Westport fine sand

Q
ie)
1

Lettuce

o
“
oO
tL 6.ob § = --05 + 68-1x
oO
2
8
= 4-OF
oO
bt
Zz
S 20r
a.

Oo i I | ]

O “02 ‘04 ‘06 ‘08 ‘10

Cd IN FERTILIZER (j2g/q soil)

Figure 2. Cadmium concentration in lettuce grown on Westport fine sand
as a function of Cd in concentrated super phosphate fertilizer
(CSP).

12


€€

TABLE B-7. CADMIUM CONCENTRATION IN PLANTS GROWN ON VIRTUE SILT LOAM SOIL AS AFFECTED BY Cd IN PHOSPHATE

FERTILIZER (MEAN OF 2 REPLICATIONS).

LOW AND HIGH SOURCES OF CSP CONTAIN 12 AND 174 ug Cd/g RESPECTIVELY.

csP Final Cd.
Source Concentration Radish Lettuce Peas
low-High Fertilizer (Soil) Root Top Top Seed Foliage
% ug/g ug Cd/g dry wt.
100-0 (MCP) 0 (0)3/ .33 78 -85
100-0 13 (.0065) 28 87 «79 Below detection limit
80-20 45 (.023) .28 98 92 of 0.20
60-40 77 (.039) 44 1.21 1.23
40-60 110 (.055) 43 1.31 1.08
20-80 142 (.071) -36 1.48 1.28
100-0 174 (.087) 43 1.45 1.24
Standard Error 036 .093 .091
Linear regression (soil Cd vs plant Cd)
Slope 1.48 8.38 5.50
Intercept 305 819 +836
S.E. y.x 056 - 066 +103
2 472 .954* .784*

al <4x 10-4 ug/g

* Sig. at .01 level.


62

TABLE B-3. DRY MATTER YIELDS FROM VIRTUE SILT LOAM SOIL IN POTS TREATED WITH MCP OR CSP FERTILIZER FROM TWO
SOURCES (MEAN OF 2 REPLICATIONS). RATES CALCULATED TO SUPPLY 100 ug P/g SOIL.

csP Final Cd
Source Concentration Radish Lettuce Peas
low-High Fertilizer (Soil) 7Root Top Top Seed Foliage
ug/g g/pot

100-0 (MCP) 0 (0)8/ 3.71 1.93 5.58 6.54 5.50
100-0 13 (.0065) 4.35 2.05 5.55 5.3] 5.67
80-20 45 (.023) 4.74 1.98 7.05 6.03 5.63
60-40 77 (.039) 4.10 2.19 5.61 5.42 6.85
40-60 110 (.055) 4.67 2.23 7.10 7.18 6.21
20-80 142 (.071) 4.96 2.16 5.94 7.49 5.37
100-0 174 (.087) 4.87 2.21 5.08 6.84 5.43
Standard Error 412 177 712 -457 -692
Mean 4.49 2.11 5.99 6.41 5.81
Percent dry matter 5.88 7.15 4.82 31.5 48.1

af <4x 1074 ug/g


TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)

1. REPORT NO. 2. I3. RECIPIENT’S ACCESSION NO.
EPA-600/3-76-053
4, TITLE AND SUBTITLE IS. REPORT DATE
Plant Uptake of Cadmium from Phosphate Fertilizer May 1976

6. PERFORMING ORGANIZATION CODE

7 AUTHOR(S) Is. PERFORMING ORGANIZATION REPORT NO.

John Reuss, H. L. Dooley, and William Griffis

lo. PERFORMING ORGANIZATION NAME AND ADDRESS 70. PROGRAM ELEMENT NO.

U. S. Environmental Protection Agency 1 AA602

Corvallis Environmental Research Laboratory, EERD,TEB [17 CONTRACT/GRANT NO.
Corvallis, Oregon 97330

Corvallis, Oregon 97330

12, SPONSORING AGENCY NAME AND ADDRESS 13. TYPE OF REPORT AND PERIOD COVERED
U. S. Environmental Protection Agency Final--FY1970-1976
Corvallis Environmental Research Laboratory 14, SPONSORING AGENCY CODE

EPA/ORD

15. SUPPLEMENTARY NOTES

16. ABSTRACT

A preliminary investigation of selected crop plants for Cadmium
uptake from various sources of commercially available fertilizer was
conducted under controlled greenhouse conditions in Corvallis, Oregon.
Results indicated statistically significant differences in Cadmium
content of plant tissue as functions of fertilizer source, mode of
application, tissues analyzed, and soil type. The highest level of
Cadmium accumulation (6 ug/g dry weight) was found in lettuce grown

on a course textured acid soil and fertilized at the rate of 100 yg P/g
soil with concentrated super phosphate (CSP) containing 174 u Cd/g
fertilizer (0.087 u Cd/g $011). It was concluded that these uptakes may
be of sufficent magnitude to be of biological significance to consumer
organisms. Further study was recommended.

KEY WORDS AND DOCUMENT ANALYSIS

DESCRIPTORS b.IOENTIFIERS/OPEN ENDED TERMS |c. cosati Field/Group

Cadmium, bioaccumulatio
and phosphate fertilizer

118, DISTRIBUTION STATEMENT 19, SECURITY CLASS (This Report) 21. NO. OF PAGES
UNCLASSIFIED 43
RELEASE TO PUBLIC 20. SECURITY CLASS (This page) 22. PRICE
UNCLASSIFIED
EPA Form 2220-1 (9-73) 38

# U.S. GOVERNMENT PRINTING OFFICE: 1976—697-181/88 REGION 10


TABLE 2. TREATMENT MATERIALS, AMOUNTS AND METHOD OF APPLICATION

FOR CADMIUM UPTAKE EXPERIMENT

Materials Method
Treatment MCP CSP DAP AN Cd-P
No. Low High Low High
Stalatanataatatate g/pot----------- ug/pot
1 1.64 1.03 Mix
2 2.0 -- coos 1.03 Mix
3 -- +1.6 A -- 1.03 Mix
4 -- (1.2 8 -- 1.03 Mix
5 -- 8 1.2 -- 1.02 Mix
6 -- 4 1.6 -- 1.03 Mix
7 -- == 2.0 -- 1.03 Mix
8 -- =e 2.0 -- 1.03 Spot
9 -- os -- -- 2.0 -- Mix
10 -- ee we we 2.0 -- Spot
am) -- 2.0 -- wooo 1.03 840 Mix
12 -- 2.0 -- -- oof 1.03 840 Spot
13 ese -- 2.0 -- -- 790 Mix
14 a -- 790 Spot

MCP - Monocalcium phosphate, reagent

CSP (low) - concentrated super phosphate, 0-46-0 12 ppm Cd
CSP (high) - concentrated super phosphate, 0-46-0, 174 ppm Cd
DAP (low) - Di-ammonium phosphate, 18-46-0, 7 ppm Cd

DAP (high) - Di-ammonium phosphate, 18-46-0, 157 ppm Cd

Cd-P - Cadmium phosphate, Cd (HyPO,)o> 39% Cd by analysis

AN - Ammonium nitrate, reagent.


