МЕТОДИЧЕСКИЕ ПРОБЛЕМЫ ХИМИКО-АНАЛИТИЧЕСКОГО ОБЕСПЕЧЕНИЯ БЕЗОПАСНОСТИ ПРОДУКЦИИ, ВЫРАЩЕННОЙ С ПРИМЕНЕНИЕМ ДИТИОКАРБАМАТОВ

Ракитский В.Н.¹, Юдина Т.В.², Федорова Н.Е.³

¹Академик РАН, доктор медицинских наук; ²доктор биологических наук, профессор; ³доктор биологических наук, Федеральный научный центр гигиены им. Ф.Ф. Эрисмана

МЕТОДИЧЕСКИЕ ПРОБЛЕМЫ ХИМИКО-АНАЛИТИЧЕСКОГО ОБЕСПЕЧЕНИЯ БЕЗОПАСНОСТИ ПРОДУКЦИИ, ВЫРАЩЕННОЙ С ПРИМЕНЕНИЕМ ДИТИОКАРБАМАТОВ

Аннотация

В статье представлены результаты исследований по изучению значимости биодеградации пестицидов класса этилен-бис-дитиокарбаматов с образованием этилентиомочевины в сельскохозяйственной продукции (винограде, огурцах, луке, картофеле, томатах), а также отдельных продуктах переработки.

Ключевые слова: дитикарбаматы, безопасность сельскохозяйственной продукции, аналитический контроль.

Rakitskiy V.N. ¹, Yudina, T.V. ², Fedorova N.E. ³

¹Academician of Russian Academy of Sciences, PhD in medicine; ²PhD in biology, professor; ³PhD in biology, Federal scientific center of Hygiene named after F.F. Erisman

METHODICAL PROBLEMS OF CHEMICAL AND ANALYTICAL SAFETY OF  PRODUCTS GROWN WITH APPLICATION OF  DITHIOCARBAMATES

Abstract

The article presents the results of the research of the significance of biodegradation ethylene-bis-dithiocarbamate formulations with the formation of ethylenethiourea in agricultural products (grapes, cucumbers, onions, potatoes, tomatoes) and some processed products.

Keywords: dithiocarbamates, safety of agricultural products, analytical control.

The problem of common chemical exposition on people, accurate estimation of levels of polluting substances present in the environment, characteristic of the determinants of earnings in the human body, cannot be achieved without modern methodologies and analytical identification xenobiotics.

In domestic agriculture permitted the use of some 600 pesticides of which 15 names dithiocarbamic acid derivatives, particularly among these are products based on ethylene-bis-dithiocarbamates - mancozeb, zineb, metiram, toxic effects are due to the formation of the main metabolite - ethylenethiourea (ETM) that are carcinogenic, mutagenic, teratogenic.

That fact is important that in the process of storage and processing of products treated with dithiocarbamates, as well as the direct cooking, ETM levels may increase, since the substance has the ability to cross-media transitions that define the importance of monitoring studies of residues of dithiocarbamates and ETM.

The data received, as well as some foreign publications [1, 2] clearly demonstrate that CS₂ values determined by using the acid digestion method of crops rich in secondary metabolism of sulfur compounds have to be interpreted carefully. Therefore, an accurate conclusion about the content of dithiocarbamate in carbon disulfide is possible with the obligatory statement of his background values in a particular culture, which provided a similar study of a sample not subjected to treatments with fungicides of this class. Taking into account this position (In view of this position), these methods used by authorities in foreign and national practice to measure the presence  dithiocarbamates in different crops.

Methodology for determining the ETM - polar, water soluble compound includes all known chromatographic techniques - chromatography in a thin layer of sorbent (TLC), gas-liquid (GLC) and high performance liquid chromatography (HPLC).

TLC method is essentially a semi-quantitative, GLC provides high sensitivity, specificity and accuracy, but there is possibility of formation of ETM in the reaction process of sample preparation as a product of the destruction of dithiocarbamate, which is present in a sample that overestimates the results.

