Element content in children hair samples

Numerous publications have been based on applying human hair as a research objective, including such issues as metabolism of micro-elements, evaluation of heavy toxic metal poisoning rate, determination of nutrition conditions (level) and diagnosis of different diseases (Agadzhanjan N.A., Skalin A.V., 2001). It is a well- known fact that human hair is the most preferable medium for different experimental researches, as its composition reveals the level and changes of those numerous micro-element traces in a human organism over a long period of time (Babikova U. F., et al., 1990).

The element hair content analysis is widely applied in the assessment of animal state (Babikova U. F., et al., 1990; Bate L.C. et al., 1965; Batzevich V.A., 1986) and the impact of different environmental pollutants on man (Revich B.A., 1990; Batzevich V.A., Jasina O.V., 1989; Batzevich V.A., 1995; Caroli S. et al., 1992; Caroli S. et al., 1994) or his \ her working place (Chlopicha J. et al., 1995). However, it is important to highlight those advantages in applying such biological material in monitoring research: 1) nontraumatic procedure in hair sampling; 2) hair as stable biological material, which, in its turn, facilitates easy storage and transportation; 3) hair samples in comparison to blood and urine samples contain a rather high residual element concentration; 4) elements accumulate on hair over a long period of time and can reflect a 1-year impact period (Björnberg K.A. et al., 2005).

Human hair is regarded as a subject of biogeochemistry, which does not study an organism or organ as a separate but as a whole item (for example, plants) (Zhuk L. I., Kist A. A., 1990). Hair chemical content reflects the general human organism state (Kist A. A., 1987) and, in its turn, is widely studied to give an ecological description of the population and to diagnosis the population health level (Rikhvanov L.P., 2006; Saet U. E. et al., 1990; Kist A. A., Zhuk L. I., 1991; Zhuk L. I., Kist A. A., 1999). Hair analysis could be applied to determine the metal concentration in medicine (Feng Q. et al., 1997; Ferreira Hadla S. et al., 2007). Micro-element content changes in different pathology cases significantly exceed the individual variations in corresponding test-groups (Mzhelskja T. I., Larski E.G., 1983). There is an interconnection between the concentration of several metals in human hair and some diseases, such as autism (Mzhelskja T. I., Larski E.G., 1983), epilepsy (Katz S.A., Chatt A., 1988) and the development of neoplasm (Lubchenko P. N. et al., 1989; Lukovenko V. P., Podryshnjak A. E., 1991).

One fact should be considered in studying human hair- its element concentration changes in accordance to race, health level (physiological state), diets, hair color, medicine application, cosmetics, geochemical conditions of habitat and work-place (Revich B.A., 1990; Agadzhanjan N.A., Skalin A.V., 2001; Baranovskaja N.V., 2003; Baranovskaja N.V., Rikhvanov L.P., 2004; Batzevich V.A., Jasina O.V., 1989; Feng Q. et al., 1996). It was established that there are significant variations of the element content in children hair throughout the year (Skalin A.V., Demidov V.A., 2000). In view of the above-mentioned factors, the element content in human hair could be different in various countries and territories. This fact causes exceeding data variation in natural hair element content.

Many authors proved that the element content in hair reflect professional diseases and industry type (Mazumder D.N.G. et al., 1988; Sturaro A. et al., 1994; Suzuki T., 1988). Hair is widely used as an indicator of mercury (Hg) influence on people who were in contact with it at their workplace (Peach D.F., Lane D.W., 1998; Pereira R. et al., 2004). Determination of metal element content in hair could be used as an effect index for potential poisonous elements (poisoning) or information of human health (McDowell M.A. et al., 2004; Sarmani S., 1987). For example, high lead content can be observed in hair earlier than in biological fluids with further development of biochemical changes, specific for this metal (Lukovenko V. P., Podryshnjak A. E., 1991).

Human hair is considered to be an excellent effect indicator of the environment impact on man (Agadzhanjan N.A., Skalin A.V., 2001; Babikova U. F., et al., 1990). Heavy metal emission (fumes), industry and heat-power plant discharge, incineration emission influence the element content in hair. Thus, hair analysis is generally used to monitor environment conditions. Chemical content in hair indicates the accumulation process of heavy metals in a human organism and is a marker of ecology-trouble territories (Mazumder D.N.G. et al., 1988). Micro-element content analysis in biological tissues of the population living within the proximity of pollution sources evaluates the distance of this or that emission and their detection specification (Mazumder D.N.G. et al., 1988; Saet U. E. et al., 1990).

