instrumental neutron activation analysis of fly ash, aerosols and hair

Journal of Radioanalytical Chemistry, Vol. 54, No. 1-2 (1979) 311-324

Nuclear Methods in Environmental Science

INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS OF FLY ASH, AEROSOLS AND HAIR

I. OBRUSNIK,* B. STARKOVA.,** J. BLAZEK,** V. BENCKO***

*Nuclear Research Institute, 1~ e~ near Prague **Air Engineering Research Institute, Prague

***Medical Faculty of Hygiene, Charles University, Prague (Czechoslovakia)

(Received April 24, 1979)

Samples of coal, slag, emissions retained on the separating devices, fly ash, aerosols and hair taken in the area of coal-fired power plant were analyzed by means of instrumental neutron activation analysis. 13 to 23 elements were determined in the samples. The data obtained for emissions and aerosols were further evaluated by calculation of enrichment factors, correlation coefficients and by the ratio matching method. The concentrations of elements determined in the hair of exposed group were compared with the data of control and out control groups as well as with the recent data found for hair in other countries. It can be seen from the results that arsenic is the most serious pollutant in the area.

Introduction

With the continued pollut ion of the biosphere as a result of discharges from

fossil-fuel combustion units, product ion of chemicals etc. man is exposed to a pos-

sible danger of contaminat ion which might give rise to large-scale harmful somatic

or genetic effects. Recently, increased values of arsenic content in the hair of

children were found in the vicinity of a power plant in the locali ty N1 in Czecho-

s lov~ia . 1 This power plant has burned a local coal of high arsenic content. Des-

pite the use of separating devices, the plant has been the main source o f pollu-

t ion in this area.

The aim of this s tudy was to investigate the relation between the elevated ar-

senic content in the hair of a non-occupationally exposed populat ion and the com-

posit ion of emissions and aerosols discharged by the plant. For this purpose, we

have analyzed various types of samples (coal, slag, emissions collected on mecha-

nical (MSD) and electrostatic (ESD) separating devices, fly ash, aerosol and hair)

Z Radioanal. Chem. 54 (1979) 311

I. OBRUSNiK et al.: INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS

taken in the area N 1. In the case of the hair analysis, a control group of boys (area N 2) was selected. Moreover, hair samples taken from greater Prague residents were analyzed as "out control" samples.

Instrumental neutron activation analysis (INAA) has been used as an analytical tool in this study. Besides arsenic, 12 (hair) up to 22 elements (emissions) have been routinely determined in above mentioned kinds of samples.

Sampling area

The coal-fired power plant studied has been situated in a valley located in northeast to southwest direction, surrounded by ranges (altitude 700-1100 m) covered with forests. A chemical factory producing carbide is located in the neighbourhood of the power plant. The combustion product of the power plant are discharged into air by two stacks with heights of i00 and 150 m. The plant is equipped with two-step separating device (MSD and ESD). Both samples of emissions and aerosols from 19 sampling stations were taken in this area. The power plant locality N 1 with code numbers of aerosol sampling stations is shown in Fig. 1.

Sampling

Stack emissions

The samples of emissions were taken both directly from hoppers of mechanical and electrostatic separating devices and from a smoke duct after passing through ESD. Sampling from gas flow was done by means of a heated isokinetic tube with dust collector equipped with fibrous filter. For comparison purposes, samples of coal used and slag were also analyzed.

Aerosols

The samples of aerosols were taken in different sampling stations (see Fig. 1) in the neighbourhood of the power plant. Samples were collected by pumping air through 60 mm diameter nitrocellulose ultrafilters (Synpor 3 - produced in Czecho- slovakia) of 1.S/am pore size by a vacuum pump. The dust concentration was determined from the difference of the weights of filters prior and after sampling. The amounts of aerosol collected on the filters varied from 2 to 20 mg. A face velocity of suction was 50 cm/s (5 m 3/h). The samples were taken 1.8 m above ground in the direction of the stack plume, i.e. downwind of the emission source. The sampling was made up to 10 km distance from the source.

312 J. Radioanal. Chem. 54 (1979)

I. OBRUSNIK et al.: INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS

Fig. 1. Map of the sampling area N 1.

Hair

The samples of hair were collected from 10 year old boys residing in villages located in 1 to 3 km distance from the power plant (area N 1). Similar group of boys from village N 2 located in 12 km distance from the source opposite to the

prevailing wind direction was used as a control. The hair of residents of greater Prague were analysed as an "out control" group. All hair samples (80-120 mg)

were dipped and washed in acetone and deionized water according to procedure recommended by IAEA. 2 (More details about the analysis of hair - see Ref.a).