0.20 ug Cd/g and are not reported. Cadmium concentrations in radish
tops and lettuce increased substantially as the proportion of high Cd
CSP was increased, but at a much lower rate than for the Westport soil.
Radish roots apparently increased slightly in Cd, but the hypothesis of
a zero slope could only be rejected at the 0.1 probability level and not
at the 0.05 level.

The effect of soils and crops can probably best be evaluated from
Table 6. With the exception of radish roots the intercepts were much
lower on the Westport fine sand than the Virtue silt loam, indicating a
higher background level from the Virtue soil as collected. The Westport
soil was from a dune area and undoubtedly had never been fertilized.
The Virtue soil was from just outside a cultivated field near a country
road and while it apparently had not been fertilized, it's history is
less clear. The total cadmium concentration for the Westport fine sand
was <0.5 ug/g and for the Virtue silt loam was 0.6 g/g. The exchange-
able (ammonium acetate extractable) cadmium concentration for Westport
fine sand was 0.05 ug/g and for Virtue silt loam was 0.1 ug/g.

The most striking effects are in the slope and in the percentages
of the Cd applied in fertilizer that was found in the plant. For radish
plants this was 5.29% on the Westport fine sand compared to 0.61% for
the Virtue silt loam. For lettuce the values were 9.40% and 0.82%
(Table 6). This calculation was based on the slope of the regression
line, the mean dry matter produced and the amount of Cd contained in the
fertilizer. The higher uptake for lettuce than radish is in agreement
with the results of Haghiri (1973) even though he applied much higher
levels of Cd than are found in fertilizers.

Cadmium concentrations and percentage uptake was less for peas than
radishes or lettuce. The 5.3 and 2.0 percent of applied Cd found in the
radishes and pea plants respectively grown in Westport fine sand (Table
6) are similar to the result of Williams and David (1973) who found 6.3
and 3.3% of the Cd applied in single superphosphate taken up by these
crops from podzolic soil with a cation exchange capacity (CEC) of 5.3
millequivalents per 100 g.

The difference in uptake by the soils is exactly what would have
been expected as the high pH associated with the free CaCO. as well as
the higher CEC in the Virtue soil would tend to lower uptake (Williams
and David, 1973, Haghiri, 1974). These two soils should represent near
maximum and minimum uptake conditions.

The biological significance to consumer organisms is not clear, but
it does not appear that it can be dismissed as unimportant. The accumu-
lation of 6.3 ug/g Cd in lettuce on a dry weight basis is only about
-315 ug/g on a fresh weight basis at 5.25 percent dry matter (94.75%
water). However, a relatively small amount of wilting to 90% water
would result in 0.63 ug Cd/g on a fresh weight basis. It would appear
that the Cd uptakes found here, particularly on the coarse textured acid


ve

TABLE B-8. DRY MATTER YIELDS OF PLANTS GROWN ON WESTPORT FINE SAND AS AFFECTED BY FERTILIZER MATERIALS
AND PLACEMENT (MEAN OF 2 REPLICATIONS).

Treatment Radish Lettuce Peas
Placement Material Cd Source Root Top Top Seed Foliage
Mix CSP (high) fertilizer 4.33 3.92 5.49 4.59 3.93
Spot CSP (high) fertilizer 2.99 2.65 +38 5.21 7.19
Mix DAP (high) fertilizer 1.61 2.20 5.07 3.50 3.92
Spot DAP (high) fertilizer 2.59 2.18 1.36 2.65 3.77
Mix CSP (low) added 3.72 3.87 3.71 3.73 3.66
Spot CSP (low) added 3.22 3.37 1.19 4.35 5.58
Mix DAP (low) added 2.20 2.90 4.48 3.82 3.90
Spot DAP (low) added 2.55 2.30 1.34 1.97 1.94

Summary of significant effects

Placement Mix 3.22 4.68
Spot 2.62 1.07
Material csp 3.56 3.45 b/ 4.47
DAP 2.24 2.39 2.99
a/ c/

Probability of Type I error <.01 except as noted.
a/ Small placement X material interaction
b/ Complex interaction, but much smaller than placement effect

c/ P <.07


CONTENTS

List of Figures
List of Tables
Acknowledgements
I Introduction
II Conclusions
III Recommendations
IV Materials and Methods
Vv Results and Discussion
VI References
VII Appendix A
Synthesis of Cadmium Dihydrogen Phosphate
Appendix B
List of Data Tables

iti

oFRWHR =

24
25

26


TABLE B-1. CADMIUM AND ZINC CONCENTRATIONS IN FERTILIZER MATERIAL USED
IN Cd UPTAKE EXPERIMENT (MEAN OF 4 REPLICATIONS).

Cd Zn
Material ug/g ug/g
CSP - low Cd 12 78
CSP - high Cd 174 1564
DAP - low Cd 7.0 14
DAP - high Cd 157 1385

27


> a )
re) oO fe)

PLANT Cd CONC (g/g)
°
ol

Figure 3.

Westport fine sand

Pea
A SEED
r § = 15 + 10-1x
r2 = -93
O FOLIAGE
- J = 16+ 3-7x
r2 = -79
© e)
ec imi
Lg-6——--o----—--® rection Mmiy
j 1 _t ! i _I
(0) 02 “04 ‘06 -08 ‘10
Cd IN FERTILIZER (prg/g soil)
Cadmium concentration in peas grown on Westport fine sand as a

function of Cd in concentrated super phosphate fertilizer (CSP).

13


6L

TABLE 7. CADMIUM CONCENTRATIONS IN PLANTS GROWN ON WESTPORT FINE SAND AS AFFECTED BY FERTILIZER MATERIAL,
PLACEMENT AND SOURCE OF Cd

Treatment Radish Lettuce Pea
Placement Material Cd_ Source Root Top Top Seed Foliage

ug Cd per g dry weight

Mix CSP (high) fertilizer 2.40 3.12 6.35 46 91
Spot CSP (high) fertilizer 1.92 2.88 4.35 46 1.05
Mix DAP (high) fertilizer 3.55 2.24 6.01 53 1.07
Spot DAP (high) fertilizer .20 <.19 28 <.19 <.19
Mix CSP (low) added 3.53 4.61 5.32 -67 81
Spot CSP (low) added 3.20 7.33 5.98 -69 +93
Mix DAP (low) added 4.05 2.71 3.61 -60 92
Spot DAP (low) added 42 <.19 1.14 <.19 <.19
Summary of significant effects
Mix CSP 2.97 3.87 5.79 5.66 81
Spot CSP 2.56 5.10 5.17 5.78 -93
Mix DAP 3.80 2.47 4.81 5.66 92
Spot DAP 31 <.19 71 <.19 <.19
Cd source effect (P < .05)
In fertilizer 2.01 2.11
Added 2.80 3.71

Probability of Type I error for main effect and interaction <.01.


