Arsenic Toxicity Studies in Soil and in Culture Solution 1 
Harry F. Clements and Jerome Munson 2 
The problem of arsenic accumulation in 
soils is one of comparatively recent import¬ 
ance. As agriculture became more intensive, 
it became necessary to use poisons to combat 
attacks of certain insects, fungi, and more 
recently, weeds. Because arsenic is very 
poisonous to plant enemies and because it 
is comparatively cheap, it was only natural 
that it should have found general use. The 
arsenic so used has for the most part ac¬ 
cumulated in the upper soil layers, and 
sooner or later becomes a menace to crop 
production. This paper is concerned with 
this problem particularly with reference to 
Hawaiian soils. 
HISTORICAL REVIEW 
Early work .—Toward the end of the last century 
and the beginning of the present century, some 
attention was given to the possibility that arsenic 
might poison the crop itself. In 1894, Lyttkens 
conducted experiments at the Halmstead Experi¬ 
ment Station in Sweden which showed plainly that 
the arsenic in the soil is a strong poison to plants. 
Stoklasa (1898), however, showed that while 
arsenic could not replace phosphorus as an essen¬ 
tial element, it had stimulative effects on the de¬ 
velopment of the assimilation organs of the oat 
plant. The issue thus became confused. While 
some presented evidence that arsenic was a poison 
to plants, others presented equally convincing evi¬ 
dence that arsenic stimulated plant growth. Bouil- 
hac (1899) reported that a number of fresh-water 
algae absorb arsenic acid from arsenates without 
apparent injury, and the growth of one appeared 
1 Published with the approval of the Director of 
the University of Hawaii Agricultural Experiment 
Station as Technical Paper 156. Manuscript re¬ 
ceived February 15, 1947. 
2 Dr. Clements is Professor of Botany and Plant 
Physiologist, University of Hawaii Agricultural 
Experiment Station. Mr. Munson was formerly a 
graduate assistant in botany. University of Ha¬ 
waii; his master’s thesis, now in the University 
Library, is incorporated in the present paper. 
more favorably influenced by arsenic acid than by 
phosphoric acid. 
The fact that arsenic is a natural component of 
most soils and not uncommon in plants tended to 
reduce the force of criticism against the use of it. 
Zuccari (1914), working in Italy, analyzed 20 soil 
samples varying in physical and chemical compo¬ 
sition and taken from different depths in different 
geological formations and at varying elevations; 
these samples showed an arsenic content varying 
from 0.187 to 6 parts per 100,000 of soil, being 
largest in soils containing the most iron com¬ 
pounds and varying almost directly with iron con¬ 
tent. 
Reichert and Trelles (1922) analyzed 20 soils 
from different parts of Argentina and found all 
but one to contain arsenic, varying in amounts 
from 0.1 to 2.25 mg. per 100 gm. of soil. 
Williams and Whetstone (1940) analyzed a 
wide range of soils for arsenic and found the 
range of naturally occurring arsenic to be between 
0.3 and 40 ppm. Vegetation found growing on 
these soils ranged from less than 0.1 ppm to 10 
ppm. 
Greaves (1934) analyzed, for total arsenic, 
water-soluble arsenic, and various soluble salts, 
50 orchard soils which had been in cultivation for 
some time and which varied widely in chemical, 
physical, and biological properties. Total arsenic 
varied from 7.2 to 367.2 pounds per acre foot. 
The water-soluble arsenic varied from 0.7 to 31.9 
pounds per acre foot. 
Greaves (1913*0 earlier reported that some vir¬ 
gin soils contain arsenic in appreciable quantities 
which comes from the decay of native rocks. Many 
cultivated orchard soils contain it in large quanti¬ 
ties, but he found no uniform relationship between 
the total quantity in different soils and the water- 
soluble arsenic of these soils. He considered that 
the solubility of arsenic is governed largely by the 
salts in the soil and the form in which the arsenic 
is applied. 
Thus, with comparatively high arsenic amounts 
not uncommon as natural components of soils, 
opinions on the danger from the use of compara¬ 
tively small additions continued to be diverse. 
Headden (1909) was perhaps the first to recog¬ 
nize the serious dangers which may accrue to or¬ 
chard trees from continued use of arsenical insec¬ 
ticides. In fact, he set off a heated controversy 
which has raged ever since. In other reports 
(1908; 1910), he recognized three types of poison- 
C151] 
