Document 7MVkQw1QoGGb532KQj3zG5REo
FILE NAME Kent KNT DATE 1950 May 4
DOC KNT118
DOCUMENT DESCRIPTION Journal Article - The Arsenic Content of Tobacco and of Tobacco Smoke - British Journal of Cancer
173 -182
THE ARSENIC CONTENT OF TOBACCO AND OF
TOBACCO SMOKE
M. E. DAFF AND E. L. KENNAWAY
From the Pathological Department St. Bartholomew's Hospital London E.C.1
Received for publication May 4 1950
PREVIOUS INVESTIGATIONS
Two recent investigations both from the United States upon the arsenic content of tobacco and the volatilization of this arsenic when tobacco is smoked have been reported The work of these authors differs from our own in that they used artificial methods of combusting the tobacco which may or may not repro- , duce the conditions present when smoking is carried out in the ordinary way and they found no brands of tobacco containing only minimal quantities of
arsenic
The Arsenic Content of Tobacco
1 Gross and Nelson 1934 employed a method which consisted of digestion
in nitric and sulphuric acids precipitation of magnesium ammonium arsenate
"
solution in hydrochloric acid and estimation by the Gutzeit method
The
analyses were made on analytical units composed of either 1 cigar 5 cigarettes
_ or 5 g smoking tobacco Five such analytical groups were analysed for each
brand studied They found the content of pooled groups of 4 cigarettes of 5
brands to range from 9.7 to 36-3 p.p.m. Table I while individual cigars showed
a wider range 8-3 to 48-4 and pipe tobacco a smaller one 26.0 to 50-0
2 Thomas and Collier 1945 using a modified Wichmann method
found that " individual cigarettes and cigars of a given brand varied widely in
arsenic content which ranged in pools of 2 to 4 cigarettes from 2 packs of 20
presumably of the same brand from 35-4 to 114 p.p.m. while cigars 13.2 to
29.5 and pipe tobaccos 22.7 to 42.8 showed a lower range Table I
Thus the cigarettes used in these two investigations showed nearly a 12fold range 9.7 to 114 p.p.m. in mean values Gross and Nelson 1934 attribute the rather narrower range found in cigarettes and in pipe tobacco compared with
cigars to the mixing which the former receive but this difference is not seen in the results for cigarettes and cigars of Thomas and Collier 1945
The Arsenic Content of Tobacco Smoke
Apparently the first estimates of the arsenic volatilized from tobacco were made by Remington 1927 who found 6 to 30 p.p.m. in American pipe and chewing tobaccos using suction by a pump he concluded that we can say roughly that half of the arsenic is evolved in the smoke "
Gross and Nelson 1934 used an apparatus drawing about 50 ml of air
through a cigarette cigar or pipe at the discharge of a syphon which took place
174
M. E. DAFF AND E. L. KENNAWAY
TABLE Arsenic Content of Tobacco Gross and Nelson 1934 Collier 1945.
Thomas and
Gross and Nelson : Cigarettes
Cigars Pipe tobacco
Brand
1 2 3 4 5
1. 1-4
As pOarts per million
Means of brands
Range in 5 pooled batches of 4 cigarettes
each :
20.7 to 25-6
'
22.9
21.1 " 26.7
.
24.1
25-3
36-3
:
33.2
.
"
9.7 " 13.0
.
11.6
22.9
26.1
:
24.7
.
25
Range in 5 single cigars from each of 5
brands :
8.3 to 48.4
. 11.6
20-6
.
. Range in 5 samples from each of4 brands
26.0 to 50.0
31.1 45
Thomas and Collier :
Cigarettes
A single pack of 20
.
* Groups of 2 to 4.
35.4 40.0 40 47.2 60 61
*
Another pack .
Cigars about
1-4
.
61.4 67.0 71.4 84.5 114.0 13.2 22.5 26-2 29.5
10 cut off at
ends
Pipe tobacco
1-5
.
