BENEFICIAL REUSE OF FGD GYPSUM IN 

AGRICULTURAL APPLICATIONS 

November 11, 2009
1:00 – 1:10 Introductions, Agenda Review Bob Spoerri & Eric Schaeffer

1:10-1:20 What is FGD Gypsum? Dave Goss

1:20-1:40 FGD Gypsum impact on metals in soils and plants Dr. Malcolm Sumner

1:40-2:00 FGD Gypsum, Soil Erosion & Water Quality Dr. L. Darrell Norton

2:00-2:10 A Farmer’s Perspective on FGD Gypsum Jack Maloney

2:10-2:30 Use of FGD Gypsum in Agriculture Dr. Warren Dick

2:30-2:50 Risk Assessment for use of FGD Gypsum in Agriculture Dr. Rufus L. Chaney

2:50-3:05 Break

3:05- 3:15 Market Factors Dave Goss

3:15-3:25 Implementing an FGD Gypsum agricultural program Bob Spoerri & Ron Chamberlain

3:25-3:55 Open Discussion John Andersen, Moderator

3:55-4:00 Next Steps and Close Bob Spoerri & Eric Schaeffer

Agenda
FLUE GAS DESULFURIZATION

(FGD GYPSUM)

How it is produced and handled 

at the Power Plant

Dave C. Goss
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Limestone Forced Oxidation Process
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Removing Dried Gypsum from Drying 

Area using Earthmoving Equipment
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Loading Trucks with Gypsum inside 

Covered Storage Shed
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Loading Barge
Beneficial Reuse of FGD Gypsum in Agriculture Applications

FGD Gypsum:

• Is calcium sulfate dihydrate – CaSO4-2H20

• Exhibits essentially the same chemical characteristics of 

mined ore gypsum

– White Sands National Monument contains 275 square 

miles of calcium sulfate dihydrate or gypsum in the 

form of sand particles 

• Is ONLY produced from forced oxidation scrubber systems 

at power plants
Beneficial Reuse of FGD Gypsum in Agriculture Applications

FGD Gypsum is NOT:

• Coal ash or derived from coal in any manner

• Phosphogypsum ( from the manufacture of fertilizers from 

phosphate ore using sulfuric acid)

• Titano-gypsum (from the production of titanium oxide for 

paints)

• Citro-gypsum ( from the production of citric acid)
EFFECT OF FLUE GAS 

DESULFURIZATION GYPSUM ON 

METALS IN SOILS AND PLANTS

Malcolm E. Sumner

Regents’ Professor of Environmental Soil 

Science Emeritus

University of Georgia

Athens, GA

malcolm296@charter.net
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Why Do We Apply Gypsum to Soils?

• To improve chemical and physical conditions

– Reclaim sodium affected (sodic) soils

– Increase yields on many soils

– Reduce runoff and erosion

– Reduce nitrogen volatilization

– Reduce phosphorus in runoff
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Examples of Yield Increases

Crop

# of sites Yield increase due to gypsum

%

Alfalfa 10 24

Bell pepper 1 49

Cantaloupe 2 32

Cotton 8 20

Cucumber 1 42

Oats 1 15

Peanuts 90 13

Sorghum 1 57

Soybean 1 51

Squash 2 39

Sugarcane 1 24

Tomatoes 12 25

Watermelon 4 51
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Outcome

• FGD gypsum

– Valuable resource for crop production

– Increases yields and quality of crops

– Highly economic soil amendment
Beneficial Reuse of FGD Gypsum in Agriculture Applications

COMPARISON OF CONTAMINANTS IN 

VARIOUS GYPSUM MATERIALS
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Element Mined Gypsum FGD Gypsum

# of 

samples

Range Mean # of 

samples

Range Mean

mg/kg mg/kg

As 20 nd-2.53 0.84 30 nd-6.93 2.06

Be 19 nd-0.07 0.03 29 nd-0.18 0.07

Cd 19 nd-0.52 0.08 30 nd-0.90 0.16

Cr 20 nd-4.20 1.57 31 0.26-6.77 2.90

Co 12 0.01-4.39 1.37 27 0.17-1.38 0.55

Cu 20 nd-8.20 1.42 31 0.23-3.71 1.42

Hg 20 0.02-0.07 0.02 28 0.05-1.12 0.30

Ni 20 nd-10.96 2.65 31 nd-14.60 3.56

Pb 20 0.28-21.6 3.39 31 0.07-9.00 1.21

Se 19 nd-1.14 0.31 28 nd-12.05 4.61

Te 15 nd-0.43 0.04 16 nd-1.40 0.09

Tl 17 nd-0.51 0.10 26 nd-0.13 0.04

Va 20 nd-42.70 4.85 28 nd-35.00 3.73

Zn 20 nd-78.00 10.57 31 0.96-28.80 8.93

nd = not detected
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Gypsum vs US-EPA 503 Pollutant Concentration Limits (PCL) (EPA3052)

Element EPA 503 FGD gypsum* Mined gypsum**

mg/kg

As 41 2.06 0.84

Cd 39 0.16 0.08

Cr 1200 2.90 1.57

Cu 1500 1.42 1.42

Pb 300 1.21 3.39

Hg 17 0.30 0.02

Ni 420 3.56 2.65

Se 36 4.61 0.31

Zn 2800 9.83 10.57

* Mean of ~25 samples ** Mean of ~ 20 samples
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Comparison of Phospho- and FGD Gypsum

Pollutant Phosphogypsum (FL) FGD Gypsum*

kg/ha (~lb/ac)

As 2.5 2.06

Cd 4 0.16

Cu 9 1.42

Pb 15 1.21

Hg 0.35 0.30

Ni 10 3.56

Se 1.5 4.61

• *Mean of ~ 25 samples
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Loading Limits for Biosolids & Maximum FGD Gypsum Application Rates

Pollutant Annual pollutant 

loading rate for 

biosolids (503)

Maximum annual 

application rate for 

FGD gypsum*

kg/ha (~lb/ac)

As 2.0 0.0206

Cd 1.9 0.0016

Cu 75 0.0142

Pb 15 0.0121

Hg 0.85 0.0030

Ni 21 0.0356

Se 5.0 0.0461

Zn 140 0.0983

* Assuming an application rate of 10 T/ha using mean element concentrations
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Outcome

• Elements of environmental concern

– As, Cr, Cd, Hg, Ni & Se slightly higher than in mined 

gypsum

– As, Cr, Cd, Hg, Se & Ni lower than in phosphogypsum

– All far below EPA 503 regulations for biosolids

– Annual loading limits for FGD gypsum far below those 

for biosolids
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Comparison of Saturated Solutions of FGD & Mined Gypsum

• Gypsum solubility

– 2.2 g/L

• Gypsum dissolved in

– Distilled water

• Or

– Conc HNO3 before dilution
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Gypsum Vs Drinking Water

Element MCL FGD Gypsum Mined gypsum

Total* Water* Total Water

:g/L

As 10 5.3 1 1.3 0.15

Ba 2000 134 18.5 130 5.5

Be 4 0.2 0.04 0.05 0.05

Cd 5 0.12 0.12 0.5 0.06

Cr 100 6.4 3.5 4.4 1.1

Cu 1300 2.9 0.11 5 2.9

Pb 15 1 0.03 0.84 0.11

Hg 2 0.62 0.08 0.03 0.02

Se 50 22 9.1 0.52 0.32

Tl 2 0.01 0.01 0.01 0.00

Zn 15 1.1 19.1 6.7

* 2.2 g gypsum/L 

- Dissolved in 

conc HNO3 or 

water
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Outcome

• Saturated solution of FGD gypsum

– Easily meets US Drinking Water Standard

• For all elements of environmental concern
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Various Grains

• Data of Arnold (1997)

• Gypsum application rate

– 4.5 T FGD Gypsum/ac (10 T/ha) applied once
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Element Treatment

