The Science of the Total Environment, 105 (1991) 109-119 Elsevier Science Publishers B.V., Amsterdam

109

Concentrations of lead, cadmium, mercury and copper in mushrooms in the vicinity of a lead smelter P. Kala~:", J. B u r d a b a n d I. Stagkovfi ~

~Faculo' of Agriculture, 370 05 ~esk~ BudEjovice, Czechoslovakia hDistrict Public Health Of[ice, 261 80 PHbram, Czechoslovakia (Received March 17th, 1990; accepted June 6th, 1990)

ABSTRACT

The concentrations of four heavy metals in 149 samples of mushroom fruiting bodies, representing ! ! species, mainly all edible, were determined by atomic absorption spectroscopy. The mushrooms were collected up to a distance of 6 km from a lead smelter in central Bohemia (Czechoslovakia) in operation since 1786. Lead was accumulated extensively by Lepiota rhacodes and Lepista nuda. Among other species, significant accumulation was found up to a distance of I km from the source. Concentrations of > 100 mg kg- t dry matter were often determined. The sali: limit of 5 mg kg- mdry matter was exceeded in most samples collected at distances of up to 6 km from the source. Concentrations of cadmium in the polluted area were generally significantly higher than in other parts of Bohemia. Cadmium was extensively accumulated by the toxic Amanita muscaria, but also by the edible Boletus edulis and Amanita rubescens, with mean values 28.6, 15.2 and 12.3rag Cdkg ~ dry matter, respectively. The Czechoslovakian statutory limit is 0.5rag Cd kg-~ dry matter. Statistically significant linear correlations between lead and cadmium concentrations were found only for Boh, tus edulis and Paxillus #lvolutus. Mercury was accumulated by Lepista nuda and Lepiota rhacodes; mean values of !!.9 and 6.5 mg Hg k g J dry matter, respectively, were found. Concentrations of mercury in most species from the study area were higher than in those from other parts of Bohemia. Lepiota rhacodes and Lcpista nuda also accumulated copper extensively with mean values of 280 arid 193 mg Cu kg- ~dry matter, respectively. INTRODUCTION In p r e v i o u s p a p e r s (Kala~: et al., 1989a,b) the c o n c e n t r a t i o n s o f several h e a v y m e t a l s in fruiting b o d i e s o f m u s h r o o m s f r o m several a r e a s o f B o h e m i a p o l l u t e d by emissions f r o m differe~a s o u r c e s were f o u n d to be in g o o d a g r e e m e n t with results o f studies f r o m v a r i o u s E u r o p e a n c o u n t r i e s . T h e c o n c e n t r a t i o n s o f c a d m i u m , m e r c u r y a n d c o p p e r d e p e n d p r i m a r i l y on the

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© 1991 - - Elsevier Science Publishers B.V.

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P. KALA~"ET AL.

species of mushroom and it is difficult to ascertain the role of environmental pollution in this respect. There is a consensus (Seeger, 1982) that mushrooms are not reliable bioindicators of pollution by Cd and Hg. The situation is slightly different for lead (Kuthan, 1979; Dolischka and Wagner, 1982; Liukkonen-Lilja et al., 1983; Lep~ov/l and Krfil, 1988); all these authors found that the fruiting bodies of mushrooms accumulate remarkably high concentrations of lead and cadmium, especially in the vicinity of highways subject to heavy traffic and in the proximity of lead-processing factories. However, previous studies were confined to a limited number of species and samples; this paper attempts to broaden our knowledge on the subject. MATERIAL

