Polish J. Environ. Stud. Vol. 15, No. 2a (2006), -9

The Content of Cadmium, Lead and Selenium in Soils from Selected Sites in Poland E. Biernacka, M. J. Małuszyński Department of Hydraulic Engineering and Environmental Recultivation, Warsaw Agricultural University, Nowoursynowska 166, 02-787 Warsaw, Poland

Abstract Cadmium, lead and selenium were determined using AAS in the surface layer (0.0-0.2m) of soils, situated in areas under different impact of anthropopressure. The concentration of cadmium and lead were higher in soils under strong anthropopressure than in soils from a region regarded as unpolluted. The Se content was higher in soils from a region regarded as unpolluted. The results suggest that contents of Cd and Pb in soils from regions under strong impact of anthropopressure are strongly positively correlated with organic matter content.

Keywords: cadmium, lead, selenium, heavy metal pollution, anthropopressure

Introduction Anthropogenic sources of heavy metals such as industrial wastes, automobile emissions, mining activity and application of chemical fertilizers, have led to their accumulation in soils. Heavy metals levels in soil are increasing also due to disposal of domestic sewage sludge on agricultural areas. Elevated cadmium and lead levels in soil may result in increased uptake by plants. This is the principal process by which heavy metals enter the food chain [1-3]. Many studies have shown that selenium has a detoxifying effect on animals poisoned with heavy metals [1, 3] but little attention has been paid to selenium protection against heavy metal toxicity in the soil plant system [4]. The aim of the present paper was to determine the content of Cd, Pb and Se in soils under different impact of anthropopressure, and to investigate relations between contents of cadmium, lead and selenium and selected properties of soils used in this study.

Material and Methods The study covered sandy soils from the surface layer (0.0-0.2m) from southern Poland (within five kilometers

around the Huta Katowice Steelworks), which is under strong impact of anthropopressure, and northeastern Poland (within five kilometers around Łomża), which is regarded as unpolluted. Soil samples were collected in accordance with the standard [5]. Soil properties were analyzed in all 18 soil samples using methods from the catalogue [6]. Determination of cadmium and lead was performed using Atomic Absorption Spectrometry (AAS) equipped with a Graphite Furnace (GF). Determination of selenium was performed using Atomic Absorption Spectrometry (AAS) equipped with a Hydride Generation (HG). Standard reference material (NIST SRM 2711) was used for quality control of the AAS measurements. All the results were analyzed using a computer-based statistical package (STATISTICA 6.0PL StatSoft Poland).

Results and Discussion The concentration of Cd, Pb and Se is listed in Table 1 and 2. The concentration of cadmium in soils from the region under strong anthropopressure has varied between 4.6 and 64.0 mg·kg-1 d.w. A similarly high concentration



Biernacka E., Małuszyński M. J.

Table 1. The content of Se, Cd and Pb in soils from the region under strong impact of anthropopressure. Sample number

Se

Cd

Pb

1

0.100

25.2

1504

2

0.090

9.2

912

3

0.288

8.8

656

4

0.620

4.6

454

5

0.158

28.8

800

6

0.818

23.2

1064

7

0.116

8.0

1568

8

0.076

54.8

1568

9

0.060

20.0

392

10

0.160

64.0

1736

11

0.068

44.8

608

mg·kg d.w. -1

Fig. 1. Correlation between cadmium concentration and organic matter content in soils under strong impact of anthropopressure.

Table 2. The content of Se, Cd and Pb in soils from the region regarded as unpolluted. Sample number

Se

Cd

Pb

1

0.164

3.2

102

2

0.368

2.4

74

3

0.182

3.2

100

4

0.108

2.4

124

5

1.570

2.0

116

6

0.160

2.0

68

7

0.172

1.4

40

mg·kg d.w. -1

was observed by Terelak et al. [7], and Pichtel et al. [8]. The Cd contents in soil samples from the region regarded as unpolluted were 1.4 – 3.2 mg·kg-1 d.w. Niesiobędzka [9] noted lower concentration of cadmium in soils from the northeastern part of Poland. Soils under strong anthropopressure contained from 392 to 1568 mg·kg-1 d.w. of lead. A similar concentration of Pb was observed by Maiz et al. [10] and Norrström and Jacks [11]. Abollino et al. [12] noted higher lead concentration in surface layer of soils (30139094 mg·kg-1). Soils from the region regarded as unpolluted contained 40-124 mg·kg-1 d.w. of lead. Niemyska-Łukaszuk et al. [13] observed similar content of that metal. The Se contents in soil samples from the region under strong anthropopressure were 0.060-0.818 mg·kg-1

Fig. 2. Correlation between lead concentration and organic matter content in soils under strong impact of anthropopressure.

d.w. The Se contents in soil samples from the region regarded as unpolluted were 0.108 – 1.570 mg·kg-1 d.w. A similar concentration of selenium was reported by Borowska et al. [14] and Zabłocki [15]. Trafikowska and Kuczyńska [16] as well as Borowska and Koper [17] found lower Se concentration in surface layer of soils. The content of cadmium and lead in soils from the region under strong anthropopressure is strongly positively correlated with the organic matter content (Fig. 1 and 2). This correlation is statistically significant.

Conclusions This paper proved that cadmium and lead concentration was higher in soils under strong anthropopressure than in soils from a region regarded as unpolluted. Generally the concentration of the examined elements depended on the impact of anthropopressure.

The Content of Cadmium... Acknowledgements This research was supported by the Polish State Committee for Scientific Research (KBN). Grant No. 0896/ P06/2001/21.

