160 
PACIFIC SCIENCE, Vol. I, July, 1947 
TABLE 6 . BEAN 
Data for the accumulation of arsenic (as ppm 
As 2 0 3 ) and phosphorus (as per cent of dry 
weight), as well as dry weights, of plants 
GROWN IN SOLUTIONS CONTAINING VARIOUS IN¬ 
CREMENTS OF TRIVALENT ARSENIC (AS SODIUM 
ARSENITE) AT DIFFERENT PHOSPHORUS LEVELS. 
ARSENIC 
IN 
SOLUTION 
DRY 
WEIGHT 
ARSENIC 
IN 
PLANT 
PHOS¬ 
PHORUS 
IN PLANT 
ppm AS2O3 
gm. 
ppm AS 2 O 3 
% dry wt. 
Low phosphorus level (P = 10 ppm) 
0.000 
42 
trace 
0.53 
.038 
49 
trace 
* .47 
.075 
58 
trace 
.44 
.113 
49 
0.9 
.44 
.150 
41 
1.2 
.50 
.263 
27 
0.9 
.69 
.375 
25 
2.1 
.63 
.488 
26 
2.1 
.56 
.600 
23 
3.9 
.63 
.750 
30 
3.7 
.50 
Medium phosphorus level (P = 
60 ppm) 
0.00 
36 
trace 
.70 
.3 
3 4 
trace 
.70 
.49 
27 
trace 
.63 
1.05 
27 
1.3 
.63 
1.65 
15 
4.8 
.69 
2.25 
6 
4.9 
.69 
2.85 
5 
7.0 
.66 
High phosphorus level (P = 120 ppm) 
0.00 
31 
trace 
.63 
.15 
31 
trace 
.72 
.49 
30 
trace 
.59 
1.13 
15 
trace 
.66 
2.25 
5 
3.3 
.75 
than they are when applied to culture solu¬ 
tion. The degree to which arsenicals are 
fixed by the soil is a characteristic of the soil 
(Crafts and Rosenfels: 1939). The objec¬ 
tives of this part of the work are: first, to 
determine the growth reaction of certain 
crop plants to arsenic levels in two Hawaiian 
soils; second, to determine the amount of 
arsenic which these plants withdraw from 
the soil; and third, to determine whether or 
not it is practicable to use certain crop plants 
to lower the arsenic levels of those soils 
which have been rendered sterile to other 
crop plants. 
Methods .—Two soils were used—one a red 
residual clay and the other a black alluvial 
soil. The red is a residual soil taken from 
the mountain slopes above Kailua, Oahu. It 
is an infertile soil which requires heavy fer¬ 
tilization for crop production. The black 
alluvial soil, taken from a papaya orchard 
near Kailua, is, on the other hand, ex¬ 
tremely fertile. In fact, it was recommended 
to us by Dr. L. A. Dean, Soils Chemist, as 
being a soil whose available phosphorus 
level was so high that no more phosphorus 
could be fixed by it. 3 The growth of plants 
in the two soils reflected not only the differ¬ 
ence in chemical composition, but also the 
difference in physical qualities, the black 
soil being very well adapted to pot work. 
These soils contained 14.7 ppm of native 
arsenic. This amount is added to the incre¬ 
ments of soil arsenic shown in the accom¬ 
panying tables. 
The soil was dried thoroughly, screened, 
and ground in a plate mill. Samples of 500 
grams each were weighed into No. 2 cans, 
after which arsenic as sodium arsenite was 
added in concentrations varying from 10 
ppm to 3,000 ppm following the methods 
described by Crafts and Rosenfels (1939). 
The soil was allowed to dry thoroughly, 
after which it was removed, pulverized again, 
mixed, and returned to the can. 
With the red soil, triplicate cans were 
used for each arsenic concentration for each 
of the three species, making a total of 225 
cans. With the black soil, only one container 
was used for each of the two species used 
for each concentration of arsenic. 
Tomato and Sudan grass seedlings were 
started on cheesecloth and transplanted to 
the cans when a few days old. Bean seeds 
were germinated in black sand and trans¬ 
planted to the cans as soon as possible. With 
tomato and bean, two plants per can were 
used, and with Sudan grass five plants. 
Drainage was provided by punching holes 
in the cans. A complete nutrient solution 
3 The phosphorus content of the two soils as ex¬ 
tracted with 0 . 002 N H 2 SO 4 was 24 ppm for the 
red soil and 250 ppm for the black soil. 
