Removal of lead and mercury by water hyacinths (Eichhornia crassipes) (Mart.) Solms and alligator weeds (Alternanthera philoxeroides) (Mart.) Griesb. was investigated. Water hyacinths demonstrated the ability to remove 0.176 mg of lead and 0.150 mg of mercury per gram of dry plant material from distilled water and river water in a 24-hour period. One acre of water hyacinths is potentially capable of removing 105.6 grams of lead and 90.0 grams of mercury per day. Alligator weeds removed 0.101 mg of lead per gram of dry plant material in a 24-hour period. This same plant also demonstrated the ability to remove a minimum of 0.153 mg of mercury per gram of dry plant material in a six hour period

Mcdonald, R. C.

Wolverton, B. C.

English

NASA Technical Reports Server

IAA T HAIAL TM-X-72723
APRIL, 1975
NASA-TM-X-72723) WATER HYACINTHS AND N75-22937
ALLIGATOR WEEDS FOR REMOVAL OF LEAD AND
MERCURY FROM POLLUTED WATERS (NASA) 14 p HC
CSCL 13B Unclas
G3/45 20735
WATER HYACINTHS AND ALLIGATOR WEEDS FOR
REMOVAL OF LEAD AND MERCURY FROM POLLUTED WATERS
By B. C. Wolverton
R. C. McDonald
REPRODUCED BY
NATIONAL TECHNICAL
INFORMATION SERVICENA A U.S. DEPARTMENT OF COMMERCENASA - SPRINGFIELD, VA. 22161
NATIONAL SPACE TECHNOLOGY LABORATORIES
BAY ST. LOUIS, MISSISSIPPI 39520
NSTL FORM 12 (JAN 1975)
https://ntrs.nasa.gov/search.jsp?R=19750014865 2020-03-22T21:30:10+00:00Z
TECHNICAL REPORT STANDARD TITLE PAGE
I. REPORT NO. 2. GOVERNMENT ACCESSION NO. 3. RECIPIENTIS CATALOG NO.
TM-X-72723
4. TITLE AND SUBTITLE 
S. REPORT DATE
Water Hyacinths and Alligator Weeds for April 11, 1975
Removal of Lead and Mercury from Polluted Waters 6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S) 8. PERFORMING ORGANIZATIONREPORT NO.
B. C. Wolverton and R. C. McDonald
9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. WORK UNIT NO.
National Space Technology Laboratories
Bay St. Louis, Mississippi 39520 It. CONTRACT OR GRANT 
NO.
12. SPONSORING AGENCY NAME AND ADDRESS 13. TYPE OF REPORT & PERIODCOVERED
National Aeronautics and Space Administration
Washington, D. C. 20546 Technical Memorandum
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
Interim program test results, NASA, Office of Applications sponsored program -
(RTOP 644-02-02) Vascular Aquatic Plants for Pollution Control and Sources of
Energy and Food.
16. ABSTRACT
Removal of lead and mercury by water hyacinths (Eichhornia crassipes) (Mart.) Solms
and alligator weeds (Alternanthera philoxeroides) (Mart.) Griesb. was investigated. Water
hyacinths demonstrated the ability to remove 0. 176 mg of lead and 0. 150 mg of mercury per
gram of dry plant material from distilled water and river water in a 24-hour period. , There-
fore, one acre of water hyacinths is potentially capable of removing 105. 6 grams of lead and
90.0 grams of mercury per day. Alligator weeds removed 0. 101 mg of lead per gram of dry
plant material in a 24-hour period. This same plant also demonstrated the ability to remove a
minimum of 0. 153 mg of mercury per gram of dry plant material in a six hour period.
Use of trade names or names of manufacturers in this report does not constitute an official
endorsement of such products or manufacturers, either expressed or implied, by the National
Aeronautics and Space Administration or any other agency of the United States GoVernment.