AND

METHODS

This study was carried out within a radius of 6 km of a lead smelter at Lhota, near Pfibrar,~, situated ,-,60km south of Prague. The smelter processed ores and concentrates of galena (PbS) frown 1786 until 1972. Since 1972 it has only processed waste materials from which lead is recovered. Until 1982, stack gases from shaft furnaces were passed through a dust separator to a 75 m high stack. The total amount of lead emitted in that year was 259 tonnes (t). A new dust separator, with an efficiency in excess of 98%, and a new stack extending to a height of 160 m have been in use since 1983. Annual total solid emissions have since decreased to ~ 26-36 t. Lead has principally been in the form of PbCl, or PbSOa, which account for 60-70% of the total emissions. A further source of lead, with limited pollution potential, is dust from heaps of waste rocks. Cadmium concentrations in the emissions are, however, low, but higher levels would be expected for the long period of lead ore processing up to 1972. The original stack was selected as the point source of contamination; the new stack is -, 100 m away. The test area is between 470 and 778 m above sea level. Its western part is covered by a well-established mixed forest, consisting mainly of spruce (Picea abies). The prevailing winds are southeasterly, southerly, southwesterly and westerly. A map of the area is shown in Fig. 1. Exposure of the area to metal pollution for > 200 years is reflected by high lead contamination of soils (Brabec et al., 1983). The surface layer (7 cm) of soil adjacent to the old stack contained 2-3 g EDTA-extractable Pb kg-~ dry matter. High levels of lead in the soil (0.65 g Pb kg -~ dry matter) were tbund to persist up to a distance of 1.6 km ENE of the stack. More data on the area are given by Lep~ovfi and Krfil (1988). Fruiting bodies of mushrooms (Basidiomycetes) were collected between 1987 and 1989. Samples were cleaned in the same manner as used for culinary purposes, cut and dried at temperatures not exceeding 50°C. Approximately

CONCENTRATIONS OF Pb, Cd, Hg A N D Cu IN MUSHROOMS f

/

N

I| !

/

/

____

//

/

,g,

((-

\

\>) ~

\

-,~k,

J

J

\

\ \ ~"

~km

H6je

Fig. 1. Map of the study area.

10g aliquots of homogenized dry mushrooms were placed in a porcelain crucible and ashed in an oven at 430-450°C for 15-20 h. Losses during ashing were 1-4% for Cd and Cu and up to 2% for Pb. The analyses were conducted in duplicate with differences between measurements of ~ 3% for lead and copper and ,,- 5% for cadmium. In some instances, only a small amount of sample was available and the concentrations of lead were found to be below the detection limit. Ashed material was dissolved in 5 ml concentrated HNO3, evaporated to dryness, heated again to 450°C, dissolved in HNO~ and diluted with redistilled water to a total volume of 50cm ~ and a final HNO3 concentration of 0.9%. Measurements were by atomic absorption spectrophotometry (AAS 3; Carl Zeiss, Jena) with flame atomization (air-acetylene) at wavelengths of 217.0 nm for Pb, 228.8 nm for Cd and 324.8 nm for Cu with sensitivities (pg cm-~) of 0.15 for Pb, 0.015 for Cd and 0.04 tbr Cu. The green alga Chlorelia Kessleri P-ACHK (Institute of Radioecology and Applied Nuclear Techniques, Ko~ice, Czechoslovakia) was used as the reference material. Differences between experimentally determined and certified concentrations were up to 3% for Cu and up to 7% for Pb and Cd. Mercury was determined in homogenized dried samples (0.1-0.2 g) using a trace mercury analyzer TMA-254 (VSCHT, Prague) with a detection limit of

! i2

p. KALA~"ETAL.

10ng Hgg -t. Mean differences between duplicates were 2%. Differences between determined and certified concentrations of mercury in the green alga P-ACHK were up to 7%. More than 10 samples for each of six species were collected; for a further five species, at least five samples of each were taken, providing a total of 149 samples. Correlations between concentrations of metals were tested by regression analysis. Concentrations of metals from the test and other areas of Bohemia were compared statistically by two-sided tests using the Welch approximation. RESULTS AND DISCUSSION

The results for lead and cadmium are given in Tables 1 and 2 and in Figs 2 and 3. Data for concentrations of cadmium (Table l) and of lead (Table 3) are given for the purpose of comparing concentrations of both metals in mushrooms from different areas of Bohemia (see Kala~: et al., 1989a). Data from areas with no geochemical sources or a point source of pollution are taken as background levels. TABLE ! Statistical comparison of cadmium concentrations (rag kg-t dry matter) in mushrooms from polluted and other areas of Bohemia Species

Polluted area

Bohemia u

I!