In the methodical workings out undertaken by us the highly performance  liquid chromatography - a method of a direct measurement of ETM values, excluding stages of degradation of the operating substance, noted above has been selected.

Certainly a promising approach in the development of analytical control as dithiocarbamates and their metabolites is application of liquid chromatography technique in combination with MS detection, especially with the atmospheric pressure ionization interface, offers new possibilities that have not been explored yet. However, still more difficult step remains the sample preparation because the instability of the dithiocarbamates, which are affected especially by pH, temperature and also plant component.

In development of the problem of minimizing or eliminating the risk of contamination of Pesticide Residues class of ethylene-bis-dithiocarbamate in 2005-2013 years  conducted a large-scale research of the significance of biodegradation mancozeb-, zineb- and metiram-containing formulations with the formation of ethylenethiourea in agricultural products (grapes, cucumbers, onions, potatoes, tomatoes) and some processed products.

Analytical control of mancozeb and ETM residues in grapes in the dynamics of selection (0-th, 15-th, 20-th day) showed the presence of the active ingredient in hygienically significant values (33 - 2.7 MRL) at the 30-th and 45-th day (crop) - its residual amounts do not exceed 0.8 - 0.9 MRLs. The maximum level of metabolite (0.7 MPL) is identified in the grape crop. In samples of onions and cucumbers significant mancozeb concentration installed only on the day of plant treatment (onions - 23.4-25.5 MPL, cucumbers - 2.4-4.8 MPL), in subsequent periods of selection (15, 20-day), the active ingredient and metabolite in the samples were not found .

In the processed products - potato chips (mancozeb residues in potato tubers 0.017 mg/kg - 0.17MRL) and tomato puree (mancozeb values in tomato 0.04 mg/kg - 0.4MRL) there is not hygienic significant values of pesticide and metabolite. Mancozeb residues in samples of grape juice made of a crop of grape (mancozeb values - to 0.9MRL) is not exceeded 0.4MRL; ETM - 0.5MRL.

Thus, exceeding the hygienic standards for active substances and metabolites in crops of potatoes, tomatoes, grapes, onions, cucumbers, as well as processed products (chips, puree and juice) is not installed. The analytic data are consistent with the materials of foreign studies [3], showing the practical absence of ETM (less than 0.005 mg/kg - the detection limit) in grape juice, made from products grown with the use of dithiocarbamate fungicides, 82% of the samples of fruits and vegetables metabolite was level of 0.001 mg/kg (maximum content - 0.06 mg/kg). As dithiocarbamate residues, which are on surface, can be substantially diminished by vigorous washing, there is extremely important data about absence of excess of hygienic standards of ETM the in grape juice as grapes at its processing aren’t washed out.

Turning to the stability of metabolite storage of analytical samples of various crops in conditions of deep-frozen (-20⁰C) as an important stage of the analytical procedure, it is necessary to note its variability. During the 12-month period more than 70 % ЭТМ remain in tomatoes and wheat, storage within 2th years is undesirable because of the 50%-s losses of substance, in apples they exceed 50 % in a year, in this connection, an admissible period of storage of these samples – 6 months.

The above date illustrate in addition to the importance of the problem and the importance of introducing modern adequate methodological approaches in order to ensure the safety of agricultural products in the consumer market.

References

1. Blasco C., Font G., Pico Y. Determination of dithiocarbamates and metabolites in plants by liguid chromatography-mass spectrometry//J. of Chromatography A.- 2004.- Vol. 1028.- No 1.- P. 267-276.
2. Houeto P., Bindoula G. and Hoffman J.R. Ethylenebisdithiocarbamates and Ethylenethiourea: Possible Human Health Hazards// Environmental Health Perspectives.- 1995.- Vol. 103.- No 6. –P. 568-573.
3. Yess N.J. Gunderson E.L. and Roy R.R. US Food and Drug Administration monitoring of pesticides residues in infant foods and adult foods eaten by infants/children.// J. Assoc. Off. Analyt. Chem. - 1993. - Vol. 76.- P. 492-507.