Virtue silt loam

20 Lettuce

oO
“NX
L=2)
2 15-
Oo
2
ro)
oO
ne}
Oo
a ost § = 84 + 5°5x
< r2 = +78
a

O l Ll 1 1 im )

O 02 04 06 ‘08 10

Cd IN FERTILIZER (g/g soil)

Figure 5. Cadmium concentration in lettuce grown on Virtue silt loam as a
function of Cd in concentrated super phosphate fertilizer (CSP).

15


82

TABLE B-2. DRY MATTER YIELDS FROM WESTPORT FINE SAND SOIL IN POTS TREATED WITH MCP OR CSP FERTILIZERS FROM
TWO SOURCES (MEAN OF 2 REPLICATIONS). RATES CALCULATED TO SUPPLY 100 ug P/g SOIL.

csp Final Cd
Source Concentration Radish Lettuce Peas
low-High Fertilizer (Soil) Root Top Top Seed Foliage
% u9/9 g/pot
100-0 (MCP) 0 (0)8/ 3.90 3.84 6.00 5.45 8.74
100-0 13 (0.0065) 3.08 3.99 5.81 4.44 9.48
80-20 45 (.023) 3.61 3.52 5.60 4.52 7.65
60-40 77 (.039) 3.66 3.78 ‘ 5.38 5.55 7.91
40-60 110 (0.055) 3.64 3.90 4.54 4.98 8.83
20-80 142 (0.071) 3.45 3.94 5.82 4.08 9.85
100-0 174 (.087) 4.33 3.93 5.50 4.60 8.93
Standard Error +421 +363 +351 +584 1.20
Mean 3.67 3.84 5.52 4.80 8.77
Percent dry matter 5.27 5.63 5.25 26.6 21.9

a <4 y 1074 ug/g.


OL

TABLE 5. DRY MATTER PERCENTAGE, DRY WEIGHT YIELDS, AND PLANT P CONCENTRATIONS FOR TREATMENTS 1-7
OF Cd UPTAKE EXPERIMENT. a/

Westport fine sand Virtue silt loam
Percent Dry Plant Percent Dry Plant
Dry Matter Matter P Dry Matter Weight P
% g/pot b % g/pot %
Radish
Root 5.27 3.67 -66 5.88 4.49 +35
Top 5.63 3.84 1.10 7.15 2.11 37
Lettuce 5.25 5.52 46 4.82 5.99 49
Pea
Seeds 26.6 4.80 -68 31.5 6.41 62
Foliage 21.9 8.77 35 48.1 5.81 +19

a/ Values represent means of 14 pots.


SECTION IT
CONCLUSIONS

Uptake of cadmium contained in phosphatic fertilizers by radish,
lettuce and peas grown on a coarse textured acid soil was shown to
be a linear function of the Cd concentration, at least over the
range of 0.0 to 0.087 ug Cd per g soil. The Cd concentration in
lettuce was over 6 ug/g dry weight when fertilized at the rate of
100 ug P/g soil with concentrated super phosphate (CSP) containing
174 ug Cd/g fertilizer (0.087 ug Cd/g soil). Percentage of Cd in
fertilizer recovered in the plants was 5.3, 9.0, and 2.0 for the
radish (top plus root), lettuce (tops), and peas (foliage plus
seeds), respectively. These uptakes may be of sufficient magnitude
to be of biological significance to consumer organisms.

Uptake of Cd in fertilizer was also linear from a calcareous silt
loam soil, but was much lower than from the acid sand. The Cd
concentration in lettuce was 1.2 ug/g dry weight when fertilized at
the rate of 100 ug P/g soil with CSP containing 174 ug Cd/g ferti-
lizer (0.087 ug Cd/g soil). Percentages of Cd recovered in the
plants were 0.6 in radish and 0.8 in lettuce. Background levels on
the calcareous silt loam soil were higher than those on the acid
sand. Cd levels in peas grown on the calcareous soil were below
the detection limit of 0.20 ug Cd/g dry weight.

Plant uptake of cadmium from di-ammonium phosphate (DAP) fertilizer
on an acid course textured soil was markedly reduced when this
material was applied in a single spot as compared to mixing through-
out the pot. Cd uptake from mixed DAP was similar to that from CSP
applied either mixed or in a spot. Placement effects in a calcar-
eous silt loam were smaller than those in the acid coarse textured
sand.


SECTION VII
APPENDIX A

Synthesis of Cadmium Dihydrogen Phosphate
(Preparation of Cd (HyPO 4) y-2H50.)

We were unable to obtain this salt through normal commercial
channels so the compound was synthesized in the following manner
using the Parker Rust Proof Company Patented procedure (1926).

The salt was synthesized in the following manner: approximately
1 gram of 100 mesh cadmium mefal was allowed to react with 20 ml of 75%
phosphoric acid held at 80-85 C. Two more 10 m1 portions of 75% phospho-
ric acid were added at intervals of several hours. When all of the
cadmium metal was consumed (visual examination), the reaction mixture
was allowed to cool. The white crystals which formed were separated
from the mother liquor by filtration. They were washed with absolute
ethanol to remove any unreacted phosphoric acid and allowed to air dry
for several hours. The crystals were then analyzed via atomic absorption
and found to contain 39% cadmium. The predicted value for cadmium in
this compound is 33%. The 6% difference might well be due to a small
amount of unreacted cadmium metal remaining with the crystals.

25


22

TABLE 10. SUMMARY OF MEANS OF MAJOR PLACEMENT AND FERTILIZER MATERIAL EFFECTS ON PLANT PHOSPHORUS CONCENTRATIONS.

Radish Lettuce Peas
Treatment Roots Tops Tops Seeds Foliage
percent of dry weight

Westport fine sand

csP 58 88 51 34
DAP -70 1.55 -60 57

Virtue silt loam

csp
Mix -35 36 -48 64 18
Spot -30 +36 44 +50 «13
DAP
Mix 39 42 48 -66 22

Spot .19 27 38 51 -10



10.

LIST OF TABLES

Characteristics of soils used in the Cd uptake
experiment.

Treatment materials, amounts and method of application
for Cadmium uptake experiment.

Cadmium levels resulting from treatments 1-7 of the Cd
uptake experiment (yg Cd/g soil).