Boletus edulis Boletus ( Xerocomus ) badius Boletus ( Suillus ) grevillei Boletus scaber (Leccinum scabrum) Lepiota rhacodes dmanita rubescens Amanita muscaria"

X

5

Sv

15

8.7

Nma x

I1

X

S~

26

20

2.3

!.3

5.5

Xm. x

19

2.7"

1.4

7.2

25

0.9

0.6

2.3

II

4.7"

i.8

8.2

7

1.6

1.2

3.0

20 8 8 28

2.9 2.3 8. ! II 2.9 3. I

II 9.6 23 50

7 10 12 20

0.7 1.0 I. 3 !5 0.9 3.0

0.5 0.6 0.9 7.8 0.4 i.2

1.7 2.0 3.3 28

Lepista nuda

6

Armillaria mellea Russula aeruginea Paxillus invohaus d

5

4.8 ~ 4.9" 12b 29 ~ 4.6 7. i

!4

3.3

6.5

25

!.6"

2.3

I0

5

!2

7

35 9.5

1.4 4.9

io

2.7

3.5

9. I

14

0.2

0. !

0.3

Significance of differences found by two-sided test with the Welch approximation: :'P < 0.01, h p < 0.05.

Toxic species. d Non-edible, but often consumed species.

CONCENTRATIONS OF Pb. Cd. Hg AND Cu IN MUSHROOMS

!i3

TABLE 2

Concentrations of lead and cadmium (mgkg-~ dry matter) at different distances from the source of pollution Sl~ecies

Number of Lead Cadmium samples n Distance from the source of pollution (km) Pb/Cd

Boletus edulis

5/5

Boletus scaber

8/!1

Lepiota rhacodes

8/8

Amamta rubescens 7/8

0-1

i-2

176

14

2-3

3-4 25

7.7

14 I! 10 4.2 3.5

i 27 I 17 66

28 I!

Lepista nuda

6/6

144

Armillaria mellea

4/5

91

!1

20 18 91 63 16 4.5

74 38 23 3.9

4-5

0-1

5.5 26 2.6 5.6 2.3

194 160 107 47 40 5.3 22 4.0 i !

!-2

2-3

20 4.4 2.7

3-4

4-5

18

9.0 3.9 4.9 3.4

8.1 7.0 6.6 4.1 3.8 3.4

5.6 9.6 3.7

23 2i

4.6

10

4.6 4.0

1!

6.3 4.2

3.5 3. ! !.8 4.8

6.6 4.4 4.2 3.0 2.3 8.7 6.3 3.0

8.7

In an assessment of the concentrations of the tbur metals the following factors, among others, should be considered: species of mushroom, age of fruiting bodies and of mycelium, and distance from the source of pollution. Probably very important, but experimentally very difficult to measure, is effect of age of the mycelium. Significant concentrations of lead were found in mushrooms collected up to a distance of 1 km from the stack (Fig. 2 and Table 2). They are comparable to results from areas surrounding lead-processing factories in Finland (Liukkonen-Lilja et al., 1983) and to the first data from studies performed in the P~ibram area (Lepgovfi and Krfil, 1988). Two species have a striking ability to accumulate lead - - Lepiota rhacodes and Lepista nuda. Lepiota rhacodes gave a mean value of 110mgPbkg -t dry ma~er at a distance of 4 - 5 k m from the source. As can be seen from Fig. 2 and Tab!e 2, the concentrations of lead did not

114

e.

mg,kg-40k I

[157.6

2: U [

i

120 100]

KALA~"ET AL

!

