Airborne Chemical Elements 

in Spanish Moss

GEOLOGICAL SURVEY PROFESSIONAL PAPER 574-E

fc«-
Airborne Chemical Elements 

in Spanish Moss

By HANSFORD T. SHACKLETTE and JON J. CONNOR

STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

GEOLOGICAL SURVEY PROFESSIONAL PAPER 574-E

A study of local and regional variation 

in airborne materials as indicated by 

chemical analysis of an epiphyte

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1973
UNITED STATES DEPARTMENT OF THE INTERIOR 

ROGERS C. B. MORTON, Secretary

GEOLOGICAL SURVEY

V. E. McKelvey, Director

Library of Congress catalog-card No. 73-600178

For sale by the Superintendent of Documents, U.S. Government Printing Office

Washington, D.C. 20402 -Price $1.25 (paper cover)

Stock Number 2401-02456
CONTENTS

Page

Abstract..................................................................................... El

Introduction..............................................................................

Responses of plants to airborne chemical elements...........

Morphology and ecology of Spanish moss...........................

Methods of study.....................................................................

Sampling plan..................................................................

Analytical methods..........................................................

Page

Methods of study Continued

Data presentation............................................................. E6

Elemental composition of Spanish moss............................... 9

Discussion of results................................................................ 42

Summary and conclusions....................................................... 44

References cited........................................................................ 45

ILLUSTRATIONS

Page

FIGURE 1. Drawings of growth habit and morphological features of Spanish moss (Tillandsia usneoides L.)............. E5

2. Photograph showing growth of Spanish moss on the tops of pond cypress ( Taxodium ascendens Brongn.)

and on the more shaded lower branches......--....-.......... ................................................................................. 6

3. Map showing Spanish moss sample localities.... .................................................................................................... 7

4. Map showing localities of Spanish moss samples containing elements not commonly detected and the concentrations of the elements............................................................................................................. 10

5-35. Maps showing ash yield and element content of Spanish moss samples:

5. Ash....................................__......_..._._...._.....__.......~ 11

6. Aluminum............................................................................................................................................................. 12

7. Arsenic.................................................................................................................................................................. 13

8. Barium.................................................................................................................................................................. 14

9. Boron.................................................................... 15

10. Cadmium............................................................................................................................................................... 16

11. Calcium..................................................... 17

12. Chromium............................................................................................................................................................. 18

13. Cobalt............................................................... 19

14. Copper................................................................................................................................................................... 20

15. Gallium.............................................................,............................................... ..................^..... 21

16. Iron..................................................................._ 22

17. Lanthanum...................................................................................................................................................... ... 23

18. Lead ............... .... . ....... .. .............. .... . . 24

19. Lithium........ ..................................................................................................................................... 25

20. Magnesium................................................................................................................................ ..... .............. 26

21. Manganese............................................................................................................................................................. 27

22. Molybdenum .. .... .... .. ............ ....... . . 28

23. Nickel................... ............ .. ..... ....... 29

24. Phosphorus....................................................................................................................................................... 30

25. Potassium.............................................................................................................................................................. 31

26. Scandium .. ...... . ....... . . . ....... .. . .. 32

27. Silver.... ................................... ... ..... .._.._.. .^ 33

28. Sodium............................................................................................................................................................. 34

29. Strontium . .......... . .. ... ....... . .... 35

30. Titanium................................................................................................................................................. 36

31. Vanadium............................................................................................................ 37

32. Ytterbium..................................................................................................................................................... 38

33. Yttrium............................................................................................................................................... 39

34. Zinc................................................................................................................................................................ 40

35. Zirconium.............................................................................................................................................................. 41

in
IV CONTENTS

TABLES

Page

TABLE 1. Spanish moss sample localities and sampling dates................................ . . . E7

2. Analytical limits of detection....................................................................................................................-.-.. 9

3. Chemical composition of Spanish moss samples and samples of soil-rooted plants from the conterminous

United States........................................................................................................................................... 43

4. Elements found in concentrations greater than average in Spanish moss samples from four kinds of sites 44
STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS

By HANSFORD T. SHACKLETTE and JON J. CONNOR

ABSTRACT

Spanish moss (Tillandsia usneoides L.), collected from its 

geographic range in Southern United States, was analyzed 

for 38 chemical elements in 123 samples. Although Spanish 

moss is an epiphyte and must obtain all of its element load 

from the atmosphere, most elements in samples of this plant 

occur in concentrations similar to those of ordinary soil-rooted 

plants. Analyses of Spanish moss samples collected at rural, 

residential, highway, and industrial locations reflected significant differences in concentrations of metals. Samples from 

industrial and highway locations are characterized as containing greater-than-average amounts of arsenic, cadmium, 

chromium, cobalt, copper, lead, nickel, and vanadium. The 

high levels of lead found in some samples from highway locations are especially noteworthy. Many samples from sites near 

the seashore contained greater-than-average amounts of sodium that is thought to have been derived from ocean spray. 

Samples from rural locations commonly contain low concentrations of the metals usually associated with industrial or 

urban activity but may contain large amounts of the elements 

that are ordinary constituents of soil dust. Four of six samples containing detectable amounts of tin were collected 

within 50 miles of the only tin smelter in the United States; 

this result suggests that elemental analyses of Spanish moss 

samples can provide an economical and rapid method of estimating the kind and relative degree of local atmospheric 

metal pollution.

INTRODUCTION

The importance of airborne materials in affecting 

the quality of the environment for organisms has 

prompted many investigators to search for materials 

and methods most suitable for measuring the concentrations and distribution of these materials. Commonly, the methods consist of various procedures for 

collecting the airborne materials by filtration and then 

chemically analyzing the materials, or for continuous 

instrumental monitoring of gaseous elements or compounds in the air. Recently, however, the degree and 

extent of airborne contamination have been evaluated by means of observation or chemical analysis 

of plants that either respond in some visible way 

to the airborne materials or have the ability to collect airborne materials by their physical structures, 

physiological functions, or both.

The use of suitable plants for measuring concentrations of airborne materials provides the advantages of (1) an integration of the periodic 

fluctuations in amounts of these materials that occur 

over relatively long periods of time, and (2) economy in sampling. A disadvantage of using plants, as 

opposed to filtration or direct monitoring, for this 

purpose is that analyses of the plants can give estimates only of the relative amounts of airborne materials at different locations, rather than the amounts 

in a known volume of air.

This study reports the use of Spanish moss (Tillandsia usneoides L.), an epiphyte (commonly called 

an "air plant") that is common in the Atlantic and 

Gulf Coastal Plains, for evaluating local and regional 

variation in airborne materials. Specimens were 

collected from industrial areas and near major 

highways, where man-related contaminants were expected to be abundant, as well as from rural areas, 

where more natural atmospheric burdens were believed to occur.

We thank Messrs. Todd Church, J. A. Erdman, 

J. R. Keith, R. R. Tidball, and J. D. Vine, of the 

U.S. Geological Survey, and Messrs. D. B. Ames, 

W. G. Haag, and Richard Harter, and Mrs. M. A. 

Erdman for assistance in collecting samples. County 

Agricultural Extension Agents in each of the States 

also submitted samples; their cooperation is gratefully acknowledged. Mrs. J. G. Boerngen assisted in 

computer processing of data, and Mrs. J. M. Bowles 

prepared the drawings from living plants. All statistical analyses were performed on the U.S. Geological 

Survey's IBM 360/65 computer and were based on 

computer programs in the Survey's STATPAC system (Sower and others, 1971). Analyses were made 

by the following Geological Survey chemists: Leon A. 

Bradley, Thelma F. Harms, Harriet G. Neiman, 

Clara S. E. Papp, and James H. Turner.

El
E2 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

RESPONSES OF PLANTS TO AIRBORNE 

CHEMICAL ELEMENTS

The effects of excessive concentrations of certain 

airborne materials on many types of organisms may 

be either deleterious or beneficial. The responses of 

plants to airborne toxic substances have been reported many times as evidence of aerial pollution, 

and the effects of this pollution were reviewed by 

the European Congress on the Influence of Air Pollution on Plants and Animals (1969).

Some plants, particularly lichens and mosses, are 

very sensitive to sulfur dioxide (and perhaps other 

gaseous compounds) in the air. More than a century 

ago Nylander (1866, p. 365) reported [translated], 

"lichens provide, through their behavior, a measure 

of the healthfulness of air, and are (one may say) 

very sensitive 'hygiometers/" The sensitivity of 

both mosses and lichens to air pollution was discussed by LeBlanc (1969). The extent and physiological condition of lichen populations were used to 

map the degree of pollution in urban and industrial 

areas by Sloover and LeBlanc (1968).

Many plant species are sensitive to concentrations 

of airborne fluorine. Symptoms of fluorine poisoning in plants were discussed by Brewer (1966, 

p. 180-196), and the "normal" fluorine contents of 

many species were given by Garber (1968, p. 42-48) 

for use in evaluating the extent of fluorine pollution 

from industrial emissions.

Although additions of extraneous materials to the 

air generally are considered to be undesirable, increased atmospheric concentrations of certain elements may be beneficial to plants. Ingham (1950) 

discussed the importance of the mineral content of 

air and rain to agriculture. Egner (1965) reviewed 

the importance to soil fertility of sulfur compounds 

that are supplied by atmospheric precipitation, and 

Riehm (1965) described the role of this source in 

supplying the biologically essential elements calcium, 

chlorine, boron, potassium, magnesium, nitrogen, 

and sodium to soils in Europe.

The absorption of atmospheric ammonia by soils 

in New Jersey was measured by Malo and Purvis 

(1964). They found that 8.2 pounds of ammoniacal 

nitrogen per acre was deposited from precipitation 

in a year, and they believed that nitrogen from this 

source was a factor in the high yields of maize that 

was grown without the addition of nitrogen fertilizers from 1958 to 1960. The direct absorption of 

atmospheric ammonia by plant leaves was demonstrated by Hutchinson, Millington, and Peters 

(1972), who stated,

We believe that our data have broad implications in regard 

to both plant nutrition and air pollution and water pollution

control. Calculations [based on their data] indicate that the 

annual NHs absorption by plant canopies could be about 

20 kg per hectare. This rate of NHs supply is large enough 

to contribute significantly to the nitrogen budget of a growing plant community and could exert a prodigious influence 

on the long-term behavior of an ecosystem.

Shacklette and Cuthbert (1967, p. 42) calculated 

that the total iodine content of certain soil-rooted 

plants could be obtained from the exchanges of atmospheric gases that accompany the process of 

photosynthesis. The total amount of atmospheric 

iodine added to the soil each year in England was 

estimated to slightly exceed the amount of iodine 

removed from the soil in a crop of kale (Chilean 

Iodine Educ. Bur., 1956).

