Background knowledge Water is anoxic

SRP, dissolved reactive P ,

filtered through 0.45 µ, colorimetric assay, molybdenum blue - ascorbic acid

S li & h dli i i h Sampling & handling: aeration or gas-tight – Interference: H2S, Fe, organic (humic) id acids

– Differs with method

  • Auto analyser
  • Auto analyser
  • Dilution
  • Holding & bench time

Holding & bench time

14

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SLIDE 15

Interference Fe & H2S in SRP analysis Effect of Aeration Effect of Aeration

Soluble Fe: 3.15 mg/L H2S: 15 mg/L, SRP= 719 µg/L g

16m Lake Magog, 11 Aug 1981

2

g , µg

12m Lake St. George, 24 June1982

15

Nürnberg 1984 Water Research 18: 369-377

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SLIDE 16

Analytical complexities in anoxic waters y p

Iron and hydrogen sulfide interferences with SRP

  • Iron: oxygenation of Fe2+ to Fe3+ and

formation of oxy-hydroxides that adsorb PO4 SRP i d ti t d → SRP is underestimated Prevention by anoxic filtration F th i t f b h i id Further interference by humic acids

  • H2S: Interference with molybdenum blue PO4

assay (reductant) assay (reductant) → SRP is underestimated Prevention by aeration before filtration

16

Prevention by aeration before filtration

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SLIDE 17

Solution: total reactive P (TRP), aerated

SRP vs TRP in anoxic hypolimnetic samples SRP vs TRP in anoxic hypolimnetic samples from 5 softwater lakes with high Fe 3 hardwater with H2S R2= 0.998, p<0.0001, n=174 TRP= 2.74 + 1.02 SRP

17

Nürnberg 1984 Water Research 18: 369-377

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SLIDE 18

Determine related variables

  • Simpler to measure:

p

– In anoxic water:

  • TRP instead of SRP
  • TP instead of SRP
  • SRP instead of BAP
  • Dissolved iron (SFe) for SRP

( )

– Secchi transparency for chlorophyll a pigment – Hydrogen sulfide smell or low redox potential i t d f l di l d instead of low dissolved oxygen

18

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SLIDE 19

TP instead of SRP in anoxic hypolimnia Hypolimnetic SRP versus TP Hypolimnetic SRP versus TP

100.0 P (g/L)

1:1

10.0 SRP 1.0

19

10 100 TP (g/L)

Nürnberg & Peters 1984

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SLIDE 20

In anoxic hypolimnia y

  • With increasing TP, an increasing

g , g proportion is SRP, at 100 µg/L about 80%

  • Almost all SRP is biologically available

BAP*

At least 90%, when small amounts of hypolimnetic water are added to large amounts of surface water *Using radioactive bioassays that analyze for PO4

20

Nürnberg & Peters 1984

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SLIDE 21

SRP instead of BAP in anoxic hypolimnia hypolimnia SRP

100

)

AP (g/L 10 BA

N 51 R2 0 99

1 10 100 1

N=51, R2= 0.99

21

Data from Nürnberg & Peters 1984

1 10 100 SRP ( g/L)

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SLIDE 22

Dissolved iron (SFe) for SRP

A i l f Fit h B Anoxic samples of Fitch Bay, Lake Memphremagog, QU, VT

R2= 0.98, p<0.0001, n=11

22

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SLIDE 23

What may be more important than LLA Outline

  • Outline -
  • Background knowledge
  • Adequate sampling & handling
  • Determine related variables

Determine related variables

  • Adequate monitoring plan

Spatial and temporal sampling – Spatial and temporal sampling – Variables to be determined

  • Use a model instead
  • Use a model instead

23

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SLIDE 24

Adequate monitoring plan g

  • 1. Spatial and temporal sampling

p p p g

– Representative or worse conditions wanted? – Bays with polluted inlets or max depth location – Reservoir sections: riverine, transition, dam – Water intake location (reservoir) – Surface vs. hypolimnion – Growing season, fall turnover, under ice

  • 2. Careful selection of variables to be measured

24

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SLIDE 25

P and Iron Profiles

  • ligotrophic Chub Lake ON S

t 13 1982

  • ligotrophic Chub Lake, ON, Sept. 13 1982

0.0 2.5 5.0 7.5 10.0 25 50 75 100

  • 5
  • 5

SRP TP

  • 10
  • 10

th (m) SRP

  • 15

SFE TFE DO

  • 15

Dep 25

  • 20

FE2 2

  • 20

25

  • 25

0.0 2.5 5.0 7.5 10.0

  • 25

25 50 75 100

µg/L mg/L

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SLIDE 26

TP, SRP Profiles

at Dam of Brownlee Reservoir

11 A 1999

at Dam of Brownlee Reservoir, 11 Aug 1999

0000 0100 0200 0300 0400 0500

P (m g/L)

10 0.000 0.100 0.200 0.300 0.400 0.500 DRP 10 20 DRP TP 30 40

epth (m)