Element content in human hair could be used as an indicator for natural technogenic environments. Taking into account the depositing property of human hair, its element content is applied in mapping technogenic polluted aureoles and territorial zoning of favorable living conditions (Saet U. E. et al., 1990; Revich B.A., 1996). It has been proved that the micro-element content in human tissues, including hair, corresponds to the element content of those technogenic geochemical anomalies where people live (Miekeley N. et al., 1998; Baranovskaya N. V., 2003). Based on the investigation of the element content in hair of the Tomsk region population, this region was divided into territorial zones in accordance to the natural-technogenic environment transformations.

Tomsk oblast is located in south-eastern West Siberia lowland, equidistant from the west and east Russian borders. It borders Krasnoyarsk territory, Kemerov, Novosibirsk and Tumen regions. Its total area is 316.9 thousand km². There are 16 administration areas within Tomsk oblast (Fig. 1), characteristic of irregular populated areas, most of which are located along highways, railways and river valleys. Tomsk region occupies a specific place within the Tomsk oblast – major industries, including agroindustrial complex, heat-power plant and petrochemical industry are located here. Thus, Tomsk region is characterized as a rather intensive technogenic area. The nuclear-fuel cycle plant- Siberian Chemical Combine (SCC) causes significant ecology problems in this region, especially in those populated areas located in the north-eastern direction from the Siberian Chemical Combine (zone of material transport by wind).

	1. Aleksandrovsk 2. Kargasovksk 3. Parabelsk 4. Kolpashevsk 5. Chainsk 6. Molchanovsk 7. Krivosheinsk 8. Shegarsk 9. Kozhevnikovsk 10. Tomsk 11. Аsinovsk 12. Pervomajsk 13. Verkhnoketsk 14. Tegyldetsk 15. Zirjansk 16. Bakcharsk
Fig. 1. Administration-territorial division of Tomsk oblast

The northern regions in Tomsk oblast (Aleksandrovsk, Kargasovksk,Parabelsk) are singled out due to the petrochemical industry located here. The remaining regions are mainly agricultural with highly-developed woodworking industry. These stated regions are considered to be zones of insignificant natural-technogenic environment transformations.

Hair samples of children from 3 to 15 (boys and girls) from Tomsk oblast were investigated. Total number of samples is 538. For comparative analysis hair samples from two Russian regions and other territories- Irkutsk oblast (36 samples), Cheljabinsk oblast (44 samples), Stolin, Belorussia (3 samples), and Pavlodar, Kazakhstan (120 samples) were also investigated.

Above-mentioned comparative selection is based on the following facts: 1) geochemical environment composition in Cheljabinsk oblast is determined by the existing nuclear-fuel cycle plant «Majak»; 2) investigated population areas in Irkutsk oblast are located near the underground nuclear explosion «Rift-3», conducted July 31, 1983 in Osinsk region, Obusa River; 3) numerous industries are located in Pavlodar itself, such as petrochemical, chemical, engineering and others, as well as, three heat-power plants; 4) Stolin, Belorussia is located out of the 1986 catastrophe zone – Chernobilsk Nuclear Power Station.

Major statistic distribution parameters correlated to hair element content (mg/kg, dry weight) of the children living in Tomsk oblast are described below (Table 1).

Analysis of these statistic distribution parameters shows that there is an irregular distribution of all investigated elements in the hair samples. Element concentration has a wide range. Such factors as standard deviation, asymmetric coefficient and others indicate those areas with evident anomaly values of investigated elements (Table 1). Detection of distinctive element distribution features in the hair of Tomsk oblast population based on statistic analysis results of investigated samples are due to the fact of geochemical environment characteristics.

Table 1.

Element content in children hair (N= 538), living in Tomsk oblast
(mg/kg, dry weight)