39.6 26.5 22.7 34.5 428
a
* These figures reprosent the actual analyses in p.p.m. on pooled groups of 2 to 4 cigarettes and hence are not calculated means though each figure represents the mean composition of the cigarettes
in one pool
three times a minute
Cigars and cigarettes were smoked down to about
"
"
1/2 in to 3/4 in 2. . " the arsenic in the puffed and unpuffed
smoke was absorbed and estimated separately The mean distribution of the
arsenic recovered in the smoke ash and butts is shown in Table II Pipe tobacco
was combusted until no residue but ash was left while about 22 per cent of the
cigars and cigarettes remained in the butts The fraction in the puffed as against the unpuffed smoke is high in the case of pipe tobacco which difference is attributed to " the dying down of the ember between puffs
TABLE Arsenic Content of Tobacco Smoke Gross and Nelson 1934 Thomas and Collier 1945.
Mean distribution of arsenic recovered
Arsenic volatilized
Gross and Nelson :
Cigarettes 5 brands .
Cigars 5 brands
.
Pipe tobacco 4 brands
L
Unpuffed Puffed
smoke smoke
1
2
70
%
. 12.3
11.0
: 5.6
5.5
-
4.6
25.9
Total smoke
3
%
23.3 11.1 30.5
Ash Ash
4
%
48.6 60-6 69.5
.
ButiButsis
5
%
28.1
.
28.3
oe.
or
c
ty
Range
Range
Mean Mean
6
7
%
%
32.2-41.3 15.1-34.7 26.1-32.8 26.1-32.8
36-1 23.0 30-6
Thomas and Collier :
Cigarettes 6 : brands
1st series
.
.
.
15+
==
: 337 SEE .
ve
2nd
. . 15+ == 19 337 SEE
.
"
3rd
15+ .
.
.
10
14
337
SEE
. .
.
355
:
Cigars 4 brands :
1st serios
.
4247
7822
11
3338
500
an
2nd
.
'
4247
7822
15
3338
8
.
3rd
: : : 4247
7822
14
3338
500
an
Pipe tobacco 4 brands
4247
23
:
+
. cee
72
90
90
100
ARSENIC CONTENT OF TOBACCO
175
Gross and Nelson 1934 devote a good deal of attention to the arrest of
volatilized arsenic in the butts indicated by the amounts assumed to be present in
the corresponding portion of the original cigar or cigarette By such calculations
they arrive at the figures given in the 6th and 7th columns of Table II which
66
are of course higher than those in Column 3.
The pipe smoker who smokes
all the tobacco does not therefore have the protection afforded by the butts of
cigars and cigarettes From the present point of view this question is not of
great interest ; the important datum is the amount of arsenic inhaled and in this
country only about one smoker in ten smokes a pipe Hansard 1945
-
Thomas and Collier 1945 used an apparatus similar to that of Gross and
Nelson 1934 which pumped 10 to 50 ml air during 1-2 seconds at second
intervals In their first series Table II cigarettes of 7 cm length were smoked
down to 1 cm in a later series only 2/3 was burned At first
.
the
arsenic found was compared with analyses of whole cigarettes from the same
pack but in view of the large differences they later cut off about 0.8 cm for
analysis ; apparently they failed to discover that this method also can be falla-
cious The first and second series show very little difference in the percentages
although in the first 10-20 ml and in the second 50 ml was drawn through
at each puff The results are in general agreement with those of Gross and
Nelson 1934 whose cigarettes contained considerably less arsenic Table I
METHODS
Gutzeit Method
Our earlier results Table IV were obtained by the Gutzeit method which depends upon the brown and yellow colours produced in paper impregnated with HgCl ; is fitted for the measurement of amounts of As between 10 and 1 g and shows differences most clearly in the range of 8 to 3 g There may be considerable differences in the matches made by different persons ; in these experiments the mean was taken of the readings made independently by two persons
unaware of the nature of the unknowns The iodometric method of Thomas and
Collier 1945 was adopted later Tables III V and VI in view of the difficulty of determining the small amounts of arsenic lost in smoking The method has the advantage that whatever may be its errors in other respects there is less disagreement over the very sharp point titration of iodine and starch about which two observers usually do not differ by more than 0.05 c.c. 0-5 g
while in the Gutzeit method greater differences are common Before we had observed the differences in arsenic content which may be
.
