Moldir Nurseitova¹

Akmaral Orynbassarova²

Tursunkul Bazarbayeva¹

¹Department of Energy and Ecology, al-Farabi Kazakh National University, Almaty, Kazakhstan

²Department of Technology of Food products and Food safety, Kazakh National Agrarian University, Almaty city, 8 av. Abai, 050010 Almaty, Kazakhstan

THE STUDY OF PCB TRANSFER TO THE MILK

Abstract

In Kazakhstan contamination by PCB is high in Kazakhstan due to the importance of sources of PCB in the country. However, in spite of this potential, the observed contaminations of food of animal origin for human consumption (milk and meat) appeared low. In this article have been described the transfer of PCBs to the Camel milk.

Key-words: PCBs, milk, Kazakhstan

Hotspots of PCBs in Kazakhstan

According to available information in 2012 /1/ the PCB polluted areas in Kazakhstan are Ablaketka district and manufacturing plant of UKKZ (Condensator plant of Ust Komenagorsk), Pond Drive UKKZ, Substation of Ekibastuz, JSC "Pavlodar Chemical Plant", Derzhavinsk polygon destruction of military equipment, Polygon of Zhangiztobinsk destruction of military equipment, former military bases in northern Balkhash. In addition of that, based on the data of Agency "Greenwomen" (2006) and analyzed production and industrial potential of the country the quantity of sources of PCB is reported /2/ By considering the number of transformers and the number of target livestock (cattle, sheep and goat, horse and camel), the maximum risk for the two indicators are the Pavlodar and East Kazakhstan region (Figure 1). . The main livestock regions in the country are: (i) South-Kazakhstan, Almaty, Zhambul and East-Kazakhstan for sheep (more than 2 000 ths heads), (ii)Almaty, South and East-Kazakhstan for cattle (more than 500 ths heads) and horse (more than 200 ths heads) , (iii). southern-west part of Kazakhstan for camel /8/.

Animal food products and ecological situation of Kazakhstan

Despite this potential of pollution, PCB contamination of food produced by animals in Kazakhstan appeared low according to the partial available published data. In a comparative study on the contamination of camel milk in Atyrau, Kyzylorda, Zhambul and South Kazakhstan oblasts, only samples from Kyzylorda oblast presented high level (0,95 ng/g) of PCB and mainly PCBs 52 and 138 /3/. Organic pollutants as PCBs being highly liposoluble, their presence in milk are linked to the fat which is in relative high proportion in camel milk in Kazakhstan (5,9-6,7%) /9/. In human breast milk from Almaty, Shymkent and two cotton growing area of South Kazakhstan Oblast (Djetisay and Kyrov), from the cities nearest of the Aral Sea (Aralsk and KyzylOrda), and from a site of petrochemical exploration on the Caspian Sea (Atyrau), the mean concentration of total PCBs was 410 ng/g fat. Concentrations of six PCB congeners (28, 52, 101, 138, 153, 180) were reported between 100 and 350 ng/g fat /4/. In Aral sea region, it was revealed that the PCBs was 1900 μg/kg in lipid of plasma of children, which was higher than in Europe /6/. PCDD/Fs in camel milk from Almaty, Atyrau, Aralsk, Shymkent were investigated. The concentration of PCDD/Fs were higher in the Atyrau oblast. This result could be linked with oil extraction in this region /7/.

Regarding the low level of organic pollutants in camel milk in polluted areas mentioned above, three hypotheses could be advanced: 1) the moving of camels in a wide areas with low pollution pressure; 2) the specific prehensive behavior would make them less exposed to ingest pollutants via the soil, the main accumulation matrix; 3) a low efficiency to digest lipids and lipophilic compounds combined to a huge storage aptitude in the humps may lead to less excretion in milk/5/.

The preliminary results of study of PCB transfer to the Camel milk

Nevertheless, the available data reported in the present paper, cannot support the understanding of the mechanisms of exposure and of detoxification. The assessment of contamination risk is not yet known in the situation of Kazakhstan. There is urgent need to achieve such studies for a convenient evaluation of the polluting impact for the human and animal population of the country. So, for understanding the ability of contamination and mechanisms of detoxification of camel by the cinetic of PCBs (polychlorinated biphenyls) in the milk, blood and hump fat tissues we did experiment with 4 lactating Bactrian Camels during 6 months. The main expected results are the definition of the dynamics of accumulation of PCBs in the milk, blood and hump fat tissues. We expect to identify the target tissues of contaminants, and explain the mechanism of accumulation of pollutants in camels. The data of the research will help to calculate the effect of PCBs on human health, who consume camel milk in ecological territories. In such way it will be possible to make more detailed recommendations to consumers regarding the wide using of products of camel breeding in the population of Kazakhstan and other countries. The preliminary results based on the monitoring of PCB content in two Bactrian camel milk for more than 4 months contaminated daily with 43.66 mg PCB per animal (1.3 µg/kg LW) for 56 days, underlined the important changes linked to the total fat. Indeed, the total PCB determined in milk (figure 1) appeared in close relationship with the totl fat excreted in milk (figure 2).

Figure 1. Total PCB determined in two camel milk after 56 days of contamination (from 21/6 to 23/8).

Figure 2.Total quantity of fat excreted in two camel milk for more than four months

However, after the end of contamination (on 23 August), in spite of the increase in fat excretion, the quantity of PCB is less important than expected by the quantity of fat. To interpret the results, the analyses of quantity of PCB in hump fat has to be achieved.

However, these preliminary results are encouraging. The determination of total PCB present in fat storage (hump) will be the key-point to understand the kinetic of decontamination and the way of excretion of PCB through the milk.

References

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