J. RadioanaL Chem. 54 (1979) 313

I. OBRUSN~K et aL: INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS

Instrumental neutron activation analysis

Irradiation

The samples for INAA were sealed in polyethylene (0.3 mm thick) bags. The

weights of samples used were 50 mg for emissions, coal and slag; 2 - 2 0 mg for aerosols and 80-120 mg for hair. A relative method of INAA with multielement standards has been routinely used. All standards were also sealed in polyethylene

with the exception of the standard of mercury (quartz ampoule). The samples and the standards were irradiated 2 - 6 hours in a core of WWR-S type nuclear reactor in l~e~ at 2 - 1017 n - m -2- s -1 .

Gamma-ray spectrometry

Each irradiated sample was counted twice. First counting was done 2 days (hair) or 3 - 5 days (other samples) after the end of an irradiation. Second measurement was

done after 3 - 4 weeks decay time. The gamma-ray spectrometer consisted of co- axial detector (5% or 9% relative efficiency, resolution (FWHM) of 2.3 keV and 2.9 keV, respectively, for 1332 keV photons of ~~ and pulses from the detector were passed through Ortec linear electronics to a 100 MHz ADC CT 102 (Inter-

technique). A computer-based 4096-channel analyzer Plurimat 20 (Intertechnique) was used as an analyzing unit. The gamma-ray spectra were processed on-line by the modified version oflPRM-01C program written in a PAL assembler. The peak areas were corrected for decay and pile-up losses during processing. The results are

expressed directly in ppm.

Results

Table 1 is a combined summary of analytical results for elemental concentrations

in coal, slag, emissions retained on mechanical (MSD) and electrical (ESD) separating devices and fly ash for the N 1 power plant. Similarly, the elemental concentrations

in aerosols taken in 19 sampling stations in the vicinity of the power plant (see Fig. 1) are shown in Table 2. The elemental composition of human hair (range, median and geometric mean) taken in the area N 1 (exposed group), in the area

N 2 (control group) and in the area of greater Prague (out control group) is sum-

marized in Table 3. The elemental concentrations for the emission and aerosol samples were used

for the following calculations:

314 J. Radioanal. Chem. 54 (1979)

I. OBRUSNtK et al.: INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS

Table 1 Elemental composition of coal, slag and emission samples

(coal-fired power plant)

Average concentration ppm

Emission Emission Element coal slag retained retained Fly ash

(N = 5) (N = 5) o n MSD o n ESD (N = 7) ( N = 7 ) ( N = 1 9 )

As

Ba

Br

Ce

Co

Cr

Cs

Eu

Fe

Hg

Hf

K

La

Na

Rb

Sb

Sc

Se

Sm

Ta

Th

U

W

410

130

50.5

16.8

3.3

17.5

47.2

0.3

18 460

<1

1.3

5 600

144

374

<10

59.9

9.0

58.2

95.8

0.3

4O 100

<1

4.0

17 420

490

420

<10

43.5

10.8

51.4

71.0

0.90

41 900

<1

3.4

15 220

1 720

494

<10

44.7

13.3

59.3

87.4

0.93

9.2 32.5

1 880 5 970

42 97

2.5 2.45

9.1 28.3

<4 <4

1.35 4.5

0.23 1.03

0.32 1.03

0.71 1.14

8.9 12.0

51 000

<1

3.0

17 320

28.6 30

5 480 5 120

110 131

3.0 6.2

22.9 23.9

<4 <4

4.3 4.4

0.92 0.75

1.03 1.1

0.80 0.85

7.1 14.6

2 325

512

73

44.3

14.7

65.2

86.4

0.5

50 330

2.1

3.1

13 310

29.1

5 610

123

7.4

23.1

20.8

3.8

0.84

1.04

0.68

8.8

Enrichment factors

E n r i c h m e n t fac tors (EF) for 6 e l emen t s have b e e n ca lcula ted , where EF is de-

f ined as a ra t io o f an e l emen t ' s c o n c e n t r a t i o n in an emiss ion (aerosol) t o some

reference e l e m e n t (Sc was chosen as a re ference e l emen t in this work ) divided b y

a similar ra t io for average crustal mater ia l . This is expressed as

J. Radioanal. Chem. 54 (1979) 315

I. OBRUSN~K et al.: INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS

Table 2 Elemental composition of aerosols taken from different sampling stations

Element

As Ce Co Cr Cs Fe* K* La Na* Sb Sc Sm Th

853 855 17.7 10.4 6.7 7.9

113 85 12.7 13.4

1.46 1.58 1.07 0.62 7.3 6.4 0.45 0.25

46 30 4.9 5.8 1.3 0.9 0.6 2.8

*Values expressed in %.

