Biological and Economic Analysis Division, Office of Pesticide Programs, US Environmental Protection Agency, USA.
Environ Sci Technol. 2011 Nov 15;45(22):9711-8. doi: 10.1021/es201278p. Epub 2011 Oct 18.
A variety of agricultural films are commercially available for managing emissions and enhancing pest control during soil fumigation. These films are manufactured using different materials and processes which can ultimately result in different permeability to fumigants. A systematic laboratory study of the permeability of the agricultural films to nine fumigants was conducted to evaluate the performance of commonly used film products, including polyethylene, metalized, and high-barrier films. The permeability, as expressed by mass transfer coefficient (cm/h), of 27 different films from 13 manufacturers ranged from below 1 × 10(-4) cm/h to above 10 cm/h at 25 °C under ambient relative humidity test conditions. The wide range in permeability of commercially available films demonstrates the need to use films which are appropriate for the fumigation application. The effects of environmental factors, such as temperature and humidity, on the film permeability were also investigated. It was found that high relative humidity could drastically increase the permeability of the high-barrier films. The permeability of some high-barrier films was increased by 2-3 orders of magnitude when the films were tested at high relative humidity. Increasing the temperature from 25 to 40 °C increased the permeability for some high-barrier films up to 10 times more than the permeability at 25 °C, although the effect was minimal for several of these films. Analysis of the distribution of the permeability of the films under ambient humidity conditions to nine fumigants indicated that the 27 films largely followed the material type, although the permeability varied considerably among the films of similar material.
市面上有多种农用薄膜可用于管理土壤熏蒸过程中的排放并增强虫害控制。这些薄膜是由不同的材料和工艺制造的，最终可能导致对熏蒸剂的渗透性不同。为了评估常用薄膜产品（包括聚乙烯、金属化和高阻隔薄膜）的性能，对农用薄膜对九种熏蒸剂的渗透性进行了系统的实验室研究。在环境相对湿度测试条件下，25°C 时，13 家制造商的 27 种不同薄膜的渗透率（以质量传递系数 (cm/h) 表示）范围从低于 1×10(-4) cm/h 到高于 10 cm/h。商业上可用的薄膜渗透率范围很广，这表明需要使用适合熏蒸应用的薄膜。还研究了环境因素（如温度和湿度）对薄膜渗透率的影响。结果发现，高相对湿度会大大增加高阻隔薄膜的渗透率。当在高相对湿度下测试时，一些高阻隔薄膜的渗透率增加了 2-3 个数量级。将温度从 25°C 升高到 40°C 会使一些高阻隔薄膜的渗透率增加 10 倍以上，尽管对其中一些薄膜的影响很小。在环境湿度条件下对九种熏蒸剂的薄膜渗透率分布进行分析表明，27 种薄膜主要遵循材料类型，尽管类似材料的薄膜之间渗透率差异很大。
