Chemical Assessment

• Most complicated, but easiest to do.

• Extreme natural variations

• What is normal?

Chemical Assessment

• Check expiration dates

• Face upstream at transect

• Monitor from area of greatest flow, but err on the side of safety!

pH

• Water’s acid/base content

• Measured on scale from 0 to 14

• pH affected by• Acids in rain• Types of soils/bedrock in area

• Low pH can be harmful to aquatic life

• Low pH can cause ammonia and heavy metals to be more soluble

pH scale

Ambient Water Monitoring Program - All Stream SitesField pH

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Field pH

6

7

8

9

10

2000 - 2009

Red lines represent the medians

Typical range for pH = 8.0 to 8.4 (rivers); 8.2 to 8.8 (lakes)Iowa average = 8.2 (rivers); 8.5 (lakes)

Iowa’s water quality standard - pH shall not be less than 6.5 nor greater than 9.0

Dissolved Oxygen• Necessary for

aquatic life• Affected by:

• Water temperature

• Season

• Time of day

• Stream flow

• Aquatic plants

• Dissolved or suspended solids

• Human impacts

Photo by IOWATER volunteer

Photo by NRCS

Dissolved Oxygen

Dawn DawnDusk

Dis

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ed O

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ge

n C

on

ce

ntr

ati

on

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

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0

5

10

15

20

25

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

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Blue line = Coldwater aquatic life criteria (7 mg/L)

Green line = Warm water aquatic life criteria (5 mg/L)

Red line= hypoxic condition (2 mg/L & lower)

Pink line = medians

Dissolved Oxygen

• Dissolved Oxygen levels of 5 mg/L or less are a concern

Nitrate-N and Nitrite-N

• Nitrogen is an essential plant nutrient.• Excess levels can cause nutrient enrichment.• Nitrate and nitrite are two forms of nitrogen.

Nitrate is very water soluble and is more common. Nitrite is less stable and quickly converts.

• Sources include:• Soil organic matter

• Animal wastes

• Decomposing plants

• Sewage

• Fertilizers

• Levels higher in late spring/early summer.

Ambient Water Monitoring Program - All Stream SitesNitrate + Nitrite as N (mg/L)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Nitrate+Nitrite-N (mg/L)

0

5

10

15

20

25

30

2000 - 2009

Typical range for Nitrate + Nitrite-N = 3 to 8.5 mg/L (rivers); 0.05 to 0.94 mg/L (lakes)Iowa average = 5.8 mg/L (rivers); 0.07 mg/L (lakes)

Iowa’s drinking water quality standard – 10 mg/L

Pink lines represent the medians

Nitrite/Nitrate Nitrogen

• Pads must be read at specified times

• Colors should be estimated to nearest color standard.

Levels of concern - Nitrite – 0.3 and greater - Nitrate – 20 & 50 mg/L

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Lanform RegionsDes Moines LobeEast-Central Iowa Drift PlainIowa-Cedar LowlandIowan SurfaceLoess HillsMississippi River Alluvial PlainMissouri River Alluvial PlainNorthwest Iowa PlainsPaleozoic PlateauSouthern Iowa Drift Plain

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Nitrate+Nitrite-N (mg/L)#S 0.4 - 2%U 2.1 - 5&V 5.01 - 10$T 10.1 - 14

Ambient Monthly Stream Monitoring Sites 2000 - 2009 (Median)

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Landforms of IowaAlluvial PlainsDes Moines LobeEast-Central Iowa Drift PlainIowan SurfaceLoess HillsNorthwest Iowa PlainsPaleozoic PlateauSouthern Iowa Drift Plain

Rivers

Nitrate+Nitrite-N (mg/L)#S 0.07 - 0.5%U 0.51 - 5$T 5.1 - 11

Ambient Monthly Lake Monitoring Sites 2000 - 2008 (Average)

Phosphorus

• An essential nutrient for plants and animals.

• Sources include:• Human, animal, or industrial wastes• Certain soils and rocks

• Excess phosphorus in water can cause excess plant growth which can cause algal blooms which may result in lower dissolved oxygen levels.

Ambient Water Monitoring Program - All Stream SitesTotal Phosphate as P (mg/L)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Total Phosphate-P

(mg/L)

0.001

0.01

0.1

1

10

100

2000 - 2009

Red lines represent the medians

Typical range for total phosphorus = 0.11 to 0.34 mg/L (rivers); 0.05 to 0.13 mg/L (lakes)

Iowa average = 0.2 mg/L (streams); 0.08 mg/L (lakes)

Phosphate

• Phosphate values of 0.6 mg/L & greater are of concern

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Lanform RegionsDes Moines LobeEast-Central Iowa Drift PlainIowa-Cedar LowlandIowan SurfaceLoess HillsMississippi River Alluvial PlainMissouri River Alluvial PlainNorthwest Iowa PlainsPaleozoic PlateauSouthern Iowa Drift Plain

Rivers

Total Phosphorus (mg/L)#S 0.05 - 0.2%U 0.21 - 0.3$T 0.31 - 0.63

Ambient Monthly Stream Monitoring Sites 2000 - 2009 (Median)

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Landforms of IowaAlluvial PlainsDes Moines LobeEast-Central Iowa Drift PlainIowan SurfaceLoess HillsNorthwest Iowa PlainsPaleozoic PlateauSouthern Iowa Drift Plain

Rivers

Total Phosphate (mg/L)#S 0.02 - 0.07%U 0.08 - 0.12$T 0.13 - 0.4

Ambient Monthly Lake Monitoring Sites 2000 - 2008 (Average)

Phosphorus

• If results are too brown or too green to read accurately, please contact IOWATER for a filtering apparatus

Chloride

• Found in salts.

• Easily dissolves in water.

• Sources include:• Human or animal wastes• Inputs from fertilizers• Road salt runoff

• Conservative tracer.

Ambient Water Monitoring Program - All Stream Sites

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Chloride (mg/L)

1

10

100

1000

2000 - 2009

Chloride

Red lines represent the medians

Typical range for chloride = 16 to 29 mg/L (rivers)

Iowa average = 22 mg/L (rivers)

Chloride

• Quantab values that fall below table on bottle should be recorded as <25 mg/L.

• If you find your chloride strips are inadequate (chloride >600 mg/L), contact IOWATER for high range chloride strips.

• Chloride values of 100 mg/L & greater are of concern.