Pb

'

lzlL

80

II

60

~l

I, l[ Ij II

"!!/

jIi I

60

tI

20

" ~l

~

'N 0

ABCDE 0-1 km

I

A BD 1-2 km

I

ACDE 2-3 km

3-4 km

4°6 km

Fig. 2. Concentrations of lead in some species of mushrooms at different distances from the source ,)f pollution. (A), Boletus badius: (B), Boletus scaber: (C), Russula aeruginea: (D), Paxillus involutus: (E), Amanita muscaria.

mrk¢o. 40"

30-

20"

ASCOE 0-I km

I

AeO 1-2kin

I

A.CE 2-3 km

I

A.COE 3-4 km

I

A.COE 4-6 km

Fig. 3. Concentrations of cadmium in some species of mushrooms at different distances from the source of pollution. (A)-(E), s ~ Fig, 2.

CONCENTRATIONS OF Pb. Cd. Hg AND Cu IN MUSI-fROOMS

!!5

TABLE 3 Concentrations of lead (mg kg ~ dry ~aatter) in mushroor,:~s from different areas of Bohemia Species

n

x

s,

-X'max

Boletus edulis Boletus badius Boletus grevillei Boletus scaber Lepiota rhacodes Amanita rubescens Amanita muscaria Lepista nuda Armillaria melh, a Russula aerughwa Pa.villus 01vohcms

20 25 7 5 10 12 15 5 7 !I 14

i.2 1.3 1.5 1. '~ 8:3 2. ! 1.4 5. ! 1.6 3.8 I. 6

i. i 0.9 0.9 0.9 10.3 0.9 1.2 1.9 1.4 5.4 O.5

4.7 4.2 3. ! 3. I 37 3.4 3.5 7.8 4.3 19 2.6

decline to the background level even at a distance of 4-5 km from the stack. This is in accord with findings of Lep~ov',i and Krfil (1988). Using their regression equations for dependence of lead concentrations on the distance from the stacks we determined that Pb levels in most edible mushrooms would be below the Czechoslovakian safe minimum of 5 mg Pb kg-~ dry matter, with the exceptions of Lepiota rhaeodes and Lepista nuda, at a distance of > 6 km from the source. The high concentrations of lead in fruiting bodies are directly attributable to very extensive contamination of substrates. Dolischka and Wagner (1982) found very low concentration factors (fruiting body/substrate) of 0.03 for Boletus edulis and only 0.002 for Bo&tus (Xerocomus) badius. Decreasing concentrations of cadmium with increasing distance from the source are illustrated by Fig. 3 and Table 2, with the exception of Amanita musearia the highly accumulating species (Table 1). Data given in Table 1 show that, for almost all species, the concentrations of cadmium in the polluted area are statistically higher, but for some species it was not proven statistically because of insufficient number of samples. Significant linear correlations (P = 0.95) between the concentrations of lead and cadmium were found only for Boletus badius (r = 0.687) and Paxiilus involutus (r = 0.550). The ability to accumulate high concentrations of cadmium appears greatest for Amanita muscaria, and also for the edible species Boletus edulis and Amanita rubescens. Among species for which there was a limited number of samples, analysis showed this ability to be typical of most species of the genus Agaricus. Concentration factors are extremely high for many mushroom species (50-300; Seeger, 1982). The Czechoslovakian safe minimum limit for cadmium of 0.5 mg kg-t dry

! 16

p. KALA(~ ET AL.

TABLE 4 Statistical comparison of mercury concentrations (mg kg-~ dry matter) in mushrooms from polluted and other areas of Bohemia Species

Polluted area /'/

Boletus edulis Boletus badius Boletus grevillei Boletus scaber Lepiota rhacodes Amanita rubescens Amanita muscaria Lepista nuda Armiilaria mellea Russula aeruginea

5 19 II 20 8 8 28 6 5 14

X

Bohemia Sx

Xmax

0.9" I. l'* 0.6 6.5 2.4'*

0.4 0.5 0.4 5.9 !.2

2.2 2.0 1.5 2! 3.8

12 0.3'* 0.9

9.4 O.I !.4

27 0.5 5.7

t/

X

Sx

Xmax

20 25 7 7 10 12 20 5 7 I0

2.3 0.4 0.3 0.7 4.4 0.6 1.6 II 0.2 0.2

0.9 0.3 0.2 0.4 2.4 0.3 3.0 9.4 0.05 0.2

4.4 1.4 0.7 !.4 8.0 1.3 14 22 0.3 0.5

'*See Table !.