References 1. KABATA-PENDIAS A., PENDIAS H. Trace Elements in Soil and Plants, third ed. CRC Press, Boca Raton, FL, pp.356, 2000. 2. TU C., ZHENG C.R., CHEN H.M. Effect of applying chemical fertilizers on forms of lead and cadmium in red soil. Chemosphere. 41, 133, 2000. 3. WŁODARCZYK B., MINTA M., BIERNACKI B., SZKODA J., ŻMUDZKI J. Selenium protection against cadmium toxicity in hamster embryos. Polish J. Environ. Stud. 9 (4), 323, 2000. 4. SHANKER K., MISHRA S., SRIVASTAVA S., SRIVASTAVA R., DASS S., PRAKASH S., SRIVASTAVA M. M. Effect of Selenite and Selenate on Plant Uptake of Cadmium by Maize (Zea mays) Bull. Environ. Contam. Toxicol. 56, 419, 1996. 5. BN-78/9180-02, Analiza chemiczno-rolnicza gleby. Pobieranie próbek. 6. OSTROWSKA A., GAWLIŃSKI S., SZCZUBIAŁKA Z. Metody analiz i oceny właściwości gleb i roślin – katalog. Wyd. IOŚ, Warszawa. pp. 334, 1991. 7. TERELAK H., STUCZYŃSKI T., MOTOWICKA-TERELAK T., PIOTROWSKA M. Zawartość Cd, Cu, Ni, Pb, Zn i S w glebach województwa katowickiego i Polski. Arch. Ochr. Środ. 23, (3-4), 167, 1997. 8. PICHTEL J., KUROIWA K., SAWYERR H.T. Distribution of Pb, Cd and Ba in soils and plants of two contaminated sites. Environ. Pollution. 110, 171, 2000.

 9. NIESIOBĘDZKA K. Metale ciężkie w aspekcie właściwości gleb w północno-wschodniej Polsce. Chem. Inż. Ekol. 5 (3), 223, 1998. 10. MAIZ I., ARAMBARRI I., GARCIA R., MILLÁN E. Evaluation of heavy metal availability in polluted soils by two sequential extraction procedures using factor analysis. Environ. Pollution. 110, 3, 2000. 11. NORRSTRÖM A.C., JACKS G. Concentration and fractionation of heavy metals in roadside soils receiving de-icing salts. Sci. Total Environ. 218, 161, 1998. 12. ABOLLINO O., ACETO M., MALANDRINO M., MENTASTI E., SARZANINI C., BARBERIS R. Distribution and mobility of metals in contaminated sites. Chemometric investigation of pollutant profiles. Environ. Pollution. 119, 177, 2002. 13. NIEMYSKA-ŁUKASZUK J., MIECHÓWKA A., MAZUREK R. Zawartość cynku, ołowiu i kadmu w glebach wybranych regionów Karpat. Zesz. Nauk. AR Kraków., 315 (48), 133, 1997. 14. BOROWSKA K., MALCZYK P., KĘDZIA W. Zawartość selenu w glebach uprawnych i leśnych województwa bydgoskiego. Arsen i selen w środowisku – Problemy ekologiczne i metodyczne. PAN pp. 33-37, 1994. 15. ZABŁOCKI Z. Porównanie zawartości selenu w glebach, roślinach i odciekach drenarskich. Arsen i selen w środowisku – Problemy ekologiczne i metodyczne. PAN pp. 44-49, 1994. 16. TRAFIKOWSKA U., KUCZYŃSKA I. Zawartość selenu w glebie pól uprawnych i łąk okolic Bydgoszczy. Zesz. Probl. Post. Nauk Rol. 471, 567, 2000. 17. BOROWSKA K., KOPER J. Zmiany zawartości selenu ogółem i przyswajalnego dla roślin w glebie pod wpływem wieloletniego nawożenia organicznego. Zesz. Nauk.

Polish J. Environ. Stud. Vol. 15, No. 2a (2006), 10-13

Lead and Cadmium in Herbal Preparations Used in the Treatment of Type 2 Diabetes and Obesity J. Błoniarz, S. Zaręba Departament and Division of Bromatology of the Medical University in Lublin, Staszica 4, 20-081 Lublin, Poland

Abstract The paper’s objective has been to determine the level of lead and cadmium in some plant preparations and aqueous extracts of herbs used in the treatment of type 2 diabetes and obesity, in order to clarify whether the amounts of the elements they contain do not pose a threat to human health. Lead and cadmium content was determined by using atomic absorption spectrometry from organic phase. Average lead concentrations in the herbal preparations were within the range from 0.020 μg∙g-1 to 0.874 μg∙g-1 and did not exceed the binding Polish norm. The amounts of cadmium amounts fluctuated on average from 0.008 μg∙g-1 to 0.371 μg∙g-1, with some samples exceeding the set limit. The herbal aqueous extracts tested are safe for the human body with respect to their lead and cadmium content, since only some of the elements contained in the herbs permeates the fusions and decoctions.

Keywords: lead, cadmium, herbal preparations, aqueous extract of herbs, atomic absorption spectrometry

Introduction Industrial dust and fume emissions, as well as increased amounts of exhaust fumes from mechanical devices in the air and chemicalization of agriculture, are the main factors influencing the increase of toxic heavy metals (among others lead and cadmium) in the human environment [1, 2]. Plants are an important link in the food chain and are part of transfer of pollution between its individual elements. Due to the lack of a biological barrier in plants against lead and cadmium and high tolerance to accumulation of the elements in most plants, their concentration in plants may pose a risk to human health [2, 3]. Interactions between lead and cadmium and other elements occurring in a human organism may adversely influence the body’s mineral homeostasis [4]. Herbal plants, in particular those picked from natural beds, sometimes contain increased contents of the said toxic elements [2, 5]. This has also been confirmed by previous studies on the level of lead and cadmium in some domestic medicinal plants and herbal preparations [6-8].

Plant medicines made from inappropriate sources (polluted by toxic heavy metals), instead of a specific therapeutic effect, may cause intoxication of the organism. For this reason lead and cadmium content was examined in a selected group of medicines – single-ingredient herbs, herbal mixtures and liquid herbal medicines, as well as aqueous extracts from herbs.

Experimental Procedures The examined material constituted herbal preparations used in the treatment of: type 2 diabetes (Herba Galegae, Pericarpium Phaseoli, Diabetosan, Diabetovar, Diabetovit, Diabetogran, Diabetosol) and obesity (Chudeus-fix, Talia-fix, Green tea, Herbaton), bought at the chemist’s and herbalist’s in 2004. Five samples of each preparation were examined in two parallel repetitions. Each sample constituted a separate production series of the medicine. Aqueous extracts (infusions and decoctions) were also made from herbs according to instructions given by the producer, using deionized water.