12 [5.

11

20

Aerosol

9

1410 16.7 5.0

70 110

1.04 0.79 4.0 0.35

52 3.5 1.0 0.7

elem/Sc (sample) EF = (1)

elem/Sc (crustal average)

World average crustal values were taken from published data. 4 Tables 4 and 5

show the enrichment factors for both emission and aerosol samples. It can be seen

from the tables that the elements enriched in emissions are usually enriched in

aerosols, too. Higher enrichment factors are often found for the elements present

in finer fractions of the emissions especially in fly ash. Very high EFs have been

found for arsenic (176 . -828 .9 for emissions and 4 8 1 - 5 9 1 9 for aerosols). Similarly, hair of the exposed group shows 3.1 times higher level of arsenic

than hair of the control group and 17.1 times higher comparing with the out con-

trol group (geom. mean).

Correlation coefficients

Correlation coefficients show which elements have a common source in the area

N 1. The correlation coefficients obtained for pairs of elements in the emission

samples are higher than 0.8 for 11.5% cases and above 0.5 for 45% cases. The

316 ~. Radioanal. Chem. 54 (1979]


(area N 1) (ppm except as noted)

sampling station

11 12

977 2158 11.5 5.5

7.7 7.6 61 224

6.1 12.4 1.05 1.32 0.35 0.94 0.8 8.3

<0.05 0.39 38 37 5.0 4.7 0.1 0.7 0.4 1.1

13

677 2.7 3.4

180 4.4 0.63 0.45 1.7 0.10

28 2.2 0.2 0.4

14

39~3 L1.9 6.9

1 ~.5 ~.5.0 1.89 0.97 9.7 0.42

~.6 5.5 1.3 0.8

15

143 3.9 3.5

48 1.3 0.78 0.44 0.9 0.08

18 2.2 0.2 0.5

16

389 3.3 4.1

67 3.7 1.24 0.62 3.7 0.08

15 3.5 0.5 0.4

1768 5.4 2.3

304

18 23

3535 5.3 4.7

65 6.8 11.8 0.98 1.83 0.69 0.40 1.4 1.2 0.09 0.05

53 23 3.1 5.6 0.4 0.3 0.8 0.8

24

2054 11.4 5

43 8.9 1.17 0.73

28 0.34

17 2.9 0.7 0.1

26

374 19

3.3 67

5.2 1.21 1.30 5.7 0.48

20 3.9 0.9 0.3

highest correlation has been found for the following pairs ,of elements: S m - L a ,

S m - Th, S m - Sc, L a - Th, L a - Sc and T h - Sc. Correlation coefficients for

aerosol samples are usually lower than those for ernissions, Only 9% of the pairs

of elements show correlation coefficients above 0:5. The highest correlations have

been found for the pairs: K - Na, Ce - Na, Ce - K, Sc - Sm, Sc - Th, Fe - Th

and Fe - Sc.

Ratio matching method s

An investigation of generic relationship among the samples of emissions and

aerosols from the area N 1 has been done according to a ratio matching method

proposed by ANDERS. ~ By using a value of a "matching cri terion" m = 1.3 and

b y calculation of a correlation matr ix for 6 elements (As, La, Ce, Cr, Sc and Sb)

relatively high correlation numbers (potential relationship) have been found for the

set of emission samples - correlation numbers ) 0.3 in 77.5% cases. Relationship

between fly ash from the power plant and the emission from a chemical factory

in the neighbourhood has not been found. Some relationship has been also found

for a set of aerosol samples; the highest correlation numbers have been obtained

for close sampling stations (stations Nos. 1, 2 and 5, 6). The longer distance from

the power plant the poorer correlation among the aerosol samples has been found.


I. O B R U S N | K e t a l . : I N S T R U M E N T A L N E U T R O N A C T I V A T I O N A N A L Y S I S

~7~ m

aa O

8 ~

O

Z x " x . , x , . x . . x . . x . . x . , x . . x . . x - ' q x . .