The "normal" concentration of carbon dioxide in 

air is generally considered to be about 300 ppm 

(parts per million), and amounts much greater than 

this may be considered undesirable for animals. Yet 

experiments have shown that above-normal concentrations of this gas in the atmosphere increase the 

growth rate of plants. Holley (1965) found that increasing the carbon dioxide content of the air in 

greenhouses to as much as 1,000 ppm was economically feasible, and at present the use of carbon 

dioxide generators is a common practice in the production of some greenhouse crops.

Many other reports have pointed out the importance to land plants of nutrient elements that are 

obtained directly or indirectly from the atmosphere. 

However, reports apparently lack conclusive experiments on the relative amounts of certain chemical 

elements absorbed by land plants from the soil solution, as opposed to amounts of these elements absorbed directly from the atmosphere (Shacklette and 

Cuthbert, 1967, p. 41). The problem of element 

source does not arise in discussing Spanish moss 

because this plant obtains all nutrients from atmospheric gases, precipitation, and airborne particulate 

matter.

Most kinds of airborne materials cause no apparent damage to plants that are subjected to them. 

However, the plants may respond by accumulating 

large amounts of certain of these materials either 

within the tissues, in deposits on the surfaces of the 

plants, or both. Ordinary terrestrial plants may incorporate airborne materials into their tissues directly through leaves or indirectly by root absorption 

of fallout material that accumulates in soils. Wohlbier (1968, p. 142) noted [translated], "Plants take 

fluorine from the soil by means of their roots, and 

from the air through the stomates of the leaves." 

Garber, Guderian, and Stratmann (1968, p. 41) concluded [translated],

The variation in fluorine enrichment in plants from experi-
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E3

mental soil that has not been polluted is insignificant in 

comparison with the possible enrichment through fluorinecontaining air pollution. Therefore, analyses of the fluorine 

content of plants can be of consequence as an important adjunct in diagnosing the effects of fluorine in areas of airborne 

industrial emissions.

The mechanisms of element absorption by, or fixation on, leaves and stems of plants are not fully 

understood; doubtless, the mechanisms vary greatly, 

depending on elements and plant species. Generally, 

the amounts of airborne substances absorbed and 

incorporated in the plant tissue cannot be distinguished from the amounts held only on the surfaces 

of leaves and stems. Washing the samples with water 

or other solvents may remove some of the surficial 

deposits that are not firmly bound to the plant surfaces. Goodman and Roberts (1971, p. 298) reported,

Earlier experiments clearly showed that it was not possible 

to wash any significant amounts of metals either from moss 

samples or grass material when it was obtained outside the 

moss desert [an area so heavily polluted from atmospheric 

fallout that mosses could not grow in it]. Grass samples taken 

inside the desert, however, bore significant quantities of washable metals. * * * as much as 45% of analysed metals could 

be removed by washing.

Maclntire, Hardin, and Hester (1952, p. 1368) 

found analyses of Spanish moss useful in measuring 

relative degrees of atmospheric fluorine at different 

locations, but they did not determine whether the 

increases in fluorine content in the experimental 

plants were due to metabolic functions of the plants 

or to chemical or physical fixation on the plant. In 

a study of air pollution as measured by analysis of 

the moss Hypnum cupressiforme, Goodman and Roberts (1971, p. 291) stated,

Further information is, however, required about the relative 

bonding energies of the metals on the exchange surfaces of 

Hypnum and the modifying influences of rainfall pH. It is 

also important to know the relative contribution to uptake 

made by dry deposition (sedimentation and diffusion of various particle sizes) and wash-out processes by rainfall.

Practical applications of the pronounced ability of 

mosses and lichens to accumulate airborne contaminants have been made recently in Europe. By 

analyzing specimens of the mosses Hylocomium 

splendens, Pleurozium schreberi, and Hypnum cupressiforme that were preserved in the Botanical 

Museum in Lund, Sweden, and that had been collected at intervals from 1860 to 1968 from the same 

locations, Riihling and Tyler (1968) were able to 

record the effect of human activity on the concentration of atmospheric lead. They wrote (1968, p. 321), 

"From values of c. 20 ppm [dry weight basis] in 

the years 1860-1875 the concentration of lead was 

more than doubled between 1875 and 1900. During 

the first half of the 20th century no measurable 

changes were observed, but after about 1950 there

was a new strong increase to a present average of 

c. 80-90 ppm." Ruhling and Tyler (1968,1969,1971) 

and Ruhling (1969, 1971) conducted studies of regional distribution of other airborne heavy metals 

by analyzing samples of mosses and other plants, and 

they found this method effective in evaluating aerial 

pollution.

Jaakkola, Takahashi, and Miettinen (1971) analyzed specimens of a lichen (Cladonia alpestris) to 

measure the airborne cadmium that was released by 

a recently constructed zinc refinery in Finland. 

Goodman and Roberts (1971) used samples of the 

moss Hypnum cupressiforme to measure the airborne 

heavy metals in some industrial areas in Wales. They 

concluded (1971, p. 291), "Our methods are much 

more rapid, inexpensive, and probably more meaningful than spot-sampling of air by filtration, for 

which prohibitive resources are needed for a few 

months' operation."

MORPHOLOGY AND ECOLOGY OF SPANISH 

MOSS

Certain morphological features of plants enhance 

their ability to accumulate airborne materials; therefore, as the physical structures among different 

species vary, so do responses to airborne materials. 

Osburn (1963) found moss and lichen mats to be 

effective filters of radioactive fallout in snow melt 

water in the Rocky Mountains. In a study of radionuclide fallout from the atmosphere, Watson, Hanson, Davis, and Rickard (1966) stated, "Directfoliar 

interception by plants is regarded as one of the principal sources of contamination from fallout materials. * * * Foliar surface area and plant density are 

therefore important factors requiring consideration 

in evaluating fallout accumulation." In the same 

study the writers pointed out (p. 1176) that greater 

accumulations of atmospheric fallout occur in plants 

(1) with persistent above-ground parts (perennial 

plants), (2) capable of obtaining water and nutrients from the atmosphere, and (3) having great 

absorptive characteristics. Mosses, lichens, Spanish 

moss, and certain other plants have all these attributes; moreover, Spanish moss has the advantage, 

for use in evaluating the kind and amount of airborne materials, of having no roots or rootlike organs and hence of having no direct contact with the 

soil.

Results of chemical element analyses of plant samples are expressed, on the basis of weight, as the 

proportion of the element of concern in relation to 

the total sample. Therefore, plants with a great 

foliar surface in proportion to their weight tend to 

accumulate greater concentrations of elements from
E4 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

the air than do other plants because their large surface area favors increased absorption and surface 

deposition of the airborne materials. Thin, small, 

numerous, and finely divided stems and leaves (or 

stemlike and leaflike organs, as occur in lichens) 

are morphological expressions of great surface area 

relative to the weight of the plant.

Spanish moss is classed as an epiphyte because it 

most commonly grows on trees. It is not parasitic 

because it gets all essential elements and water from 

the air and produces its own food by photosynthesis. 

It is in the pineapple family (Bromeliaceae), and 

most species in this family are epiphytes with highly 

specialized morphological adaptations that assist in 

obtaining water and other materials from the air. 

The morphology of this plant was outlined by Garth 

(1964), who also gave the major references in the 

literature.

The plant body consists of a sinuous pendant stem 

that bears curved filiform leaves at nodes on the 

stem (fig. 1A). The entire plant body, except the 

flowers and seed capsules, is closely invested with 

overlapping translucent scales (fig. 1H), each scale 

being attached to the stem or leaf at a central point 

(fig. 1G). These abundant scales greatly increase the 

surface of the plant that is exposed to the air. Aso 

(1909), on the basis of experiments he conducted on 

lithium nitrate absorption, concluded that salts could 

pass through the scales into the plant. The ability 

of the scales to entrap airborne participate matter 

is obvious. The scales also assist in water absorption 

by the body of the plant and contribute to the ability 

of the plant to withstand drying even when placed 

in a strong dessicant (Billings, 1904).

Small yellow flowers (fig. IB) borne terminally 

on short branches that arise from leaf axils (fig. 1A) 

appear usually in March and April and probably are 

self-pollinated. The seed capsules (fig. 1A and C) 

begin to form in June but do not mature until the 

following December and January (Garth, 1964). The 

capsules then open (dehisce), and each releases 10 to 

20 seeds (fig. ID). Each seed bears a plume of long 

epidermal hairs (fig. IE) that add buoyancy to the 

seed and enable it to become airborne. If the seed 

falls on a suitable substrate, such as the rough bark 

of a tree or a mass of Spanish moss plants, the small 

barbs at the joints of the hairs (fig. IF) assist the 

seed in adhering to the substrate (Billings, 1904, 

p. 107). After germination of the seed, rootlike organs (rhizoids) attach the plant to the substrate 

(fig. 17) but do not function as absorbing organs 

(Garth, 1964). These anchoring organs soon degenerate, and the plant is supported only by its densely 

intertwined stems and leaves.

The factors responsible for the occurrence of 

Spanish moss at particular locations, and for its regional distribution, are imperfectly understood, although the ecology of the plant has been investigated 

extensively. In many large areas Spanish moss is 

extremely abundant and grows on almost any kind 

of support, whereas in others it occurs at discontinuous locations or is found only closely associated with 

ponds and streams. It grows on both living and dead 

trees and in full sun exposure or in shade (fig. 2). 

Masses of the plants are torn from the supporting 

trees by winds, and if dropped at suitable locations, 

they continue growth and establish new colonies. 

Garth (1964) suggested that the distribution of 

Spanish moss in the United States is related to major 

storm paths which arise in Mexico and move laterally over the coastal plains.

The northern limit of the distribution of Spanish 

moss (fig. 3) is controlled in some manner by seasonal temperatures, although the plant will endure 

short periods of freezing weather and snowfall. 

Transplant experiments have proved that it will survive and reproduce at favorable locations as much as 

75 miles north of its natural range (Garth, 1964). 

Its western limit, in east-central Texas, probably is 

controlled by the frequency of rainfall. Garth (1964) 

demonstrated that the plant could survive only about 

3 to 4 months if deprived of rain, even if natural 

high humidity was maintained around the plant.

METHODS OF STUDY 

SAMPLING PLAN

The collection of samples for this study was begun 

in 1965 and was continued through 1970 as opportunities arose while we were engaged in other field 

studies. The general plan was to obtain samples from 

as many areas as possible at sites spaced about 50 

miles apart throughout the range of Spanish moss. 

In order to obtain samples from some areas that 

we could not visit, County Agricultural Extension 

Agents in selected counties were requested to collect 

and submit samples, and 22 agents responded. In 

addition, single samples were contributed by several 

other persons.