11

Lead and Cadmium in Herbal... Samples of the studied preparations, herbal infusions and decoctions were dry mineralized at a temperature of 450°C. The burning process was accelerated by using a 15% aqueous solution of nitric acid (V) – (HNO3– Suprapur, Merck), ashes were dissolved in 5 cm3 of a 10% aqueous solution of hydrochloric acid (HCl – Suprapur, Merck) and moved quantitatively to measuring flasks by use of deionized water. Lead and cadmium content was determined by atomic absorption spectrometry (AAS) from an organic phase, which comprised 4-methylpentan-2-on (MIBK). The elements had been previously connected into comprehensive ammonic 1-pyrrolidinecarbodithionian (APDC) [9] in a Thermo Elemental’s SOLAAR M 5 device. The accuracy of lead and cadmium determination in herbs was checked by using the added pattern method. The 2.0 μg (n=5) and 4.0 μg (n=5) of lead pattern and 0.4 μg (n=5) and 0.8 μg (n=5) of cadmium pattern was added to melting pots with an averaged 5 gram weighed amount of herbal mixture. Then the procedure was similar to the one with the assayed samples. Recoveries were on average: 93.5% for lead and 96.5% for cadmium.

The study results are presented in Table 1 and 2. Arithmetical average ( x ), standard deviation (± SD) and content range (min. – max.) was given and the extent of lead and cadmium extraction from herbs to the aqueous phase was estimated.

Results and Discussion Under ordinary conditions, plants contain little lead, maximum up to several, rarely up to a dozen of mg∙kg-1 in dry substance. Plants from polluted areas may cumulate the element, mainly in aerial parts and in smaller amounts in roots. Intensity of lead uptake depends on the type and species of a plant and the soil conditions [4]. In plants meant for consumption the acceptable content of the element is limited. In dry herbs the content of lead cannot exceed 2.00 mg∙kg-1, and in herbal teas and tea – 1.00 mg of lead in 1 kg of dry substance of the product [4]. In the examined preparations lead levels were varied. The smallest amounts of the elements were determined in liquid herbal medicines: from 0.020 to

Table 1. The lead content in herbal preparations, aqueous extract of herbs and degree of extraction.

No

1. 2.

Arithmetical average ( x ), standard deviation (±SD), content range (min. – max.) Lead content in aqueous The name of preparation Lead content, Degree of extraction, % extract of herbs, μg from 1 -1 μg∙g g of herbs Preparations used in the treatment of type 2 diabetes Herbs 0.166 ± 0.053 30.1 ± 6.8 0.566 ± 0.164 Goat rue’s herb Herba Galegae 0.358 – 0.775 0.126 – 0.256 20.0 – 36.0 0.062 ± 0.012 26.8 ± 5.4 0.234 ± 0.044 Beans pod Peric.Phaseoli 0.192 – 0.295 0.044 – 0.074 19.7 – 32.8 Mixed herbs

3.

Diabetosan

4.

Diabeto-var

5.

Diabetovit

0.485 ± 0.117 0.238 – 0.605 0.179 ± 0.047 0.125 – 0.250 0.349 ± 0.070 0.288 – 0.433

0.139 ± 0.037 0.098 – 0.195 0.065 ± 0.017 0.047 – 0.089 0.097 ± 0.022 0.079 – 0.130

28.9 ± 3.7 23.0 – 32.9 36.4 ± 2.7 32.3 – 39.3 27.9 ± 2.4 25.4 – 30.6

Other forms of the medicines 6.

Diabetogran

7.

Diabetosol *)

0.076 ± 0.026 0.048 – 0.107 0.020 ± 0.004 0.015 – 0.025 Preparations used in obesity

8.

Chudeus-fix

9.

Talia-fix

10.

Green tea

11.

Herbaton*)

*) liquid form of the medicine

0.195 ± 0.054 0.128 – 0.267 0.577 ± 0.094 0.488 – 0.733 0.874 ± 0.256 0.441 – 1.060 0.054 ± 0.020 0.036 – 0.075

0.082 ± 0.027 0.054 – 0.117 0.209 ± 0.024 0.180 – 0.244 0.381 ± 0.124 0.177 – 0.505

41.6 ± 4.9 33.8 – 45.9 36.4 ± 1.9 33.3 – 38.1 43.1 ± 3.0 40.1 – 47.8

12

Błoniarz J., Zaręba S.

Table 2. The cadmium content in herbal preparations, aqueous extract of herbs and degree of extraction. Arithmetical average ( x ), standard deviation (±SD), content range (min. – max.) No

1. 2.

Cadmium content in aqueous extract of herbs, μg from 1 g of herbs Preparations used in the treatment of type 2 diabetes Herbs 0.025 ± 0.006 0.156 ± 0.032 Goat rue’s herb Herba Galegae 0.113 – 0.200 0.018 – 0.031 0.006 ± 0.001 0.037 ± 0.013 Beans pod Peric.Phaseoli 0.023 – 0.056 0.004 – 0.008 The name of preparation

Cadmium content, μg∙g-1

Degree of extraction, %

16.0 ± 3.7 11.4 – 19.9 17.6 ± 4.5 12.5 – 23.1

Mixed herbs 3.

Diabetosan

4.

Diabeto-var

5.

Diabetovit

0.070 ± 0.014 0.051 – 0.090 0.103 ± 0.021 0.080 – 0.137 0.128 ± 0.023 0.105 – 0.167

0.006 ± 0.002 0.004 – 0.008 0.019 ± 0.002 0.016 – 0.022 0.011 ± 0.003 0.008 – 0.015

8.7 ± 1.7 6.7 – 11.3 18.3 ± 1.5 16.1 – 20.0 8.3 ± 1.1 7.1 – 9.7

Other forms of the medicines 6.

Diabetogran

7.

Diabetosol*)

0.031 ± 0.011 0.020 – 0.047 0.016 ± 0.003 0.012 – 0.020 Preparations used in obesity

8.