O

�9 ' ' ~

~ 0 ~ ~ 0 ~ 0 ~ ~ l l l l l f l l l t . t

O , O

~ ~ ~ z ~ ~ ~ ~ ~ ~ ~ ~ o ~ . . . ~ ~ o o ~ o o ~

0

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0 0

�9 o ~ 6 o ~

2 2 ~ 2 o ~ . ~ . ~ �9

. . . ~ �9 O O ,

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3 1 8 J. Radioanal. Chem. 54 (1979)

I. OBRUSN[K et al.: INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS

Table 4 Ertrichment factors calculated for some elements found

in emission samples

Emission

Element

As

Sb

Cs

W Br

Se

Retained on MSD (N:7)

176.2

9.2

16.0

3.3

Retained on ESD (N=19)

592,7

18.2

19.0

6.6

Fly ash (N=7)

828.9 22.4

18.0

4.1

15.3

140

Table 5 Enrichment factors calculated for some elements

in aerosol samples (area N 1)

Sampling station

1

2

3

4

5

6

7

8

9

11

12

13

14

15

16

18

23

24

26

Element

~ Cs Fe

8.9 1.2

13.4 1,2

12.0 1.1

5.3 1.1

2.9

2.8

5.5

1.4

4.0

2.4

9.5

16.4

4.5

4.4

3.8

19.6

2.3

3.0

3.4

15.4 0.9

17.6 0.9

11.1 3.7

18.6 0.4

163 1.0

6.3 1.0

13.7 0.5

10.4 3.4

23.6 0.6

3,1 2.2

5.5 1.1

11.4 2.3

10.9 0.8

15.9 1.5

6.9 1.2

Co Sb

1.3 442

1.6 657

1.6 362

1.4 300

1.7 218

1.9 253

2.7 647

0.8 78

1.7 t040

1.8 532

1,9 551

1.8 891

1,5 331

1.9 573

1.4 300

0.9 A97

1.0 287

2.0 410

1.0 359

As

923

1433

1214

481

1688

1798

3201

1482 3318

1609

3781

2534

5919

535

915

4697

5198

5832

790



o 0

0

0J

r~

3 2 0 J. Radioanal. Chem. 54 (1979)

I. OBRUSNIK et al.: INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS

Table 7 Average concentrations of some elements in hair of residents

of different countries (geometric mean except as noted)

Locality

N1 N2 Prague

(Czechoslovakia)

Tokyo

Japan

Rural res. (Canada) Urban res. (Canada) Urban near refi-

nerie s (Canada)

Italy

Iraq

India

Hong Kong

Concentration of element, ppm

As Hg

2.4 0.72 0.74 0.89

0.14 0.55

0.22 3.86

0.084 3.8

0.68 1.2 0.75 2.0

1 . 9 2.3

- 1.5

0.26 0.73

0.07

0.30 2.77

+Average f rom geome t r i c means for b o t h sexes.

*Median.

Sb

0.22 0.41

0.33

0.038

0.065

7.9 9.7

14.6

0.01

1.2

0.09

0.072

Se

0.34 0.49

0.51

3.06

0,70

1.8 1.9

2.3

0.2

0.92

1.32

0.58

Reference Zn

233.6 this 177 work

182

163 7+

176 8

185 9* 190

82

157 10

165 11

128 12

200 13"

Mutual relationship between emission and aerosol samples has been also tested by

the ratio matching method. The highest correlations with emissions have been ob-

served for the aerosols taken in the sampling stations 3, 4, 8, 15 and 26.

C o n c l u s i o n s

It can be seen from the enrichment factors that the concentration of arsenic

in the emissions, fly ash and aerosols is elevated in the area N 1. Moreover, the

concentration of arsenic (geometric mean 2.4 ppm) in the hair of non-occupation-

ally exposed children (area N 1) is elevated in comparison with the hair samples

taken in other countries (see Table 7) except the concentration of As in the hair

of urban residents near refineries from Canada.9 The concentration of As in the

hair of control group (area N 2) - 0 . 7 4 ppm could be explained by the fact that

the area N 2 is situated relatively near (12 km) to the power plant; the concentra-

J. Radioanal. Chem. 54 (1979) 321 21


I , ,, - COctt (105 rag)

ii ~ ~ - - ,,,,.,oo : :,~

I I I ~ , ~ | .~ ,-., ~ ,o III ~6~ ~ ,~ ~. ~ .~ ~ ~ ] ~ l a ~ ~ I - ~ " ~ ~ o~ ~

~ o ~ , ~ _ . ~ I ' ~ ~ o ~ o I ~ ~' ~.~_ < ~. o

0 500 I000 ~ 2000

Ch~nnel number

Fig. 2. Gamma-ray spectra of samples of coal, fly ash, aerosol and hair taken in the exposed area N 1.