Samples were obtained from a wide variety of 

habitats, including roadsides, industrial and urban 

areas, remote locations in forests and swamps, ocean 

beaches, and agricultural areas. Special efforts were 

made to procure some specimens from sites at the 

western and northern limits of the plant's range. The 

samples were pulled from trees or other supports, 

and visible extraneous matter was removed from the 

samples before they were placed in cardboard boxes 

and shipped to the U.S. Geological Survey laboratories in Denver.
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E5

FIGURE 1. Growth habit and morphological features of Spanish moss (Tillandsia usneoides L.). A, mature plant bearing a 

seed capsule; B, flower; C, immature seed capsule; D, dehiscence of the mature capsule, which releases the seed; E, airborne seed, with plume of epidermal hairs; F, distal portion of a single epidermal hair; G, a peltate epidermal scale; H, 

portion of stem, showing imbricated translucent scales; /, young seedling attached to a branch by means of rhizoids.
E6 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

FIGURE 2. Growth of Spanish moss on the tops of pond 

cypress (Taxoditim ascendens Brongn.) and on the more 

shaded lower branches. Okefenokee Swamp, Charlton 

County, Ga. Photographed July 23, 1963.

The sampling sites are plotted in figure 3 and 

described in table 1. All samples were analyzed in 

the winter of 1970-71. Although the gain or loss of 

elements during storage of the samples could not be 

precisely evaluated, we noted no correlation between 

storage time and concentrations of the more volatile 

elements.

ANALYTICAL METHODS

In order to minimize the effects of analytical drift, 

the samples were arranged in a randomized order 

before being submitted to the laboratories, and they 

were analyzed in the same sequence. The unwashed 

samples were ovendried and then pulverized in a 

blender. A wet-digestion method was used to prepare 

the samples for determining their arsenic, mercury, 

and selenium concentrations. For determining the 

concentrations of other elements in the samples, portions of the pulverized plants were transferred to

ceramic crucibles, weighed, and burned to ash in an 

electric muffle in which the heat was increased 50 °C 

per hour to a temperature of 550°C and held at this 

temperature for about 24 hours. The ash was then 

weighed to determine the ash yield of the dry plant 

sample. A colorimetric method was used to analyze 

the ash for phosphorus content, and an atomic absorption method was used for determining cadmium, 

calcium, lithium, potassium, sodium, and zinc. Concentrations of the remaining elements in ash were 

determined by a semiquantitative emission spectrographic method (Myers and others, 1961).

The values obtained by spectrography were reported in geometric brackets having boundaries, in 

percent, of 1.2, 0.83, 0.56, 0.38, 0.26, 0.18., 0.12, and 

so forth; the brackets are identified by their respective geometric midpoints, 1.0, 0.7, 0.5, 0.3, 0.2, 0.15, 

and so forth. Thus, a reported value of 0.3 percent, 

for example, identifies the bracket from 0.26 to 0.38 

percent as the analyst's best estimate of the concentration present. The precision of a reported value is 

approximately plus or minus one bracket at the 

68-percent level of confidence and plus or minus two 

brackets at the 95-percent level.

The approximate limits of detection of the analytical methods that were used are given in table 2. 

Some combinations of elements in a sample, however, 

affect these limits. For example, concentrations 

somewhat lower than these values may be detected 

in unusually favorable materials, whereas these limits of detection may not be attained in unfavorable 

materials.

DATA PRESENTATION

The concentration of each element in each sample 

(or its ash) and the location of the corresponding 

sample site expressed as degrees and minutes of 

latitude and longitude were entered on automaticdata-processing cards. The analytical values were 

transformed to logarithms through a computer program which also determined the minimum and maximum values and the basic statistics. In addition, the 

program reported all occurrences of missing data, 

indicated the concentrations that were beyond the 

limits of detection of the analytical methods, and 

printed both a histogram of the analytical values and 

an accompanying table of frequencies and cumulative frequencies for each class designation on the 

histogram.

The table of frequencies could be used to divide 

the range of reported values into five classes so that 

as far as possible about 20 percent of the values fell 

into each class. For some elements the limited ranges 

in values prohibited use of more than two or three 

classes to represent the total distribution. Class-in-
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E7

x

/NORTH 

/ '^CAROLINA

Approximate western and northern 

limit of Spanish Moss distribution./

TEXAS / \ ?* '290/,28I

J \29 >9ffa *<4t 274 >27f^-C

T r

100 200 300 400 500 KILOMETERS

FIGURE 3. Spanish moss sample localities (described in table 1). Seashore sites are plotted offshore.

TABLE 1. Spanish moss sample localities and sampling dates

Locality 

(fig. 3)

Laboratory No. 

(D414-)

Sampling 

date

Locality

State County or parish Area

29.......

30......

31.......

32.......

33......

34.......

35.......

36......

37.......

38.......

39.......

40.......

41.......

42.......

43.......

50.......

..376.. 

..330. 

..337..

..299.. 

..413. 

..349..

-June 1965.............

...........do.................

. do 

..397.. 

..324.. 

..384- 

..336.. 

..321.

..do... 

..do... 

..do..

. Louisiana.............

..Alabama 

............do....... 

..Natchitoches- 

..Monroe............

..Henry..............

.Georgia. . 

...........do................

.July 1965..............

...........do.................

...........do.................

..........do.................

...........do.................

-do..

..Irwin...........

..Jeff Davis... 

..Bacon..........

............do.............

...........do.............

...........do.............

............ do.............

..do..

..409.. 

..303. 

..333.. 

..329. 

..411.

. do. ........

.September 1965..

..North Carolina.. 

..South Carolina.. 

..do..

..Glynn.. . 

..Dodge. . 

..Bleckley.......

..Emanuel . 

.Burke 

..North Carolina.. 

.Texas. . 

..Brunswick.. 

.Horry 

..Florence 

.Onslow.......

-Brazoria....

51..

52..

53..

54.. 

55- 

56.. 

58..

59

60

61

62

63

67

68..

69..

70.

71..

72.

73.

74.. 

81.

95..

96..

199..

200..

201..

202.

203..

204..

205..

..301. 

..348. 

..312.

..do.. 

..do.. 

..do..

..Florida .... 

..Mississippi. 

..Georg

-414.. 

..346..

-308.. 

..368..

-do.. 

..do..

-do..

-do..

.Florida.... ....

.South Carolina.. 

..Texas ............

..Florida .

.Sarasota.... 

..Lawrence.. 

-Baker.........

.Dixie.. ..

..Charleston.... 

.Victoria.. 

.Palm Beach..

-404......... ......... do.. .. Texas.. .Karnes.

 311..... 

 372 

 . 339 ....... .

...... do .

 .... do.... .......

........ do 

.. do. ..

 . do.. ..

.............. ...Florida............... ............... Volusia.. ...................

............. Ii

 I]

 .7

 ..... T]

..355.. 

..357.. 

..332..

..do-

..do-

.October 1965..

-314.. 

..383..

-326..

.September 1965.. 

...do.................

....do................

.. do..... 

-Louisiana.. 

.Florida......

.Louisiana............

.Florida...... .......

..North Carolina..

..Orange........ ...........

..Terrebonne...............

.Wakulla .........- .

.East Baton Rouge.. 

-Dade... ................

..Tyrrell . 

-418.. 

. 309.. 

..405..

..338..

.408..

.399..

334..

-325.. 

..373.. 

..360.. 

..356..

............do...............

.October 1965.....

.March 1966 

............do...............

.January 1969....

...........do...............

.December 1968..

..........do...............

............do...............

 do. . 

...........do ....

..Florida. . ....... ....

..Florida........... ....

..Texas...................

..Florida. . 

..Georgia... . 

............do................

..Florida................

............do................

...........do................

 do. ......

 do................

..Indian River.............

. Broward....................

..Colorado.....................

..Okaloosa. ....

-Chattahoochee.. 

..Sumter...............

.Jlillsboro............

..Polk 

.. Seminole............

-Alachula. ......

..Levy...................

.2 miles E. of Clarence.

.U.S. Route 84, at Perdue Hill on Alabama River.

..State Route 10, 2 miles E. of Shorterville.

..State Route 32, 10 miles E. of Ocilla.

..U.S. Route 23, 5 miles NW. of Hazelhurst.

-U.S. Route 1, 4 miles S. of Alma.

-St. Simons Island, near Fort Fredrica.

-State Route 117, at Rhine.

-State Route 87, 12 miles N. of Cochran.

-State Route 192, 3.5 miles W. of Stillmore.

-U.S. Route 25, 10 miles N. of Waynesboro.

-State Route 211, 3 miles W. of Supply.

-U.S. Route 17, at Little River.

-State Route 378, 2 miles W. of Lake City.

-State Route 17, 1 mile S. of Verona.

-5 miles NW. of Angleton, Farm Road 521, at 

Oyster Creek.

-On Wilkinson Road.

-6 miles S. of Monticello, near Pearl River.

-Mixed pine-hardwood forest.

-In city park, Cross City.

-Edisto Island.

-Bank of Guadalupe River, near Victoria.

-Junction of Pike and Belvedere Road, West Palm 

Beach.

-Bank of San Antonio River. 

In St. Augustine. 

In Sebring. 

In Georgetown. 

7 miles SW. of Opp. 

In DeLand.

-- At 2350 E. Michigan Ave., Orlando.

--In Gibson.

-3.5 miles W. of Crawfordville.

-R. 1 E., T. 8 S.

-Paradise Key, Everglades National Park.

-Near Albemarle Sound shore, 0.5 miles N. of 

Columbia.

-At Vero Beach.

-On Prospect Road, Fort Lauderdale.

-At rest stop, State Route 71, 8 miles NW. of

Columbus.

..On Fort Walton Beach. 

..U.S. Route 280, 8 miles E. of Cusetta. 

.-State Route 49, 3 miles S. of Andersonville.

-State Route 60, in Limona, about 5 miles E. of 

Tampa.

-State Route 33, at Eva.

..U.S. Route 17-92, at margin of Lake Jessup.

..U.S. Route 441, 1 mile S. of Micanopy.

-U.S. Route 41, 2 miles S. of Morriston.
E8 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY 

TABLE 1. Spanish moss sample localities and sampling dates Continued

Locality Laboratory No. Sampling _________________________________Locality________________________________ 

(fig- 3)______(D414-)_________date________________State______________County or parish___________________Area_______________

206- --310 .. . -.. - .. do -. .. . - - ....do--..--..-...... . Manatee............. ^ Route 41, undisturbed lot at N. edge of

Bradenton. 

207........................375................................do............................................do...............................-..CharIotte..........................-..U.S. Route 41, 5 miles W. of Murdock.

208........................379........-.....................do..-.......................................do..................................Highlands............................-U.S. Route 27, 5 miles S. of Sebring.

209... ..............343 .......................... do.......................................... do ...................... ....Polk ................................... State Route 60, at edge of Bartow.

210........ ..........370.. ...........January 1970. .. ..North Carolina... .Pasquotank . . U.S. Route 158, 10 miles E. of Sunbury.