17. KEY WORDS 18. DISTRIBUTION STATEMENT
Unclassified - unlimited
19N SECURITY CLASSIF. (o thisreprTLt 20. SECURITY CLASSIF.(o th P(JAN) 2197
Unclassified Unclassified
NSTL FORM 13 (JAN 1975)
TECHNICAL MEMORANDUM X-72723
WATER HYACINTHS AND ALLIGATOR WEEDS FOR
REMOVAL OF LEAD AND MERCURY
FROM POLLUTED WATERS
INTROD UCTION
The ability of vascular plants to absorb and concentrate toxic elements
from soils.in which these plants are grown was recognized as early as 1937
(1). Recently, Wolverton demonstrated the ability of water hyacinths (Eich-
hornia crassipes) (Mart.) Solms, a floating aquatic plant, to rapidly remove
cadmium and nickel from waters polluted with these two important toxic
.metals (2). This work demonstrated the potential of vascular aquatic plants
in removing other toxic elements from waters in which these plants are grown
by means of root absorption and concentration. Another floating aquatic plant
which is a promising candidate for removing chemical pollutants from waste
waters is alligator weeds (Alternanthera philoxeroides)(Mart.) Griesb. This
plant is highly prolific and can tolerate higher levels of salinity than water
hyacinths (3, 4).
Lead and mercury are two other very important toxic metals that are
found in trace quantities throughout the terrestrial and aquatic environment
(5, 6). Lead is one of the most abundant pollutants of the human environment
and contaminant of the human body. The uptake of lead by terrestrial plants
has been the subject of numerous studies in recent years (7, 8, 9, 10, 11, 12).
Its principle source today is tetra-ethyl lead, an anti-knocking chemical added
to gasoline (13). Lead oxide has been the principle white pigment of paint for
over 2, 000 years.
Lead and mercury are both normal soil constituents with lead ranging
from 1 to 200 ppm and mercury up to 0.8 ppm (12, 13). Unlike lead, inorganic
mercury does not accumulate in the body, but organic mercury is deposited in
fat and nerve tissue where it is less mobile.
Environmental pollution by toxic metals can be a much more serious
and insidious problem than pollution by organic substances. Unlike most organic
substances, metals are not degradable by natural processes.
Both the chemical behavior and the toxicity of mercury are further
complicated by the ability of microorganisms to convert inorganic mercury to
a highly toxic organic form, which enters the food chain of fish and other
aquatic life. The seriousness of water pollution by mercury in industrial
effluent was accentuated by the occurrence of Minamata disease from 1953 to
1960 in Japan, caused by methyl mercury poisoning (13).
MATERIALS AND METHODS
Water hyacinths (Eichhornia crassipes) (Mart.) Solms, were grown by
vegetative reproduction from parent stock collected in February of 1975 from
nearby bayous. Alligator weed (Alternanthera philoxeroides) (Mart.) Griesb.
were also grown by vegetative reproduction from parent stock collected in
Pearl River County, Mississippi. All plants were transferred to a greenhouse
and maintained between 25 0 C and 30*C in metal troughs filled with tap water.
Commercial plant food was added every two weeks.
One liter glass cylinders containing either 800 ml of distilled water or
East Pearl River NSTL water were contaminated with mercuric chloride and
lead nitrate and used as containers for individual water hyacinths ranging from
2.2 to 4.6 grams dry weight. Five hundred milliliter glass Erlenmeyer
flasks filled almost to capacity with 575 ml of distilled water or East Pearl
River NSTL water contaminated with the same two metals were used as con-
tainers for two to four alligator weeds whose total dry weight per container
ranged from 3. 0 to 3. 6 grams. Each experimental arrangement included one
plant control free of heavy metals and one metal control free of plants. Slight
fluctuations in controls occurred due to evaporation and resulting volumetric
adjustments with distilled water. This may cause concentration curves to be
slightly more or less than the originally prepared concentrations. These stud-
ies were conducted simultaneously inside a well lighted building which was
maintained at 25*C + 5°C.
The mercury and lead contaminated solutions were prepared by
diluting separate 1000 mg per liter atomic absorption standard solutions
obtained from Fisher Scientific Company. Initial pH's and mercury and lead
concentrations of the contaminated distilled water and river water and of the
metal free controls were determined before the plants were added. The con-
centrations were again monitored after 3, 6, and 24 hours exposure to the
plants. The pH's were monitored after 24 hours exposure.
The lead concentrations were monitored by atomic absorption spectro-
scopy after each sample was acidified to pH 3 with concentrated nitric acid.
All mercury analyses were determined by a flameless atomic absorption
technique (14).
2
RESULTS AND DISCUSSION
Alligator weeds and water hyacinths demonstrated their ability to
rapidly absorb mercury and lead from contaminated river and distilled waters.