Soybean Corn Wheat

# Obs Range Mean# Obs Range Mean# Obs Range Mean

mg/kg mg/kg mg/kg

As Control 5 0.005-0.005 0.00 2 0.005-0.005 0.00 2 0.005-0.006 0.01

Gypsum 5 0.005-0.107 0.03 2 0.005-0.009 0.01 2 0.005-0.008 0.01

Cu Control 5 19.19-20.3 19.60 2 1.39-5.01 3.20 2 1.59-4.99 3.29

Gypsum 5 19.43-20.39 19.70 2 1.69-5.00 3.35 2 1.67-4.76 3.21

Mo Control 5 0.144-0.443 0.22 2 0.145-0.185 0.17 2 0.158-0.43 0.29

Gypsum 5 0.146-0.445 0.22 2 0.146-0.187 0.17 2 0.335-0.395 0.37

Ni

Control 5 0.221-0.377 0.26 2 0.34-0.361 0.35 2 0.196-0.367 0.28

Gypsum 5 0.221-0.385 0.22 2 0.338-0.361 0.35 2 0.207-0.397 0.30

Pb Control 5 0.238-0.404 0.30 2 0.241-0.30 0.27 2 0.116-0.129 0.12

Gypsum 5 0.238-0.421 0.31 2 0.243-.0298 0.27 2 0.119-0.128 0.12

Se Control 5 0.049-0.544 0.15 2 0.042-0.087 0.06 2 0.040-0.42 0.04

Gypsum 5 0.05-0.549 0.15 2 0.064-0.088 0.07 2 0.040-0.046 0.04

Zn

Control 5 40.25-45.84 43.04 2 10.52-17.14 13.83 2 12.29-20.01 16.15

Gypsum 5 40.29-46.21 42.96 2 10.5-15.69 13.10 2 10.26-20.46 15.36
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Cotton

• Gypsum application rate

– 4.5 T FGD Gypsum/ac (10 T/ha) applied once
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Element Treatment

Leaf Soil Seed

# Obs Range Mean # Obs Range Mean # Obs Range Mean

mg/kg mg/kg mg/kg

As Control 4 0.99-1.94 1.88 6 0.76-9.64 5.12 3 0.16-0.33 0.24

Gypsum 4 0.75-2.41 1.73 6 0.78-8.47 4.91 3 0.16-0.26 0.22

Cu Control 4 5.4-10.7 7.43 5 3.42-12.2 8.25 3 3.71-6.52 5.11

Gypsum 4 5.4-10.9 7.80 5 3.54-14.4 7.55 3 3.73-6.86 5.23

Cd Control 4 0.10-0.14 0.12 6 0.05-0.13 0.10 3 0.02-0.07 0.04

Gypsum 4 0.11-0.23 0.16 6 0.05-0.13 0.10 3 0.02-0.06 0.04

Cr Control 4 2.00-7.24 5.02 6 2.30-14.8 9.96 3 0.08-1.94 1.18

Gypsum 4 2.40-25.9 9.77 6 2.65-16.2 9.29 3 0.17-1.91 1.22

Pb Control 4 0.20-0.50 0.34 6 1.59-21.6 11.42 3 0.06-0.66 0.28

Gypsum 4 0.20-0.50 0.31 6 1.44-14.1 9.64 3 0.02-1.05 0.38

Mn Control 4 87-155 129.00 6 115-1036 466.00 2 15.7-29.4 22.50

Gypsum 4 118-294 197.00 6 202-508 363.00 2 17.0-31.0 24.00

Hg Control 4 0.03-0.11 0.08 6 0.03-0.10 0.07 3 0.01-0.03 0.02

Gypsum 4 0.03-0.10 0.08 6 0.03-0.10 0.07 3 0.00-0.02 0.01

Mo Control 4 0.25-1.07 0.53 6 0.10-2.32 0.79 3 0.00-0.15 0.06

Gypsum 4 0.21-0.75 0.38 6 0.11-0.78 0.47 3 0.00-0.16 0.07

Ni Control 4 0.80-2.57 1.83 6 1.05-3.96 2.71 3 0.50-0.76 0.65

Gypsum 4 1.08-8.59 3.55 6 1.21-4.29 2.71 3 0.37-0.80 0.45

Se Control 4 0.41-0.74 0.60 6 0.15-1.21 0.46 3 0.05-0.72 0.30

Gypsum 4 0.49-0.72 0.64 6 0.15-1.38 0.52 3 0.05-1.09 0.43

Zn Control 4 28.9-53.0 39.50 6 2.13-31.4 18.59 3 16.9-37.4 23.92

Gypsum 4 28.6-51.7 39.90 6 2.49-34.4 19.26 3 14.6-37.4 22.53
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Yellow Squash

• Gypsum application rate

– 2T FDG Gypsum/ac (5 T/ha) applied annually
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Element Treatment

Leaf Soil Fruit

# Obs Range Mean # Obs Range Mean # Obs Range Mean

mg/kg mg/kg mg/kg

As Control 2 0.12-0.53 0.33 2 1.47-3.25 2.36 2 0.34-0.51 0.43

Gypsum 2 0.34-0.58 0.46 2 1.27-3.10 2.18 2 0.39-0.40 0.40

Cu Control 2 6.84-17.7 12.27 2 4.71-13.2 8.95 2 7.97-17.4 12.68

Gypsum 2 6.94-13.4 10.17 2 4.83-12.4 8.62 2 9.43-11.6 10.51

Cd Control 2 0.25-0.26 0.26 2 0.05-0.12 0.08 2 0.06-0.07 0.07

Gypsum 2 0.34-0.46 0.40 2 0.06-0.15 0.11 2 0.06-0.07 0.07

Cr Control 2 1.38-4.39 2.88 2 8.38-8.52 8.45 2 5.52-9.09 7.31

Gypsum 2 1.92-4.18 3.05 2 6.70-76.2 41.45 2 1.68-4.11 2.90

Pb Control 2 0.24-0.42 0.33 2 7.15-11.0 9.07 2 0.13-0.14 0.14

Gypsum 2 0.18-0.45 0.32 2 7.28-26.6 16.95 2 0.07-0.14 0.11

Mn Control 2 295-972 634.00 2 157-693 425.00 2 74.9-112 93.45

Gypsum 2 236-444 340.00 2 221-890 555.50 2 46.7-113 79.85

Hg Control 2 0.07-0.29 0.18 2 0.05-0.06 0.06 2 0.07-0.44 0.26

Gypsum 2 0.06-0.07 0.07 2 0.05-0.06 0.06 2 0.06-0.07 0.07

Mo Control 2 0.56-1.97 1.27 2 0.42-0.46 0.44 2 0.21-1.96 1.09

Gypsum 2 0.45-1.16 0.81 2 0.25-0.44 0.35 2 0.22-1.23 0.73

Ni Control 2 1.16-2.96 2.06 2 3.96-8.86 6.41 2 2.45-7.55 5.00

Gypsum 2 1.08-2.60 1.84 2 3.45-8.64 6.04 2 1.41-2.06 1.74

Se Control 2 0.49-0.56 0.53 2 0.59-0.64 0.62 2 0.35-0.39 0.37

Gypsum 2 0.50-0.58 0.54 2 0.51-0.73 0.62 2 0.38-0.44 0.41

Zn Control 2 172-191 181.50 2 10.6-115 62.80 2 61.8-73.6 67.70

Gypsum 2 170-411 290.50 2 11.0-71.6 41.32 2 50.1-83.2 66.70
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Tomato

• Gypsum application rate

– 2T FGD Gypsum/ac (5 T/ha) applied annually
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Element Treatment