Chudeus-fix

9.

Talia-fix

10.

Green tea

11.

Herbaton*)

0.106 ± 0.021 0.073 – 0.127 0.371 ± 0.093 0.256 – 0.501 0.100 ± 0.016 0.075 – 0.114 0.008 ± 0.002 0.005 – 0.010

0.025 ± 0.003 0.021 – 0.027 0.068 ± 0.019 0.054 – 0.098 0.017 ± 0.004 0.014 – 0.023

23.8 ± 4.4 20.8 – 31.5 18.3 ± 2.4 15.3 – 21.5 17.4 ± 2.3 14.6 – 20.2

*) liquid form of the medicine

0.054 mg∙kg-1, on average. In the other preparations lead contents fluctuated from 0.076 mg∙kg-1 to 0.577 mg∙kg-1 and 0.874 mg∙kg-1 in green tea samples (average contents). Low lead contents in herbal products were determined by Ekpa [11], from 0.11 to 0.15 mg∙kg-1, Steenkamp et al. [12] to 1.48 mg∙kg-1, Chizzola et al. [13] from 0.02 to 2.08 mg∙kg-1; in herbal preparations for children from 0.11 to 1.00 mg∙kg-1, and in herbals for adults from 0.32 to 2.63 mg∙kg-1 [8]. Plant tolerance to considerably high lead concentrations is high and may increase in environments polluted by the element. Larger amounts of the element in herbs were determined by: Kwapuliński et al. [6] from 2.82 to 11.67 mg∙kg-1, Mirosławski et al. [6] from 2.07 to 20.0 mg∙kg-1, AbouArab et al. [6] to 14.2 mg∙kg-1, Haider et al. [5] to 18.47 mg∙kg-1 and Naitham et al. [15] to about 6.00 mg∙kg-1 in herbal-fruit teas. An average cadmium content in plants is rather small; in plants’ aerial parts it is most often 0.05 to 0.20 mg∙kg-1, usually not exceeding 1 mg∙kg-1, expressed in dry matter of a plant product. There are also plants which may cu-

mulate the element from cadmium polluted soil, mainly in their roots [4]. The cadmium content in dry herbs cannot exceed 0.30 mg∙kg-1, and in herbal teas and tea – 0.10 mg∙kg-1 of the product [10]. The amounts of cadmium determined in the examined liquid herbal medicines were rather small, on average from 0.008 to 0.016 mg∙kg-1. In the other preparations the mean cadmium content fluctuated from 0.031 to 0.371 mg∙kg-1. Varied amounts of cadmium were found in herbs from Austria, from 0.01 to 0.75 mg∙kg-1, on average [13]. Increased contents, up to 5.50 mg∙kg-1, of the element were also determined in medicinal plants and herbal mixtures [6, 7, 14]. Although herbal plants sometimes contain large amounts of lead and cadmium, only part of their contents permeates herbal infusions and decoctions. The percentage of lead extraction in the examined herbs versus the aqueous phase was from 26.8% to 43.1%, on average, and for cadmium – from 8.3% to 23.8%. A similar ratio was determined by Trętowska et al. [16].

Lead and Cadmium in Herbal... Conclusions Based on the examination, it can be concluded that the average content of lead in herbal preparations used in the treatment of type 2 diabetes and obesity does not exceed the binding norm in Poland. It was only in some green tea samples that over 1.00 mg of the element was determined in 1 kg of the product. The amounts of cadmium detected in most of the tested samples were within the permissible values. Because only some of the lead and cadmium contents of herbs permeated into the aqueous extracts, the infusions and decoctions prepared from these herbal preparations do not pose a risk to human health.

References 1. JUNG M.C., THORNTON I. Heavy metal contamination of soils and plants in the vicinity of a lead-zinc mine, Korea. Appl. Geochem. 11, 53, 1996. 2. REIMANN C., KOLLER F., KASHULINA G., NISKAVAARA H., ENGLMAIER P. Influence of extreme pollution on the inorganic chemical composition of some plants. Environ. Pollut. 115, 239, 2001. 3. ODUKOYA O.O., AROWOLO T.A., BAMGBOSE O. Pb, Zn, and Cu levels in tree barks as indicator of atmospheric pollution. Environ. Int. 26, 11, 2000. 4. KABATA-PENDIAS A., PENDIAS H. Biogeochemia pierwiastków śladowych. PWN, Warszawa 1993. 5. HAIDER S., NAITHANI V., BARTHWAL J., KAKKAR P. Heavy Metal Content in Some Therapeutically Important Medicinal Plants. Bull. Environ. Contam. Toxicol. 72, 119, 2004.

13 6. KWAPULIŃSKI J., MIROSŁAWSKI J., ROCHEL R., WIECHUŁA D., KRAŚNICKI A., IWANEK K. Zawartość metali ciężkich w wybranych mieszankach ziołowych. Pol. Tyg. Lek. 49, 23, 1994. 7. MIROSŁAWSKI J., WIECHUŁA D., KWAPULIŃSKI J., ROCHEL R., LOSKA K., CIBA J. Występowanie Pb, Cd, Cu, Mn, Ni, Co i Cr w wybranych gatunkach roślin leczniczych na terenie Polski. Bromat. Chem. Toksykol. 28, 363, 1995. 8. BŁONIARZ J., ZARĘBA S., RAHNAMA M. Zawartość kadmu i ołowiu w ziołach, preparatach ziołowych oraz w naparach wykonanych z tych ziół stosowanych u dzieci i dorosłych. Przegl. Lek. 58(Supl. 7), 39, 2001. 9. SAPEK A. Sposób analizowania próbek gleb mineralnych na zawartość niektórych składników stosowany w IMUZ w Falentach. Problemy Agrofizyki. 12, 103, 1974. 10. Rozporządzenie Ministra Zdrowia z 13.01.2003. Załącznik nr 1: Maksymalne poziomy zanieczyszczeń metalami szkodliwymi dla zdrowia. 2003. 11. EKPA O.D. Nutrient composition of three Nigerian medicinal plants. Food Chem. 57, 229, 1996. 12. STEENKAMP V., von ARB M., STEVART M.J. Metal concentrations in plants and urine from patients treated with traditional remedies. Foren. Sci. Int. 114, 89, 2000. 13. CHIZZOLA R., MICHITSCH H., FRANZ CH. Monitoring of metallic micronutrients and heavy metals in herbs, spices and medicinal plants from Austria. Eur. Food Res. Technol. 216, 407, 2003. 14. ABOU-ARAB A.A., ABOU D.M.A. Heavy metals in Egyptian spices and medicinal plants and the effect of processing on their levels. 48, 2300, 2000. 15. NAITHANI V., KAKKAR P. Evaluation of Heavy Metals in Indian Herbal Teas. Bull. Environ. Contam. Toxicol. 75, 197, 2005. 16. TRĘTOWSKA J., KROSZCZYŃSKI W., OPRZĄDEK K., SYROCKA K. Metale i kwasy organiczne w liściach wybranych roślin. Bromat. Chem. Toksykol. 32, 285, 1999.

