Citation:

Oudejans, L., A. Mysz, E. Snyder, B. Wyrzykowska-Ceradini, J. Nardin, D. Tabor, J. Starr, D. Stout, AND P. Lemieux. Remediating Indoor Pesticide Contamination from Improper Pest Control Treatments: Persistence and Decontamination Studies. D.Aga (ed.), JOURNAL OF HAZARDOUS MATERIALS. Elsevier Science Ltd, New York, NY, 397(122743):1-11, (2020). https://doi.org/10.1016/j.jhazmat.2020.122743

Impact/Purpose:

The improper and excessive use of pesticides in indoor environments can result in adverse human health effects, sometimes necessitating decontamination of a residential or commercial building to reduce potential occupant exposure. Decontamination studies evaluated the effectiveness of several liquid-based surface decontaminants against pesticides on indoor surfaces. These results will inform responders and public health officials on potential decontamination approaches to remediate indoor surfaces, will reduce unnecessary pesticide exposure to occupants, and will contribute to the development of standard protocols for decontamination.

Description:

Under the U.S. Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), it is a violation to use a pesticide in a manner inconsistent with the product’s labeling (commonly referred to as pesticide misuse or misapplication). The improper and excessive use of pesticides in indoor environments can result in adverse human health effects, sometimes necessitating decontamination of a residential or commercial building to reduce potential occupant exposure. A lack of information on effective approaches to remediate pesticide residues from indoor surfaces prompted the decontamination and persistence studies described in this work. Decontamination studies evaluated the effectiveness of several liquid-based surface decontaminants against pesticides on indoor surfaces. Building materials, representing nonporous and porous surfaces, were contaminated with common pesticides, including malathion, carbaryl, fipronil, deltamethrin, and permethrin as well as commercial formulations thereof. Pesticide surface concentrations were representative of the pesticide-specific levels measured during field investigations involving misapplications of pesticides in homes or businesses (25–2,400 µg/100 cm2 surface concentration range). Decontamination testing occurred via a single or repeated application of the decontaminant without further mechanical removal or rinse steps. Decontaminants were both off-the-shelf and specialized solutions representing various chemistries (hypochlorite, hydrogen peroxide, quaternary ammonium compounds and ammonium salts). The persistence of surface residues was also investigated to assess the potential reduction of pesticide mass on surfaces under simulated indoor environmental conditions. Pesticides included in this study were found to be highly persistent over a 140-day period, especially in a dark indoor environment. Indoor light conditions can lead to degradation of some of the pesticides, but significant amounts remain after 140 days. Decontamination efficacy results indicated that the application of household bleach or specialized decontaminants (EasyDECON® DF200 and Sterilex® Ultra-Kleen) offered the highest efficacy for malathion and carbaryl. Bleach and EasyDECON®DF200 decontaminants effectively removed other targeted pesticides and commercial pesticide formulations. The presence of selected toxic decontamination byproducts (e.g., oxons) were qualitatively confirmed in a limited number of samples for selected pesticide-decontaminant combinations. These results will inform responders and public health officials on potential decontamination approaches to remediate indoor surfaces, will reduce unnecessary pesticide exposure to occupants, and will contribute to the development of standard protocols for decontamination.

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