found within a single cigarette three successive pieces were cut from a cigarette
of Brand - weighing 0.1499 g B 0.1527 g and C 0.1429 g To the middle
piece B was added 1 ml of the standard solution = 10 ug As
0Gutzeit
estimations upon the whole of A and C and upon 1/2 of B gave about 7 gin
each one hence if this cigarette happened to be of fairly uniform composition
about 14 gor 82 per cent out of 17 gwas recovered Gutzeit method is described under " Other Brands " below
Another test of the
Method of Thomas and Collier 1945
The estimations upon Brands P and C were usually carried out upon amounts
of 20 to 30 gas a method which is sufficiently accurate within this range
176
M. E. DAFF AND E. L. KENNAWAY
allows of duplicate estimations upon single cigarettes containing 40 to 60 g
The method and apparatus of Thomas and Collier 1945 were tested using the
standard solution of As
1O0 gin 1 ml either alone or added to an aliquot
part of a solution containing a combusted cigarette or ash and stump Table III
TABLE Percentage Recovery of Arsenic by Method of Thomas and Collier 1945
Arsenic pg
100
50
30
20
10
Standard solution alone :
Number of estimations
:
Range
:
:
.
.
Mean
:
.
.
.
.
11
.
2
.
4
.
6
.
4
. 90-2-99.0 . 85.0 94.0 . 87.4-92.4 . 90-0-107.5 . 98-0 105-0
94.6
.
89.5
-
90.3
.
97.5
.
100.25
Standard solution -+ combusted
cigarette or ash and stump :
Number of estimations
:
6 5 .
.
an
.
.
Range .
.
.
.
an
.
os
. 77.5-88.5 . 74.0-100.0
Mean
.
.
.
:
.
.
.
.
we
.
83.2
:
87.0
With the pure solution the results were less accurate with the higher amounts
30 to 100 g than with the lower 10 to 20 ug though with the latter the titra-
tion error is of course considerable as 0.05 ml ****** 0.5 g Cassil and Wichmann
"
"
1939 claim
. . . an average recovery of 99.5 per cent of amounts from
5 to 500 pg In the presence of the combusted products the recovery is less
complete between 80 and 90 per cent Gross 1933 has drawn attention to the
occurrence of such errors in the estimation of arsenic in tobacco which are
attributed to uncombusted residues of pyridine and nicotine ; we failed to obtain satisfactory results by the method which he devised to overcome this difficulty Fortunately the defect was of the same order with both the smoked and unsmoked material so that the measurement of the arsenic volatilized was not affected
ARSENIC CONTENT OF CIGARETTES AND OF ASH AND STUMP
In the previous investigations summarized above artificial methods of smoking
were employed air being drawn through a pipe cigar or cigarette by means of a
pump This process might be fallacious as there is no warrant that the
apparatus reproduces the conditions present when tobacco is smoked in the usual
way We have confined our experiments wholly to cigarettes smoked by one or
other of three persons accustomed to this form of smoking and they were asked
to do this in their ordinary way ; the two brands used P and C are in common
use in this country The ash and stump were dropped into separate weighing
bottles in our earlier experiments but latterly the two have been analysed
together ; the amount of arsenic found if less than that in the cigarette should indicate the amount volatilized in the smoke of which a part must have been
inspired But actually the problem is by no means simple the difficulty being
to ascertain the arsenic content of the cigarette originally Table IV
The data in Table IV show that the amount of arsenic As
O g in whole
cigarettes or in portions of these from 5 packages of one brand P ranges from 24 to 106 and in one package from 56 to 106 while Brand C shows a smaller
range 28 to 61 Hence it is impossible to infer the arsenic content of cigarettes about to be smoked unless the average of a very large number is ascertained
Before this width of range was realized we obtained many contradictory results
showing amounts in the ash and stump which were sometimes less and sometimes
more than that thought to be present originally
ARSENIC CONTENT OF TOBACCO
177
TABLE Range of Arsenic Content in Two Brands of Cigarettes Method See also Tables V and VI
Gutzeit
Brand P
& Whole cigarettes
.