These results are depicted in Figures 1 through 8 as percent of initial metal
concentration remaining as a function of time for the metal control and metal-
exposed plant system. Tables 1 through 4 include the experimentally deter-
mined values used in all plots, as well as the pH values and dry plant weights.
pH measurements ranged from 6.2 to 6. 7.
In a 24-hour period, the water hyacinths removed a maximum of
0. 176 mg of lead and 0. 150 mg of mercury from a static water system per
gram of dry plant material. Based on this optimum removal rate of lead and
mercury and on an optimum growth rate of approximately 600 Kg of dry plant
material per hectare per day, one hectare of water hyacinths could potentially
remove 105. 6 grams of lead and 90. 0 grams of mercury per day. This heavy
metal removal rate is based on continually harvesting the metal saturated
plants.
Alligator weeds removed a maximum of 0. 101 mg of lead per gram of
dry plant material from a static water system in a 24-hour period. These
plants also reduced the initial mercury levels of 0. 875 ppm in river water
and 0. 920 ppm in distilled water below the detection limit of 1. 0 ppb after
6 hours. Based on this data, alligator weeds can remove a minimum of
0. 153 mg of mercury per gram of dry plant material in a 6-hour period.
Further laboratory experiments are also being conducted at the
National Space Technology Laboratories to evaluate the abilities of water
hyacinths and alligator weeds to remove other heavy metals, as well as
organic pollutants and nutrients.
3
Table 1. Removal of Lead and Mercury from River Water Systems
During a 24-Hour Period Utilizing Water Hyacinths as Absorption Filters
River Water
Initial Hg Dry Plant pH Range 3 Hours 6 Hours 24 Hours mg of Metals Removed per
and Pb (ppm) Material (g) 0-24 Hrs. (ppm) (ppm) (ppm) Grainm of Dry Plant Material
1.091 Pb 4.3 6.5-6.5 0.221 0.176 0.058 0.192
1.091 Pb 3.5 6.5-6.35 0.279 0.324 0.147 0.216
0.875 Hg 4.3 6.5-6.5 0.402 0.259 0.071 0.150
0.875 Hg 3.5 6.5-6.35 0.464 0.393 0.205 0.153
Background levels 2.8 6.2-6.1 <0.008 <0.008 <0.008
of Pb in River H2 0
Background levels 2.8 6.2-6.1 <0.001 <0.001 <0.001
of Hg in River H20
Pb concentration
in Pb-Hg Controls 6.5-6.7 1.055 1.073 1.127free of plants
Initial: 1.091 ppm
Hg concentration
in Pb-Hg Controls 6.5-6.7 0.821 0.813 0.723
free of plants
Initial: 0.875 Hg
Table 2. Removal of Lead and Mercury from Distilled Water Systems
During a 24-Hour Period Utilizing Water Hyacinths as Absorption Filters
Distilled Water
Initial Hg Dry Plant pH Range 3 Hours 6 Hours 24 Hours mg of Metals Removed per
and Pb (ppm) Material (g) 0-24 Hrs. (ppm) (ppm) (ppm) Gram of Dry Plant Material
0.529 Pb 2.2 6.40-6.15 0.103 0.074 0.044 0.176
0.529 Pb 4.0 6.40-6.10 0.103 0.059 0.029 0.100
0.920 Hg 2.2 6.40-6.15 0.188 0.107 0.054 0.315
0.920 Hg 4.0 6.40-6.10 0.152 0.080 0.054 
0.173
Background levels
of Pb in Distilled
Water 4.6 6.70-6.20 <0.008 <0.008 <0.008
Background levels.