Leaf Soil Fruit

# Obs Range Mean # Obs Range Mean # Obs Range Mean

mg/kg mg/kg mg/kg

As Control 6 0.55-3.67 1.79 6 1.70-4.66 3.07 4 0.24-1.63 0.72

Gypsum 6 0.61-2.83 1.46 6 1.89-4.73 2.97 4 0.35-0.94 0.62

Cu Control 6 233-760 457.00 6 0.42-16.2 10.64 4 7.24-15.6 10.75

Gypsum 6 135-871 445.50 6 0.76-16.0 9.08 4 9.34-15.1 12.05

Cd Control 6 0.39-0.97 0.70 6 0.04-0.11 0.08 4 0.06-0.16 0.12

Gypsum 6 0.37-1.40 0.94 6 0.04-0.27 0.12 4 0.11-0.23 0.18

Cr Control 6 1.57-14.6 5.45 6 4.03-21.9 12.12 4 0.64-8.12 3.48

Gypsum 6 1.52-11.0 5.41 6 4.29-14.7 9.77 4 0.66-8.19 4.74

Pb Control 6 0.06-0.68 0.31 6 0.17-12.1 7.48 4 0.05-0.32 0.12

Gypsum 6 0.06-0.79 0.32 6 0.17-9.53 7.10 4 0.05-0.72 0.31

Mn Control 5 320-640 491.00 5 98-232 161.20 2 14.3-15.8 15.03

Gypsum 5 257-726 447.60 5 67-246 136.80 2 18.3-19.9 19.10

Hg Control 6 0.02-0.10 0.05 6 0.04-0.10 0.06 4 0.01-0.10 0.04

Gypsum 6 0.02-0.10 0.05 6 0.02-0.10 0.06 4 0.01-0.10 0.04

Mo Control 6 0.28-1.16 0.71 6 0.26-0.38 0.32 4 0.35-0.87 0.54

Gypsum 6 0.18-1.18 0.62 6 0.20-0.41 0.27 4 0.18-0.74 0.48

Ni Control 4 1.72-5.63 3.79 6 0.23-11.5 5.42 2 0.43-2.81 1.62

Gypsum 4 1.86-3.43 2.76 6 0.58-9.89 5.47 2 0.39-0.51 0.45

Se Control 6 0.12-6.34 3.01 6 0.32-0.87 0.53 4 0.11-7.35 2.06

Gypsum 6 0.79-7.90 3.62 6 0.29-0.71 0.45 4 0.27-6.56 1.98

Zn Control 6 28.1-51.5 41.80 6 27.4-41.6 33.24 4 18.7-28.2 22.35

Gypsum 6 28.2-47.7 38.86 6 28.2-47.7 34.25 4 26.5-47.7 32.41
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Peanuts

• Gypsum application rate

– 0.5 T/ha (1.25 T/ha) applied annually
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Element Treatment

Leaf Soil Seed

# Obs Range Mean # Obs Range Mean # Obs Range Mean

mg/kg mg/kg mg/kg

As Control 15 0.16-2.24 1.56 22 1.40-53 6.81 9 0.16-1.12 0.54

Gypsum 15 0.10-2.38 1.48 22 1.21-8.47 4.21 9 0.05-1.12 0.78

Cu Control 15 3.30-19.69 7.90 22 0.31-13.86 6.65 9 0.67-9.33 3.19

Gypsum 15 4.33-10.92 7.13 22 0.41-14.35 6.68 9 0.32-11.08 2.83

Cd Control 15 0.08-0.27 0.14 22 0.03-0.30 0.10 9 0.03-0.08 0.06

Gypsum 15 0.03-0.18 0.11 22 0.04-0.19 0.11 9 0.03-0.10 0.08

Cr Control 15 1.40-10.96 4.36 22 1.94-27.4 8.05 9 1.94-8.94 3.65

Gypsum 15 1.58-6.66 3.60 22 1.68-27.65 7.06 9 0.91-8.24 4.49

Pb Control 15 0.06-1.58 0.36 22 1.00-17.3 6.45 9 0.05-0.50 0.17

Gypsum 15 0.06-1.51 0.31 22 0.24-14.08 5.09 9 0.03-0.50 0.17

Mn Control 9 56-289 141.00 12 18.3-1625 425.00 2 15.6-20.0 17.80

Gypsum 9 23-267 120.00 12 20.2-1365 276.00 2 17.0-19.5 18.25

Hg Control 15 0.03-0.10 0.04 22 0.02-0.10 0.05 9 0.03-0.05 0.04

Gypsum 15 0.03-0.10 0.04 22 0.02-0.10 0.05 9 0.00-0.06 0.03

Mo Control 15 0.03-0.72 0.15 22 0.13-2.94 0.47 9 0.04-0.44 0.28

Gypsum 15 0.06-0.65 0.17 22 0.13-2.11 0.45 9 0.07-0.89 0.40

Ni Control 9 0.77-2.32 1.34 18 0.25-11.94 1.98 9 0.50-5.38 1.22

Gypsum 9 0.45-2.17 1.38 18 0.32-6.37 1.64 9 0.68-3.41 0.98

Se Control 15 0.25-6.14 1.60 22 0.22-0.72 0.30 9 0.05-1.00 0.33

Gypsum 15 0.25-3.82 1.25 22 0.19-0.75 0.30 9 0.02-1.00 0.33

Ag Control 9 0.05-0.15 0.10 18 0.10-0.50 0.25 7 0.01-0.25 0.18

Gypsum 9 0.01-0.15 0.09 18 0.10-0.50 0,23 7 0.01-0.25 0.16

Zn Control 15 16.3-101 44.80 22 13.8-127 28.90 9 16.9-41.4 30.90

Gypsum 15 17.7-98.5 39.30 22 10.9-170 21.90 9 5.75-40.8 29.40
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Cantaloupe

• Gypsum application rate

– 2 T/ac (5 T/ha) applied annually
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Element Treatment

Leaf Soil Fruit

# Obs Range Mean # Obs Range Mean # Obs Range Mean

mg/kg mg/kg mg/kg

As Control 6 0.31-0.44 0.35 2 1.34-3.90 2.63 5 0.10-0.71 0.51

Gypsum 6 0.20-0.57 0.35 2 1.66-5.44 3.55 5 0.17-0.93 0.66

Cu Control 6 7.26-11.40 10.22 2 3.93-4.85 4.39 5 4.88-9.89 6.33

Gypsum 6 7.03-12.72 9.87 2 4.09-5.11 4.60 5 5.10-9.16 6.31

Cd Control 6 0.13-1.05 0.53 2 0.05-0.12 0.08 5 0.06-0.09 0.07

Gypsum 6 0.23-0.72 0.48 2 0.05-0.09 0.07 5 0.05-0.11 0.08

Cr Control 6 0.63-6.05 4.70 2 7.81-10.64 9.23 5 1.70-3.50 2.81

Gypsum 6 2,12-5.05 4.00 2 9.71-24.81 17.30 5 0.90-3.11 2.56

Pb Control 6 0.30-0.84 0.54 2 5.35-7.41 6.38 5 0.05-0.37 0.25

Gypsum 6 0.21-1.13 0.62 2 6.14-9.60 7.87 5 0.06-0.36 0.24

Mn Control 6 80-513 243.00 2 68.0-79.4 68.70 5 21.0-50.5 34.70

Gypsum 6 165-278 225.00 2 43.1-84.2 63.30 5 26.3-80.2 42.73

Hg Control 6 0.02-0.05 0.03 2 0.03-0.05 0.04 5 0.01-0.20 0.06

Gypsum 6 0.02-0.05 0.03 2 0.03-0.05 0.04 5 0.01-0.03 0.02

Mo Control 6 0.07-0.25 0.15 2 0.21-0.41 0.31 5 0.07-0.13 0.11

Gypsum 6 0.05-0.25 0.12 2 0.22-0.73 0.48 5 0.09-0.22 0.17

Ni Control 6 2.23-4.58 2.88 2 1.76-4.95 3.36 5 0.62-1.70 1.35

Gypsum 6 1.77-2.87 2.16 2 2.03-5.07 3.55 5 0.60-1.93 1.58

Se Control 6 0.18-0.79 0.56 2 0.33-0.66 0.50 5 0.41-0.73 0.44

Gypsum 6 0.13-0.88 0.63 2 0.36-0.74 0.55 5 0.39-0.56 0.35

Ag Control 6 0.05-0.08 0.07 2 0.05-0.10 0.08 5 0.05-0.20 0.15

Gypsum 6 0.05-0.08 0.07 2 0.06-0.10 0.08 5 0.06-0.20 0.16

Zn Control 6 51.7-70.4 57.60 2 18.14-56.1 37.00 5 26.2-35.5 29.67

Gypsum 6 41.8-85.1 54.40 2 7.47-19.05 13.26 5 24.5-38.8 30.00
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Outcome

