A test method for the evaluation of protective glove materials used in agricultural pesticide operations.

The ASTM Standard Test Method for Resistance of Protective Clothing Materials to Permeation by Liquids and Gases (F 739-85) and the recommended permeation cell have been modified to permit the testing of protective clothing materials for permeation by the low volatility, low water solubility active ingredients present in many pesticide formulations. The modification makes use of solid collection medium, a thin (0.02-in. thick) sheet of silicone rubber, to collect permeants. Those compounds permeating the protective material can then be desorbed into an appropriate solvent and analyzed using conventional methods and instruments. A series of permeation tests have been conducted using samples of 10 common, commercially available protective glove materials and the modified cell. Permeation of the active ingredient as well as carrier solvent components of several concentrated pesticide formulations containing low volatility, low water solubility active ingredients and aromatic hydrocarbon carrier solvents has been monitored. The relative breakthrough and the total mass of material permeating the glove materials appears to be strongly related to the concentration of the aromatic carrier solvent present in the formulations studied to date. The collection method was found to be less useful for monitoring the permeation of active ingredients, which have reasonably high water solubilities. The results obtained by using this method with samples of protective glove materials challenged by several concentrated pesticide formulations are described. For these formulations containing xylene boiling range aromatic solvents, gloves made of nitrile rubber, butyl rubber, and Silver Shield were most resistant to permeation; natural rubber and polyethylene glove materials were least resistant.

Migration of BHT and Irganox 1010 from low-density polyethylene (LDPE) to foods and food-simulating liquids.

The most widely used food-wrapping material is low-density polyethylene (LDPE). Food-wrap grades contain antioxidants to minimize degradation during processing and, in the final films, such additives are normally present at levels of several hundred ppm. During use, the antioxidants may migrate into food stored in LDPE wraps. Two typical antioxidants, BHT and Irganox 1010, were radiolabelled to allow accurate analytical measurement of the extent of their migration into foods and food-simulating liquids (FSL). The results show that BHT, a much smaller and more volatile molecule than Irganox 1010, migrates more rapidly into foods, but the differences are less for FSL. In most instances, migration appears to be controlled by diffusion of the antioxidant in the polymer, and the quantity lost can be correlated in a linear fashion with the square root of time. With aqueous FSL, and, presumably aqueous-type foods, however, anomalies result; the migration is often erratic, but is more closely related to time than to the square root of time. A tentative model developed to explain these facts assumes that the antioxidants decompose in aqueous media and the net migration rate is controlled largely by the rate of chemical decomposition. It is also shown that dry foods can be surprisingly effective sinks for antioxidants under typical storage conditions.

Migration of Irganox 1010 from ethylene-vinyl acetate films to foods and food-simulating liquids.

In a series of experiments on the migration of the antioxidant Irganox 1010 from ethylene-vinyl acetate (EVA) films into food-simulating liquids and foods, the antioxidant was found to migrate rapidly from EVA film into n-heptane, 100% ethanol and corn oil. The rate of migration into these media was greater from EVA than from low-density polyethylene (LDPE) under comparable conditions. In contrast, little migration of Irganox 1010 was recorded on exposure of the EVA film to aqueous media, whereas migration from LDPE into such media was relatively high.

Indirect food additive migration from polymeric food packaging materials.

Many foods contact polymeric packaging materials which contain residues of the polymerization process or additives employed to facilitate processing. The extent of migration of such materials from the packaging to foods is the focus of the present article. A major experimental program using eight polymer-migrant systems is described. Migration was measured to food-simulating liquids (FSL) and to foods. Accelerated tests were conducted with FSL under FDA guidelines conditions so as to develop correlations between such data and those found using foods under normal storage temperatures and shelf lives. In the majority of tests, the migration was found to be approximately proportional to the square root of time, to increase significantly with a rise in temperature, and to be proportional to the initial concentration of migrant in the polymer. Stirring in the FSL or food phase was generally not important except for the system involving dioctyl adipate migrating from polyvinyl chloride film. In some instances, after a period of time, migration rates became very low, and this effect was attributed to saturating the FSL or food phase with migrant. The foods comprised a variety of types, including liquid, semisolid, solid, and dry; both oily and aqueous foods were included. The physical steps involved in migration include the diffusion of the migrant from the interior of the film to the surface, where it can dissolve in the external FSL or food phase. The nature of the FSL or food is shown to be very important in that components can penetrate the polymer and dramatically increase migration rates. Consistent with the FDA guidelines in effect at the time of this study, testing was performed with five FSL (water, 3% acetic acid, 8% and 50% ethanol, and n-heptane) at 49 degrees C. Detailed comparisons were made between the migrations to foods and to FSL; following are the more relevant conclusions. (1) Three percent acetic acid showed no advantage over water as a food simulant even in those cases where the food could be considered acidic in nature. (2) Water, when used as an FSL at 49 degrees C for 5 days, overestimated migration in aqueous foods in about 75% of the cases. In some instances, however, the water phase became saturated with migrant. In other situations, this test protocol underpredicted migration--especially in those cases where there were components in the food that were able to penetrate into the polymer and enhance migration (such as orange juice).(ABSTRACT TRUNCATED AT 400 WORDS)