211...................-..318................................do.....-......................-...........do....-.............-.--...-.-....Dare.-------.------.-.-..-----....-.--.U.S. Route 158, 3 miles N. of Kitty Hawk.

212........................340................................do...........-.................-..........do.............................---..Washington......-..-............State Route 64, 8 miles E. of Rober.

213........................300................................do............................................do.......-.-..................----..Robeson.............................-.Interstate Highway 95, at Lumber River, 3 miles

S. of Lumberton.

214.. ..............317 . ...do .........................South Carolina. .............. Dillon....................................-U.S. Route 301, 1 mile N. of Latta.

215. 351.... .....................do............................................do.................... .......Marion....... ......... .State Route 501, at Little Pee Dee River.

216..... ............353 ........................do.._____.. . .............do.. ..............................Charleston.......... . ..U.S. Route 17, at W. city limits of Charleston.

217........................366............... ...........do ..............................do.. .. ....................Beauford ....................... Hunting Island State Park.

218 - .....- .387.. ....-..- ..- .do ... -.-..-... .-..do--.-----.. .........-....do-... ^^ Field, 200 yards from the beach, Hilton

Head Island. 

219........................393-..... ... .. ..do .... .......Georgia .... ...... .Chatham.... ......... ....Savannah Beach, near the lighthouse, Tybee

Island. 

220........................313................................do.-.......-..............................do..................................Emanuel.................. .......U.S. Route 80, 2 miles E. of Adrian.

221........... ......364..... . ... do........ .......... ................do..................................Laurens ...................U.S. Route 80, at Ford Branch, 3 miles W. of

Dublin. 

222........................342................................do............................................do..............-.----..........--..Houston.................................Interstate Highway 75, 2 miles S. of Perry.

223.... 398.. ...........do...-......................................do...............---.--......-...-.-Lowndes.... -Interstate Highway 75, 2 miles N. of Valdosta.

224... ... 319... ..........................do ...... ......... ...... Florida..................... ..........Hamilton.... ........................Interstate Highway 75, at Jasper-Madison exit.

225...............-......335................................do....................-...-..-..........do...............-............--..Suwanee.... .... .............U.S. Route 90, at Wellborn.

226 ....... . .362................................do............................................do .................... Jefferson ..........U.S. Route 90, 1 mile W. of Monticello.

227 ......407 . . do ...................................do . ............................Gadsden....... .. .U.S. Route 90, 5 miles W. of Gretna.

228 . . .. 378 ......- . ... -do ............--. ... ---.do- - ....... .Holmes -.... ^ 79, 3 miles N. of Bonifay.

229........................385................................do..................................A]abama................ . - Geneva...................................County road, 5 miles NE. of Hartford.

230........................315................................do. .. ..Florida. . ...............................Bay. .............. U.S. Route 98, W. side of Panama City.

231...- .. ... .298 ... .. .....- ...do- ...--...... ..do- .-..... .- ....Walton . ..---^^^^ Route 98, bridge at Philips Inlet, 2 miles W.

of Sunnyside. 

232........................305................................do..................,...............Alabama......... .. ........ Baldwin..... ........ ....... ..On the beach at Josephine.

, 233--..... - ..402 - ....- -...do-.... -..--- -do-....-...... ......... .Mo Mle-.. ........................... Interstate Highway 10, 5 miles W. of Mobile.

234........................371................................do.................... .. .Mississippi. ........ ......Hancock .. ............. ....In Bay St. Louis.

235.... . .....396................................do.................... Louisiana... . .. ....St. Tammany. ...............Junction of U.S. Routes 90 and 190, 4 miles W.

of Perlington. 

236-.-.-..........-410...... . do....... ...............................do... . ....Tangipahoa .. U.S. Route 190, at Robert.

237.....................-420................................do...... ..... ......do..................................St. Landry.. ...... ..At Krotz Springs.

238........................363....... ...........do............................................do........... ........Avoyelles .. .... ....State Route 1, at Maureville.

239-.-......--.-.412...-.--.-..----.do.-.----..-...---..........do....... . ..Pointe Coupee. .............State Route 1, 2 miles S. of Batchelor.

240......-...............306................................do............................................do.........................- Ascension..............................U.S. Route 61, at Sorrento.

241........................304.... .. ..... do.................... .....................do.... ... .............St. Tammany .. State Route 25, at Folsom.

242........................417.................. .............do..................................Mississippi........................... Walthall................................State Route 5, at Mississippi-Louisiana Sta4

line.

243....... .....-419......................February 1970 ........................do...........-..... ........Marion...................................U.S. Route 98, at Columbia.

244........... ..377...................... ........do.--...--. ..do..................................Forest.... . U.S. Route 11, on bank of Leaf River, at

Hattiesburg.

245..... ............307....... .....- ...do........ .............................do............................ . ..Perry. .. ....................State Route 15, on bank of Leaf River, at

Beaumont.

246.. ............ 322...... .......................do............................................do.......... ........Greene...................................State Route 63, on bank of Chickasawhay River,

at Leakesville.

247.......... .......345.....-.......... ......do. ................. .......Alabama.... ........................Washington.......- .State Route 56, 7 miles W. of Chatom.

248 . 367...-............-. ...do.. .................................. do .. .....................Clarke....................................U.S. Route 84, 1 mile W. of Whatley.

249... . 350......-.......................do............................................do......... .................Conecuh.................................U.S. Route 84, 2 miles E. of Belleville.

250. ......406.... ........... ..do. .......................... ........do ........Lowndes ................Interstate Highway 65, 3 miles S. of Letohatchee

exit. 

251 ..344.... ......... .. .do...... ..............................do............................... ..Elmore.. ........................U.S. Route 231, at the Tallapoosa River.

254 .........400....... ........April 1970 ............ ...Florida................................ ..Collier. ...........................Coximba area, Marco Island.

259........................323. ..................May 1970... . ........Texas ..............................San Patricio.........................Bank of Nueces River, near Sandia.

261 ... ....... 394.. ... do................................ ...do.... ...........................Live Oak .......................State Route 59, at the Nueces River.

263. .....................386................................do............................................do..................................A^ansas................................. State Route 35, 1 mile N. of Aransas Pass.

265..,. ........... 395..... .. ..... ..do . . .. ..... . .do. ..... .. . . Cnlhoun....... .. . ..............State Route 35, near the Guadelupe River.

266........................328................................do............................................do..................................Matagorda............................State Route 35, 2 miles E. of Blessing.

267........................416................................do............................................do..................................Fort Bend .In Sugar Land.

268............. ........331 ............................do............................................do.................................. Harris........................... Interstate Highway 10, 5 miles E. of junction

with Interstate Highway 610.

269.---. ---390--.....--..--....-do.--- --. ... ..do.................................. Chambers.................... .. Interstate Highway 10, at E. side of Trinity

River, Wallisville.

270............. .341....... ........ do............................................ do ....................... Jefferson... .. ......Interstate Highway 10, at W. city limits of

Beaumont. 

271 359 . .- ..... do.. ............. . ....do.. .......................Orange..........- .... .Interstate Highway 10, at W. side of Orange.

272........................347........-.....................do..................................Louisiana........-.........-...-.--..--Calcasieu............... .U.S. Route 171, 4 miles N. of Lake Charles.

273........................365................................do............................................do..................................Vernon..................................State Route 8, at the Sabine River bridge.

274........................374................................do...................-............Texas.......... . ......Jasper .............................U.S. Route 190. 1 mile E. of Neches River.

275. .302...................... do........................................... do ......... ..............Tyler. ......................... U.S. Route 190, 1 mile E. of Polk County line.

276............... .....316.. ................ do......... ............ ..........do ......... ........... .Polk ... U.S. Route 190, 1 mile E. of San Jacjnto.

277........................358................................do... ...............................do.................................. Walker .. ...State Route 30, 10 miles W. of Huntsville.

278... .............. 380.......-............ ...... do.......................................... .do. ................ ...Grimes ............................State Route 90, 1 mile S. of Navasota.

279 .......392...-................ ...do.. ............................ ...do....... ....................Washington ...................U.S. Route 290, 5 miles W. of Brenham.

281........................381 . April 1970................. -..Florida................................... Pinellas ........... ..........At Crvstal Beach.

282........................403.... .............June 1970..............................Mississippi....... .Yazoo.....................................U.S. Route 49W, 6 miles W. of Yazoo.

284.......-..............391................................do............................................do........ ..... .......Hinds............... ...............Interstate Highway 55, at Pearl River, 2 miles

S. of Jackson. 

286. ...... .......327 .........................do .. ... .....................do.................................Jefferson ......................State Route 28, 18 miles W. of Union Church.

287........................401................................do............................................do . ..............................Adams . .U.S. Route 61, 4 miles W. of Natchez.

288 .................388 ....-..........do....-......... . .Louisiana .... .Concordia ....................U.S. Route 84, 2 miles W. of Wildsvilie.

289. .......... .369................................do........................ ...................do.....- .......La Salle.... .................U.S. Route 165, 5 miles NE. of Tullos.

290........................415................................do............................................do..................................CaldweH.................................U.S. Route 165, at Columbia.

291...... .... .......389 ........................do..................................... .. do . ...................... Franklin ......................... State Route 4, 1 mile NE. of Winnsboro.

292........................354................................do............................................do..................................Richland................................State Route 17, 4 miles N. of Delhi.

293........................382................................do..................................Arkansas...............................Ashley.....................-.....-.-State Route 8, 1 mile W. of Parkdale, on Cutoff

Creek. 

294........................352................................do............................................do..................................Lafayette..................... .U.S. Route 82, 2 miles E. of Red River.
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E9

terval code numbers were assigned to each analytical 

value; these numbers were entered on base maps by 

an automatic plotter at the proper geographical location of the corresponding sample and then replaced 

with symbols as shown in figures 5 to 35.

The geometric means and geometric deviations 

given in figures 5 to 35 are antilogs of the arithmetic 

means and standard deviations, respectively, of the 

logarithms of the analytical values. Where some of 

the concentrations for an element were determined 

to be less than the sensitivity of the analytical 

method (table 2), the means and standard deviations 

of the logarithms were estimated by means of a 

censored-distribution technique devised by Cohen 

(1961). Means estimated by the use of this technique may be lower than the limits of detection for 

certain elements, as is illustrated by the mean arsenic content of 0.79 ppm in Spanish moss (fig. 7), 

whereas the limit of detection for arsenic is 1 ppm 

(table 2). Further discussions of the treatment of 

censored frequency distributions of geochemical data 

and of the use of geometric means and geometric 

deviations were given by Miesch (1967) and Shacklette, Sauer, and Miesch (1970).