.
.
.
9 Cigarettes 7 wholes and 2 halves .
:
5 Pieces from 3 cigarettes
.
.
.
1 Piece from each of 4 cigarettes
.
:
6 Successive pieces cut from 1 cigarette
.
Package and
number of
cigarettes
.
A 100
:
~ B 20 .
:
C 10
.
:
D 20
.
.
D 20
.
13 Estimations on mixed tobacco of 10 cigarettes
Range in 5 packages of Brand P
.
.
E 10
.
As O ...g
As
O
Range
49.5-76.6 55.9-106.2 27.2-34.3 35.8-59-7
Mean
.
67.8
-
82.3
.
30-7
-
49-6
58.4 51.9 41.5 58.4 2
58-7 38-8
|
23.9-31.9
6
23.9 10623.9 106
46.1
27.5
my
Brand C.
10 Pieces from 5 cigarettes
:
:
.
5 Successive pieces cut from 1 cigarette
-
A 20
:
33.4-61-5
.
A 20 54-2 43-1 51-8 30 .
51.0
20 11 Estimations on mixed tobacco of 10 cigarettes
28.3-50-3
.
9"
00
7
Range in two packages of Brand C
. A and 40
28-3-61.5
51.3 46.1
38.5
These results are reckoned as gg in order to give a uniform basis of comparison But as the weight of most cigarettes does not differ very much from one gram the figures give a rough measure of the arsenie in one cigarette which is of moro obvious practical interest A quantity expressed
interest
as gg is numerically the same as parts per million
70- 70-
60-
50-
a
aw
lm
20 10-
FIG Consecutive analyses of cigarettes and of ash and stump Cigarette Ash and stump
Brand P.
cigarette The Gutzeit method enables an estimation to be made upon 1/5 to 1/10 of a
cigarette such as those of Brands P and .. We therefore cut off such portions for analysis from cigarettes of which the remainder was smoked in the manner described The results were again contradictory and we found that such suc-
cessive portions may show a range of 38-8 to 58-7 or 100 151 in P and of 30.6 54-2 or 100 177 C Table IV
In the hope of obtaining more uniform material the papers were removed
from the cigarettes of a package of 10 or 20 and the tobacco mixed by hand and
178
M. E. DAFF AND E. L. KENNAWAY
minced with scissors Cigarettes were made by rolling this tobacco in papers in a machine a filter being inserted at one end to keep the contents from falling out But even this treatment does not give satisfactory results it is very
difficult to take up samples of such material which will contain constant propor-
tions of the coarser and finer particles as the latter tend to fall away from the
former the tobacco would have to be ground to a powder similar to snuff to
;
secure uniformity
The analyses ranged in the ratio of 100 133 in P and of
100 178 C. Moreover the minced tobacco even when moistened is not easy
to smoke in the same way as ordinary tobacco
; Adjacent cigarettes of Brand P from a much larger package containing 100
were taken but these at first showed a wide range 49.5 to 76 Table IV After
2
the adoption of the method of Thomas and Collier 1945 in place of that of : <4
a row in this box of more uniform composition this
Gutzeit we came upon
of the former method
change cannot be accounted for by the greater accuracy
Successive single cigarettes or pairs were combusted as such or smoked alter-
nately The analyses of 30 consecutive cigarettes Table V and Fig 1 showed
TABLE Consecutive Analyses of Cigarettes and of Ash and Stump Method of Thomas and Collier 1945
As O g
Cigarette
48.3 48.6 51.3 52.7
Ash and stump
. 46.7 . 41.1 : 43.0 . 471
41.3
:
35.4
46.7
.
51.7
50.5
.
47.0
62.9
.