Factors and levels used in Treatments 7-14.

Dry matter percentage, dry weight yields, and plant P
concentrations for treatments 1-7 of Cd uptake experi-
ment. Values represent means of 14 pots.

Summary of the slope and intercepts of the regression
of plant Cd concentration on Cd added in fertilizer,
and percentage of added Cd found in plants.

Cadmium concentrations in plants grown on Westport
fine sand as affected by fertilizer material, place-
ment and source of Cd.

Cadmium concentration in plants grown on Virtue silt
loam soil as affected by fertilizer material, placement
and source of Cd.

Summary of means of major placement and fertilizer
material effects on dry matter yields.

Summary of means of major placement and fertilizer
material effects on plant phosphorus concentrations.

Page

10

7

19

20

21

22


LIST OF FIGURES

Cadmium concentration in radishes grown on Westport
fine sand as a function of Cd in concentrated super
phosphate fertilizer (CSP).

Cadmium concentration in lettuce grown on Westport
fine sand as a function of Cd in concentrated super
phosphate fertilizer (CSP).

Cadmium concentration in peas grown on Westport fine
sand as a function of Cd in concentrated super
phosphate fertilizer (CSP).

Cadmium concentration in radishes grown on Virtue
silt loam as a function of Cd in concentrated super
phosphate fertilizer (CSP).

Cadmium concentration in lettuce grown on Virtue

silt loam as a function of Cd in concentrated super
phosphate fertilizer (CSP).

iv

12

13

14

15


PLANT Cd CONC (g/g)

4-0

3:0

2:0

Figure 1.

Westport fine sand
Radish

TOP

y = -43 + 32°5x
r2 = -966

ROOT

r § = -36 + 23-7x
a r2 = -986
L i i 1 i J
(0) 02 04 ‘06 08 ‘10

Cd IN FERTILIZER (g/g soil)

Cadmium concentration in radishes grown on Westport fine sand

as a function of Cd in concentrated super phosphate fertilizer
(CSP).

1


SECTION I
INTRODUCTION

The cadmium (Cd) content of phosphate ores used in fertilizer
manufacture is highly variable. Values of 130 mg Cd per kg for ores
from the western United States as compared to 9 mg/kg for Florida ores
have recently been published (Anon. 1974). In 11 samples of 18-46-0 (N,
P,0,, K,0), presumably of Idaho origin, the Cd content ranged from 7.4
t6 756 fig/kg 2! Ten of the samples exceeded 50 mg/kg and 6 exceeded 125
mg/kg. Seven samples of 0-46-0 ranged from 86 to 114 mg Cd per kg.

A substantial body of literature is available concerning uptake of
Cd by plants, but in most cases reported levels applied. to the soil were
much higher than would occur due to the Cd content of phosphate fertili-
zers. Reports of Schroeder and Balassa (1963) and Williams and David
(1973) indicate that detectable amounts may be taken up from this
source. This report describes an experiment conducted to evaluate
uptake of Cd by some common food crop plants from phosphate fertilizers
containing levels of Cd commonly encountered in materials manufactured
from western ores. The work was undertaken in response to a request
from the U.S. Environmental Protection Agency Region 10 personnel for
assistance in evaluating the possibility of undesirable Cd levels in
foodstuffs resulting from use of these fertilizers. Specific objectives
of the project include:

a. To provide information concerning the probability that plant
Cd levels of biological significance to consuming organisms
would occur as a result of use of high Cd fertilizers.

b. To provide information concerning the effect of soil proper-
ties and the chemical form and placement of phosphate fer-
tilizer on Cd uptake.

It was not possible to test a large number of soils for Cd
uptake within the scope of this project. Therefore, it was decided to
restrict these initial studies tg, two soils: (1) an acid coarse textured
soil in which the activity of Cd" would remain relatively high and
favor plant uptake and (2) a medium textured soil containing free Caco,
which would tend to depress Cd solubility and uptake.

The results reported here are preliminary and the data will be
subjected to further analysis. Also considerable care is required in
projecting greenhouse experiment results to field conditions.

a/ Unpublished data, U.S. Environmental Protection Agency. Region 10.
Seattle. 1


TABLE 6. SUMMARY OF THE SLOPE AND INTERCEPTS OF THE REGRESSION OF
PLANT Cd CONCENTRATION ON Cd ADDED IN FERTILIZER AND
PERCENTAGE OF ADDED Cd FOUND IN PLANTS

Westport fine sand Virtue silt loam
Plant Intercept Slope Uptake Intercept Slope Uptake
ug/g af & b/ ug/g af bf
Radish
Root +36 23.7 2.17 31 1.5 (NS) .17
Top +43 32.5 3.12 82 8.38 44
5.29 61
Lettuce -.05 68.1 9.40 84 5.5 -82
Pea
Seed +15 10.1 1.21 -- -- --
Foliage +16 3.7 81
2.02

a/ ug Cd/g plant per ug fertilizer Cd/g soil

b/ Percent of Cd in fertilizer found in plant

W7


Ecological Research Series

ANT UPTAKE OF CADMIUM FROM
PHOSPHATE FERTILIZER

ED S7%>,
s &>

2 3
g SZ :
8 <
% oO
Vp, Ss
4L prow’

Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Corvallis, Oregon 97330


SECTION IV
MATERIALS AND METHODS

The two soils selected for the experiment were (1) Westport fine
sand (Typic udipsamment), an acid dune soil from near Bandon, Oregon;
and (2) Virtue silt loam (Xerollic durargid). a calcareous soil from
near Nyssa, Oregon.

Soils were dried, mixed, and crushed to pass a 1/2 cm screen prior
to potting. Plants were grown in paraffin coated paper containers
approximately 20 cm in diameter and each containing 4 kg air dry soil.
Selected soil properties are shown in Table 1. Due to the Jow organic
matter content, 2 1/2 percent by weight of an acid peat was mixed with
the Westport soil to improve water holding capacity. Analyses of the
Westport soil shown in Table 1 were from samples taken after the peat
was added. Measured pH of the Westport soil varied from 4.5 to 5.3 when
sampled at different times. These differences were apparently due to
low buffering capacity.

Fertilizer materials used in this study were obtained by Region 10
EPA personnel. They included concentrated superphosphate (CSP) and di-
ammonium phosphate (DAP) with a low and high cadmium level sample of
each (Table 2). While both CSP samples were nominally 0-46-0 (N, P.0,,
K,0) and both DAP samples were nominally 18-46-0, they were from entirely
d¢fferent sources.