All data analysis in this study is based on logarithms of reported concentrations because minor elements commonly tend to exhibit positively skewed 

frequency distributions. The geometric mean is the 

best measure of central tendency in log normally 

distributed data and, as such, is an estimate of the 

typical or most common concentration for the element. The range from the geometric mean multiplied 

by the geometric deviation to the geometric mean 

divided by the geometric deviation generally includes 

about two-thirds of the analytical values. About 

95 percent of the values occur in the range from 

the geometric mean multiplied by the square of the 

geometric deviation to the geometric mean divided 

by the square of the geometric deviation. For example, the geometric mean cadmium content of ash 

of Spanish moss is 7.9 ppm, and the geometric 

deviation is 1.65 (fig. 10). Thus, probably about 

two-thirds of a large group of randomly selected 

samples will have cadmium contents in the range 

7.9^1.65=4.8 ppm to 7.9x1.65=13.0 ppm, and about 

95 percent will have cadmium contents in the range 

7.9-f-1.652=2.9 ppm to 7.9xl.652=21.5 ppm.

ELEMENTAL COMPOSITION OF SPANISH MOSS

Chemical analyses of Spanish moss were performed 

first by Wherry and Buchanan (1926) and later 

by Wherry and Capen (1928) ; the analyses indiTABLE 2. Analytical limits of detection

[Analyses made by semiquantitative spectrographic method, except as indicated. Dry plant material was used for arsenic, mercury, and selenium 

analyses ; plant ash was used for analyses of all other elements. Data reported in parts per million]

Element Lower limit 

of detection

20

n

3

2

50

2.5

2150

300

2

7

2

10

15

9n

70

9n

24

50

2

Element

Nickel........ . .........

Silver ......... ................

Tin.......... .............. .....

Zinc........................ ....

Lower limit 

of detection

........ M).5

7

....... 150

....... 10

....... 20

....... *2

....... 250

....... 10

n

....... 1

........ 2 100

....... 10

9n

........ 5

....... 15

....... 2

........ 20

225

....... 20

1Analyzed by colorimetric method. 

2Analyzed by atomic absorption method.

cated that the plant obtains a wide range of chemical elements from the atmosphere. Maclntire, 

Hardin, and Hester (1952) transplanted specimens 

of Spanish moss that contained about 27 ppm fluorine in ash when growing in Florida to sites in 

Tennessee at different distances from factories that 

emitted fluorine from their stacks. After 3 months 

the fluorine content of the transplanted specimens 

ranged from 100 ppm to as much as 2,418 ppm on 

a dry-weight basis, the amount in the specimen 

being inversely proportional to the distance of the 

sample from the factory. Shacklette and Cuthbert 

(1967, p. 43) reported that the iodine content of 

five Spanish moss specimens averaged 5 ppm in dry 

matter and ranged from 4 to 7 ppm.

Martinez, Nathany, and Dharmarajan (1971) 

reported lead analyses of eight Spanish moss samples from Baton Rouge, La., from sites near heavily 

traveled highways and from sites more distant from 

heavy traffic. They found that the lead concentration was greatest in the samples from sites near 

highways, with a maximum of 0.085 percent (850 

ppm) in the dry samples, whereas samples from 

sites more distant from highways contained as little 

as 0.0051 percent (51 ppm). The percentages of 

ash obtained by burning the samples were not given; 

if the ash yield of these samples was similar to the 

mean ash content of samples analyzed in the present 

study (4.5 percent of dry weight), their maximum 

lead concentration would convert to about 18,700 

ppm in ash, and their minimum lead concentrations 

would convert to about 1,122 ppm in ash. These 

values are well within the range (70 to 50,000 ppm 

lead in ash) given in figure 17 of the present report.
E10 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

Benzing and Renfrow (1971) analyzed samples 

of Tillandsia circinata Schlecht., a small epiphyte 

closely related to Spanish moss. They reported concentrations of the nutritive elements calcium, magnesium, nitrogen, phosphorus, potassium, and 

sodium in samples of prefruiting, fruiting, and postfruiting plants from six sites in southern Florida. 

Although considerable variation was found in the 

concentrations of these elements among sites and 

growth stages, plants in the prefruiting stage generally contained more potassium, magnesium, and 

phosphorus than plants in other growth stages. 

Trends in growth-stage concentrations of the other 

elements were not pronounced, although the postfruiting stage at one sampling site contained the 

largest amounts of magnesium, calcium, and sodium.

Shacklette (1972) reported that the cadmium 

concentrations in the Spanish moss samples discussed in the present report ranged from 2.2 to 27 

ppm in ash. The concentrations were thought to be 

related to the degree and kind of aerial pollution at 

the locations where the samples grew.

The ash yield and the concentrations of selected 

elements in the samples of Spanish moss collected

in this study are presented in figures 5 to 35. Sample 

localities indicated by symbols in these figures are 

referred to by locality numbers in figure 3 and are 

described in table 1.

Concentrations of all elements but arsenic, mercury, and selenium (figs. 4-35) are given as parts 

per million in ash. The percentages of ash obtained 

by burning the dry samples are given in figure 5. 

The parts per million of an element in ash can be 

converted to approximate parts per million in the 

dry material by means of the following equation:

Element (ppm) in dry plant = element (ppm) in ash

ash content (percent)

X

100

The elements beryllium, cerium, germanium, mercury, neodymium, niobium, selenium, and tin were 

not commonly detected in the samples. The localities 

where samples containing these elements were collected and the concentrations of the elements in the 

samples are shown in figure 4.

Some elements were looked for in all samples 

but were not found. These elements, analyzed by the 

semiquantitative emission spectrographic method, 

and their lower detection limits, in parts per million,

^NO

I 

\ 

v

\

TEXAS

_-^-.

SOUTH

v S CAROLINA 

\ GEORGIA "*>

A~T

ARKANSAS * \

| f I \ taHUK.Ol.ft

<^ *!:SSISSIPPl| ALABAMA\ Nd 15Q

r 

 ~~*i o« on i 

Sel.«

I Ce 300^ / 

\ Ndl50>/- 

\,Nb20j{__-

- LOUISIANA (

Sn 20

Sn 2Q

Sn 30 

Sn

1 I I I T

100 200 300 400 500 KILOMETERS

FIGURE 4. Localities of Spanish moss samples containing elements not commonly detected and the concentrations of 

the elements. Mercury (Hg) and selenium (Se) values are expressed as parts per million in dry plant material; 

beryllium (Be), cerium (Ce), germanium (Ge), neodymium (Nd), niobium (Nb), and tin (Sn) values are expressed as parts per million in ash.
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS Ell

are as follows: Gold, 40; hafnium, 200; indium, 

20; platinum, 60; palladium, 2; rhenium, 60; tantalum, 400; tellurium, 4,000; thallium, 100; thorium, 

400; and uranium, 1,000. If lanthanum or cerium 

was found in a sample, the following elements, with

their stated lower detection limits, were specifically 

looked for in the same sample: Dysprosium, 

100; erbium, 100; gadolinium, 100; holmium, 40; 

lutetium, 60; terbium, 600; and thulium, 40. Though 

looked for, none of these elements was found.

\

I I I 

0 100 200 300 400 500 KILOMETERS

25

20

15

Si 10

Symbol, and percentage of total samples represented by symbol

TG ^T^T

CM CM CO CO CO O) O CM

ASH, IN PERCENTAGE OF DRY WEIGHT

Geometric mean, 4.6

Geometric deviation, 1.46

Number of samples and analyses, 123

FIGURE 5. Ash yield of Spanish moss.
E12 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

N

Symbol, and percentage of total samples 

represented by symbol

40

30

§ 20

10 -

-

~n i i m i m o o o o

« CM co in r«»

o o o o o

 

0

o~

1

s

"

(.

\

o 

o

CM

;6

i

§

CO

1

o 

o

in

|

o 

P

p~

14

i i

0 0 

0 0

0 0

A

ALUMINUM, IN PERCENTAGE IN ASH

Geometric mean, 4.08

Geometric deviation, 2.21

Number of samples and analyses, 123

100 200 300 400 500 MILES

0 100 200 300 400 500 KILOMETERS

FIGURE 6. Aluminum content of Spanish moss.
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E13

Symbol, and percentage of total samples 

represented by symbol 

70

60

50

> 40

z

LU

=>

a

LU

£ 30

20

10

O

ARSENIC, IN PARTS PER MILLION 

IN DRY MATERIAL

Geometric mean, 0.79

Geometric deviation, 1.5 5

Number of samples and analyses, 116

0 100 200 300 400 500 MILES

I______|______|

1 I I I 

0 100 200 300 400 500 KILOMETERS

FIGURE 7. Arsenic content of Spanish moss.
E14 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

Symbol, and percentage of total samples 

represented by symbol

40

30

20

10-

£ I 58 

O I O l« I

in r- CD in

« eMcomr~.eDmT CM

BARIUM, IN PARTS PER MILLION IN ASH

Geometric mean, 564

Geometric deviation, 2.32

Number of samples and analyses, 123

0 100 200 300 400 500 MILES

I. I . ,1.1, I______I

0 100 200 300 400 500 KILOMETERS

FIGURE 8. Barium content of Spanish moss.
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E15

IT ---

s

\

Symbol, and percentage of total samples

represented by symbol 

70

60

50-

>: 40-

u. 30-

20-

10-

OJ

o

-

-

_

1

<±> r^

Q

\ o

o

1

o

CO

OJ

1

0

o

CM

in

1 o

0 

CO

BORON, IN PARTS PER MILLION IN ASH

Geometric mean, 150

Geometric deviation, 1.34

Number of samples and analyses, 123

100

I

200

I

300 

I

400 

I

i ' i i i r

0 100 200 300 400 500 KILOMETERS

500 MILES 

_I

FIGURE 9. Boron content of Spanish moss.
E16 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

0 100 200 300 400 500 KILOMETERS

Symbol, and percentage of total samples represented by symbol

2U

> 15

0 J

z

UJ

=>

a

£ 10

5

0

-

=k=

«?

o psi

u

c

c

II I

-> oo

M tVI

Dl'

p

p

?

si

O

_L_

r 

e«i

p

*

M

t

a

^

n

ic

u

Q

 >

i

>"

u

o

 >

D

^

1

*! 

r»-

>2

u

o

8

 >

o

n

1

oo

a>

> 21

1

PO

 "

1 1 1 1

<n oo o a> *f- oo

<M ^- r- o> <M >»

CADMIUM, IN PARTS PER MILLION IN ASH

Geometric mean, 7.9

Geometric deviation, 1-65

Number of samples and analyses, 122

FIGURE 10. Cadmium content of Spanish moss.
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E17

Symbol, and percentage of total samples 

represented by symbol

30

0

FREQUEr fs»

O

10 

n

6"

-

~n i

i i

CM 

O

3

e

1

CO

CM

0

1

oo

1 1

« ^ CM PO

CALCIUM. IN PERCENTAGE IN ASH 

Geometric mean, 10.07 

Geometric deviation, 1.56 

Number of samples and analyses, 123

100 200

. I

300

I .