• Levels of all elements of environmental concern

– VERY LOW in soil, tissue, fruit and seeds

– Alfalfa and tomato tissue sometimes high in Se

• Not due to FGD gypsum

• Environmental heterogeniety likely responsible

• No consistent trends from gypsum application

– In soils, tissue, fruits or grains

– Variations probably due to heterogeniety
Beneficial Reuse of FGD Gypsum in Agriculture Applications

COMPARISON OF VARIOUS SOIL 

HEAVY METAL DATA BASES
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Element Treatment

Sumner Alloway Adriano

World US

# Obs 

Range Mean Range Mean Mean Mean

mg/kg

As Control 40 0.76-53 5.46 0.5-15 10

Gypsum 40 0.78-8.47 4.05

Cu Control 39 0.31-16.2 7.42 1-150 20 25

Gypsum 39 0.41-16.0 7.24

Cd Control 40 0.03-0.30 0.09 0.3-11 1 0.3 0.5

Gypsum 40 0.04-0.27 0.11

Cr Control 40 1.95-27.4 9.27 0.2-837 200 53

Gypsum 40 1.68-76.2 10.44

Pb Control 40 0.17-21.6 7.51 13 10 20

Gypsum 40 0.17-26.6 6.99

Mn Control 29 18-1036 337.54 50-11500 850 560

Gypsum 29 20-1365 259.81

Hg Control 40 0.02-0.10 0.05 0.001-0.46 0.11

Gypsum 40 0.02-0.10 0.05

Mo Control 40 0.10-2.94 0.49

Gypsum 40 0.11-2.11 0.43

Ni Control 36 0.23-11.94 3.23 0.8-439 40 20

Gypsum 36 0.32-9.89 3.06

Se Control 40 0.15-1.21 0.38 0.6-1.6 1.5

Gypsum 40 0.15-1.38 0.39

Zn Control 40 2.13-127 29.83 0.7-987 50 50 54

Gypsum 40 2.49-170 24.05
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Outcome

• Levels of all elements of environmental 

concern

– Well within normal ranges for soils
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Conclusions

• In FGD gypsum applications to soils

– Levels of elements of environmental concern

• Well within normal ranges for soils

• No consistent variations in heavy metals due to FGD gypsum

– In soil

– In tissue

– In fruits or seeds

• Pose no threat to the environment or food chain
Beneficial Reuse of FGD Gypsum in Agriculture Applications

THANK YOU FOR YOUR 

ATTENTION

University of Georgia

First Public Funded University in the United States
USING GYPSUM TO AFFECT 

SOIL EROSION PROCESSES 

AND WATER QUALITY

Dr. L Darrell Norton, Research Soil 

Scientist USDA-ARS National Soil 

Erosion Research Laboratory, Purdue 

University, West Lafayette, IN
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Rainwater is Natural Distilled and 

Low in Electrolytes
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Both Physical and Chemical Processes Occur 

at the Time Scale of Raindrop Impact
Beneficial Reuse of FGD Gypsum in Agriculture Applications

This Leads to Surface Sealing
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Runoff Causing Soil Erosion and 

Removal of Chemicals
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Offsite Water Quality Problems
Beneficial Reuse of FGD Gypsum in Agriculture Applications

This Leads to Surface Sealing
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Natural Occurring Geologic Deposits
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Synthetic Production from 

Clean Air Regulations
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Synthetic Gypsum as a 

Soil Amendment
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Gypsum Use in USA

Source USGS, 2004

• Total use 39,000,000

• Mined 18,000,000

• Synthetic 11,000,000

• Imports 10,400,000

• Cement 4,700,000

• Agriculture 1,000,000
Beneficial Reuse of FGD Gypsum in Agriculture Applications

DeWitt, Iowa Site

Fayette silty clay loam

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

5 1015 20 25 3035 40 45 5055 60

Duration [min]

0.00

20.00

40.00

60.00

80.00

mm/h

soil loss [g/m^2*s]
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Fayette PAM+FBCBA Treatment

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

5 10 15 20 25 30 35 40 45 50 55 60

Duration [min]

0.00

20.00

40.00

60.00

80.00

mm/h

soil loss [g/m^2*s]
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Effect of Gypsum and PAM on Soil Erosion by 

Concentrated flow on Steep Road Construction Slopes
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Soil Structural Differences 

(Control left Gypsum on right)
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Detachment by Flow reduced by 

Gypsum+PAM
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Effect of Gypsum on Erosion

0

5

10

15

20

25

30

35

Control Gypsum

Runoff (mm)

Soil Loss (g/10 sq m)

SRP (mg/sq m)
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Gypsum Effect on N and P

0

2

4

6

8

10

12

14

No-Till Gypsum Manure Man+Gyp

SRP (mg/L * 10)

TP (mg/L)

Nitrate (mg/L)

TN (mg/L)
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Conventional No-tillage on Vertisol

in Villadiego, MX
Beneficial Reuse of FGD Gypsum in Agriculture Applications

No-Till System with Gypsum 

on Vertisol in Villadiego, MX
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Vertisol with Severe Cracking (Control)
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Vertisol Amended with Gypsum
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Effect of Gypsum on infiltration/drainage 

on a Paulding clay

Gypsum

No Gypsum

Ponding
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Root Biomass Increased
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Gypsum Application on Left 

w/o on Right
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Water Stress Reduced with 

Gypsum and PAM
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Random Corn Ears Amended with 

Gypsum on Left and Control, Colorado
Beneficial Reuse of FGD Gypsum in Agriculture Applications

RCRA Total Elements in Materials

Added (USEPA 3051)

Material As Ba Cd Cr Hg Pb Se

ppm ppm ppm ppm ppb ppm ppm

FGD #1

<1.3 22.2 0.39 7.2 0.1635 <0.77 3.5

FGD #3

1.4 20.4 0.55 6.8 0.2320 <0.77 <2.3

Mined 

Gypsum

<1.3 46.6 0.11 2.2 0.0001 <0.77 <2.3

Soil 9.4 170.8 1.47 30.3 0.0261 16.06 3.5
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Hg in Plant Corn Tissue Kingman, 2008

Type Trt Hg (ppb) S (ppm) N(%) C (%)

Ear Leaf None 4.88 2245 2.99 44.20

Ear Leaf 2000 FGD 6.30 2855 2.84 43.16

Ear Leaf 2000 PG 4.51 2575 2.92 43.29

Stover None 6.29 1159 0.73 44.15

Stover 2000 FGD 6.20 927 0.70 36.03

Stover 2000 PG 6.52 1185 0.73 44.21

Grain None 2.31 1095 1.37 44.34

Grain 2000 FGD 3.22 1135 1.36 44.24

Grain 2000 PG 3.28 1129 1.33 44.06
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Kingman, IN Hg in Water -60cm 2008

Date Rate (lbs) Product pH ppt

Hg

7/18/2008 2000 FGD 7.11 17.09

7/23/2008 2000 FGD 7.53 19.54

7/18/2008 0 None 7.41 28.37

7/23/2008 0 None 7.8 67.98

7/18/2008 2000 Mined 7.29 65.32

7/23/2008 2000 Mined 6.8 18.96
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Hg in Runoff Water Kingman, IN 2009

Plot Trt

Hg Conc. 

ppt Average

6 Control 18.6 12.24

10 Control 6.4

15 Control 11.8

1 6000 lb/ac Fly Ash 11.7 9.88

7 6000 lb/ac Fly Ash 10.2

14 6000 lb/ac Fly Ash 7.8

8 6000 lb/ac FGD 25.1 24.08

9 6000 lb/ac FGD 18.4

11 6000 lb/ac FGD 28.7
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Hg uptake in Corn Shoots 6 after six weeks 

subjected to perched water table

Treatment

Hg

Drainage 

condition ppb

Freely 

Drained

Control 4.57 a

FGD Gypsum 3.75 a

Glyphosate 6.43 a

FGD Gyp.+Glyph. 4.13 a

Perched 

water 

table (-

5cm)

Control 55.92 b

FGD Gypsum 61.88 b

Glyphosate 61.98 b

FGD Gyp.+Glyph. 64.54 b
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Conclusions

• FGD gypsum has a multitude of uses in agriculture 

• Reduced soil erosion and runoff

• Improvement of physical properties

• Ca and S Fertility

• Improved water quality

• Potential for improved N and P efficiency

• FGD Gypsum has no significant uptake in corn on 

adverse potential to water quality for a poorly 

drained midwestern soil.

