Radiation Protection and Environment

ARTICLE
Year
: 2011  |  Volume : 34  |  Issue : 1  |  Page : 66--68

Measurement of some radiologically and nutritionally important trace elements in human milk and commercially available milk


Suma Nair, RS Sathyapriya, MG Nair, Prabhat Ravi, Sharda Bhati 
 Internal Dosimetry Section, Health Physics Division, Bhabha Atomic Research Centre, Bombay, India

Correspondence Address:
Suma Nair
Internal Dosimetry Section, Health Physics Division, Bhabha Atomic Research Centre, Bombay
India

Abstract

Milk is considered to be a complete food and an almost indispensable part of the diets of infants and children. In this paper we present the concentration of some radiologically and nutritionally important trace elements such as Th, Cs, Co, Rb, Fe, Ca and Zn present in human milk and commercially available milk. The trace elements in human and other milk samples were determined using instrumental neutron activation analysis technique. The results show that higher concentrations of Th, Cs, Ca and Rb were found in ordinary milk samples in comparison with the human milk samples. Whereas, a higher concentrations of Fe and Co were observed in human milk samples. These data will be useful for the nutritional and biokinetic studies of these elements in infants and children of different age groups.



How to cite this article:
Nair S, Sathyapriya R S, Nair M G, Ravi P, Bhati S. Measurement of some radiologically and nutritionally important trace elements in human milk and commercially available milk.Radiat Prot Environ 2011;34:66-68


How to cite this URL:
Nair S, Sathyapriya R S, Nair M G, Ravi P, Bhati S. Measurement of some radiologically and nutritionally important trace elements in human milk and commercially available milk. Radiat Prot Environ [serial online] 2011 [cited 2019 Sep 21 ];34:66-68
Available from: http://www.rpe.org.in/text.asp?2011/34/1/66/93959


Full Text

 1. Introduction



Milk is considered to be a complete food and an almost indispensable part of the diets of infants and children. It is the only food during the first few months of human life and is of paramount importance for the studies of human nutrition. Milk is a complex and unique secretion synthesized in the mammary glands from precursors available from circulatory blood. A fraction of the radionuclide incorporated by the mother either by ingestion or inhalation, is transported into human milk and is thus transferred into suckling infants. Ingestion of human milk is an important pathway for the incorporation of radionuclides during the early months of an infant. The most resent work on internal dosimetry by the ICRP is the estimation of radiation doses to the embryo and fetus from radionuclides ingested by the mother (ICRP publication 88, 2001) and the dose coefficients for suckling infants (ICRP publication 95, 2004). The data reported by ICRP in these two reports are based on Caucasian population and hence may not be applicable for Indians. The measurement of the concentration of the important trace elements in human milk and other commercially available milk samples was therefore initiated in Internal Dosimetry Section of Health Physics Division which will be used for estimating the daily dietary intake of trace elements by infants and children of different age groups.

As part of this work, human milk samples and commercially available milk samples were analysed using instrumental neutron activation analysis (INAA) method and determined the concentration of Th, Cs, Co, Rb, Fe, Ca and Zn present in the samples. This paper, presents the mean concentration of some radiologically and nutritionally important trace elements in human milk and commercially available milk samples and which will be useful for the nutritional and biokinetic studies these elements.

 2. Materials and Methods



2.1 Sampling and sample preparation

About 30 ml milk samples from healthy mothers were collected and freeze dried, powdered and made homogenized. Milk samples of three popular brands of commercially available milk packets were also collected. About 100 ml of these milk samples were also freeze dried, and powdered and made homogenized. Three aliquots of each sample, weighing about 500 mg were taken in pre-cleaned polythene bags for analysis. About 200 mg of Standard Reference materials (SRMs) like citrus leaves and orchard leaves obtained from NIST -USA were taken in pre-cleaned polythene bags, which are used as standards in the present study.