The treatment set utilized is shown in Table 2. In addition to the
above materials, reagent grade monocalcium phosphate dihydrate (MCP).
and cadmium dihydrogen phosphate prepared in the laboratory (Appendix
A), were utilized in selected treatments. The ammonium nitrate (AN)
added to the CSP treatments supplies the same total N as the DAP treat-
ments. All treatments supply a total of 100 yg P (245 ug P,0,) per g of
soil. In addition to the materials shown in Table 2, 0.39 g RNO, and
0.34 g K,SO, were mixed with the soil in each pot to supply K, S} and
additional A

The treatment set shown in Table 2 contains two subsets, each
designed to yield specific information. Treatments 1-7 supply increa-
sing amounts of Cd in the range of 0 to .087 ug Cd per g soil as shown
in Table 3. All treatments in this subset utilize CSP as a fertilizer
source and all treatments were thoroughly mixed with the soil utilizing
a twin shel] blender. Treatments 7-14 comprise a 2° factorial experi-
ment with factors and levels as shown in Table 4. This set is designed
to evaluate the effect of cadmium source, fertilizer material (CSP vs
DAP), and mix vs spot application, on uptake of Cd by the plants. The
spot application is intended to simulate band application in the field.
In this method all treatment materials were placed in a single spot
located at the center of the pot and 5 cm below the soil surface.
Lateral distance from the seeds to the spot was also approximately 5 cm.

4


SECTION IIT
RECOMMENDATIONS

This investigation was intended to be preliminary in nature.
Uptake of cadmium from phosphate fertilizer materials appears to be high
enough to warrant further investigation. Results indicate three areas
of particular interest.

(1) Uptake of Cd by food crops from phosphate fertilizers applied
to acid soils of low cation exchange capacity.

(2) The effects of cummulative doses of high Cd fertilizers on
acid soils and on soils that do not maintain high Cd activity such as
the calcareous silt loam used in this study is not known and should be
investigated.

(3) The reduced Cd uptake by spot (or band) placement of di-
ammonium phosphate fertilizer should be further investigated. The
results shown here suggest that this placement might have potential as a
management technique to reduce Cd uptake on coarse textured soils. The
theoretical soil chemistry of this effect should be understood as well
as possible field applications.


9€

TABLE B-10.

MEAN PHOSPHORUS CONCENTRATION IN PLANTS GROWN ON WESTPORT FINE SAND AS AFFECTED BY FERTILIZER
MATERIAL AND PLACEMENT (MEAN OF 2 REPLICATIONS).

Treatment Radish Lettuce Peas
Placement Material Cd Source Root Top Top Seed Foliage
%P

Mix CSP (high) fertilizer 58 93 -50 70 +35
Spot CSP (high) fertilizer -49 73 45 70 -36
Mix DAP (high) fertilizer 71 1.46 -68 -61 47
Spot DAP (high) fertilizer .72 1.66 .55 63 74
Mix CSP (low) added -66 1.04 -56 -60 27
Spot CSP (low) added 57 82 53 62 235
Mix DAP (low) added 72 1.56 -60 65 56
Spot DAP (low) added 73 1.41 56 61 49
Summary of significant effects

csP 58 88 51 a 34

DAP -70 1.55 -60 57

Probability of Type I error of main effects shown <.01.

a/ Main effect not significant; interaction with source <.05.


SECTION VI
REFERENCES

Anonymous. 1974. Development document for effluent limitations guide-
lines and new source standards for the basic fertilizer chemicals.
EPA-440/1-74-011-9. United States Environmental Protection Agency,
Washington, DC.

Haghiri, F. 1974. Plant uptake of cadmium as influenced by cation
exchange capacity, organic matter, zinc, and soil temperature. J.
Environ. Quality 3:180-183.

Haghiri, F. 1973. Cadmium uptake by plants. J. Environ. Quality.
2:93-95.

Schroeder, H. A., and J. J. Balassa. 1963. Cadmium: Uptake by vege-
tables from superphosphate in soil. Science 140:819-820.

Parker Rust Proof Co. British Patent 270820 (1926).
Williams, C. H., and D. J. David. 1973. The effect of superphosphate

on the cadmium content of soils and plants. Aust. J. Soil Res.
11:43-56.

24


On the Westport soil radishes root and top weights are decreased by
use of DAP fertilizer as compared to CSP, and radish tops and lettuce
were depressed by spot application of either fertilizer. The reason for
these effects were not completely clear but the DAP did increase plant P
concentrations in most plants (Table 10) independent of placement. This
indicates that phosphorus from the spot placed DAP was utilized even
though on this soil Cd was not. While these growth effects do compli-
cate interpretation they simply do not account for the nearly complete
lack of Cd uptake from spot placed DAP.

The effects of treatment on dry matter yields and phosphorus
concentration was quite different on the calcareous Virtue soil (Table 9
and 10). Here yields were consistently depressed by spot placement of
fertilizer. This is probably due to lower availability of phosphorus
as phosphorus concentrations were depressed by spot placement on this
soil, particularly in the case of the DAP.

These effects of placement and fertilizer material on yield and
plant phosphorus concentration may be of agronomic interest but we are
concerned with them here in relation to interpretation of the Cd uptake
data. It should not be implied that these effects are related to the Cd in t
fertilizer. They are useful in evaluating whether the plant was utilizing
the nutrients supplied by a particular material and placement.

The most important effect noted in this section of the experiment
was the lack of Cd uptake from spot placement of DAP on the acid soil.
This effect may have important implications as a management technique,
and therefore should be further investigated from both theoretical and
application standpoints. Effects of material and placement on Cd uptake
on the calcareous soil were less dramatic but may still warrant further
investigation.

23


ACKNOWLEDGEMENTS

This investigation was made possible by the contributions and
support of many people. Among others we would like to acknowledge the
help of Dr. Gerald Simmonson of the Oregon State University Soil Science
Department and Fred Gilderman and Burrel Lovell of the USDA Soil Conser-
vation Service for assistance in obtaining the soils.

We would particularly like to thank Dan Krawczyk and the personnel
of the CERL Laboratory Services Branch for their effort in providing the
analyses of the plant samples and Ron Silberman for his help with the
statistical analyses.

The investigation was suggested by Region 10 personnel. Fertilizer
samples were obtained by Carolyn Wilson of the Region 10 office, who
also made valuable suggestions concerning the manuscript, as did Dr.
Dave Tingey of the CERL. Fertilizer analyses were performed by the
Region 10 laboratory. Seeds were furnished by Northrup King.

vi


PLANT Cd CONC (yg/Qg)

~
o)

a

fe)

°
a

Virtue silt loam
Radish

J = 82+ 8-4x
25 -954

r

y= 31 + 15x

r2 = -472
- A A x a
“za
1 1 _t | i J
O -02 -04 “06 ‘08 10

Cd IN FERTILIZER (g/g soil)

Figure 4. Cadmium concentration in radishes on Virtue silt loam as a function

of Cd in concentrated super phosphate fertilizer (CSP).

