Assessment of health risks associated with using N,N-diethyl-m-toluamide-based repellents (DEET)

N,N-diethyl-m-toluamide (DEET, CAS No. 134-62-3) is one of the first effective synthetic active substances used to prevent bites from blood-sucking insects. According to the parameters of acute toxicity, DEET is classified as a moderately hazardous substance upon acute exposure. No sensitizing effect has been identified, and it has a moderate irritating effect on the skin. It has a pronounced irritating effect on the mucous membranes of the eyes and a skin-resorptive effect. The problem of effects produced by repellents on health is caused by their widespread use among adults and children to protect themselves from blood-sucking insects.

The aim of this study is to substantiate reference doses for repellents and, based on the obtained data, to assess the risk for human health associated with using DEET-based repellents.
Two repellents were studied; both were sprays containing 7.5 % DEET (for children) and 50 % DEET (for adults). The ex-periments were conducted on 120 non-pedigree white rats of different ages kept in the institute's vivarium. The study relied on using conventional methods for assessing toxicity and hazards of repellents and biochemical methods for analyzing blood serum.

We studied the skin-resorptive effect of repellents with different DEET content on the functional state of immature and mature rats. Inactive, threshold, and effective doses were determined for each product, and reference doses were calculated. Based on the findings, the hazard coefficients were calculated for various conditions of using repellents for adults and children.

The study established that the hazard quotient for health was 0.068 when using a repellent with 7.5 % DEET content in conformity with the user guidelines and this was considered a minimal risk level. When using a product with 50 % DEET content, the hazard coefficient is 0.186 and this refers to a permissible (acceptable) risk level.