400

I

500 MILES

I ' \ I

0 100 200 300 400 500 KILOMETERS

FIGURE 11. Calcium content of Spanish moss.
E18 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

\

V.

Symbol, and percentage of total samples 

represented by symbol

50

40

30

20

10

 13

m

T- *- CM CO

« ^ CM co in r~ o un

CHROMIUM, IN PARTS PER MILLION IN ASH

Geometric mean, 57

Geometric deviation, 1.73

Number of samples and analyses, 123

100 200

I

300

I .

400

I

500 MILES

I ' I I I I 

0 100 200 300 400 500 KILOMETERS

FIGURE 12. Chromium content of Spanish moss.
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E19

ITs

V,

\

\

v r -\

Symbol, and percentage of total samples 

represented by symbol

30

20

10 

n

0 

CM

o

1-

-

\

*>»

1

~CM 9

\

to

CM

9

I

 "

 |

1 I ill

\ / r- r- CM CO IT) rCOBALT, IN PARTS PER MILLION IN ASH

Geometric mean, 9.8

Geometric deviation, 1.83

Number of samples and analyses, 123

100 200 300 400 500 MILES 

I_____I_____I

1 I 

0 100 200 300 400 500 KILOMETERS

FIGURE 13. Cobalt content of Spanish moss.
E20 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

C 

s

\

^

\

Symbol, and percentage of total samples 

represented by symbol

40

30

20

10

0

14 23| 16 16

« evi co ir> r- o ir> o

COPPER, IN PARTS PER MILLION IN ASH

Geometric mean, 148

Geometric deviation, 2.01

Number of samples and analyses, 123

100

I

200 300

I

400

I

I I 

100 200 300 400 500 KILOMETERS

500 MILES

_I

FIGURE 14. Copper content of Spanish moss.
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E21

Symbol, and percentage of total samples

represented by symbol 

40

30 -

20-

10

r~

o

1

CN

9

I

00

1

05rvj

^~

 

1 1 1 l

r>» r>» o m O O O

\, « CNJ co in

100

I

200 

I

300

I

400

I

500 MILES

^ T T 1 I 

0 100 200 300 400 500 KILOMETERS

FIGURE 15. Gallium content of Spanish moss.

GALLIUM, IN PARTS PER MILLION IN ASH

Geometric mean, 10

Geometric deviation, 1.71

Number of samples and analyses, 114
E22 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

I -

\

r ~~v

r

s

; d ->

/ 

/

\

\ \

\

{ i

;. «_ t

^v-^-^ \ $*

9^^ i

v ^»»» '\» v* r« . J®

J S

i 9 L

, )* 'AT7 '

« 

« « <

V^

 » «,

LO O

7«9

Symbol, and percentage of total samples 

represented by symbol

ou

40

^ 30

0

z

uu

13 

CJ

UU

cc"- 20

10

0

6"OJ

-

-

O LO O O 

» t OJ CO

1

0

in

1

o

r--

in

3

l o

o

«

1

0

CO 

CO

0

1

o 

o

4

1

o

0

M 

»

0

o

o < « t>J co in

IRON, IN PERCENTAGE IN ASH

Geometric mean, 1.58

Geometric deviation, 1.87

Number of samples and analyses, 123

100 200

I

300 400

I

i r

0 100 200 300 400 500 KILOMETERS

500 MILES

I

FIGURE 16. Iron content of Spanish moss.
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E23

s V ~ - OJCT O eo 10 4--gV °t

Symbol, and percentage of total samples 

represented by symbol

au

80

70

60

| 50

UJ

a

UJ

oc 40

u.

30

20

10

n

2

-

-

-

_

~

-

-

-

,

n «

i

>25

1

 4

iTT

LA LA r*» O LA

V

LANTHANUM, IN PARTS 

PER MILLION IN ASH

Geometric mean, 14

Geometric deviation, 3.80

Number of samples and analyses, 123

100 200 300 400 500 MILES

~ I I [ I 

0 100 200 300 400 500 KILOMETERS

FIGURE 17. Lathanum content of Spanish moss.
E24 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

s

\

\

X r'

\

\ I r

0 100 200 300 400 500 KILOMETERS

20

Symbol, and percentage of total samples 

represented by symbol

10

,24 ,20

I I I

to in r-

« »- CM f) to r o in ca

r- ~- CM CO to

LEAD, IN PARTS PER MILLION IN ASH

Geometric mean, 4,170

Geometric deviation, 3.16

Number of samples and analyses, 123

FIGURE 18. Lead content of Spanish moss.
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E25

I -

 s \

^

\

\

r ~^

^^A^.

s

/ 7 -r~ ~,-J\

/

L ^. r* . *4t «

' »5

1 ^0/9

\

\ 

\

\

eV

 (

n. CT

--^"""v^x*/

 T s- °y

*A «^ ^

.< / '

Q « JL

9 9 9- , 

« 

« * 3

\ 9 0^C»

\ QL-tfA,'

o > * L OQ o/

o1-

3

«

S *

i \

V^

'i «

"o o.

?J3°,

Symbol, and percentage of total samples

represented by symbol 

50

40 -

30 -

20

10

(.) 

9

U 

15

y 

40

 >

27

_

 

9

« « CM CO s s

LITHIUM, IN PARTS PER MILLION IN ASH 

Geometric mean, 22.4 

Geometric deviation, 1.53 

Number of samples and analyses, 122

100

I

200 300 

I

400 500 MILES

I I I I I 

100 200 300 400 500 KILOMETERS

FIGURE 19. Lithium content of Spanish moss.
E26 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

\

Symbol, and percentage of total samples

represented by symbol 

50

40-

30-

20

10

O

in r-. o in o

<3

i

0

i 

CO

1

o

1

0

1

o

100

I

200 300

I

500 MILES

I I 

0 100 200 300 400 500 KILOMETERS

FIGURE 20. Magnesium content of Spanish moss.

MAGNESIUM, IN PERCENTAGE IN ASH

Geometric mean, 4.5

Geometric deviation, 1.73

Number of samples and analyses, 123
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E27

\

30

20

10

Symbol, and percentage of total samples 

represented by symbol

O

CM 1 ,T

9 I 

o o o

O O O O

* CM

MANGANESE, IN PARTS PER MILLION IN ASH

Geometric mean, 2,300

Geometric deviation, 2.60

Number of samples and analyses, 123

100 200 300

I

400 500 MILES

I ' I I I I I

0 100 200 300 400 500 KILOMETERS

FIGURE 21. Manganese content of Spanish moss.
E28 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

-x

Symbol, and percentage of total samples 

represented by symbol

100

90

20

10

V - - c*

MOLYBDENUM, IN PARTS

PER MILLION IN ASH

Geometric mean, 3.7

Geometric deviation, 1.80

Number of samples and analyses, 123

0 100 200 300 400 500 MILES

I______I______I______I i i r

0 100 200 300 400 500 KILOMETERS

FIGURE 22. Molybdenum content of Spanish moss.
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E29

Symbol, and percentage of total samples

represented by symbol 

40

30

20

10

CM CO

9 Id

« « evi 

NICKEL, IN PARTS PER MILLION IN ASH

Geometric mean, 39

Geometric deviation, 1.74

Number of samples and analyses, 123

100 200 300 400 500 MILES

0 100 200 300 400 500 KILOMETERS

FIGURE 23. Nickel content of Spanish moss.
E30 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

I ,

Symbol, and pei 

55

50

40

o

LU

= 30 o

UJ

DC 

U.

20

10 

0

\ o

o

v. <3

1

\

Q <ty#g^

f

\

-N--4

centage of total samples represented by symbol

-

-

r

\

o

0

oo

0 3 

20 26

i 1 1

g 

41

1

9 

11

i i

o o o o o o

000000 05 ^- ^- CM » in

*

71, IT

000 

000 

O CM CO

100 200 300 400 500 MILES

0 100 200 300 400 500 KILOMETERS

FIGURE 24. Phosphorus content of Spanish moss.

»- » ' o ^- o» o» r- - 

 T- CM co in

PHOSPHORUS, IN PARTS PER MILLION IN ASH

Geometric mean, 9,371

Geometric deviation, 1.55

Number of samples and analyses, 123
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E31

Symbol, and percentage of total samples 

represented by symbol

3U

40

>_ 30

o

UJ

Z3

a

UJ 

DC

"- 20

10

0

6"

-

-

i 1 i MIMI

r» o in o o o

3

1

0

1

I

0

1

0

CO

1

0

o i r>j ro tr> r~ o tr> o

»- « f>J

POTASSIUM, IN PERCENTAGE IN ASH

Geometric mean, 9.41

Geometric deviation, 1.74

Number of samples and analyses, 123

0 100 200 300 400 500 MILES

 ' 

0 100 200 300 400 500 KILOMETERS

FIGURE 25. Potassium content of Spanish moss.
E32 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

Symbol, and percentage of total samples 

represented by symbol

tu

30

20

10

n

a

o

-

-

-

1

CO

*

1

CO

*

1

 1

i ~T~

0 100 200 300 400 500 MILES

l.i.l. I . I ._____I______I

0 

n7

100 

!iri1

200 300 400 500 KILOMETERS

FIGURE 26. Scandium content of Spanish moss.

SCANDIUM, IN PARTS PER MILLION IN ASH

Geometric mean, 5.85

Geometric deviation, 1.89

Number of samples and analyses, 100
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E33

I .

s

V

\

\

r ~v

S

T"~ \

w

,*">-^-

r ~

1i

i

i

-"-"NX!