matter was exceeded by nearly all samples. Wild mushrooms are a very popular delicacy in Czechoslovakia and also in other countries of Central Europe. Consumption is highest in late summer and the autumn. A normal daily intake for an adult is ~ 300-500 g fresh mushrooms, which is 30-50 g dry matter. However, many people consume > 10kg of fresh and preserved TABLE 5 Significant linear correlations among metal concentrations in mushrooms from the polluted

ar e a Species

n Pb/other metal

Boletus edulis Boletus badius Boletus greviilei Boletus scaber Lepiota rhacodes Amanita rubescens Amanita muscaria Lepista nuda Armillaria mellea Russula aeruginea Paxillus involums

5/5 i 8l ! 9 8/I ! ! 7/! 9 8/8 7/8 28/28 6/6 4/5 14/14 25/25

up < 0.01.

bp < 0.02.

Pb-Cd

Pb-Hg

Pb-Cu

a

c d

b c c

a c cp < 0.05.

d c dp < 0.10.

Cd-Hg

Cd-Cu

Hg-Cu

CONCENTRATIONS OF Pb. Cd. Hg AND Cu IN MUSHROOMS

I !7

mushrooms each year. According to F A O / W H O (1976), acceptable weekly intakes of lead and cadmium for adults are 3 and 0.5 mg, respectively. Mercury concentrations could only be compared for eight species (Table 4). Lepista nuda and Lepiota rhacodes were found to be the most extensive accumulators of mercury. For four species the concentrations are significantly (P < 0.01) higher in the polluted area and increases for Russula aeruginea and Lepiota rhacodes may be assumed. These results differ from those from Finland (Liukkonen-Lilja et al., 1983), where no influence of a lead-processing factory was found. Significant linear correlations between concentrations of lead and mercury were only found for Russula aeruginea and those between cadmium and mercury were only found for Boletus badius (Table 5). According to F A O / W H O (1976), the acceptable weekly intake of mercury is 0.3 mg, of which a maximum of 0.2 mg can be in the form of the toxic methylmercury cation CH3Hg÷; however, its occurrence in mushrooms is low, usually only a few percent (Seeger, 1982; Bargagli, 1986). Seeger (1982) reported the mercury concentrations in mushrooms and proposed that up to 2 m g k g -I dry matter was safe. The acceptable weekly intake of mercury would be exceeded by one meal prepared from mushrooms containing 6-10 mg kg -I dry matter. This would probably be for the widely consumed Lepiota rhacodes. The Czechoslovakian safe minimum is 0.5 mg Hg kg-~ dry matter. Concentrations of copper in mushrooms (Table 6) are notably higher than in higher plants. Similarly, as in our previous work (Kala~ et al., 1989b), TABLE 6 Statistical comparison of copper concentrations (mgkg ~ dry matter) in mushrooms from polluted and other areas of Bohemia Species

Polluted area

Bohemia m

Boletus edulis Boletus badius Boletus grevillei Boletus scaber Lepiota rhacodes Amanita rubescens Amanita muscaria Lepista nuda Armillaria mellea Russula aeruginea Paxillus involutus

~"bSeeTable I.