50 60

De

26

70

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SLIDE 27

27

Brownlee Reservoir, Snake River Hells Canyon Complex, ID/OR

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SLIDE 28

Brownlee

Brownlee Dam Site 5 RM 290

71

Site F Site 6 Below Brownlee Dam (Outflow)

Brownlee Reservoir, ID/OR

RM 290

Richland P

  • w

d e r R i v e r Eagle Creek C r e e k Brownlee 86

RM 286 Site E RM 295 Site 4 RM 300

Total length: 100 km Deep section: 48 km

Sturgill Creek ek Daly Creek

RM 300 Site 3 5

Deep section: 48 km Depth: 60 m

Cree Dennet

Site C OREGON IDAHO Camping Boat Ramp Site 3.5 Site D RM 310 Site D

Depth: 60 m Width: <1 km

Rive B u r n t Creek R

  • c

k

Site C RM 317 Surface composite sample taken here

*

McCall 86 95 30 Brownlee Dam

Site 3 RM 322

Weiser Weiser Cambridge Weiser River ver 55 71 86 95

Site B RM 327

28

Boise Weiser 84

Site 1 RM 345 (Inflow)

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SLIDE 29

0.150 1999 2000

Brownlee Reservoir,

0.100 TP (mg/L) 2000

Gradient along axis

Total phosphorus

0.000 0.050 280 290 300 310 320 330 340 350

  • --- Shallow ---
  • --- Deep ----

Inflow Outflow

p p concentration averages in the surface water in summer 1999 and 2000

280 290 300 310 320 330 340 350 Location (RM)

0.060 0.040 P (mg/L)

SRP concentration averages in the surface

0.000 0.020 DRP

  • ------ Deep -------

Outflow

  • ---- Shallow ---

Inflow

averages in the surface water in summer 1999 and 2000

29

280 290 300 310 320 330 340 350 Location (RM) Jul-Sep 1999 May-Sep 2000

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SLIDE 30

Adequate monitoring plan (2) g ( )

  • 1. Spatial and temporal sampling locations

2 C f l l ti f i bl t b d

  • 2. Careful selection of variables to be measured

& determine limits necessary for meaningful study That interfere with analytical procedures (Fe H S) – That interfere with analytical procedures (Fe, H2S) – That correlate with analyzed variable (SFe vs. SRP) – That can replace needed variable That can replace needed variable (NO3 instead of blooms) – That are measured routinely and frequently in i di (TP h h SRP) comparison studies (TP rather than SRP) – That are input to a specific model to be used (TDP instead of TP in river models)

30

(TDP instead of TP in river models)

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SLIDE 31

Careful selection of variables to be measured (2)

P Fractions in Water P Fractions in Water

  • TP - total P: digested then molybdenum-blue (MB)

analysis for PO4

  • SRP (DRP) - soluble reactive P: filtered through 0.45 µ

then MB (PO biologically available) then MB (PO4, biologically available)

  • TRP - total reactive P: (unfiltered) MB
  • PRP - particulate reactive P: TRP-SRP (Fe-P)

pa cu a e eac e S ( e )

  • DP - total dissolved P, filtered, then digested, then MB
  • PP - particulate P: TP-DP (seston, plankton)
  • BAP – biologically available P (bioassay)

31

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SLIDE 32

What may be more important than LLA Outline

  • Outline -
  • Background knowledge

Background knowledge

  • Adequate sampling & handling

D t i l t d i bl

  • Determine related variables
  • Adequate monitoring plan

– Spatial and temporal sampling – Variables to be determined

  • Use a model instead

– example Muskoka lakes

32

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SLIDE 33

Muskoka lakes on the Canadian Shield (Central Ontario)

33

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SLIDE 34

External Load

Atmosphere

InternalLoad

Morphometry z/Ao0.5 A i Atmosphere Watershed (Landuse, Geology) Shoreline z/Ao Anoxic Factor

Release

Rate Shoreline Development Upstream

Prediction of TP e g Lake Shore De elopment Model e.g. Lake Shore Development Model

Annual A P Hydrology

Morphometry

  • Water load q

Epilimnetic S P

34

Average P

  • Water load qs
  • Pred Retention

Summer P

After Nürnberg & LaZerte 2004

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SLIDE 35

TP concentration from Internal Load in 500 Muskoka Lakes 500 Muskoka Lakes

) 10.00 P (

g L-1

) 1.00 n d u c e d P 0.10 a l l

  • a

d i n I n t e r n

35

10 External load induced P ( g L-1) 0.01

6 10 30

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SLIDE 36

Internal Load Increases from Development in Muskoka Lakes Muskoka Lakes

10.000 P ( g L-1 ) 1.000 d u c e d P 0.100 a l l

  • a

d i n 0.010

  • f

i n t e r n a 0 001 0.010 c r e a s e

  • Development Index =

(P developed – P natural) / P natural

36

0.001 0.010 0.100 1.000 Development Index 0.001 I n

P natural

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SLIDE 37

Low Level Analysis y P bl ith LLA

  • Problems with LLA
  • What may be more important

y

– Know, what the analysis is for – Consider, what is known about the , system: Background knowledge – Adequate sampling, handling, and q p g g monitoring plan

37