 ~~ ;

c -7

r i *

t

/

>

> Mo ' ^°°t°

oo

o

r

\

O obo '

QOTJL

0 °3^^

> OJ^

0*0^ 0 c

ot--^

0 0 ( ,

0 e o^d o (-?K

^X>

Symbol, and percentage of total samples 

represented by symbol

110

100

10

« « fMcoio

v

SILVER, IN PARTS PER MILLION IN ASH

Geometric mean, 0.12

Geometric deviation, 5.42

Number of samples and analyses, 123

200

I

300 400

I

500 MILES

_I

I I I I I 100 200 300 400 500 KILOMETERS

FIGURE 27. Silver content of Spanish moss.
E34 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

I ,

s

 ^

\

)

r v

20

10

Symbol, and percentage of total samples 

represented by symbol

oL^r-M OiriOOOOOOOOOOOO

« CM CO If) OlAOOOOOOO

« « tvi

SODIUM, IN PERCENTAGE IN ASH

Geometric mean, 2.2

Geometric deviation, 4.05

Number of samples and analyses, 123

100 200 300 400 500 MILES

0 100 200 300 400 500 KILOMETERS

FIGURE 28. Sodium content of Spanish moss.
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E35

I -

Symbol, and percentage of total samples 

represented by symbol

30

20

10

0

c

c

-

-

1 1 1

0 0 O in

n

i

0 

0 

CM

|

O 

0 

CO

en

CN

9

\ §in

o

CO

1

0

o

0 

CN

|

O

0

o

-

 1

1 1 1 III

O CD O O O 

CD CD O CD CD 

LO CD CD CD CD 

« CN CO in 1^

STRONTIUM, IN PARTS PER MILLION IN ASH

Geometric mean, 704

Geometric deviation, 1.85

Number of samples and analyses, 123

0 100 200 300 400 500 MILES

h 

0 100 200 300 400 500 KILOMETERS

FIGURE 29. Strontium content of Spanish moss.
E36 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

I 

Symbol, and percentage of total samples 

represented by symbol

40

30

20-

10

o~

-

ir> o o o

*- CM CO 10 

0000

1

o 

o

c

1

o

35

^

»

 

0

CO 

CM

O

1

o

0, 

CM

9

1

a

1

I

o

a M 

»

|

O 

O

r»

TITANIUM, IN PERCENTAGE IN ASH

Geometric mean, 0.23

Geometric deviation, 1.96

Number of samples and analyses, 123

0 100 200 300 400 500 MILES

-h ' 

0 100 200 300 400 500 KILOMETERS

FIGURE 30. Titanium content of Spanish moss.
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E37

I 

s 

\

\

\

Symbol, and percentage of total samples 

represented by symbol

50

40

30

20

10

O 3

I I

i i i i

s

VANADIUM, IN PARTS PER MILLION IN ASH 

Geometric mean, 91 

Geometric deviation, 1.73 

Number of samples and analyses, 123

0 100 200 300 400 500 MILES

I______|______I______|

I I I I I 

0 100 200 300 400 500 KILOMETERS

FIGURE 31. Vanadium content of Spanish moss.
E38 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

 \

V A~-~\

Symbol, and percentage of total samples 

represented by symbol

30

20

10

n

O

CO

-

-

|

3 

oo

1

CO

1

« 

05 CO

 

\/ « « e>J M 

YTTERBIUM, IN PARTS PER MILLION IN ASH

Geometric mean, 2.4

Geometric deviation, 1.81

Number of samples and analyses, 123

0 100 200 300 400 500 MILES

 I. I.I. '______I

0 100 200 300 400 500 KILOMETERS

FIGURE 32. Ytterbium content of Spanish moss.
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E39

I 

A~-~\

-M'

/ ''

a«

£ ~? j' *--T~-"\

/

L >x

"» t 13 M e

! ***/ -

\ 9 * <*P 9 ®o

\ft 3^ ^*°e

\ 

\

\

 r* ®« ^ 

1® 3« _ __»_ A J_

* / o 3 o/x3fez=i*^r^ "\®^

^._ v (4,

X V. "V(~\f

- y d. Q/

\ £? I

*?: F i

8 I

AT"!

"^P 0 \

o

Of

 »

s

v.

Symbol, and percentage of total samples

represented by symbol 

40

30

20

10

i 11

evj evj co in r-~ o ir> V *~ "~

YTTRIUM, IN PARTS PER MILLION IN ASH

Geometric mean, 25

Geometric deviation, 1.78

Number of samples and analyses, 123

0 100 200 300 400 500 MILES

i I______I______I______I______I

I I I I I 

0 100 200 300 400 500 KILOMETERS

FIGURE 33. Yttrium content of Spanish moss.
E40 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

\

Symbol, and percentage of total samples 

represented by symbol

30

= 20

10

0

I I I

g g

r » CM M 115

ZINC, IN PARTS PER MILLION IN ASH

Geometric mean, 1,235

Geometric deviation, 1.83

Number of samples and analyses, 123

100 200 300 400 500 MILES

 

0 100 200 300 400 500 KILOMETERS

FIGURE 34. Zinc content of Spanish moss.
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E41

\

w

30

20

10

Symbol, and percentage of total samples 

represented by symbol

O 9

o o to o o o

i CM CO lO

ZIRCONIUM, IN PARTS PER MILLION IN ASH

Geometric mean, 110

Geometric deviation, 2.12

Number of samples and analyses, 123

100 200 300 400 500 MILES 

_I

0 100 200 300 400 500 KILOMETERS

FIGURE 35. Zirconium content of Spanish moss.
E42 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

DISCUSSION OF RESULTS

Although most species of flowering plants are 

believed to absorb only minor amounts of nutritive 

elements through their leaves (Fried and Broeshart, 

1967, p. 119) and therefore must depend largely 

on absorption by roots, Spanish moss must obtain 

all nutritive elements by means of leaf and stem 

absorption. Some gases, including carbon dioxide, 

oxygen, sulfur dioxide (Berger, 1965, p. 232), chlorine (Berger, 1965, p. 248), and ammonia (Hutchinson and others, 1972), that come in contact with 

ordinary plant leaves are absorbed directly and are 

used in metabolic processes. These gases are thought 

to be similarly utilized by Spanish moss, although 

such utilization has not been proved experimentally. 

Particulate matter and materials in solution that 

become lodged on Spanish moss plants are analogous 

in function to the soil in which ordinary rooted 

plants grow. Analyses of Spanish moss samples reveal not only the chemical elements in the plant 

tissue but also those that are lodged on the plant 

surfaces, and the concentrations of elements in the 

two groups cannot be differentiated with certainty. 

Metabolic processes probably have only a minor 

effect on the concentrations of most elements discussed in this report. This effect may be largely 

the immobilization of certain nutritive elements in 

tissues of the plant, so loss of these elements through 

leaching by rainfall is reduced. However, both essential and nonessential elements may be held by 

chemical bonding to organic molecules in the plant, 

as was suggested by Goodman and Roberts (1971, p. 

289). Therefore, the action of Spanish moss in accumulating airborne materials probably consists of 

more than simple atmospheric filtration.

Dissemination of Spanish moss occurs most commonly by wind transport of vegetative fragments of 

the plant rather than by seed dispersion. Most 

masses of Spanish moss that were collected as 

samples probably originated from such fragments, 

and for this and other reasons they cannot be traced 

back to their origins or ages as individual plants. 

A sample of Spanish moss, a perennial plant, is a 

composite of tissues of different ages, and there is 

no practical method of determining the age of the 

oldest tissue that is included. The increase in mass 

of a plant of this type tends to be exponential rather 

than linear; therefore, the samples are weighted to 

a substantial but unknown degree in favor of tissues 

of more recent growth. Although the effects of this 

loading cannot be measured readily, they must be 

considered in evaluating the role of this plant as an 

integrator of time increments of airborne materials.

For these reasons, analyses of Spanish moss samples 

probably reflect most strongly the atmospheric burdens of recent months or years, although some portion of a sample may be 10 or more years old.

In order to determine if the morphological and 

physiological features which adapt Spanish moss to 

an epiphytic habitat result in accumulations of kinds 

and amounts of elements different from the accumulations in ordinary soil-rooted (terrestrial) 

plants, comparisons can be made by using data that 

are now available. A study of the chemical composition of soil samples from 912 sites throughout the 

conterminous United States (Shacklette, Hamilton, 

Boerngen, and Bowles, 1971; Shacklette, Boerngen, 

and Turner, 1971) did not report .analyses of the 

plants that were sampled concurrently with the soil 

samples. Summary analytical data for these plant 

samples and for Spanish moss samples are given in 

table 3.

The terrestrial plants that were sampled included 

a wide variety of life forms trees, shrubs, broadleafed herbs, and grasses as well as different plant 

parts. Element concentrations in these plant samples 

ranged widely; moreover, the suite of samples was 

heavily weighted in favor of woody plants (trees 

and shrubs). For these reasons, we believe that in 

comparing element concentrations in this heterogeneous group (terrestrial plants) with those of an 

entirely homogeneous group (Spanish moss), geometric mean values in Spanish moss are better 

compared with the central two-thirds ranges of the 

terrestrial plant analyses than with the geometric 

means.

The average percentages of ash obtained by burning dry plants of the two groups are very similar. 

However, the typical concentrations of aluminum, 

cobalt, chromium, gallium, iron, sodium, lead, titanium, vanadium, and zirconium in ash of Spanish moss 

samples exceed the upper limit of the expected 67- 

percent range in ash of the soil-rooted plants. The 

extremely high concentrations of lead in Spanish 

moss undoubtedly reflect the fact that most samples 

were collected at sites near highways. Some samples 

of Spanish moss had a greater concentration of one 

or more of the elements chromium, copper, gallium, 

lead, vanadium, and zirconium than was found in 

any sample of soil-rooted plants. One sample of 

Spanish moss contained 15 ppm germanium in ash, 

an element that is very rarely reported to occur 

in plants.

No element concentrations in Spanish moss were 

unusually low, although concentrations of the macronutrient elements potassium and phosphorus are 

near the lower end of the expected 67-percent range
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E43

TABLE 3. Chemical composition of Spanish moss samples and samples of soil-rooted plants from the conterminous United

States

[Geometric means and ranges of elements reported as parts per million in ash. GM, geometric mean ; GD, geometric deviation ; ratio, number of samples in

which the element was detected to total number of samples ; ....... no data available]

i Spanish moss

Element, 

and ash

Ag.............................

Al......................... ......

Ac

B................................

Ba.. ........................ ...

Be..... .........................

Bi......... ......................

Ca..............................

Cd.................. ............

Ce...............................

Co..............................

Cr...............................

Cu..............................

Fe..............................

Ga..............................

Ge... ...........................

Hg=............................

K................................

La..............................

Li...............................

Mg.............................

Mn.............................

Mo.............................

Na..............................

Nb... ...........................

Nd..............................

Ni.. .............................

P................. . ........ ...

Pb..............................

Sc...............................

Se=.............................

Sn..............................

Sr...............................

Ti...............................

V..................... ...........

Y.......... .....................

Yb..............................

Zn..............................

Zr........... ..................

