Abstract

RIOS, Francisco Teodoro; WIERNA, Norma Rosario; RUGGERI, María Alejandra  and  BOVI MITRE, María Graciela. Determination of ethylenethiourea in chard treated with Zineb: Effect of wet heat by boiling. Acta toxicol. argent. [online]. 2016, vol.24, n.3, pp.180-186. ISSN 1851-3743.

Zineb is a pesticide belonging to the family of ethylenebisdithiocarbamates (EBDC) widely used in the province of Jujuy, Argentina. The toxicity of this fungicide is given by the ethylenethiourea (ETU) which is the main product of degradation. The ETU has mutagenic, teratogenic and carcinogenic effects in animals. The EPA classifies it as a probable human carcinogen. The aim of the study was to determine the transformation of Zineb to ETU in cultivated chards in Jujuy, by treatment with humid heat. The method is based on extraction of ETU with water and subsequent extraction of the aqueous phase with dichloromethane. The extract was cleaned by alumina column chromatography and the ETU was quantified by HPLC with a UV-Visible detector at 232 nm. An experimental cultivation of chards was carried out and the Zineb fungicide was applied and then quantified at different time periods. The ETU was quantified with and without application of moist heat. The concentration of ETU in heat treated chards was 8.07 mg/kg and after 30 days decreased to 0.05 mg/kg, representing a decrease of more than 99 % over the initial concentration. Simultaneously, Zineb concentration in chard was initially determined as 44 mg/kg and, 36 days later, the Zineb concentration decreased to 3.83 mg/kg, representing a 91% decrease with respect to the concentration of the pesticide at the beginning. Detection of ETU in chards subjected to heat treatment confirms the transformation of the fungicide Zineb to a degradation product classified by the IARC as group 3. This puts into discussion the current Argentine regulations since, at the end of the deficiency times the presence of potentially toxic metabolites or degradation products is not evaluated.

Keywords : Ethylenethiourea; Zineb; Chards; Heat treatment.

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