Polish J. Environ. Stud. Vol. 15, No. 2a (2006), 14-16

Selenium Content in Placenta, Maternal and Cord Blood from Subjects of Podlasie Region M. H. Borawska1, M. E. Zujko2, M. Kulikowski3, K. Socha1, R. Markiewicz1, A. Witkowska2 Department of Bromatology, 2Department of Food Commodities Science and Technology, Department of Obstetric-Gynecological Nursing, Medical University, Kilińskiego 1, 15-089 Białystok, Poland 1

3

Abstract The aim of this study was to evaluate selenium content in placenta, maternal blood and cord blood of 100 pregnant women at the term delivery. Selenium content in mineralized placenta samples and in serum was assayed by electrothermal absorption spectrometry (ETAAS) technique. The results showed low selenium status among pregnant women from Podlasie region compared with recently published data from other regions and countries.

Keywords: selenium, placenta, maternal serum, cord serum

Introduction

Experimental Procedures

Selenium is an essential element for human beings, known for its role in regulating the growth and development of the fetus [1]. In order to maintain a positive balance adults need about 1 μg of dietary Se per kilogram of body mass per day, but the requirement for Se for pregnant women increases as a result of Se transport to the fetus [2]. Selenium deficiency in maternal diet during pregnancy may be the cause of spontaneous abortion and diseases of newborn babies [3]. Our earlier study performed in the Department of Bromatology showed that Se concentration in the blood of mothers who delivered infants with the locomotor’s system malformations was significantly lower than in those who delivered healthy infants [4]. Selenium concentration in the human organism depends on the amount of Se in food, which reflects the content of this element in the environment. It has been well documented that selenium levels in subjects from different regions of Poland are rather low [5]. Therefore, in the present study we surveyed pregnant women from Podlasie region, who are vulnerable to Se deficiency, on selenium content in placenta, and maternal and cord blood.

One hundred pregnant women, aged 18-39 years (mean age 27 years) participated in this study during the 3-year period between 2001 and 2003 (30 women in 2001-2002 and 70 women in 2002-2003). Placenta samples, maternal and cord blood were taken during the labour from these women who delivered healthy infants. We obtained the consent of the local Committee of Ethics to perform the examinations (No. R – I – 003/33/2000). The placenta samples were mineralized with concentrated nitric acid in a microwave mineralizer BM-1z instrument UniClever (Plazmatronika, Poland). Selenium content in the mineralized placenta samples and in the serum of maternal and cord blood was assayed by the electrothermal absorption spectrometry (ETAAS) technique on a Z-5000 spectrometer, Hitachi, Japan. Certified reference materials – Seronorm MIO 181, as control for serum analysis, and Beef Muscles BCR 184 serving as control for placenta samples, were used to test the accuracy of the method. Results of the quality control analyses were in a good agreement with the reference values. The Statistica 6.1 software (StatSoft, Inc.) was applied for the data computation using the following statistical tests: Student’s t-test, Mann-Whitney U-test and Pearson’s correlation co-

15

Selenium Content in Placenta... efficients. P-values of < 0.05 were considered statistically significant. The Department of Bromatology, where the selenium analysis was performed, participates in a quality control program for trace elements analysis supervised by the National Institute of Hygiene and the Institute of Nuclear Chemistry and Physics.

Results and Discussion The postpartum mean body mass index (BMI) of women was 24.3 ± 4.3, while the mean birth weight of newborns was 3.38 ± 0.5 kg. Mean selenium content in placenta, maternal serum and cord serum was 80.63 ± 26.8 ng·g-1, 42.41 ± 15.7 ng·mL-1, 30.01 ± 9.2 ng·mL-1, respectively. It is noteworthy that selenium in the placenta and cord serum was positively correlated to the selenium concentration in maternal serum (r=0.22, p > > > > >

exchangeable (6.30 – 17.93%); easy soluble (3.94 – 14.80%); easy soluble (0.26 – 9.82%). exchangeable (5.06 – 8.51%); exchangeable (1.36 – 5.97%); easy soluble (0.24 – 7.94%).

0.2 mol (NH4)2C2O4 · dm –3 + 0.2 mol H2C2O4 · dm –3 + 0.1 mol C6H8O6 · dm –3 Calculation as difference between total amount of elements and sum of the six above fractions.

F6 bound to crystalline FeOx F7 residual

Calculation as difference between total amount of elements and sum of the five fractions.

F6 residual

0.2 mol (NH4)2C2O4 · dm –3 + 0.2 mol H2C2O4 · dm –3

F5 bound to amorphic FeOx

0.1 mol NaOH · dm –3

0.025 mol C10H22 N4O8 · dm –3

F5 bound to organic matter

F4 bound to organic matter

1 mol NH2OH · HCl · dm –3 + 1 mol CH3COONH4 · dm –3

1 mol CH3COONH4 · dm –3

1 mol NH4NO3 · dm –3

Extracting reagent

0.2 mol (NH4)2C2O4 · dm –3 + 0.2 mol H2C2O4 · dm –3

1 mol CH3COOH · dm –3

1 mol NH4Cl · dm –3

deionized H2O

Extracting reagent

Zeien and Brümmer’s method Fraction (nr and nominal) F1 easily soluble F2 exchangeable F3 bound to MnOx

F4 bound to Fe-Mn oxides

F1 easily soluble F2 exchangeable F3 bound to carbonates

Fraction (nr and nominal)

Tessier et al. method in own modification

Table 1. Schemes of the sequential extraction methods of zinc and copper used in the investigated forest Luvisols.