• Improved yields and sustainability of agriculture
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Questions?
A FARMER’S PERSPECTIVE ON 

FGD GYPSUM

Jack Maloney
Beneficial Reuse of FGD Gypsum in Agriculture Applications
Beneficial Reuse of FGD Gypsum in Agriculture Applications
Beneficial Reuse of FGD Gypsum in Agriculture Applications
Beneficial Reuse of FGD Gypsum in Agriculture Applications
Beneficial Reuse of FGD Gypsum in Agriculture Applications
Beneficial Reuse of FGD Gypsum in Agriculture Applications
Beneficial Reuse of FGD Gypsum in Agriculture Applications
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Questions?
SYNTHETIC GYPSUM AND 

AGRICULTURAL APPLICATIONS

Warren Dick and Dave Kost

School of Environment and Natural Resources

The Ohio State University, Wooster, OH
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Gypsum from New South 

Wales, Australia

Gypsum Powder

Gypsum is a very soft mineral composed of calcium sulfate dihydrate, with the 

chemical formula CaSO4·2H2O. The word gypsum is derived from a Greek word 

meaning "chalk" or "plaster". Because the gypsum from the quarries of the 

Montmartre district of Paris has long furnished burnt gypsum, this material has 

often been called plaster of Paris. Gypsum is water-soluble. The source of gypsum 

is both mined and synthetic.

What is Gypsum?
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Summary of Gypsum and Benefits

in Agriculture

qCa and S source for plant nutrition

qSource of S and exchangeable Ca to

ameliorate subsoil acidity and Al3+ toxicity

qFlocculate clays to improve soil structure and

reclaim sodic and high magnesium soils

(Also as growth media component for mushroom 

production - approximately 60 kg/ton compost)
Wooster, 

Ohio

Year

Beneficial Reuse of FGD Gypsum in Agriculture Applications

Reduction in Atmospheric S Deposition

q Increasing in importance as cause for crop S deficiencies

q Loss of soil organic matter

q Reduced annual S deposition

§ 34 kg/ha in 1971

§ 19 kg/ha in 2002
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Average Corn Yields from 2002 to 2005 

(Ohio, USA)

N Rate (kg ha-1)

0 50 100 150 200 250

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

Y=5.80+0.029x-0.00009x2 (R2=0.85)

Y=5.19+0.021x-0.00003x2

 (R2

=0.96)

S

No S
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Ca

Ca

Soil Acidity

Ca

Ca from lime 

will not reach 

the subsoil

Soil Acidity Soil Acidity

Soil Acidity

Ca

Soil Surface

Ca Ca
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Ca Ca

Al Al

Ca

Al

SO4 Ca

Clay platelet in subsoil

Al

Gypsum applied to surface of soil with acidic subsoil

H+

Toxic

H

Al Al H+ H

SO4

Non-toxic

Al
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Typical pH profile for a Blount soil

3 4 5 6 7

10

20

30

40

50

60

70

Depth (cm)

pH

pH

Al3+
Beneficial Reuse of FGD Gypsum in Agriculture Applications

limestone limestone + gypsum

1 2 3

Corn Root Density m/1000 cm3

Depth

(cm)

20

40

60

80 Modified from Farina & 

Channon, SSSAJ (1988)

CaSO4 + Al3+ Al(SO4)+ + Ca2+

(toxic) (non-toxic)

Gypsum can ameliorate 

aluminum toxicity, 

especially in the subsoil, 

by forming soluble 

complexes with Al3+.
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Gypsum and Sodic Soil Reclamation in China

Comparison of field with (background) and 

without (foreground) FGD by-product gypsum
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Development of Network for FGD Gypsum Use in Agriculture

November 17-19, 2009

Indianapolis, IN

November 4 (afternoon), Pittsburgh, PA

https://www.acsmeetings.org/

http://www.oardc.ohio-state.edu/

agriculturalfgdnetwork

Workshop sponsored by:

Combustion ByProducts Recycling Consortium 

(CBRC)

Electric Power Research Institute (EPRI)

The Ohio State University

U.S. Department of Energy/National Energy 

Technology Laboratory
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Development of Network for FGD Gypsum Use in Agriculture
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Development of Network for FGD Gypsum Use in Agriculture
Beneficial Reuse of FGD Gypsum in Agriculture Applications











 






Beneficial Reuse of FGD Gypsum in Agriculture Applications

Development of Network for FGD Gypsum Use in Agriculture

http://www.oardc.ohio-state.edu/agriculturalfgdnetwork/
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Development of Network for FGD Gypsum Use in Agriculture
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Development of Network for FGD Gypsum Use in Agriculture
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Development of Network for FGD Gypsum Use in Agriculture

 --------------------------------------------------------------------------------------------

Rep Treatment P K Ca Mg S 

Sample ID tons/A mg/g mg/g mg/g mg/g mg/g

1 FGD 55 Check0 4113.3 4253.8 339.4 1691.6 1498.3

2 FGD 57 Check0 3943.9 4281.1 368.8 1681.7 1550.3

3 FGD 62 Check0 4440.8 4356.9 367.4 1856.8 1564.5

4 FGD 63 Check0 4178.1 4524.6 373.9 1856.4 1546.0

1 FGD 54 FGDGyp10 3585.9 3877.8 372.8 1593.0 1665.3

2 FGD 59 FGDGyp10 3978.7 4176.0 413.4 1761.4 1831.4

3 FGD 61 FGDGyp10 4102.5 4054.1 362.2 1836.8 1709.2

4 FGD 64 FGDGyp10 3450.6 3735.2 352.0 1611.8 1676.7

1 FGD 56 CommGyp10 3575.0 3857.3 388.9 1610.3 1791.0

2 FGD 58 CommGyp10 3686.6 4033.9 402.0 1676.2 1851.4

3 FGD 60 CommGyp10 3880.0 3904.2 396.4 1707.2 1823.6

4 FGD 65 CommGyp10 3926.6 4132.6 443.2 1775.1 1970.3

Rep Treatment As Ba Be Cd Co 

Sample ID tons/A mg/g mg/g mg/g mg/g mg/g

1 FGD 55 Check0 <1.284 10.040 <0.091 <0.048 <0.146

2 FGD 57 Check0 <1.284 9.608 <0.091 <0.048 <0.146

3 FGD 62 Check0 <1.284 7.315 <0.091 <0.048 <0.146

4 FGD 63 Check0 <1.284 9.307 <0.091 <0.048 <0.146

1 FGD 54 FGDGyp10 <1.284 5.624 <0.091 0.051 <0.146

2 FGD 59 FGDGyp10 <1.284 4.702 <0.091 0.082 <0.146

3 FGD 61 FGDGyp10 <1.284 4.462 <0.091 0.138 <0.146

4 FGD 64 FGDGyp10 <1.284 6.135 <0.091 0.131 <0.146

1 FGD 56 CommGyp10 <1.284 5.279 <0.091 0.050 <0.146

2 FGD 58 CommGyp10 <1.284 5.816 <0.091 0.061 <0.146

3 FGD 60 CommGyp10 <1.284 3.340 <0.091 0.151 <0.146

4 FGD 65 CommGyp10 <1.284 4.380 <0.091 0.101 <0.146

 

Great River Energy, North Dakota

Gary Site

2007 Wheat Grain Chemistry
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Development of Network for FGD Gypsum Use in Agriculture

