Experimental evaluation of chronic oral exposure to lewisite oxide

Introduction. In order to ensure the federal state sanitary and epidemiological control (supervision) over the degree of contamination by toxicants of facilities where chemical weapons have been eliminated, it is necessary to have appropriate hygienic standards. However, for the most toxic and hazardous among the products of the destruction of toxic substances, 2-chlorvinylarsinoxide, there is no experimentally justified maximum permissible concentration of its content in the water of reservoirs. At the same time, the chronic toxicity of the compound, which is a key section in the development of this safety standard, has not been investigated.

Material and methods. The object of research was 2-chlorvinylarsinoxide (lewisite oxide, C₂H₂ClAsE, CAS No. 3088-37-7). Specific gravity: d₄²⁰ = 1.524 g/cm³; mass fraction of the substance – 96%. It is formed during the hydrolysis of lewisite, is poorly soluble in water, and has high stability.

Results. Chronic intragastric intake of lewisite oxide into the rat body at doses of 0.05 mg/kg, 0.015 mg/kg and 0.005 mg/kg was accompanied by changes in the complex of indicators. At the same time, a linear dose-effective dependence was registered. Thus, the maximum number of statistically significant changes was detected when exposed to a chemical agent at the highest level and amounted to 18, of which 5 had bisigmal deviations from similar indicators in the control group. In the second experimental group, a decrease in the toxic effect was recorded, as evidenced by 12 significant shifts in indicators, two of which exceeded two sigma relative to the control. In the third experimental group of rats, the ratio under consideration was 5/0, and significant deviations in the indicators mainly had unidirectional residual signs of the general toxic effect of the compound, which is characteristic of it in higher doses.

Limitations. The study of the chronic toxicity of lewisite oxide does not provide for an assessment of its long-term effects.

Conclusion. Based on the current diagnostic criteria, the compound dose of 0.005 mg/kg is accepted as the threshold for chronic general toxic effects. The revealed features of the negative effect of lewisite oxide are taken into account when substantiating its MPC in the water of reservoirs.

Compliance with ethical standards: The experimental study was approved by the independent ethics committee at the Scientific Research Institute of Hygiene, Toxicology and Occupational Pathology of the FMBA of Russia (Protocol No. 3 dated December 11, 2023).

Authors’ contribution:
Maslennikov А.А. – concept and design of the research, analysis of the results, writing the text;
Khodykina N.V. – planning and execution of the research;
Grishina M.A. – statistical data processing;
Velikorodnaya Yu.I. – collection and processing of the material;
Novikova O.N. – editing;
Dulov S.A. – concept and design of the research, analysis of the results, editing;
Zemlyanoy A.V., Yerunova N.V., Kucherskoy S.A. – analysis of the results, editing.
All co-authors – approval of the final version of the article, responsibility for the integrity of all parts of the article.

Conflict of interests. The authors declare no conflict of interests.

Funding. The study was conducted within the framework of the State contract "Experimental studies to substantiate the maximum permissible concentration of chlorvinylarsinoxide in the water of water bodies for household, drinking, cultural and domestic water use".

Received: September 17, 2025 / Revised: September 29, 2025 / Accepted: October 2, 2025 / Published: November 19, 2025

1. Ptichkin S. Chemical weapons destruction facilities are being transferred to civilian service. Rossiyskaya Gazeta (RG.RU): [website]. 09/28/2020. URL: https://rg.ru/2020/09/28/obekty-po-unichtozheniiu-himoruzhiia-perevodiat-na-grazhdanskuiu-sluzhbu.htm (date of request: 07/04/2025). (in Russian)

2. Chachilo P. The bar on the highest mark. Economics / Peter Chachilo. Udmurtskaya Pravda: Republican socio-political newspaper. 2019; 22 Aug. URL: https://udmpravda.ru/rubrics/ekonomika/371145-planka_na_vysshey_otmetke/ (date of reference: 07/04/2025). (in Russian)

3. Franke Z. Chemistry of toxic substances [Ximiya otravlyayushhix veshhestv]. Translated from German/ Z. Franke, P. Franz, V. Warnke. Ed. Knunyanz I.L. and Sterlin R.N. Moscow: Ximiya. 1973;1: 236. (in Russian)

4. Savin Yu.I., Vishenkova E.M., Pasinkova E.M. Investigation of the behavior of mustard gas and lewisite in water and soil under conditions imitating natural environments. Zhurnal Rossijskogo ximicheskogo obshhestva im. D.I. Mendeleeva. Problemy` unichtozheniya ximicheskogo oruzhiya. 1995; 39(4): 121–5. (in Russian)

5. Kolb V.G., Kamyshnikov V.S. Handbook of clinical biochemistry [Spravochnik po klinicheskoj bioximii]. Minsk: Belarus, 1982; 368. (in Russian)

6. Kebot E., Meyer M. Experimental immunology [E`ksperimental`naya immunologiya]. Moscow: Medicinе; 1968, 681. (in Russian)

7. Zaks A.S., Bykova A.A., Yushkova T.A. Express micromethod for determining the number of T- and B-lymphocytes in human blood. Laboratornoe delo. 1986; 4: 242–3. (in Russian)

8. Blinov N.I. Determination of serum immune proteins according to the turbidity reaction with zinc sulfate ю Clinical laboratory diagnostics in veterinary medicineх [Opredelenie immunny`x belkov sy`vorotki po reakcii pomutneniya s sul`fatom cinka. Klinicheskaya laboratornaya diagnostika v veterinarii. Moscow: Agropromizdat, 1985; 211–2. (in Russian)

9. Fedoseeva V.N., Ordin G.V., Kovalchuk L.V. et al. Guidelines for immunological and allergological methods in hygienic research [Rukovodstvo po immunologicheskim i allergologicheskim metodam v gigienicheskix issledovaniyax] Moscow: Promedek; 1993. 320. (in Russian)

10. Smirnova O.V., Kuzmina T.A. Determination of bactericidal activity of blood serum by photonephelometry. Zhurnal mikrobiologii, e`pidemiologii i immunobiologii. 1966; 4: 8–11. (in Russian)

11. Indirect hemagglutination reaction. Collection of articles/ ed. by T.V. Piradze. [Reakciya nepryamoj gemagglyutinacii. Sbornik statej. Otv. red. T.V. Piradze]. Leningrad: Leningradskij NII e`pidemiologii i mikrobiologii im. Pastera. Leningrad: 1981. (in Russian)

12. Khabriev R.U. Guidelines for the experimental (preclinical) study of new pharmacological substances [Rukovodstvo po e`ksperimental`nomu (doklinicheskomu) izucheniyu novy`x farmakologicheskix veshhestv]. Moscow: Medicine, 2005. (in Russian)

13. Lakin G.F. Biometrics. [Biometriya]. Moscow: Vysshaya shkola. 1990. (in Russian)