F6 residual

Fraction (nr and nominal) F1 easily soluble F2 exchangeable F3 bound to organic matter F4 bound to carbonates F5 bound to stable organic-mineral and mineral compounds

Calculation as difference between total amount of elements and sum of the five above fractions.

conc. HCl

1 mol HCl · dm –3

0.1 mol NaOH · dm –3

0.5 mol NaHCO3 · dm –3

deionized H2O

Extracting reagent

Hedley’s method modified by Tiessen and Moir

100 Kalembasa D., Pakuła K.

101

Fractions of Zinc and Copper...

Fraction:

Genetic horizon

Stawiska

Korczew

Gołobórz

Profile

Table 2. Some properties of the forest Luvisols. Deph (cm)

Ol Ah Eet IIBt IICca Ol Ah Eet IIBt IICca Ol Ah Eet IIBt IIC

2–0 0 – 21 21 – 48 48 – 83 83 – 120 2–0 0 – 20 20 – 44 44 – 88 88– 140 2–0 0 – 18 18 –58 58 – 98 98 –150

< 0.02

< 0.002

% fraction of diameter in mm 15 5 14 3 48 32 52 26 20 6 19 5 53 30 53 23 20 8 18 6 39 23 40 17

Method by Tessier et al. easily soluble exchangeable ▬▬▬▬ ▬▬▬

pHKCl 5.08 3.08 3.55 3.48 7.29 4.81 3.36 3.65 3.32 7.32 5.16 3.26 3.56 3.34 5.68

T

Corg

mmol(+)·kg-1

g·kg-1

700 107 54.0 187 362 545 75.2 43.6 176 366 647 86.0 49.2 146 138

472 20.3 5.00 1.60 1.40 443 12.0 2.30 1.90 1.55 459 16.1 3.70 2.00 1.30

Method by Zeien and Brümmer bound to organic matter residual ▪▪▪▪▪▪▪ ▬▪▪▬

Znt

Cut mg·kg-1

47.4 29.9 22.2 46.7 39.1 36.8 31.4 24.7 46.8 38.7 35.5 31.5 24.3 44.3 33.0

Method by Hedley

Fig. 1. The percentage (mean for three soils) of the selected fractions of zinc and copper in their total content.

15.2 4.49 3.79 15.6 12.9 14.6 5.63 4.05 15.9 11.5 15.3 5.48 4.46 14.2 12.5

102

Kalembasa D., Pakuła K.

Fig. 2. Mobility index (mean for soils; %) of zinc in the forest Luvisols.

Fig. 3. Mobility index (mean for soils; %) of copper in the forest Luvisols

Table 3. The coefficient values of the correlation between the fractions of zinc separated by the three sequential extraction methods and some properties of the forest Luvisols. Method by Tessier et al.

Hedley

Zeien and Brümmer

F1

F2

F5

F2

0.81

1

F5

-0.27

-0.26

1

F6

-0.54

-0.50

-0.36

Znt

0.25

0.17

Corg

0.96

pHKCl

F6

F1

F2

F4

F2

0.87

1

F4

0.85

0.88

1

1

F7

-0.83

-0.79

-0.51

0.09

0.67

Znt

0.08

0.01

0.68

0.43

-0.46

Corg

0.91

0.11

-0.14

0.15

0.21

pHKCl

CEC

0.82

0.50

0.38

-0.36

F5(1.39) F7(87.2) > F3(7.86) > F4(2.04) > F1(1.00) > F2(0.74) > F6(0.64) > F5(0.56)

Ol: Ah: Eet: IIBt: IIC:

F7(39.4) > F1(25.4) > F2(18.2) > F5(9.51) > F6(7.49) > F4(0.0) = F3 (0.0) F7(97.2) > F1(0.81) > F2(0.77) > F5(0.66) > F6(0.55) > F4(0.0) = F3 (0.0) F7(97.7) > F5(0.63) > F1(0.57) > F6(0.51) > F2(0.50) > F4(0.0) = F3 (0.0) F7(96.7) > F5(1.25) > F6(0.80) > F3(0.68) > F4(0.24) > F2(0.17) > F1(0.10) F7(97.5) > F5(1.21) > F6(0.71) > F3(0.41) > F4(0.15) > F2(0.10) > F1(0.08)

152

Pakuła K., Kalembasa D.

Table 1. Design of sequential extraction of elements by Zeien and Brümmer’s method [4]. Number of fraction

Nominal fraction

Extracting reagent

F1

Easily soluble

1 mol NH4NO3 · dm–3

F2

Exchangeable

1 mol CH3COONH4 · dm

F3

Bound to MnOx

1 mol NH2OH · HCl · dm –3 + 1 mol CH3COONH4 · dm–3

F4 F5

Bound to crystalline FeOx

F7

Residual

pH

24 h

natural

24 h

6.0

–3

Bound to organic matter Bound to amorphic FeOx

F6

Time of extraction

0.5 h

6.0

0.025 mol C10H22 N4O8 · dm –3

1.5 h

4.6

0.2 mol (NH4)2C2O4 · dm–3 + 0.2 mol H2C2O4 · dm–3

4h

3.25

0.5 h

3.25

-

-

0.2 mol (NH4)2C2O4 · dm–3 + 0.2 mol H2C2O4 · dm–3 + 0.1 mol C6H8O6 · dm–3 Calculation as difference between total amount of elements and sum of the six fractions.

*

Genetic horizon

Stawiska

Korczew

Gołobórz

Profile

Table 2. Some properties of the forest Luvisols investigated.