Al B Cu Fe Fe Mn Mo Na Zn

mg/g mg/g mg/g mg/g mg/g mg/g mg/g mg/g mg/g

<6 .9 8 5 <1 .5 2 3 2.71 5 9 .4 4 5 4 .1 5 6 2 .4 6 <0 .2 2 5 <13.04 3 7 .9

<6 .9 8 5 <1 .5 2 3 2.85 5 7 .9 3 5 5 .2 0 6 4 .3 2 <0 .2 2 5 <13.04 4 4 .2

<6 .9 8 5 1.61 3.35 6 1 .1 6 5 8 .8 5 6 3 .9 0 <0 .2 2 5 <13.04 5 0 .9

<6 .9 8 5 1.63 3.75 5 9 .9 5 5 6 .6 6 7 0 .3 5 <0 .2 2 5 <13.04 4 2 .5

<6 .9 8 5 <1 .5 2 3 2.37 5 5 .3 1 5 0 .2 9 6 0 .3 1 <0 .2 2 5 <13.04 4 0 .3

<6 .9 8 5 <1 .5 2 3 3.36 6 1 .2 4 5 7 .3 8 6 5 .6 0 <0 .2 2 5 <13.04 5 6 .1

<6 .9 8 5 1.68 3.09 5 5 .8 1 5 1 .5 6 7 0 .1 2 <0 .2 2 5 <13.04 4 9 .6

7.83 <1 .5 2 3 2.73 5 0 .5 8 4 8 .1 5 6 2 .3 5 <0 .2 2 5 <13.04 3 8 .9

<6 .9 8 5 <1 .5 2 3 3.34 5 5 .2 4 5 0 .9 2 6 4 .9 0 <0 .2 2 5 <13.04 4 3 .4

<6 .9 8 5 <1 .5 2 3 3.11 5 9 .7 1 5 5 .6 2 6 7 .7 0 <0 .2 2 5 <13.04 4 8 .1

<6 .9 8 5 2.23 2.91 5 5 .5 8 5 3 .2 7 7 0 .5 2 0.69 <13.04 5 5 .0

<6 .9 8 5 <1 .5 2 3 3.70 6 1 .1 4 5 8 .0 5 6 8 .9 0 <0 .2 2 5 <13.04 5 4 .8

 Cr Li Ni Pb Sb Se Si Sr V 

mg/g mg/g mg/g mg/g mg/g mg/g mg/g mg/g mg/g

<0 .1 9 4 9.143 1.295 <0 .7 7 4 <1 .0 4 7 <2 .3 2 1 7 1 .3 2 9 2.153 <0 .2 9

<0 .1 9 4 9.796 1.222 <0 .7 7 4 <1 .0 4 7 <2 .3 2 1 3 8 .8 0 9 2.461 <0 .2 9

<0 .1 9 4 7.020 0.958 <0 .7 7 4 <1 .0 4 7 <2 .3 2 1 5 0 .5 8 5 2.419 0.37

<0 .1 9 4 8.693 1.612 <0 .7 7 4 <1 .0 4 7 <2 .3 2 1 5 4 .9 7 3 2.370 <0 .2 9

<0 .1 9 4 4.823 1.443 <0 .7 7 4 <1 .0 4 7 <2 .3 2 1 2 7 .1 9 0 2.172 <0 .2 9

<0 .1 9 4 4.711 1.351 <0 .7 7 4 <1 .0 4 7 <2 .3 2 1 4 5 .5 0 8 2.619 <0 .2 9

<0 .1 9 4 4.143 1.215 <0 .7 7 4 <1 .0 4 7 <2 .3 2 1 4 6 .7 1 6 2.589 <0 .2 9

<0 .1 9 4 5.777 1.456 <0 .7 7 4 <1 .0 4 7 <2 .3 2 1 3 8 .3 8 7 2.233 <0 .2 9

<0 .1 9 4 4.963 1.204 <0 .7 7 4 <1 .0 4 7 <2 .3 2 1 3 3 .0 3 2 2.543 <0 .2 9

<0 .1 9 4 5.557 1.617 <0 .7 7 4 <1 .0 4 7 <2 .3 2 1 3 5 .1 3 7 2.273 <0 .2 9

<0 .1 9 4 <3 .4 0 3 1.186 <0 .7 7 4 <1 .0 4 7 <2 .3 2 1 3 2 .7 6 1 2.263 <0 .2 9

<0 .1 9 4 4.570 1.474 <0 .7 7 4 <1 .0 4 7 <2 .3 2 1 4 1 .6 8 1 2.414 <0 .2 9
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Development of Network for FGD Gypsum Use in Agriculture

Rep Treatment % Nitrogen % Carbon % Sulfur Hg

tons/A ppb or ng/g

1 Check0 2.65 43.70 0.237 2.161

2 Check0 2.83 43.46 0.284 3.655

3 Check0 2.86 43.36 0.268 1.096

4 Check0 2.77 44.06 0.242 1.276

1 FGDGyp10 2.69 43.52 0.315 1.415

2 FGDGyp10 2.86 43.42 0.300 1.297

3 FGDGyp10 2.84 43.69 0.308 1.086

4 FGDGyp10 2.66 43.54 0.265 2.169

1 CommGyp10 2.85 43.61 0.299 1.719

2 CommGyp10 2.88 43.54 0.295 1.420

3 CommGyp10 3.09 43.81 0.383 2.123

4 CommGyp10 2.91 43.37 0.309 0.905

Check0 = No gypsum applied

FGDGyp10 = FGD gypsum at 10 tons/A

CommGyp10 = Commercial gypsum at 10 tons/A

Treatment Descriptions
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Earthworm Study








Beneficial Reuse of FGD Gypsum in Agriculture Applications

Earthworm Study

Concentrations of elements in 

the FGD gypsum and mined 

gypsum used
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Earthworm Study

Effects of gypsum on 

concentrations of elements in 

soil in 2008
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Earthworm Study

Effects of gypsum on 

concentrations of elements in 

plant tissue from the second 

harvest in 2008.
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Earthworm Study

Effects of FGD gypsum on 

the number and biomass of 

earthworms
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Earthworm Study

Effects of gypsum on 

concentrations of elements in 

earthworm tissue in 2008
Beneficial Reuse of FGD Gypsum in Agriculture Applications

THANK 

YOU!
RISK ASSESSMENT FOR USE OF 

FGD GYPSUM IN AGRICULTURE

Rufus L. Chaney

Senior Research Agronomist

USDA-ARS-EMBUL

Beltsville, MD
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Old vs. New FGD-Gypsum

• Old FGD-Byproduct contained much of the elements in 

fly ash, such that B, As, Se, etc. were a source of 

concern depending on the coal source used.

–Used at limestone rate for alfalfa, FGDB supplied B, Ca, 

alkalinity and Se that served as fertilizers without causing 

excessive transfer of toxics to crops.

• New FGD-Gypsum produced post fly ash removal 

contains very low levels of all trace elements.

–Difficult to find potential adverse effects of constituents of 

present high quality FGD-Gypsum.
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Alternative Beneficial Uses: FGD-Gypsum

• Calcium fertilizer for peanuts, etc.

• Sulfate fertilizer for many crops.

• Improve water infiltration.

–Reduce soil erosion/crusting.

• Reduce P runoff by Ca precipitation.
Beneficial Reuse of FGD Gypsum in Agriculture Applications

• Pathway Highly Exposed Individual

• 1. SoilèPlantèHuman Farm markets; 2.5% of food.

• 2. SoilèPlantèHuman Home gardens; 60% of garden 

foods for lifetime; 1000 t/ha

• 3. SoilèHuman 200 mg/day soil/dust ingestion; 1000 t/ha

• 4. Sol èPlantèAnimalèHuman Farms; 45% home-grown meat; 1000 t/ha

• 5. SoilèAnimalèHuman Grazing ruminants; soil is 2.5% of 

annual diet; 45% home-grown meat.

• 6. SoilèPlantèAnimal 100% of livestock feeds grown on soils;

• 1000 t/ha

• 7. SoilèAnimal Grazing ruminants; 2.5% soil in diet.

Pathways for Risk Assessment of Elements in Soils, and Highly 

Exposed Individuals-1.
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Pathways for Risk Assessment of Elements in Soils, and Highly 

Exposed Individuals-2.