of Hg in Distilled
Water 4.6 6.70-6.20 <0.001 <0.001 <0.001
Pb concentration
in Pb-Hg Controls
free of plants
Initial: 0.529 ppm 6.40-6.75 0.544 0.588 0.485
Hg concentration
in Pb-Hg Controls
free of plants
Initial: 0.920 ppm 6.40-6.75 0.848 0.768 0.804
Table 3. Removal Rates of Lead and Mercury from River Water Systems
During a 24-Hour Period Utilizing Alligator Weeds as Absorption Filters
River Water
Initial Hg Dry Plant pH Range 3 Hours 6 Hours 24 Hours mg, of Metals Removed per
and Pb (ppm) Material (g) 0-24 Hrs. (ppm) (ppm) (ppm) Gra mn of Dry Plant Material
0.968 Pb 3.3 6.3-6.35 0.839 0.706 0.471 0.087
0.968 Pb 3.5 6.3-6.2 0.559 0.676 0.353 0.101
0.875 Hg 3.3 6.3-6.35 0.045 <0.001 <0.001 0.153
0.875 Hg 3.5 6.3-6.2 0.026 <0.001 <0.001 0.144
Background levels
of Pb in River
Water 3.4 6.2-6.15 <0.008 <0.008 <0.008
Background levels
of Hg in River
Water 3.4 6.2-6.15 <0.008 <0.008 <0.008
Pb concentration
in Pb-Hg Controls
free of plants
Initial: 0.968 ppm 6.3-6.45 0.903 0.968 0.821
Hg concentration
in Pb-Hg Controls
free of plants
Initial: 0.875 ppm 6.3-6.45 0.777 0.875 0.813
Table 4. Removal Rates of Lead and Mercury from Distilled Water Systems
During a 24-Hour Period Utilizing Alligator Weeds as Absorption Filters
Distilled Water
Initial Hg Dry Plant pH Range 3 Hours 6 Hours 24 Hours mg of Metals Removed per
and Pb (ppm) Material (g) 0-24 Hrs. (ppm) (ppm) (ppm) Gram of Dry Plant Material
0.529 Pb 3.6 6.4-5.8 0.266 0.206 0.125 0.065
0.529 Pb 3.6 6.4-6.0 0.265 0.206 0.143 0.062
0.920 Hg 3.6 6.4-5.8 0.018 <0.001 <0.001 0.147
0.920 Hg 3.6 6.4-6.0 0.018 <0.001 <0.001 0.147
Background levels
of Pb in Distilled
Water 3.0 6.7-6.2 <0.008 <0.008 <0.008
Background levels
of Hg in Distilled
Water 3.0 6.7-6.2 <0. 001 <0.001 <0.001
Pb concentration
in Pb-Hg Controls
free of plants
Initial: 0. 529 ppm 6.4-6.6 0.456 0.529 0.554
Hg concentration
in Pb-Hg Controls
free of plants
Initial: 0.920 ppm 6.4-6.6 0.786 0,.813 0.848
90 - 90
0 - 1Control free of water
hyacinths
80 - Contained 3. 5 g water 80 ontrol free of water
hyacinths
S70 -Contained 4.3 g water hyacinths70 hyacinths 70 Contained 4. 3 g water
h s hyacinths
6060 Contained 3.5 g water
E 60 -hyacinths
, 50 550 -
S40- 40
30- 30
20 - L 20
0 1  0
0 0 -i r
0 3 6 9 12 15 18 21 24 0 3 6 9 12 15 18 21 24
Time in Hours Time in Hours
Figure 1. Graphic Representation of Removal Rates of Lead from Figure 2. Graphic Representation of Removal Rates of Mercury
River Water Containing Water Hyacinths and Lead-Mercury From River Water Containing Water Hyacinths and Lead-Mercury
Control Free of Plants Control Free of Plants
1000-
90 -
Control free of water - ---
80- hyacinths 80so-
Contained 2.2 g water
M70 hyacinthsSContained 4.0 g water 70- - - L Control free of water
hyacinths hyacinths
h at60- _ - Contained 2.2 g water
S60ou- hyacinths
S-- - - Contained 4.0 g water
50- 50- hyacinths
4040- 403
30- 30-
20- 20-
10- 10-
0 3 6 92 15 18 2121 24
Time in Hours Time in Hours
Figure 3. Graphic Representation of Removal Rates of Lead from Figure 4. Graphic Representation of Removal Rates of Mercury
Distilled Water Containing Water Hyacinths and Lead-Mercury From Distilled Water Containing Water Hyacinths and
Control Free of Plants Lead-Mercury Control Free of Plants
8
ORIGINAL PAGE IL
OF POOR QUALITY
100 100 ...