Deph (cm)

Ol Ah Eet IIBt IICca Ol Ah Eet IIBt IICca Ol Ah Eet IIBt IIC

2–0 0 – 21 21 – 48 48 – 83 83 – 120 2–0 0 – 20 20 – 44 44 – 88 88– 140 2–0 0 – 18 18 –58 58 – 98 98 –150

< 0.02

< 0.002

% fraction of diameter in mm 15 5 14 3 48 32 52 26 20 6 19 5 53 30 53 23 20 8 18 6 39 23 40 17

Corg pHKCl

CEC

5.08 3.08 3.55 3.48 7.29 4.81 3.36 3.65 3.32 7.32 5.16 3.26 3.56 3.34 5.68

700 107 54.0 187 362 545 75.2 43.6 176 366 647 86.0 49.2 146 138

Tit

Bat

Srt

Lit

*

g · kg-1 472 20.3 5.00 1.60 1.40 443 12.0 2.30 1.90 1.55 459 16.1 3.70 2.00 1.30

mg · kg-1 6.74 90.7 101 130 150 17.3 121 133 119 141 104 147 112 56.3 71.0

63.2 20.4 17.4 66.2 61.3 93.5 27.9 20.5 59.3 52.7 49.6 29.0 22.2 50.9 45.9

19.2 5.06 4.08 16.9 38.9 14.0 7.51 7.26 14.9 40.4 10.2 6.76 5.41 10.7 12.7

0.32 3.02 3.57 19.9 18.2 0.30 6.59 6.83 19.7 15.9 0.28 6.17 6.26 14.4 13.8

mmol(+)·kg-1

Fig. 1. Mobility index (mean for soils; %) of titanium, barium, strontium and lithium in the forest Luvisols.

2. The sequential fractionation analysis of titanium, barium, strontium and lithium compounds according to Zeien and Brümmer’s method showed their different amounts in the separated fractions. The highest amounts of these metals were determined in the residual fraction (F7). In the mineral horizons of the soils the lowest amounts of titanium and lithium were separated in the following fractions: easily soluble (F1), exchangeable (F2), bound to MnOx (F3) and bound to organic matter (F4); barium – in easily soluble (F1) and exchangeable (F2) fractions; strontium – in bound to amorphic FeOx (F5) and bound to crystallinity FeOx (F6). 3. The statistical evaluation of the results demonstrated that the amounts of titanium, barium, strontium and lithium in separated fractions revealed some

153

Content of Ti, Ba, Sr, Li...

Table 3. The coefficient values of the correlation between the fractions of titanium, barium, strontium, lithium and some properties of the forest Luvisols. Parameter

Total content

Corg

pHKCl

CEC

< 0.02

< 0.002

Element

Fraction F1

F2

F3

F4

F5

F6

F7

Ti

-0.979

-0.970

-0.974

-0.575

0.711

0.876

-0.743

Ba

0.451

-0.453

-0.774

-0.738

-0.764

-0.811

0.662

Sr

-0.818

-0.654

-0.846

-0.935

-0.672

-0.864

0.917

Li

-0.661

-0.664

0.940

0.944

-0.581

-0.612

0.635

Ti

0.999

0.993

0.992

0.581

-0.786

-0.934

0.816

Ba

0.881

0.374

-0.519

-0.387

-0.526

-0.630

0.350

Sr

-0.088

0.225

-0.526

-0.252

0.296

0.002

0.176

Li

0.999

0.998

-0.406

-0.409

0.995

0.998

-0.999

Ti

0.178

0.141

0.120

-0.438

-0.746

-0.499

0.711

Ba

-0.419

-0.536

-0.595

-0.647

-0.446

-0.434

0.615

Sr

-0.662

-0.577

-0.875

-0.855

-0.660

-0.801

0.842

Li

0.211

0.206

0.150

0.168

0.216

0.209

-0.222

Ti

0.894

0.865

0.859

0.384

-0.908

-0.956

0.925

Ba

0.625

-0.405

-0.771

-0.693

-0.745

-0.806

0.588

Sr

-0.455

-0.358

-0.723

-0.602

-0.390

-0.400

0.542

Li

0.911

0.910

-0.416

-0.413

0.943

0.931

-0.921

Ti

-0.978

-0.999

-0.976

-0.327

-0.398

-0.303

0.402

Ba

-0.994

-0.942

-0.980

-0.997

-0.788

-0.705

0.990

Sr

-0.997

-0.995

-0.480

-0.907

-0.934

-0.950

0.924

Li

-0.953

-0.921

0.930

0.937

0.996

0.947

-0.449

Ti

-0.949

-0.968

-0.893

-0.161

-0.150

-0.075

0.157

Ba

-0.941

-0.897

-0.952

-0.956

-0.779

-0.685

0.956

Sr

-0.944

-0.945

-0.362

-0.781

-0.832

-0.838

0.804

Li

-0.915

-0.864

0.992

0.994

0.984

0.997

-0.646

α = 0.01 r = 0.33; α = 0.05 r = 0.25

significant correlation with certain properties of the Luvisols analysed, especially with the total content of a metal, organic carbon amount, pH, CEC, particles of size in diameter < 0.02 mm and < 0.002 mm.

References 1. KABATA-PENDIAS A., PENDIAS H. Biogeochemia pierwiastków śladowych. PWN, Warszawa, pp 364, 1999.

2. KALEMBASA S., KALEMBASA D. The quick method for the determination of C:N ratio in mineral soils. Polish J. Soil Sci., 25(1), 41, 1992. 3. ZEIEN H., BRÜMMER G.W. Chemische Extraktion zur Bestimmung von Schwermetallbindungsformen in Böden. Mitteilgn. Dtsch. Bodenkundl. Gesellsch., 59, 505, 1989. 4. SALBU B., KREKLING T., OUGHTON D.H. Characterization of radioactive particles in the environment. Analyst, 123, 843, 1998. 5. ROGÓŻ A. Zawartość litu w wybranych profilach glebowych z terenu województwa krakowskiego. Zesz. Probl. Post. Nauk Roln., 448a, 297, 1997.