Pathway Highly Exposed Individual

• 8. SoilèPlant Sensitive crops; strongly acidic;

1000 t/ha.

• 9. SoilèSoil Biota Earthworms; microbes; metabolic 

function of soil; 1000 t/ha.

• 10. Soil BiotaèSoil Biota Predator Shrews; 1/3 of diet presumed to be 

earthworms full of Soil; 1000 t/ha.

• 11. SoilèAirborne DustèHuman Tractor operator; 1000 t/ha.

• 12. SoilèSurface waterèHuman Subsistence fishers.

• 13. SoilèAir®Human Farm households

• 14. Soilègroundwater®Human Well water on farms.
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Complex Equilibria of Metal Ions with Components 

of Soil Environments

Adsorbed ç

on Fe/Mn è

Occluded in 

Fe/Mn oxides

íì

Plant

Roots

ëî

Soil

Microbes

é

íì

Soil Solution

Ni2+ + L ↔ NiL

éê

Inorganic

Solids L = Ligands

Organic

Inorganic

Ni(OH)2 Ni-Silicate

NiO Ni-Al-hydroxide

Chelated to Organic Matter

Humics; fulvics

ëî

Plant

Shoots
Beneficial Reuse of FGD Gypsum in Agriculture Applications

• Insolubility or adsorption in soil or plants roots:

– Cr, Pb, Fe, Hg, Sn, Au, Ag, Zr, Al, F, Ti, etc.

• Phytotoxicity limits plant yield at levels which are not toxic for 

lifetime consumption by livestock:

– Zn, Cu, Ni, As, Mn, B, etc.

• Exceptions to Soil-Plant Barrier:

– Cd, Se possible risk to humans

– Mo, Se, (Co) possible risk to livestock

• Barrier can be circumvented by direct ingestion of biosolids; 

Volatilization of Hg is separate risk.

– Fe, F, Pb, As, Hg may comprise risk in high on surface.

Soil-Plant Barrier

PROCESSES IN SOILS OR PLANTS THAT PREVENT 

EXCESSIVE FOOD-CHAIN TRANSFER OF ELEMENTS
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Use of 503 Limits for Materials Other Than Biosolids

• In the absence of regulations for other materials, some have 

used the 503 limits.

• Should never consider use of Ceiling Limit.

• APL limit might be acceptable if other elements are not source 

of risk and material is applied at low fertilizer rates.

• Biosolids contain adsorptive materials (Fe oxides) which lower 

risk of applied metals; field derived plant uptake factors needed 

for other materials.

• Other elements may be more important than for biosolids, e.g., 

Boron

• High pH due to source may affect risk (Se, Mo).
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Risk Assessment for Beneficial Use of Spent Foundry Sand

• USDA-ARS and Ohio State worked with US-EPA to conduct a risk 

assessment for beneficial use of spent foundry sand in agricultural 

applications.

– Manufactured soil assumed to contain 50% by weight Spent Foundry Sand 

(SFS) as lifetime home garden for soil and garden crop exposure.

– The Risk Assessment was completed in 2009, and is now undergoing external 

EPA Peer Review.

– Errors in use of the EPA Exposure Factors Handbook for risk assessment would 

have limited soil As, but correction of garden foods intake database use gave 

unlimited beneficial use of SFS with 12 ppm As.

– 95th %ile of background soil as practical element limit; SFS contained lower 

levels of elements than US soils.
Beneficial Reuse of FGD Gypsum in Agriculture Applications

USDA/OSU SFS Characterization

• Spent foundry sand characterization

–43 Samples from 37 foundries in 13 states

–31 iron, 6 steel, 4 aluminum and 2 non-leaded brass

–Total metals, leachable metals, phenolics, PAHs (includes 

dioxins, furans, dioxin-like PCBs)

• Effects on plants/soil biota

–Importance of good agronomic practices (e.g. soil pH 

appropriate for plants)
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Scope of Risk Evaluation

Evaluated Non-olivine molding sands from iron, steel, 

and aluminum foundries.

–Not Evaluating Olivine Sands

• Insufficient data

• Olivine contains about 2000 ppm Ni which can dissolve is soils 

become strongly acidic.

–Excluded SFS from foundries that cast alloys that are high 

in Co, Cr, Cu, Ni, Pb, and Zn (e.g. stainless steel, brass, 

bronze, pewter)
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Evaluation Steps

• Obtain SFS-specific data

–Trace elements at low detection limits.

–Xenobiotics likely to be present.

– Nutrients.

• Review SFS-specific data

–Constituents, properties

–Environmental behavior (e.g. plant survival/uptake) 

• Develop/Choose Conceptual Model

• Screen out exposure pathways, constituents

• Model remaining pathways, constituents

• Characterize risk w/in context of soil science

• Conclusions
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Screening / Modeling

Inhalation of Fugitive Dust

• Resident Downwind of Soil Blending Facility

• Conservative estimate of particulate concentrations

• Calculated screening values

Results: All SFS concentrations at least order of 

magnitude below screening values 
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Screening / Modeling (cont.)

Leaching to Groundwater: Screening 

constituents

–Compared SFS leachate to MCLs, NSDWSs

–Presumed soil contained 50% SFS by dry weight and 

comprised large soil area.

Results: Screened out phenolics, PAHs, 

dioxins/furans/dioxin-like PCBs, most metals.

• As, (Be, Cd, Sb) remained for further study
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Screening / Modeling (cont.)

• Leaching to Groundwater: Modeling

–10,000 runs of probabilistic model (IWEM)

–High-end exposures compared to MCLs

–Results: all exposure conc. estimates below 

benchmarks.
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Screening / Modeling (cont.)

Home gardener - ingestion of produce, soil: screening 

constituents

–Soil assumed to be 50% SFS and large enough to provide 

garden foods to high end hime gardener.

–Compared soil conc. to human and ecological Soil 

Screening Levels.

–Results: phenolics, PAHs, dioxin/furan/dioxin-like PCBs, 

most metals screened out.

• As, Mn, Ni, Pb remained for further study
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Screening / Modeling (cont.)

Ingestion of Produce & Soils: Modeling Home 

Gardener

– EPA’s Biosolids Methodology.

– Probabilistic Model Runs for 1 mg/kg.

– Used high-end hazard estimates to calculate conservative screening 

values

– Compared high-end SFS concentrations to screening values

Results: SFS concentrations below screening values
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Soil Background

• SFS media similar to natural soils.

• As, Co, Fe, Mn, and Ni all have similar distributions 

to national soils, usually lower.

• Example: As 95th percentile in SFS is lower than 

median of national background.
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Comparing As in Spent Foundry Sand and US Soils

0 1 2 3 4 5 6 7 8 9 1011121314151617181920

0

2

4

6

8

10

12

14

SFS Dataset, 2009

 N=39

Number of Samples

SFS As Concentration, mg kg-1

0 1 2 3 4 5 6 7 8 9 1011121314151617181920

0

5

10

15

20

25

30

35

40

45

USGS Dataset, 2005

 N=254

Number of Samples

Soil As Concentration, mg kg-1

SFS:

95th %ile : 4.1

50th %ile: 1.1

US Background Soils:

95th %ile: 12

50th %ile: 5
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Conclusions for SFS

• Non-Olivine Iron, Steel, and Aluminum Spent 

Foundry Sands:

–Have constituent concentrations similar to that of 

native soils

–Do not pose a threat to human health or the 

environment when used:

• As an ingredient in manufactured soils used at 50% of dry 

weight of home garden soil.

• As an ingredient in soil-less media

•In roadway sub-base
Beneficial Reuse of FGD Gypsum in Agriculture Applications
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Composition of Old CCPs (mg/kg)

MN 23 Fly Ash 59 FGDs

Dowdy Furr et al., 1977 Kost et al., 2005

Mean Min Max Mean Min Max

B 824. 255. 10. 600. 145. 68. 948.

Mo 7.4 8.6 <0.02 63.7

Se 8.4 1.2 17. 3.6 2.7 23.0

As 85.6 2.3 312 75. 5.2 386.