GM

0.12

.79

560

7.9

9.8

16,000

...... 94,000

99

76

39

9,400

4,200

c Q

21

700

9 OHO

91

2.4

1,200

4.6

GD

5.42 

2.21 

1.55 

1.34 

2.32

i.56 

1.65

1.83 

1.73 

2.01 

1.87 

1.71

l"74 

3.80 

1.53

1.73 

2.60 

1.80 

4.05

1.46 

1.74 

1.55 

3.16 

1.89

I'isb

1.85 

1.96 

1.73

1.78 

1.81 

1.83 

2.12

1.46

Range

<1-20 

1,500->100,000 

<l-2 

70-300 

50-2,000

'2

18,000-320,000 

.8-27 

200-300

<7-70 

7-1,500 

20-2,000 

1,000-50,000 

<7-50

J 15 

<.5-.7 

6,000-200,000 

<50-150 

8-90

5,000-100,000 

200-10,000 

<7-20 

1,100-240,000 

15-20

J 150 

7-200 

2,400-48,000 

70-50,000 

<5-20

n 

20-30 

100-7,000 

150-7,000 

15-500

<20-150 

<2-30 

140-4,600 

<20-700

2.2-34

Ratio

16: 

120: 

54: 

123: 

123:

3:

123: 

122: 

3:

98: 

123: 

123: 

123: 

95:

1: 

8: 

123: 

36: 

122:

123: 

123: 

29: 

123:

4 

123: 

123: 

123: 

68:

4: 

6: 

123: 

123: 

123:

94 

91 

123 

121

123

123 

123 

116 

123 

123

123

:"l23 

: 122 

:123

:123 

:123 

:123 

:123 

:114

:123 

:116 

:123 

:123 

:122

;123 

:123 

:123 

:123 

:123

:36 

:123 

:123 

:123 

:100

:123 

:123 

:123 

:123 

:123

:123 

:123 

:123 

:123

:123

GM

6,500

240 

390

120,000 i"

.94 

9.6 

100 

3,600 

.20

130,000"

30,000 

1,100 

4.2 

4,600

32 

16 

20,000 

86

880" 

260 

11

450" 

14

5.3

GD

3.52

2.10 

3.75

£"69

5.83 

2.85 

1.98 

2.52 

9.83

1.82

2.05 

4.38 

3.94 

4.00

6.21 

2.84 

2.27 

6.17

3.78 

3.49 

4.15

2.73 

3.45

1.98

Soil-rooted plants

Range

<1-70 

<150->100,000

<30-3,000 

2-70,000

<2-100 

<20-30 

1,600-430,000

1,000-1,500

<5-300 

<1-700 

5-1,500 

100-70,000 

<3-30

8,800-450,000 

<50-1,500

1,000->100,000 

30-100,000 

<2-500 

400-360,000 

'30

<150-1,500 

<5-500 

1,600-400,000 

<10-15,000 

<7-30

<10-70 

<10-20,000 

<7-15,000 

<7-300

<10-700 

<1-70 

<25-5,800 

<20-500

.43-65

Ratio

88: 

1,109:

1,135: 

1,151:

8: 

4: 

988:

2:

232: 

1,096: 

1,153: 

1,153: 

150:

1,006: 

46:

1,120: 

1,153: 

459:

277: 

1

11 

1,028 

991 : 

980: 

43:

22: 

1,145: 

1,122: 

694:

161 

101 

642 

470

1,152

: 1,125 

: 1,117

:"l,150 

1,151

: 1,153 

: 1,125 

:988

:1,117

: 1,122 

: 1,139 

: 1,153 

: 1,153 

: 1,105

:"l,006 

: 1,125

: 1,153 

: 1,153 

: 1,124 

:277 

: 1,120

:50 

: 1,139 

:991 

: 1,145 

: 1,153

:"l,152 

: 1,152 

: 1,149 

: 1,123

: 1,128 

: 1,109 

:643 

: 1,152

: 1,152

Central 

67-percent 

range

1,900-23,000

110-500 

100-1,500

45,000-320,000

.16-5.5 

3.4-27 

51-200 

1,400-9,100 

.02-2.0

71,000-240,000

15,000-62,000 

250-4,800 

1.1-17 

1,200-18,000

5.2-200 

5.6-45 

8,800-45,000 

14-530

230-3,3.00 

75-910 

2.7-46

170-1,235 

4.1-48

2.7-11

VA11 analyses were the same in samples in which the element was detected. 

^Analyses reported on dry weight basis.

for soil-rooted plants and concentrations of magnesium and calcium are nearer the center of the 

range. Cerium, potassium, and niobium were the 

only elements that occurred at lower levels in a 

Spanish moss sample than in any sample of soilrooted plants represented in table 3.

The capability of Spanish moss to serve as a longterm integrator of local airborne element loads is 

suggested by data in figure 3. In most plant ash, 

tin generally occurs in concentrations below the 

limit of analytical detection, and tin was quantitatively recorded in only six of the 123 Spanish moss 

samples. Four of the six samples were collected in 

the Houston-Galveston area in Texas. Because all 

123 samples were analyzed in a sequence randomized 

with respect to geographic location, the probability 

of four samples in a localized area containing detectable concentrations of tin by chance alone is quite 

small. We hypothesize, therefore, that the atmosphere in this area carries unusually high concentrations of tin. This hypothesis seems confirmed by

the fact that a tin smelter, the only one in the 

United States, is located at Texas City, Tex. (Lewis, 

1971, p. 1066), across the bay from Galveston.

In order to characterize possible differences in the 

local airborne element load, analyses of five samples 

from each of four kinds of areas, classified according 

to their principal economic uses, were examined, and 

the elements that occurred in concentrations greater 

than the geometric mean are shown in table 4. More 

complete descriptions of the sample localities are 

given in table 1.

Table 4 shows that high concentrations of arsenic, 

cadmium, chromium, cobalt, copper, lead, nickel, 

and vanadium in Spanish moss samples occur in 

areas where high rates of vehicular and industrial 

emissions are expected.

The influence of ocean spray on sodium concentrations in the samples is indicated in figure 28. 

All samples (except one from Texas) that have 

greater-than-average sodium concentrations are 

from locations where airborne saltwater is expected
E44 STATISTICAL STUDIES IN FIELD GEOCHEMISTRY

TABLE 4. Elements found in concentrations greater than average in Spanish moss samples from four

kinds of sites

Locality 

(fig-3)

Locality

State County or 

parish Area Elements

Rural sites (agricultural and recreational uses)

32............Georgia.............................Irwin.....................................................................................Al, Ba, Fe, Mn, Sc, Li, and Zr.

35..................do...............................Glynn .............................St. Simons Island.......................B, Li, Mg, P, K, Na, and V.

59............Texas................................Karnes............................San Antonio River.....................Al, Cr, Ga, Fe, Sc, Ti, and Zr.

72............Florida..............................Dade................................Paradise Key......... .....................Ca, Mg, and Na.

294............Arkansas..........................Lafayette... ........................................................ ................Co and P.

Sites near highways with heavy traffic

213. ...

224.... . ...

233..........

250..........

268..........

...North Carolina. 

....... ..do. ..... ... ............

....... Robeson... ...... ............Interstate 95.... ... .......... ....Al, As, Cd, Cr, Co, Cu, Ga, Fe, Pb, Li, Ni, 

K, Sc, Ti, V, Yb, Y, and Zr.

........ .....Cd, Ca, Pb, Mg, Mn, and Zn.

.... . .Cd, Co, Cr, Cu, Ga, Fe, Pb, Li, Mg, Mn, Mo,

Ni, K, Sc, Na, Sr, Ti, and V. 

........ ......Al, B, Ca, Cr, Co, Ga, Fe, Li, Mo, Ni, Sc, Sr,

Ti, V, Yb, and Y. 

....... .......Ba, Cd, Ca, Cr, Co, Cu, Fe, Pb, Mg, Mn, Ni,

Sr, and Zn.

Urban sites (residential and business uses)

54............Florida.............................. Dixie...............................Cross City................ ......... ..Ca.

58..................do.................................Palm Beach...................West Palm Beach....................Ca, Na, and Sr.

71............Louisiana . ....... East Baton Rouge.... .Baton Rouge.............. Ha, B, Cd. Co, Fe, Mg, Mn, Ni, K, and Sr.

206-.........Florida-. .....................Manatee-..-.. ..............Bradenton............ .... ......Ca, Li, Mg, P, Na, and Sr.

243............Mississippi.- ..................Marion............................Columbia.................... ..Ba, Cd, Co, Fe, Mn, K, Sr, and Ti.

Urban sites (industrial and other uses)

201.. 

216.. 

230.. 

270..

287..

.Florida ..........

.South Carolina. 

..Florida....... ...

..Texas......... .

.Mississippi.

.Hillsboro........................ Limona industrial park...........As, B, Cd, Cu, Fe, Mo, Ni, P, Na, V, and Zn.

.Charleston......................Charleston..................... ...Cd, Cr, Co, Cu, Mg, Ni, Na, and V.

.Bay..... ..... ..........Panama Citv............ Al, Cd, Cr, Cu, Fe, Pb, Mg, Na, V, and Zn.

. Jefferson.............. ..-Beaumont .. Al, Ba, Cd, Ca, Cr, Co, Cu, Ga, Fe, La, Pb,

Ni, Sc, Sr, and Ti. 

.Adams........................ Near Natehez...... .............Ba, Cd, Cr, Co, Fe, Pb, Mn, and K.

to be present at times, and no sample that contains 

less-than-average amounts of sodium is from such a 

location. Elements that are common constituents of 

soil dust, such as aluminum, calcium, magnesium, 

and iron, are found in samples from all areas.

Multivariate statistical analysis methods are being 

used to provide further interpretations of element 

distribution patterns in these Spanish moss samples, 

and the results of this study are planned to be 

presented in a subsequent paper.

SUMMARY AND CONCLUSIONS

1. Airborne chemical elements, which are accumulated by many species of plants, may contribute 

to the nutrition of the plant or may produce toxic 

effects. These elements are carried as gases, solutes, 

or participate matter and may be actively or passively accumulated by the plant.

2. The concentration of airborne elements in the 

plant is thought to be determined by the concentrations present in air or airborne materials, the inherent ability of the plant to absorb the elements, 

the ratio of plant surface to total mass, and the 

length of time that the plant is exposed to the air.

3. Perennial plants which have a high surfaceto-mass ratio and which have no direct connection 

to the soil by means of a conductive system are 

effective integrators of airborne materials over time.

Analyses of lichens, mosses, and Spanish moss have 

been used to estimate the degree of atmospheric 

contamination.

4. Elemental analyses of Spanish moss samples 

collected from rural, residential, highway, and industrial locations reflect significant differences in 

concentrations of metals. Samples from industrial 

and highway locations can be characterized as containing greater-than-average amounts of arsenic, 

cadmium, chromium, cobalt, copper, lead, nickel, 

and vanadium. The high levels of lead found in some 

samples from highway locations are especially noteworthy. Of 123 samples analyzed, only six were 

found to contain tin; four of these grew in the 

Houston-Galveston area and are believed to reflect 

the presence, in the area, of a tin smelter, the only 

one in the United States.

5. Many samples from sites near the seashore 

contained greater-than-average amounts of sodium 

that is thought to have been derived from ocean 

spray. Samples from rural locations commonly contain low concentrations of the metals usually associated with urban or industrial activities.

6. Results of this study indicate that elemental 

analysis of Spanish moss can be used as an economical and rapid method of estimating the kind and 

relative concentration of airborne chemical elements 

among locations over a period of months or years.
AIRBORNE CHEMICAL ELEMENTS IN SPANISH MOSS E45

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* U.S. GOVERNMENT PRINTING OFFICE: 1973 O 543 576/8