14


le

TABLE B-5. PHOSPHORUS CONCENTRATION IN PLANTS GROWN ON WESTPORT FINE SAND SOIL TREATED WITH MCP OR CSP

FERTILIZER FROM TWO SOURCES (MEAN OF 2 REPLICATIONS).

RATES CALCULATED TO SUPPLY 100 ug P/g SOIL.

csP Final Cd

Source Concentration Radish Lettuce Peas
low-High Fertilizer (Soil) Root Top Top Seed Foliage

% ug/g %P
100-0 (MCP) 0 (0)2/ 75 1.04 45 69 £35
100-0 13 (.0065) -70 1.08 -45 -66 36
80-20 45 (.023) -65 1.04 44 -67 35
60-40 77 (.039) 64 1.04 47 -73 31
40-60 110 (.055) -66 1.06 «47 66 239
20-80 142 (.071) 62 91 47 .69 .38
100-0 174 (.087) ~59 +93 50 -70 «35
Standard Error -031 023 025 -046 042
Mean -656 1.10 -462 -682 352

af <4x 107" ug/g


2

TABLE B-6. CADMIUM CONCENTRATION IN PLANTS GROWN ON WESTPORT FINE SAND AS AFFECTED BY Cd IN PHOSPHATE
FERTILIZER (MEAN OF 2 REPLICATIONS). LOW AND HIGH SOURCES OF CSP CONTAIN 12 AND 174 ppm ug Cd/g RESPECTIVELY.

csP Final Cd
Source Concentration Radish Lettuce Peas
Tow-High Fertilizer (Soil) Root Top Top Seed Foliage
% ug/g ug Cd/g dry wt.
100-0 (MCP) 0 (0)8/ 50 .38 .20 <.19 <.19
100-0 13 (.0065) 37 47 44 <.19 <.19
80-20 45 (.023) +90 1.18 1.34 +33 <.19
60-40 77 (.039) 1.21 2.11 2.20 55 235
40-60 110 (.055) 1.64 2.12 4.08 81 42
20-80 142 (.071) 2.10 2.76 4.18 +95 -40
100-0 174 (.087) 2.41 3.12 6.33 -91 46
Standard Error (log normal distribution) 157 133 088 -082 -079
Linear regression (soil Cd vs plant Cd)
Slope 23.7 32.5 68.1 10.1 3.7
Intercept 356 -433 -0.49 -149 +163
S.E. yx -0987 -218 +438 094 ~056
r? -986** -966** + 969%* «929%* .789*

af <4x 1074 ug/g

** significant at .01 level *sig. at .05 level


02

TABLE 8. CADMIUM CONCENTRATION IN PLANTS GROWN ON VIRTUE SILT LOAM SOIL AS AFFECTED BY FERTILIZER MATERIAL,
PLACEMENT AND SOURCE OF Cd

Treatment Radish Lettuce Peas _
Placement Material Cd Source Root Top Top Seed Foliage

ug Cd per g dry weight

Mix CSP (high) fertilizer +43 1.72 1.23
Spot CSP (high) fertilizer 77 2.53 2.41 Below detection
Mix DAP (high) fertilizer 37 1.46 1.25 limit of 0.20
Spot DAP (high) fertilizer 44 1.00 81
Mix CSP (low) added 45 1.48 1.07
Spot CSP (low) added 1.12 3.22 3.49
Mix DAP (low) added 47 1.49 1.38
Spot DAP (low) added 57 1.03 1.08
Summary of significant effects
Mix CSP 1.60 1.15
Spot CSP 2.87 2.94
Mix DAP 1.47 1.31
Spot DAP 1.02 +94

Main effects and interaction shown significant probability of Type I error <.01


DISCLAIMER

This report has been reviewed by the Corvallis Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for
publication. Mention of trade names or commercial product does not
constitute endorsement or recommendation for use.

ii


LE

TABLE B-11. MEAN PHOSPHORUS CONCENTRATIONS OF PLANTS GROWN ON VIRTUE SILT LOAM AS AFFECTED BY FERTILIZER

MATERIAL AND PLACEMENT (MEAN OF 2 REPLICATIONS).

Treatment Radish Lettuce Peas
Placement Material Cd Source Root Top Top Seed Foliage
%P
Mix CSP (high) fertilizer 35 37 -48 +65 14
Spot CSP (high) fertilizer 28 29 -42 49 «15
Mix DAP (high) fertilizer 239 36 47 66 28
Spot DAP (high) fertilizer 17 28 38 51 08
Mix CSP (low) added 35 +36 47 -63 22
Spot cSP (low) added 32 42 -46 52 11
Mix DAP (low) added -38 48 48 -65 17
Spot DAP (low) added 2] 26 38 51 17
Summary of significant effects
Mix CSP +35 36 -48 64 18
Spot CSP -30 36 44 50 13
Mix DAP 39 42 -48 -66 22
Spot DAP +19 27 38 51 -10
a/ b/ a/

Probability of Type I error.

<.01 for placement, <.05 for material and interaction except as noted.

a/ Additional interaction with sources.

b/ Only placement effect significant.


TABLE 3. CADMIUM LEVELS RESULTING FROM TREATMENTS 1-7 OF THE Cd
UPTAKE EXPERIMENT (ug Cd/g SOIL)

Treatment Cd Concentration

ug Cd/g

1 0

2 - 0065

3 0226

4 0387

5 -0548

6 0709

7 -0870

TABLE 4. FACTORS AND LEVELS USED IN TREATMENTS 7-14

Fertilizer Material Placement Cd Source
1. Concentrated super 1. Mixed with soil 1. High Cd
phosphate, 0-46-0 fertilizer

2. Di-ammonium phosphate, 2. Spot application 2. Cd (H,PO,)
18-46-0 added td Tow
Cd fertilizer



SECTION V
RESULTS AND DISCUSSION
REPLACEMENT SERIES TREATMENTS

Results from the two treatment subsets were quite different and
will be discussed separately. The progressive replacement of the low Cd
CSP source with the high Cd CSP did not detectably affect dry matter
yields for any of the crops on either soil. Mean dry matter yields and
percentages are summarized in Table 5. Treatment means and standard
errors are included in Appendix B. Plants in treatments 1-7 generally
appeared healthy and grew well with the exception that the pea vines in
some pots exhibited early senescence and yields of both pea foliage and
seeds was highly variable. This was apparently unrelated to treatment.
The lack of any growth effects due to treatments simplifies interpre-
tation of the cadmium concentration data as dilution or concentration
effects due to growth differences are not likely to be important.