3 �9 10 ~'

a~

~6

u

2,10"

i0 z.

a~

) o 560

_l_

c~

fl

Fly ash (52rag)

~i r rod = 2 h

tdecag = 6days

tcount =ZO rain

, t 1000 1500

Channel number


322 ,I. Radioanal, Chem. 54 (1979}


~c 3 =lOZ'

:~ 2~10 4

10 4 7 .c e!

o

0 SO0

Aerosol sample t ,trod = 2 h t ~ecag = 3dOgS t count =30 mJn

",t

3

Channel number

2000


2 ~I0 4

10 ~

~ J _ l . ~ l-k:li . . . . p ie (125 mg)

E ~ l | ~ tdecou = 3ck;tyS

-~ / /

�9

t# r~ ao ~ c

] -- "J " J ~ " J t ' J ~ ' - - ' - - ' - a ~ ' J ~ " - - J * - ~ r J . . .

500 1000 1500

co e-~ r5 u~ (*~co t<

..f -..T w,

"K

Channel n u m b e r

L 2000


Z Radioanal. Chem. 54 (1979) 323 2 1 "

I. OBRUSN[K et al.: INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS

tion of As in the hair of out control group (greater Prague) is much lower -

0.14 ppm.

Photopeaks of 7 6 As are very distinct in the spectra of coal, fly ash, aerosol and

hair taken in the exposed area N 1 (see Figs 2 - 5 first counting 2 - 5 days after

the end of irradiation).

It can be concluded from the results that hair can be used as very suitable in-

dicator of environmental exposure of man and instrumental neutron activation

analysis of hair for some toxic and trace elements can be used as an analytical

tool for this purpose. The thermal power plant is a primary source of environ-

mental pollution in the area N 1. The results of INAA of coal, emissions, fly ash,

aerosols, hair and probably also soils, water etc. show the pathways of an environ-

mental pollution.

The authors wish to thank to Dr. E. VAN~O, Head of District Hygienic Station in Prie- vidza, for technical help with collection of hair samples.

References

1. V. BENCKO, K. SYMON, Environ. Res., 13 (1977) 378. 2. Yu. S. RYABUKHIN, A report on the Co-ordinated Research Programme, IAEA(RL)50

(October 1978). 3. I. OBRUSN[K, V. BENCKO, Radiochem. Radioanal. Lett., 38 (1979) 189. 4. K. H. WENEPOHL, "Chemical fractionation in the sedimentary environment", Origin and

distribution of the Elements (AHRENS, L. H. Ed.), Pergamon Press, London, 1968. 5. I. OBRUSNIK, B. ST~t, RKOVJ,, J. BLA~EK, Proc. of Symposium on Measurement, Detection

and Control of Environmental Pollutants, IAEA-SM-206/12, IAEA, Vienna 1976. 6. O. U. ANDERS, J. Radioanal. Chem., 16 (1973)643. 7. A. IMAHORI, I. FUKUSHIMA, S. SHIOBARA, K. TOMURA, M. SUZUKI-YASUMOTO, M.

YUKAWA, M. TERAI, Proc. Symp. On Nuclear Activation Techniques in tile Life Sciences, IAEA-SM-227/16, IAEA, Vienna, 1978.

8. T. TAKEUCHI, T. HAYASHI, J. TAKADA, M. KOYAMA, Proc. Symp. on Nuclear Activation Techniques in the Life Sciences, IAEA-SM-227; 17, IAEA, Vienna, 1978.

9. A. CHATTOPADHYAY, R. E. JERVIS, Proc. Symp. on Trace Substances in Environmental Health, Columbia, Missouri, 1974, p. 31.

10. G. F. CLEMENTE, L. CIGNA ROSSI; G. P. SANTARONI, Proc. Syrup. on Nuclear Activation Techniques in the Life Sciences, IAEA-SM-227/13, IAEA, Vienna, 1978.

11. H. AL-SHAHRISTANI, K. M. SHIBAB, M. JALIL, Proc. Symp. on Nuclear Activation Techniques in the Life Sciences, IAEA-SM-227/7, IAEA, Vienna, 1978.

12. J. ARUNACHALAM, S. GANGADHARAN, S. YEGNASUBRAMENIAN, Proc. Symp. on Nuclear Activation Techniques in the Life Sciences, IAEA-SM-227/24, IAEA, Vienna, 1978.

13. L. S. CHUANG, J. F. EMERY, J. Radioanal. Chem., 45 (1978) 169.

324 J. Radioanal. Chem. 54 (1979}

instrumental neutron activation analysis of fly ash, aerosols and hair

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