/'/

X

5 19

52 42 27 18 28& 41 40b 193b 31 28 57

II 20 8 8 28 6 5 14 25

Sx

35 22 7

Xmax

n

X

109 88 43

20 25 7

27 40 22

Sx

Xmax

16 17 6

77 76 31 21 228 52 47 135 24 59 68

6

36

7

13

5

101 14 17 52 II 9 17

480 66 82 255 47 55 101

l0 12 20 5 7 i0 14

li0 37 30 103 20 33 47

45 7 8 27 3 12 17

118

p. KALA(~ETAL.

accumulation of copper was found for Lepiota rhacodes and Lepista nuda, two species that accumulate lead and mercury extensively. Nevertheless, no significant P b - C u and H g - C u correlations were found for these two species, but for Boletus edulis, Boletus scaber and for a n o t h e r three species significant correlations were found between Pb and C u and for Amanita rubescens between H g and Cu (Table 5). Concentrations of copper in Lepiota rhacodes and Lepista nuda are significantly higher in the polluted area than in other areas of Bohemia. Increased concentrations also occur in Amanita muscaria and Boletus edulis. It is not yet clear whether or not high copper concentrations can be a nutritive source; Schellmann et al. (1980) reported that the availability of copper from mushrooms is low. The Czechoslovakian safe limit of 250rag C u k g -I dry matter was exceeded only by Lepio~,a rhacodes. Considering that m u s h r o o m s are not the only source of lead, cadmium and mercury, it is wise to restrict consumption of m u s h r o o m s from most of the polluted area; within a radius of 1 km of the source o f contamination mushrooms should not b~, co~::,lmed at all. ACKNOWLEDGEMENTS The authors wish to thank M r K. Magek from Pfibram for collecting most of the m u s h r o o m samples, D r Eva Vanfi~kovfi for statistical analyses and Dr M . K . Woolford for language correction of the manuscript. REFERENCES Bargagli, R., 1986. Accumulo di mercurio nei fimghi eduli ed eventuali implicazioni per i consumatori, Micol. Ital., 15: 23-29. Brabec, E., P. Cudlin, O. Rauch and M. ~koda, 1983. Lead budget in a smelter-adjacent grass stand. In: Proc. Int. Conf. Heavy Metals in the Environment, Heidelberg, 1983. CEP Consultants Ltd, Edinburgh, pp. ! 150- I ! 53. Dolischka, J. and I. Wagner, 1982. Investigation about lead and cadmium in wild growing edible mushrooms from differently polluted areas, la: W. Baltes, P.B. Czedik-Eysenberg and W. Pfannhauser (Eds), Recent Developments in Food Analysis. Verlag Chemic, Weinheim, pp. 486--49I. FAO/WHO, 1976. List of maximum levels recommended for contaminants by the Joint FAO/WHO Code~ Alimentarius Commission. Se:ond Series. CAC/FAL, Rome, 3: I-8. Kala~, P., M. Wittingerov/t, I. Sta[kov/t, M. ~im/tk and J. Bastl, 1989a. Obsah rtuti, olova a kadmia v houb/tch. Cesk. Hyg., 34: 568-576. Kala~, P., M. Wittingerovfi and I. Sta[kov/t, 1989b. Obsah sedmi stopov~,ch prvkfl v jedi~,ch houbfich. Potravin. V~dy, 7: 131-136. Kuthan, J., 1979. Die Auswertung des Bieigehaltes im Bronze-R6hrling - - BoletusaereusBull. ex Ft. - - entlang einer der Verkehrsadern in Bulgarien. (~eskfi Mykol., 33: 58-59. Lep~ov/t, A. and R. Kr/tl, 1988. Lead and cadmium in fruiting bodies of macrofungi in the vicinity of a lead smelter. Sci. Total Environ., 76: 129-138. Liukkonen-Lilja, H., T. Kuusi, K. Laaksovirta, M. Lodenius and S. Piepponen, 1983. The

CONCENTRATIONS OF Pb. Cd. Hg AND Cu IN MUSHROOMS

! 19

effect of a lead processing works on the lead, cadmium and mercury contents of fungi. Z. Lebensm. Unters. Forsch., 176: 120-123. Schellmann, B., M.-J. Hilz and O. Opitz, 1980. Cadmium- und Kupferausscheidung nach Aufnahme von Champignon-Mahlzeiten. Z. Lebensm. Unters. Forsch., 171: ! 89-192. Seeger, R., 1982. Toxische Schwermetalle in Pilzen. Dtsch. Apoth. Ztg., 122: 1835-1844.