Element	Minimum	Maximum	Mean	Std. Err.	Std.Dev.	Median	Geometric Mean	Skewness
Na	2,0000		603,8	25,98	602,66		387,23	3,15
Ca			2626,95	99,11	2298,72		1864,18	3,32
Sc	0,0001	0,52	0,048	0,004	0,09	0,02	0,02	2,94
Cr	0,03	129,3	4,71	0,39	9,11	1,6	1,45	6,11
Fe			522,28	49,53	1148,73		136,05	3,17
Co	0,001	3,9	0,26	0,015	0,35	0,15	0,12	3,96
Zn			182,2	3,53	81,85		164,89	1,45
As*	0,1		0,71	0,026	0,55	0,5	0,49	1,05
Se	0,001	57,6	0,88	0,16	2,99	0,6	0,52	18,39
Br	0,26	895,2	12,65	1,78	41,22	5,4	5,79	18,6
Rb*	0,08		1,93	0,13	2,97		1,12	10,4
Sr*	0,05		14,31	0,69	13,11		6,99	5,98
Ag	0,1	20,6	0,47	0,06	1,34	0,21	0,24	11,46
Sb	0,01	1,5	0,12	0,008	0,18	0,04	0,06	3,54
Cs*	0,005	0,97	0,08	0,003	0,07	0,05	0,06	4,79
Ba*	0,001		15,43	0,69	14,69		5,04	1,37
La	0,001	2,8	0,27	0,01	0,32	0,18	0,14	2,88
Ce	0,001	8,63	0,41	0,03	0,70	0,2	0,2	5,99
Sm	0,002	2,4	0,1	0,007	0,16	0,04	0,03	6,62
Eu*	0,002	0,16	0,02	0,0009	0,02	0,01	0,01	2,01
Tb*	0,004	0,08	0,01	0,0004	0,007	0,01	0,01	6,36
Yb*	0,008	3,90	0,05	0,009	0,21	0,03	0,03	15,56
Lu*	0,0004	0,14	0,008	0,0005	0,01	0,005	0,005	5,46
Hf	0,001	0,59	0,06	0,004	0,09	0,03	0,03	2,98
Ta*	0,003	0,08	0,036	0,001	0,02	0,03	0,03	0,95
Au	0,0001	5,28	0,06	0,01	0,25	0,029	0,02	17,92
Hg	0,05	75,5	3,35	0,40	7,68	0,9	1,01	4,93
Th	0,0001	3,5	0,07	0,01	0,29	0,02	0,02	7,81
U	0,005	1,98	0,16	0,009	0,22	0,1	0,09	4,11

Notes: N – sample number; * - average calculation based on samples, where 50% of the values are less than determination range.

Irregular element distribution in children hair indicates those factors which significantly distort the natural distribution. It should be noted that the distribution of Na, Ca, Co, Br, Ag, La, Ce, Sm, Lu, Hf, Au, Hg, Th, U in accordance to Kolmagorov – Smirnov criterion is conformed to the lognormal law, while the distribution type Zn, Se is close to normal. Distribution of Sc, Cr, Fe, Sb is complex, but in general closer to lognormal.

Data of element content in human hair (Tomsk oblast) is compared to reference data (Man. Medico-biological data, 1977) and the results of different authors (Saet U. E. et al., 1990; Rodushkin I., Axelsson M.D., 2000; Ward N.I. et. al., 1987) (Table 2).

However, contemporary references include insignificant data information on the content and behavior of chemical elements in a human organism. This fact is due to the development of analytical methods and the quick – changing situation at the local level. Those references, containing information of hair composition, list a limited number of elements. At the same time, the following issue- content and concentration of a whole series of elements, such as rare earth elements, thorium, uranium and scandium has not been investigated sufficiently.

The above-mentioned analysis shows that the data on chemical element content in the population hair (Tomsk oblast) is comparable to reference data, though, in some cases, there are several specific features (Table 2). The content level of such elements as Na, Ca, Co, Sr is higher in Tomsk oblast than in other regions. There is significantly high barium content in children hair (15,4 ± 0,67 mg/kg, dry weight) which is three times more than that stated in reference data in accordance to reference man (Man. Medico-biological data, 1977).Content level of Sc (0,05 ± 0,004 mg/kg, dry weight) and Cr (4,7 ± 0,4 mg/kg, dry weight) is also high. The specific feature of the chemical content in children hair (Tomsk oblast) is the increased concentration of rare earth elements La, Ce, Sm and radioactive elements Th, U. The data correlation of the element content in children hair (Tomsk region) to data from other regions of Russia, including Belorussia and Kazakhstan is described in Table 3. There is a rather high concentration of Na, Ca, Sc, Cr, Fe, Co and also some rare earth elements La, Ce, Hf in hair samples of children living in Tomsk oblast. A significant high content level of La, Lu, Sm and Th was found in the hair samples of children living, not only in Tomsk oblast, but also in Cheljabinsk oblast. Such a high concentration in hair is due to the impact of nuclear-fuel cycle enterprise (Seversk, Ozersk).

Table 2.