Cd <0.5 2.3 <0.5 40.7

Zn 33.9 119. 5.0 469.

Cu 52.4 177. 13.3 1490.

Ni 16.9 33.0 12.4 156.

Pb 22.7 11.3 5.0 139.

Cr 32.7 16.9 11.4 89.3
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Trace Elements in Gypsum and Soils

Element FGD-Gypsum Mined-Gypsum 95%ile Soil

• As 3.4 <2.6 12.

• B 42.4 <3.0 .

• Cd 1.2 0.2 0.6

• Co 1.0 0.3 17.6

• Cr 13.2 5.1 70.

• Cu <0.8 <0.8 30.1

• Mo 1.8 0.6 2.16

• Ni 5.0 2.3 37.5

• Pb 2.1 <1.5 38.0

• Se 18.8 <4.6 1.0

• Zn 16.5 4.3 103.

OSU preliminary dataset from EPRI.
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Present Considerations of As Limit at US-EPA

• EPA concludes that soil may not exceed 0.4 mg As/kg without risk 

thru soil ingestion by children.

• This concentration is below As in normal US soils.

• Many question the validity of the 0.4 mg/kg limit for soil As (10-5

lifetime cancer risk).

• EPA considering 20-fold increase in As cancer slope. 

• For iron foundry sands, some sands are above the 0.4 mg/kg level, 

but lower than normal soils such that application of spent foundry 

sand would reduce “risk” from ingestion of background soils.

• Foundry sand risk assessment accepts use on land.

• EPA previously attempted to make fly ash hazardous due to As level 

but were caught with bad calculations.
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Concentrations of As in US Soils

Mean Range N Reference

• 7.2 <0.1-97 1318 US: Shacklette & Boerngen, 1984

• 11.3 0.1-194 >3000 World: Ure and Berrow, 1982 

• 0.42 0.1-50.6 441 FL: Chen, Ma & Harris, 2002

• 5.8 1.0-18.0 254 USGS: Smith et al., 2005

• 7.6 1.2-18.4 585 CA: Chang et al. (2006)

• 0.69 0.04-4.8 43 Foundry Sand: Dungan (2007)

How should the US deal with background soil As which varies with 

parent rock As levels and soil formation processes, as well as historic 

agricultural and industrial practices?
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Distribution of Soil As Concentration in California Soils 

(Chang et al, 2007)

As Soil Content (mg kg-1)

0 5 10 15 20

Number of Observation

0

20

40

60

80

100

Mean=7.64

GM =6.91

N = 585
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Statistic mg kg-1 DW

Mean 5.8

Minimum 1.0

Maximum 18.0

Median 5.0

90th 10.0

95th 11.4

99th 13.0

EPA-SSL 0.426

Distribution of Soil As Concentrations in Recent 

USGS Transects of USA (Smith et al., 2005) [N=256]
Beneficial Reuse of FGD Gypsum in Agriculture Applications

0 1 2 3 4 5 6 7 8 9 1011121314151617181920

0

5

10

15

20

25

30

35

40

45

USGS Dataset, 2005

 N=254

Number of Samples

Soil As Concentration, mg kg-1
Beneficial Reuse of FGD Gypsum in Agriculture Applications

0 1 2 3 4 5 6 7 8 9 1011121314151617181920

0

2

4

6

8

10

12

14

SFS Dataset, 2009

 N=39

Number of Samples

SFS As Concentration, mg kg-1
Beneficial Reuse of FGD Gypsum in Agriculture Applications

0 1 2 3 4 5 6 7 8 91011121314151617181920

0

2

4

6

8

10

12

14

SFS Dataset, 2009

 N=39

Number of Samples

SFS As Concentration, mg kg-1

0 1 2 3 4 5 6 7 8 91011121314151617181920

0

5

10

15

20

25

30

35

40

45

USGS Dataset, 2005

 N=254

Number of Samples

Soil As Concentration, mg kg-1
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Summary/Conclusions

• New FGD-Gypsum is low in trace elements and other problem 

contaminants compared to background soils.

• Presuming low trace element levels, FGD-Gypsum will be below the 

95th %-ile of background US soils.

• The Spent Foundry Sand Risk Assessment found no risk to humans 

or the environment when elements were below the 95th %-ile of US 

soils.

• Dioxins, PAHs, and other xenobiotics were also subjected to risk 

assessment.

• Questions about Hg emissions remain, but it seems difficult to 

conclude it would be a new and significant hazard to prohibit use of 

FGD-Gypsum
BREAK
FGD PRODUCTION AND 

MARKET TRENDS

Looking Back and Looking Ahead

Dave Goss

for ACAA
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Production Trends

Year Tons

Produced

Tons 

Used

Wallboard Disposal

2008 17,754,939 10,853,344 8,533,732 6,901,595

2007 12,300,000 9,228,271 8,254,849 3,071,729

2006 12,100,000 9,561,489 7,579,187 2,538,511

2005 11,975,000 9,268,365 8,178,079 2,706,635
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Future Production

• As more power plants add air emission scrubbers, 

more FGD gypsum will be produced

• Anticipate volumes in excess of 25 million tons 

annually

• Not all will be used in wallboard or cement 

production

• Some will go into agriculture where market 

conditions permit
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Marketing Considerations

• Does the gypsum meet quality needed for crop use? 

• Not all crops can use FGD gypsum effectively 

• Is the delivery distance economically achievable?

• Market saturation may limit expansion in some regions

• Regulatory acceptance is important

• Negative perception or stigma could cause market loss 
Beneficial Reuse of FGD Gypsum in Agriculture Applications

Conclusions

• Agricultural use of FGD gypsum is likely to increase 

significantly

• Shifting from wet impoundments to mechanically 

dewatered systems will allow more FGD gypsum to be 

stored for future use

• However, larger amounts of FGD gypsum will be 

disposed of in the future requiring new landfill 

facilities

• Increased agricultural use could reduce landfills 

needed
IMPLEMENTATION

Ron Chamberlain &

Bob Spoerri
Beneficial Reuse of FGD Gypsum in Agriculture Applications

• Permitting for agricultural use by States- requirements 

vary

• BRM holds permits in 2 States, applications in process 

in 5 other States

• Typically considered under State Environmental 

Departments Water regulations

• State Agricultural Departments typically issue licenses 

and collect taxes

Regulation of FGD Gypsum in Agriculture
Beneficial Reuse of FGD Gypsum in Agriculture Applications

• Materials Testing against Clean Water Act Part 503 

Standards for land application of “Exceptional Quality” 

Bio-solids

• Management Plan Required

o Appropriate utilization

o Materials Handling

o Application Rates

o User Information Sheets

o Storage requirements

• Record Keeping and Reporting

o Individual application site

o Statewide volumes

Common State Permitting Procedures
Beneficial Reuse of FGD Gypsum in Agriculture Applications

FGD Composition Breakdown

(mg/kg)

Part 503 

Exceptional 

Quality 

BioSolid

FGD Gypsum 

Typical Range 

per USEPA

BRM 

Customer 

Plant A

BRM 

Customer 

Plant B

Metal

Arsenic 41 .6-4.0 <.43 2.4

Cadmium 39 .2-1.2 0.042 n.d.

Copper 1500 1.1-4.7 no data 4.6

Lead 300 .8-12.0 1.5 n.d.

Mercury 17 .01-1.4 0.97 0.08

Molybdenum 75 .5-12.0 0.31 2.89

Nickel 420 .73-20.1 2.6 2.6

Selenium 100 2.0-30.0 12 4.12

Zinc 2800 3.4-47.5 5.5 10

n.d. = Not Detectable
Beneficial Reuse of FGD Gypsum in Agriculture Applications

• Appropriate Utilization

o Soil Properties

o Soil Test Values

o Field Observations

§ Water

§ Soil Structure

§ Crop development

§ Biological systems

• Materials Handling

o Transport

o Land Application

• Application Rates

• User Information Sheets

• Storage requirements

Management Plan
DISCUSSION:

Q & A
THANK YOU