44.7
55.8
:
40.5
51.8
:
40.5
48.2
.
45.2
40.2
.
30-8
60-5
:
39.6
56.1
.
46.0
42.7
.
39.2
Brand P.
Mean
50.5
.
Loss per cent -- 15.8
42.6 P === 001
the that an
of 15.8 per cent of the arsenic is lost in the process of smoking
average
been volatilized this loss is statistically significant P -
and had presumably
to Brand C of which the largest boxes
0.001 The same method was applied
in 18
a loss of only
available contained 50 the first two rows showed
cigarettes
which was not statistically significant P = 0.2 The first two
7.6 per cent
of more uniform composition and showed
rows of another box Table VI were
in 22 cigarettes a significant loss of 13-7 per cent P = 0.01 Three cigarettes
in the 3rd row taken for ashing yielded exceptionally large amounts of arsenic
ARSENIC CONTENT OF TOBACCO
179
4.
g 3
ae mean of 3 = 63
g this figure is 40 per cent above the mean of the other
cigarettes ashed from this box which caused the mean amounts in this row to be
actually greater by 5.4 per cent in the ashed than in the unashed cigarettes
70
60- 60- 60-
NAY
YT
K
/ AL
Upper left
| Lower left
q
!
Upper right
Lower right
Fig Consecutive analyses of cigarettes and of ash and stump Cigarotte Ash and stump
Brand C.
TABLE Consecutive Analyses of Cigarettes and of Ash and Stump Brand C. Box of 50. Method of Thomas and Collier 1945
As 0 As 0 gg
rr
Ash Cigarette
and Loss per P.
.
stump
cont
Upper left row
so
As.0 ...g.fg....g.fg.
Cigarette Ash and stump Upper right row
en
Loss per
cent
56.4 51.6
56.7
53.6 60.7 40.6
36.6
52.1
44.1
48.4
41-6
oe
55.2
ve
62.9
|
66.2
45.3
36.7
59.6 42.7 41.2
f 63.1
.
Mean:
53.3
46.3
13.1
0.1
51.9
2
54.7
. Lower left row
Lower right row
52.7
52.7
50.7
63.4
44.5
45-5
43.6
36.7
53.9
|
33.2 44.3
50.9
31.5
55.3 49.1 15.0
Both left rows
Or
68.3 47.7 2
13
13.7
0.1 0.01
50-5 . 41.3
Whole box ey 53-2 47.5
18.2 18.2 10.7
0.05 0.01
180
M. E. DAFF AND E. L. KENNAWAY
05 The 4th row showed a loss of 18-2 per cent which is just significant P =
in spite of the small numbers 12 cigarettes involved The analyses upon the whole box showed a significant loss of 10.7 per cent P = 0.01 The whole course of the analyses on this box is shown in Fig 2
Several estimations on from 10 to 20 cigarette papers whether bought in
packetosr taken from cigarettes gave amounts between 0.75 and 2 ghence -
the quantity in a single cigarette is negligible The papers and cork from 10 C cigarettes gave 1.25 ug
BRANDS OTHER THAN ENGLISH
Cigarettes of thirteen other brands were examined some by the Gutzeit method and some by that of Thomas and Collier 1945 Three known American _
brands gave figures 25 to 47 g rather lower than the means 50 to 55 gg
of the English brands P and C Table VII All the eight Turkish brands showed
TABLE Brands other than English
American :
Brand
Number of cigarettes
As
uOg per g
Brand A
.
:
:
:
126
.
35-2
F
,
.
:
.
126
:
41 47.0
> Bs
126
.
30-0 25-3 26-3 26.9 31.2
Turkish : Brand
1 in two portions
4 whole
1 in two portions
2 whole
Ni ash + stump
1.03 mil 4.3 nil ash +
stump nil
.
0.5 1.9
4.0 1.08
108 1-0 0-9
2.1
1.1
1
0.5
Nil
3.4
French
:
1.5 ? Rhodesian
.
.
.