Mean plant phosphorus concentrations are shown in Table 5. Phosphorus
concentrations by individual treatments are included in Appendix B. In
most cases, the phosphorus concentrations in the plants were not affected
by treatment, but on the Virtue silt loam soil the probability of no
effects was <.05 for radish tops and <.01 for pea foliage. The pattern
for the radish tops was not consistent, so the results may be spurious,
but in pea foliage on this soil the P concentration was depressed slightly
when the proportion of high Cd CSP was increased. This was probably
related to the chemical properties of the fertilizers from the two
sources rather than any effect related to the Cd level. These few
apparent effects on phosphorus concentration are probably not important
in terms of interpreting Cd effects in this portion of the experiment.

The Cd concentrations in plants grown on Westport fine sand increased
markedly when high Cd CSP was substituted for low Cd CSP. The results
were highly significant and could generally be represented by a linear
regression. Plots and regression lines for the Westport soil are shown
in Figures 1-3. Individual treatment means are included in Appendix B.
Some difficulty was encountered with the regression analysis of the pea
data from the Westport soil, where the low levels of fertilizer Cd
resulted in plant levels below the analytical detection limit of 0.20
ug/g. In this case the value for the highest Cd treatment registering
at or below the detection limit was assumed to be 0.20 ug/g and values
from the lower treatment levels were not included in the regression.
This procedure resulted in 6 treatments being used to determine the
regression for pea seeds and 5 treatments for pea foliage.

The effect on plant Cd concentration on the Virtue soil was not as
dramatic but was measurable for the radish and lettuce plots and regres-
sion lines for the Virtue soil are shown in Figures 4 and 5. Pea seeds
and foliage from this soil were almost all below the detection limit of


EPA-600/3-76-053
May 1976

PLANT UPTAKE OF CADMIUM FROM PHOSPHATE FERTILIZER

by
John Reuss, H. L. Dooley, and William Griffis

Ecological Effects Research Division
Corvallis Environmental Research Laboratory
Corvallis, Oregon 97330

U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
CORVALLIS ENVIRONMENTAL RESEARCH LABORATORY
CORVALLIS, OREGON 97330


oe

TABLE B-4. PHOSPHORUS CONCENTRAITON IN PLANTS GROWN ON VIRTUE SILT LOAM SOIL WITH MCP OR CSP FERTILIZER FROM
TWO SOURCES (MEAN OF 2 REPLICATIONS). RATES CALCULATED TO SUPPLY 100 ug P/g SOIL.

CSP Final Cd

Source Concentration Radish Lettuce Peas
low-Hi gh Fertilizer (Soil) Root Top Top Seed Foliage

% ug/g %P
100-0 (MCP) 0 (0)2/ 36 43 60 64 20
100-0 13 (.0065) 34 41 51 59 .29
80-20 45 (.023) 32 235 46 62 21
60-40 77 (.039) +38 35 -48 -60 24
40-60 110 (.055) 36 +36 245 64 15
20-80 142 (.071) +33 235 47 64 15
100-0 174 (.087) 235 +39 49 65 14
Standard Error 025 -014 047 021 -0199
Mean ~349 374 -492 -619 -193

* kk

*Significant at .05 level
**Significant at .01 level

af <4x 10°4 ng/g


soil, would justify further investigation in regards to uptake of Cd
from fertilizer in soils in which Cd is likely to remain active. Vir-
tually nothing is known concerning effects from repeated dosage, and
this aspect should be studied in calcareous as well as acid soils.

The effect of treatment on plant nitrogen were generally small and
statistical significance could not be demonstrated in most cases. These
data are not included in the report.

PLACEMENT AND SOURCE EFFECTS

The results of treatments 7-14 (Table 2) clearly show that fertili-
zer materials and placement affect the Cd uptake, and that this effect
is not the same on the two soils. The most striking effect is the lack
of Cd uptake from spot placed DAP on the Westport fine sand soil (Table
7). Even though approximately the same total amount of Cd was applied
in all treatments in this subset, the Cd uptake is very low wherever DAP
was applied in a spot treatment. This was generally true whether the Cd
was native in the fertilizer or added to the fertilizer as Cd (HPO, do
By contrast the spot placement of CSP on this soil did not genergi1y
reduce Cd uptake as compared to CSP mixed with the soil, nor did the use
of DAP instead of CSP reduce Cd uptake when the fertilizers were mixed
with the soil. The reason for the marked decrease in Cd uptake due to
the spot placement of DAP on the acid soil is not known, but it is
probably related to the neutral or slightly basic reaction of DAP as
compared to the acid CSP.

The dramatic decrease due to spot placement of DAP did not occur on
the Virtue silt loam soil (Table 8), where significant treatment effects
could only be discerned in the lettuce and radish tops. In both these
cases Cd uptake appeared to be slightly decreased by spot placement of
DAP and increased by spot placement of CSP. Mixed treatments of both
fertilizers resulted in similar levels in the plant.

Cadmium uptake in radishes grown on Westport find sand (Table 7).
with added Cd (HyPO,) was slightly higher than that from Cd found in
the fertilizer. “In val other cases no differences could be detected
between native Cd and Cd added to the fertilizer. This would indi¢ate
that if this material were used to artifically increase the Cd level of
fertilizers the uptake would probably be at least as great as that from
fertilizers containing a similar amount of native Cd.

The possibility that differences in Cd levels could be due to
different growth effects of the various fertilizers, or simple lack of
uptake due to positional unavailability must be considered. The treat-
ments did affect plant dry weight and phosphorus levels in a number of
cases. Summaries of significant effects are shown in Tables 9 and 10.
Data from individual treatments are included in Appendix B, Tables 8-11.

18


RESEARCH REPORTING SERIES

Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into five series. These five broad
categories were established to facilitate further development and application of
environmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The five series are:

1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research

4. Environmental Monitoring

5. Socioeconomic Environmental Studies

This report has been assigned to the ECOLOGICAL RESEARCH series. This series
describes research on the effects of pollution on humans, plant and animal
species, and materials. Problems are assessed for their long- and short-term
influences. Investigations include formation, transport, and pathway studies to
determine the fate of pollutants and their effects. This work provides the technical
basis for setting standards to minimize undesirable changes in living organisms
in the aquatic, terrestrial, and atmospheric environments.

This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.


B-1.

B-2.

B-3.

B-4.

B-5.

B-7.

B-8.

B-9.

APPENDIX B
LIST OF DATA TABLES

Cadmium and Zinc concentrations in fertilizer material used in
Cd uptake experiment (mean of 4 replications).

Dry matter yields from Westport fine sand soil in pots treated
with MCP or CSP fertilizers from two sources. Rates calculated
to supply 100 ug P/g soil.

Dry matter yields from Virtue silt loam soil in pots treated
with MCP or CSP fertilizer from two sources (mean of 2 replica-
tions). Rates calculated to supply 100 ug P/g soil.