2.2 Analytical Procedure

There are few suitable analytical methods available to determine the concentrations of trace elements in nano gram levels found in most of the biological samples. The analytical method employing neutron activation analysis was found to be one of the most effective in determining the concentration of Th, Cs, Co, Rb, Fe, Ca and Zn in milk samples. The advantage of NAA over other analytical methods lies in the fact that it is blank free and matrix independent technique. It is also adequately sensitive for the measurement of elemental concentration in nanogram levels. The INAA technique (Dang et al. 2001) was used for the determination of the concentration of these elements in human milk and in other milk samples. All the samples were irradiated with the corresponding standards for 14 hrs at neutron flux of 10 13 ns/cm 2 /sec in APSARA reactor at BARC. After irradiation the samples and standards were allowed to cool and then counted for the characteristic gamma rays of activation products, using HPGe detector coupled to 4k multi channel analyzer. The Th, Cs, Co, Rb, Fe, Ca and Zn present in milk samples were quantified by comparison of the induced activities formed in the sample and the respective standards. The details of the nuclear parameters for the isotopes produced on neutron irradiation of these elements, their half-lives and minimum detection limits achieved by using INAA are given in [Table 1].{Table 1}

 3. Results and Discussion



[Table 2] gives the results of analysis of human milk and other milk samples. The results show that the mean concentration of Th, Cs, Co, Rb, Fe, Ca and Zn in human milk are 2.41ng/g, 21.90 ng/g, 68.90 ng/g, 7.63μg/g, 50.23μg/g, 1.8 mg/g and 43.45μg/g respectively and those contained in commercially available milk samples are 4.78 ng/g, 32.57 ng/g, 8.56 ng/g, 40.69 μg/g, 7.92 μg/g, 6.8 mg/g and 47.19 μg/g respectively. The range of concentration of these elements in human milk and commercially available milk samples are also shown in the table.{Table 2}

It is also understood from the [Table 2] that the concentrations of Th, Cs, Ca and Rb were higher in ordinary milk in comparison with the human milk. This may be due to the high abundance of these elements in the environment, which can be present in the ordinary milk through grass - cow pathway. Whereas, a higher concentrations of 50.23 μg/g of Fe and 68.90 ng/g of Co were observed in human milk samples. This may be due to the high intake of iron rich food/supplements during the pregnancy and lactation period. However, the concentration of Zn present in human milk and commercially available milk samples were found to be comparable.

 4. Conclusions



The concentration of some radiologically and nutritionally important trace elements such as Th, Cs, Co, Rb, Fe, Ca and Zn in human milk and commercially available milk were determined using instrumental neutron activation analysis technique. The concentrations of Th, Cs, Ca and Rb were found to be high in ordinary milk in comparison with the human milk. This may be due to the high abundance of these elements in the environment, which can be present in the ordinary milk through grass-cow pathway. Whereas the human milk samples show significantly higher concentrations of 50.23 μg/g of Fe and 68.90 ng/g of Co. This may be due to the high intake of iron rich food/supplements during the pregnancy and lactation period. The concentration of Zn found in human and commercially available milk samples were comparable. The estimated mean concentration of radiologically and nutritionally important trace elements such as, Th, Cs, Co, Rb, Fe, Ca and Zn in human milk and commercially available milk samples will be useful for the nutritional and biokinetic studies these elements in infants and children of different age groups.

 5. References





IAEA (2004), International Commission on Radiological Protection, Dose coefficients for suckling infants, 2004, ICRP publication 95, Vienna.IAEA (2001), International Commission on Radiological Protection, Estimation of radiation doses to the infants from radionuclides ingested by the mother, 2001, ICRP publication 88, Vienna. Dang H. S., Jaiswal D.D., Pullat V.R. Parameswaran M. and Suma Nair (2001), The estimation of daily intake and organ content of some selected trace elements of importance in radiation protection and nutrition in Indian population for application of the data to study their bio-kinetics, Final report to IAEA on Research Contact No.RC-8919/Japan.