Polish J. Environ. Stud. Vol. 15, No. 2a (2006), 154-164

The Quality of Element Determinations in Plant Materials by Instrumental Methods P. Pasławski1*, Z. M. Migaszewski2** Central Chemical Laboratory, Polish Geological Institute, 4 Rakowiecka Str., 00-975 Warsaw, Poland 2 Pedagogical University, Institute of Chemistry, Geochemistry and the Environment Div., 5 Chęcińska Str., 25-020 Kielce, Poland

1

Abstract This report presents an assessment of uncertainty related to sampling, sample preparation and analysis of plants. This specific issue is illustrated by examples derived from biogeochemical studies performed primarily in the Holy Cross Mountains (Góry Świętokrzyskie), as well as from interlaboratory comparative analyses made in the Central Chemical Laboratory of the Polish Geological Institute in Warsaw and other European laboratories. The chemistry of plants is affected by many environmental and biological variables that must be considered when sampling a given species or its part/organ. These variables considerably modify the uptake of elements from soils, rocks, water and air. The better we understand all these interrelationships that influence the chemical variability in plants, the more clear picture of uncertainty we obtain. Another problem that cannot be overlooked is sample preparation, as well as analytical method and technique used. These three principal stages influence the quality of results obtained, and consequently, the adequate assessment of environment quality.

Keywords: plants, sampling, sample preparation, elements, instrumental methods, uncertainty

Introduction A major problem of biogeochemical studies is in understanding various interrelationships between organisms and environmental or biotic variables, as well as in interpretation of complex results. There are numerous, sometimes unpredictable, physicochemical and biological factors that influence concentrations of elements and organic compounds in vegetation. All these factors must be considered prior to sampling. In addition, to better interpret the results of chemical analyses, we must become more familiar with some uncertainties that are ingrained in a sequential treatment of a given plant sample. One of the most crucial issues in assessing the state of the environment is the quality of results derived from chemical analyses and uncertainty of analytical measurements. The quality of plant analysis depends mainly on the following *Corresponding author: e-mail: [email protected] **email: [email protected]

principal stages: (1) sampling, (2) mechanical (washing, grinding) and chemical (ashing, acid digestion) sample preparation, (3) chemical analyses with different instrumental methods and techniques. Each of these stages can be a source of partial uncertainty that influences the results obtained, and consequently, the assessment of the environmental quality. This issue was discussed on the basis of the results derived from the plant biogeochemical studies carried out primarily in the Holy Cross Mountains (Góry Świętokrzyskie) [1–10], comparative interlaboratory analyses made in the Central Chemical Laboratory of the Polish Geological Institute and other European laboratories, and from different data presented in the selected references cited [11–14].

Plant Sampling – a Dose of Uncertainty There are four basic precautions that must be followed during sampling. The sample collected should be:

155

The Quality of Element...

variables that affect physiological processes, phenology is highly unpredictable. Daily, seasonal and annual variations in insolation, temperature and precipitation may greatly alter the spatial and temporal distribution of elements in various plant species or their tissues. Our studies also suggest that plant samples should not be collected after long rainfalls due to the substantial removal of some of chemical species. Our estimates are that the unpredictable environmental and biological variables mentioned above may be a source of considerable uncertainty, in some cases roughly 70-80%. All these facts put some constraints on the selection of a specific plant species or its organ for biogeochemical studies. Different plants species, and even their tissues, show distinct variations in the concentrations of elements. This is induced primarily by diverse assimilation abilities (Table 1). Considering this, the obtained results provide evidence that each plant species and its natural environment must be considered separately. The sampling uncertainty should reach 20% at the maximum provided that all the precautions mentioned above are followed during collecting plant samples. The best solution to this problem would be collecting plant samples by three separate investigation groups and then preparing a mixed sample for further analysis.

(i) representative for a given medium (geochemical environment), (ii) free from contaminants, (iii) homogenous, and (iv) natural, i.e. unaltered during storage, transportation and preparation [6, 11]. Each stage may bring about a random or systematic error (see table in [15]). However, this problem is far more complex when it comes to collecting plant samples. Diverse concentrations of elements in individual plant species are affected by a variety of environmental variables, i.e., topographic (elevation, aspect), climatic (insolation, wind, pressure systems, moisture), hydrologic, and edaphic factors (soil moisture, texture, pH etc.). It should be stressed that most of them generally correspond to the geologic setting of study area [1–4, 7–10]. The angle of the slope and its aspect control the evapo-transpiration processes which in the northern hemisphere is more intense on south facing slopes. In the moderate climatic zone, northern slopes keep more moisture (snow lies longer there), but on the other hand, they are shorter exposed to the sun [16[. Another example is the production of metal chelating acids (especially usnic acid and atranorin) in larger amounts by lichens as elevation increases – causing metal concentrations in lichens at higher elevations to be higher [17]. However, the true “roulette” is related to physiological and genetic factors because pure chance can have a major influence. In general, the most effective uptake of many nutrients including trace elements occurs at the peak of growing season, i.e. in May – June in temperate climate. That is the main reason why the specific plant species or individual plant organs collected in May or June reveal distinctly higher concentrations of elements than their equivalents collected in October. An exception to this rule is the lichen species Xanthoria parietina that reveals an increase in thalli by about 25% in the winter compared to the summer [18]. In addition, some of the specific plant species (plant “hyperaccumulators”) show the enormous metal-binding capacity [5, 6, 11]. Of the environmental

Sample Preparation This stage encompasses mechanical (washing, grinding) and chemical (ashing, acid digestion) sample preparation [14, 19, 20]. However, there are different approaches to plant washing. Most researchers are strongly opposed to plant washing, due to the potential danger of removing waxes, airborne particulates and some of the elements from plant tissue surfaces. This is of special importance

Table 1. Concentrations of selected trace metals in various tissues of an individual Scots pine (Pinus sylvestris L.) tree and Hypogymnia physodes (L.) Nyl. (lichen) thalli from the vicinity of Daleszyce in south-central Holy Cross Mountains [1]. Pine tissues/lichen thalli

Al

Cd

Cr

Cu

Fe

Hg

Mn

Ni

Pb

Zn

mg·kg

-1

Root

52