Phosphorus concentration in plants grown on Virtue silt loam
soil with MCP or CSP fertilizer from two sources (mean of 2
replications). Rates calculated to supply 100 ug P/g soil.

Phosphorus concentration in plants grown on Westport fine sand
soil treated with MCP or CSP fertilizer from two sources (mean
of 2 replications). Rates calculated to supply 100 ug P/g
soil.

Cadmium concentration in plants grown on Wesport fine sand as
affected by Cd in phosphate fertilizer (mean of 2 replica-
tions). Low and high sources of CSP contain 12 and 174 ppm ug
Cd/g respectively.

Cadmium concentration in plants grown on Virtue silt loam soil
as affected by Cd in phosphate fertilizer (mean of 2 replica-
tions). Low and high sources of CSP contain 12 and 174 ug
Cd/g respectively.

Dry matter yields of plants grown on Westport fine sand as
affected by fertilizer materials and placement (mean of 2
replications).

Mean dry matter yield of plants grown on Virtue silt loam as
affected by fertilizer material and placement (mean of 2
replications).

Mean phosphorus concentration in plants grown on Westport fine
sand as affected by fertilizer material and placement (mean of
2 replications).

Mean phosphorus concentration of plants grown on Virtue silt
loam as affected by fertilizer material and placement (mean of
2 replications).

26


SE

TABLE B-9.

PLACEMENT (MEAN OF 2 REPLICATIONS).

MEAN DRY MATTER YIELD OF PLANTS GROWN ON VIRTUE SILT LOAM AS AFFECTED BY FERTILIZER MATERIAL AND

Treatment. Radish Lettuce Peas

Placement Material Cd_ Source Root Top Top Seed Foliage
Mix CSP (high) fertilizer 4.87 2.12 5.08 5.43 6.84
Spot CSP (high) fertilizer 3.14 1.72 2.04 7.12 4.84
Mix DAP (high) fertilizer 4.12 1.86 6.27 6.27 4.08
Spot DAP (high) fertilizer 2.69 1.60 1.36 1.36 6.24
Mix CSP (low) added 3.70 2.00 5.24 5.17 5.58
Spot CSP (low) added 2.70 1.56 2.01 4.65 4.94
Mix DAP (low) added 4.44 2.28 5.11 5.30 7.14
Spot DAP (low) added 2.53 1.67 2.87 3.95 5.13
Summary of significant effects

Mix 4.27 2.09 5.42 5.91

Spot 2.76 1.64 2.07 5.27

a/

Probability of Type I error <.01 except as noted.

a/ Main effect probability complicated by interaction.
Tow Cd DAP.

Spot placement lower than mix except for the


le

TABLE 9. SUMMARY OF MEANS OF MAJOR PLACEMENT AND FERTILIZER MATERIAL EFFECTS ON DRY MATTER YIELDS.

Radish

Lettuce Peas

Treatment Roots

Tops Tops. Seed Foliage

g dry weight per pot

Westport fine sand

Mix
Spot
csP 3.56
DAP 2.24

Virtue silt loam

Mix 4.27
Spot 2.76

3.22 4.68

2.62 1.07 2/

3.45

2139 3/

2.09 5.42 5.91 4
164 2.07 5.27

a/ Interaction present, but relatively minor compared to main effect

b/ Complex interaction with fertilizer source.


TABLE 1. CHARACTERISTICS OF SOILS USED IN THE Cd UPTAKE EXPERIMENT.

Westport Virtue
Fine Sand Silt Loam
pH
1:2 Soil:water 4.5 8.4
Organic matter Percent
Wet digestion 0.6 1.19
Total Nitrogen Percent
Kjeldahl 01 -08
Cation exch. Cap. m. eq/100g
Neutral N. NH,0 Ac 2.2 20.0
Extractable P2/ ug/g n 13
Free carbonates Percent as Caco, 0.0 2.2
Total Cadmium ug/g. <0.5 0.6
Soluble Cadmium2/ g/g. 0.05 0.1

a/ NaHco, extraction for Virtue soil, dilute HC1-NHyF for Westport soil

b/ Total Ammonium Acetate Extractable.


The Cd source comparison is intended to evaluate the effect of adding
Cd(H,P0,), as compared to a similar amount of native Cd in the fertilizer.
In the fabtorial subset all DAP treatments contain a total of .080 ug Cd
per g soil while all CSP treatments contain .087 ug/g.

Three common garden crops were grown: garden peas, Pisum sativum
L. cultivar Little Marvel; radish, Raphanus sativus L., cult. early
Scarbet Globe; and leaf lettuce, Lactuca sativa L., var. crispa cult.
Oak Leaf. Two replications were placed in a completely random arrange-
ment. Total pots in the experiment numbered 168. Pots were planted
March 27, 1975 with the exception of the garden peas on the Westport
soil which were planted April 4. Plants were thinned to 6 plants per
pot for radishes and lettuce and 3 plants per pot for peas shortly after
emergence. Daytime temperature in the greenhouse were 75°F + 5°; and
night temperatures were 65° + 5°.

Field capacity moisture percentages (W/W) were determined for each
soil by applying water to the surface of a soil column and gravimetri-
cally determining the soil water content above the wetting front after
allowing a 24 hour equilbration period. Pots were weighed daily and
deionized distilled water added to replace loss by evaportranspiration.
Initially the total weight maintained corresponded to about 75 percent
of field capacity. This total weight increased to field capacity as
roots were established and evaporative demand increased.

Radishes were harvested May 1. The edible root portions and the
tops were harvested separately. Plants were rinsed with deionized
water, fresh weight determined and dry weight determined after freeze
drying. Lettuce was harvested May 8. The tap root constituted only a
very small portion of the total weight and this was not included in the
foliar sample. Peas were harvested May 28 from the Virtue soil and June
2 from the Westport soil. Samples from these crops were handled in the
same manner as the radishes. Pea materials were not rinsed except for a
few basal portions of the stems that were contaminated with soil.

For total Kjeldahl nitrogen and total phosphorus determinations 50
mg plant samples were digested in a block digester using H,SO, and HgO
(Kjeldahl method). Colorimetric determinations were then far ‘ied out
with an automated analyzer. For total Kjeldahl nitrogen, NH, was
determined using the indophenol blue color formed from reactton with
sodium phenate and hypochlorite ion. Phosphorus was determined using
molybdo-phosphoric acid reduced to molybdenum blue complex with ascorbic
acid.

Cadmium analyses were carried out using approximately a 1 g sample
digested in a block digestor with 2:1 nitric-perchloric acid, followed
by Cd determination on an atomic adsorption spectrophotometer. Zinc
analyses are in progress and will be reported later.