Apparel fabrics as barriers to pesticide penetration

In this research, a controlled laboratory method to expose fabrics to pesticide spray for pesticide penetration measurement was devel oped. Pesticide penetration was measured as a function of the fabric variables construction, surface treatment, fiber content, thickness, air permeability, weight, surface energy and spray rating. In addition, variations of pesticide chemical class were investigated.

A spray chamber, delivering a controlled amount of pesticide spray to fabric samples was designed, built and validated. This equipment allows fabrics to be exposed in controlled laboratory conditions using a spray like that used in field spraying.

Twenty-three fabrics were tested in this study including fabrics representing clothing worn by agricultural workers, disposable fabrics designed for protective apparel, experimental fabrics, and fabrics designed to compare fiber content and surface treatments. These properties were compared with the amount of pesticide that penetrated through the fabrics and those properties having the greatest influence on penetration were identified.

Four pesticides were used in this study. Chemical classes of chlorinated hydrocarbons and organophosphates were represented. The pesticide was applied in spray form to a multilayer sample containing the test fabrics. The samples were allowed to dry, the layers were then separated, the pesticide was extracted from each layer, and the quantity of pesticide determined to the nanogram level using gas chromatography.

Results showed the fabric variables of construction, thickness, air permeability, surface treatments, and fiber content influenced penetration. Fabric construction influences other fabric variables of thickness and air permeability, however, fabric construction had the largest impact on penetration. Fabrics of twill construction allowed less penetration than fabrics of plain construction or four nonwovens. Thickness also had a large influence on penetration; as fabric thickness increased, penetration decreased. Air permeability had some influence; as air permeability increased, penetration increased. The effect of surface treatments was dependent on the specific treatment; impermeable coatings eliminated penetration, repellent and soil release finishes reduced penetration, and durable press finishes increased penetration. Fiber content had a small impact on penetration; fabrics containing cotton allowed less penetration than fabrics of 100% polyester.

Pesticide penetration did vary depending on pesticide. Differences were not related to chemical class but were thought to be due to the inert ingredients of the formulations.