Comparative analysis of evaluation level of the chemical element concentration in human hair (mg/kg, dry weight)

Element	Average element content
Tomsk oblast Mean ±Std Err (N=538)
Na	603 ± 25		12,9 ± 0,75
Ca	2626 ± 99		678 ± 161
Sc	0,05 ± 0,004	n \ d	0,0098 ±0,0015	0,0014	0,0079
Cr	4,7 ± 0,4	3,8	1,09 ±0,1	0,167	0,558
Fe	522 ± 49		87 ± 20,5	9,6	33,77
Co	0,26 ± 0,02	0,00295	0,13 ± 0,014	0,013	0,0762
Zn	182 ± 3,5		n \ d		n \ d
As	0,7 ± 0,03*	2,0	n \ d	0,085	0,158
Se	0,87 ± 0,15	n \ d	0,5 ± 0,7	0,830	n \ d
Br	12,6 ± 1,7	12,5	2,37 ± 0,016		6,82
Rb	1,9 ± 0,4*	23,5	1,97 ± 0,02	0,093	0,445
Sr	14,3 ± 0,7*	0,05	n \ d	1,20	n \ d
Ag	0,47 ± 0,6	3,45	0,18 ± 0,007	0,231	0,164
Sb	0,12 ± 0,07	6,5	0,1 ± 0,014	0,022	0,134
Cs	0,08 ± 0,004*	n \ d	n \ d	0,00067	0,708
Ba	15,4 ± 0,67*	5,0	n \ d	0,640	4,901
La	0,27 ± 0,01	n \ d	0,085 ± 0,02	0,035	0,043
Ce	0,4 ± 0,03	n \ d	0,18 ± 0,002	0,039	0,057
Sm	0,1 ± 0,01	n \ d	0,009	n \ d	n \ d
Eu	0,02± 0,001*	n \ d	n \ d	n \ d	n \ d
Tb	0,01 ± 0,0004*	n \ d	n \ d	n \ d	n \ d
Yb	0,05 ± 0,01*	n \ d	n \ d	n \ d	n \ d
Lu	0,008± 0,0005*	n \ d	n \ d	n \ d	n \ d
Hf	0,06 ± 0,004	n \ d	n \ d	0,0054	n \ d
Ta	0,04 ± 0,001*	n \ d	n \ d	0,0044	n \ d
Au	0,06 ± 0,01	0,08	0,02	0,030	0,0662
Hg	3,25 ± 0,4	6,0	n \ d	0,261	3,313
Th	0,07 ± 0,01	n \ d	n \ d	0,0013	n \ d
U	0,17 ± 0,01	n \ d	n \ d	0,057	n \ d

Notes: N – sample number; n\ d. – no data; * -average calculation based on samples, where 50% of the values are less than determination range; 1 - Man. Medico-biological data, 1977; 2 - Saet U. E. et al., 1990 – children living in non-black earth zone of Russia; 3 - Rodushkin I., Axelsson M.D., 2000. – adults living in north-east Sweden (N=114); 4 - Ward N.I. et. al., 1987. – adults and children from Sophia, Bulgaria (N=36).

There is a rather high U concentration in children hair samples from Irkutsk oblast and Pavlodar, Kazakhstan. The reason of which could be the natural peculiarities of these regions. Another important factor is the significantly low index ratio of Th to U in these regions (Th/U = 0.06), while in other regions it includes 0.4 – 0.5.

The regional hair differences in Tomsk oblast is reflected in its geochemical series (Table 4). In comparing the concentration coefficient, obtained in the normalization of average values, to indexes from reference data (Saet U. E. et al., 1990), it has been observed that there is a significant difference in obtained values for several elements which, in its turn, underlines the fact of various sources of this or that element.

The geochemical element spectrum in the hair of children from Tomsk oblast is rather diverse, and the concentration coefficient is more than 2 for practically the whole series. This fact proves the assumption that the hair element content in the population of Tomsk region is complex and predominantly includes specific technogenic features.

The geochemical series for Tomsk and Cheljabinsk oblasts are analogous (Table 4). Both series, i.e elements with coefficient more than 1, start with sodium and end in stibium. At the same time, there exist identical elements for both regions Na, Sm, La, Br, Co, Ca and Au, while the following elements are only characteristic of Tomsk oblast Fe, Sc, Cr, Ag, Ce, and where the series Sc is only found in Tomsk oblast. The same sources of an element explain such a common geochemical association of these two different regions.

The element spectrum within the geochemical series in the children hair from Irkutsk oblast mainly reflects natural component content. Based on comparative data of some authors (Saet U. E. et al., 1990), it should be noted that a high Fe content in hair is specific for Tomsk and Irkutsk oblasts, while selenium content only for Irkutsk oblast and Kazakhstan. High Ag concentration in investigated hair is a specific feature for Kazakhstan.

Tomsk oblast was conventionally divided into five zones in accordance to the extent of the technogenic environment transformations: (1) area with high extent of technogenic environment transformations; (2) regions with highly- developed petroleum production; (3) Tomsk region (the most intensive technogenic environment); (4) Seversk, where the Siberian Chemical Plant (SCP) is located; (5) populated areas located in the north-eastern direction from the Siberian Chemical Plant (zone of material transport by wind).

The element content in children hair in above-mentioned zones is shown in the following diagrams - Fig. 2 and Fig. 3.

Table 3.

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