90 ,-..-- 90
80 _ \.80 . -
- Control free of plants
SContained 3.3 g alligator
70 - r 70 - weeds
S-- Contained 3. 5,g alligator
r _ 60 weeds60 \
S. °
50 . 50
40 40
3 - -Control free of plants
30 30 "
Contained 3. 3 g alligator weeds
20 -20
- - Contained 3. 5 g alligator weeds I
10 - 10
0 0+ --
0 3 6 9 12 15 18 21 24 0 3 6 9 12 15 18 21 24
Time in HoursTime in Hours
Figure 5. Graphic Representation of Removal Rates of Lead Figure 6. Graphic Representation of Removal 
Rates of Mercury from
From River Water Containing Alligator Weeds and River Water Containing Alligator Weeds and Lead-Mercury
Lead-Mercury Control Free of Plants Control Free of Plants
100. 100
90- -- Control free of plants 90 -----
Contained 3.6 g of
80 alligator weeds 80
70 Contained 3.6 gof - - - Control free of plants
70alligator weeds 70
SContained 3.6 g alligator
S6060f weeds
50 50
40- 
4 0
30 - 30
20- 20
10- 10
0 3 6 9 12 15 18 21 24 0 3 6 9 12 15 18 21 24
Time in Hours Time in Hours
Figure 7. Graphic Representation of Removal Rates of Lead from Figure 8. Graphic Representation of Removal Rates of Mercury 
from
Distilled Water Containing Alligator Weeds and Lead-Mercury Distilled Water Containing Alligator Weeds and Lead-Mercury
Control Free of Plants Control Free of Plants
9
REFERENCES
1. Hurd-Karrer, A.M. and Poos, F.W. 1936. Science, 84:252.
2. Wolverton, B. C. 1975. Water Hyacinths for Removal of Cadmium
and Nickel from Polluted Waters. NASA Technical Memorandum
TM-X-72721.
3. Weldon, L.W., Blackburn, R.D., and Harrison, D.S. 1969.
Common Aquatic Weeds. U.S. Dept. of Agr. Handbook No. 352.
4. Boyd, C. E. 1970. Vascular Aquatic Plants for Mineral Nutrient
Removal from Polluted Waters. Econ. Bot. 24:95-103.
5. Schroeder, H.A. and Balassa, J.J. 1961. Abnormal Trace Metals
in Man: Lead. J. Chron. Dis., 14:408-425.
6. Hazards of Mercury. 1971. Special Report to the Secretary's
Pesticide Advisory Committee, Department of Health, Education
and Welfare. Environmental Research, 4:1-69.
7. Marten, G. C. and Hammond, P.B. 1966. Lead Uptake by Brome-
grass from Contaminated Soils, Ag Ron. J., 58:553-554.
8. Cannon, H. L. and Bowles, J. M. 1962. Contamination of Vegeta-
tion by Tetraethyi Lead. Science, 137:765-766.
9. Warren, H. V. and DeLavault, R. E. 1962. Lead in Some Food
Crops and Trees. J. Sci. Food Agric., 13:96-98.
10. Smith, W. H. 1973. Metal Contamination of Urban Woody Plants.
Environ. Sci. Tech., 7:631-636.
11. Koeppe, D. E. and Miller, R. J. 1970. Lead Effects on Corn
Mitochondrial Respiration. Science, 167:1376-1377.
12. Rolfe, G. L. 1973. Lead Uptake by Selected Tree Seedlings.
J. Environ. Quality, 2:153-157.
10
REFERENCES (CONT'D)
13. Schroeder, H. A. 1973. Trace Elements and Man (The Devin-
Adair Co., Publishers, Old Greenwich, Conn.).
14. Hwang, J. H. and Malenfant, A. L., Canadian Spectroscopy. 1971.
16(4).
11
APPROVAL
WATER HYACINTHS AND ALLIGATOR WEEDS FOR
REMOVAL OF LEAD AND MERCURY
FROM POLLUTED WATERS
By B. C. Wolverton
and
R. C. McDonald
The information in this report has been reviewed for security classi-
fication. Review of any information concerning Department of Defense or
Atomic Energy Commission programs has been made by the NSTL Security
Classification Offier. This report, in its entirety, has been determined to
be unclassified.
This document has also been reviewed and approved for technical
accuracy.
TTT'TT'n7 IT A TTIT TV
Director, Applications Engineering
National Space Technology Laboratories
12


Water hyacinths and alligator weeds for removal of lead and mercury from polluted waters

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