* i.e. colour not distinctly different from that of blank
very low amounts nil to 4 g and similar results were given by a packet brought from France and by cigarettes supposed to contain Rhodesian tobacco After these results were obtained we came upon a short note by H. Popp 1928 of Frankfurt a M. giving the following results :
Arsenic p.p.m.
Tobacco from the Palatinate .
.
.
5.1
Macedonia cigarette tobacco
0.7
Java .
.
.
.
.
.
0.33
Brazil
.
.
.
4.6
He comments upon the much higher figures of Remington 1927 and suggests the possible importance of insecticides
The possibility was considered that the very low results given by Turkish cigarettes were due to some constituent having an inhibiting effect on the re-
ARSENIC CONTENT OF TOBACCO
181
actions Two portions weighing a 0-25 and b 0-24 g were cut from a Turkish cigarette and to b was added before combustion 0-8 ml of the standard solution containing 8 gAs 03The Gutzeit method gave in a an amount not different from that of the blank and in b 7 gAs^ z
DISCUSSION
The most likely source of the arsenic present in some tobaccos which has been
suggested by several authors is the spraying of the adult plants with insecticides
and this particulate method of application would explain the difficulty in obtaining
concordant analyses If the arsenic were absorbed by the roots one might expect
a more uniform distribution In some areas the seedlings only are sprayed and
presumably this arsenic is lost in the course of transplantation and further growth
We are obtaining data about the use of arsenical solutions in the areas where the
tobaccos examined are grown
Of the arsenic volatilized in smoking a part must escape while the cigarette
is not in the smoker's mouth and a part of what he inspires is expired again
hence the amount retained is no doubt very small We have no data about the
size of the particles in which the arsenic is carried The problem differs from those
of other inhaled substances in that the nasal cavity which is especially adapted
to arrest particles is not involved in inspiration The percentages of arsenic
volatilized in these experiments 7.6 to 18-2 are similar to those recorded for
cigarettes by Thomas and Collier 1945 mean 14 and 19 lower than those of
Gross and Nelson 1934 mean 23-3 and much lower than that of Remington
1927 50 If a person smokes 50 cigarettes with a mean arsenic content of
50 gand 15 per cent of this escapes he has volatilized 0.375 mg As
wOhich
is the amount contained in 0-0375 c.c. of Fowler's solution official dose 0-125
to 0-5 c.c.
SUMMARY
The arsenic content of 15 brands of cigarettes has been estimated and a range
from nil to 106 ugg As hOas been observed ; the lowest amounts were found
in nine brands classed as Turkish French and Rhodesian The concentration
of arsenic in cigarettes containing the larger amounts is very variable; this
irregularity is perhaps due to a method by which the arsenic may have been introduced namely by the spraying of the plants with insecticides An estimate
was made of the amount of arsenic volatilized in smoking by comparing th"
: content of cigarettes and of the ash and stumps derived from them but the wide range of arsenic content makes it difficult to infer the amount present originally
in a cigarette which is to be smoked The results indicated that from 7.6 to 18.2 per cent of the arsenic present was lost in smoking ; this figure is of the same
order as but somewhat lower than that obtained by some previous investigators
who have used artificial methods of smoking
We wish to express our thanks to the British Empire Cancer Campaign the
Anna Fuller Fund and the Jane Coffin Childs Fund for Medical Research for
grants We are much indebted to Mr. Frank Goulden A.R.I.C. for advice upon the estimation of arsenic
M. E. DAFF AND E. L. KENNAWAY
REFERENCES
CASSIL C. C. AND WICHMANN H. 1939 J. Ass Off agric Chem Gross C. 1933 Ind Eng Chem Anal Ed 5 58 Idem AND NELSON O. 1934 Amer J. Publ Hith 24 36 Hansard 1945 Parliamentary Debates 407 626 Popp 1928 Z. angew Chem 41 838 REMINGTON R. 1927 J. Amer chem Soc 49 1910 THOMAS M. D. AND COLLIER T. 1945 J. Industr Hyg Toxicol
Wash 22 27 201
436