1.1 This specification covers plastic materials that are designed to ultimately biodegrade when in contact with soil without diminishing the value or utility of the soil or creating any adverse impact on the environment via the degradation products. These plastic materials can be used to make products for horticultural, agricultural, and soil erosion control applications (e.g. mulch films) that are applied in or on soil where, after use, they can aerobically biodegrade. 1.2 This specification defines criteria for showing sufficient inherent biodegradability and absence of negative effects in topsoil of plastic materials in primary forms (resin pellets). The referenced biodegradability is an innate property of the plastics used and implies that biodegradation will start immediately after exposure to soil. 1.3 The effective degradation rate of a product made with a plastic biodegradable in soil will be clearly affected by its size, shape, thickness. The assessment of the effect of said characteristics on the degradation rate of biodegradable products in real life applications is outside the scope of this standard specification. Refer to the proper standard specifications, if available, if information on product degradation is sought. 1.4 This specification does not cover field performance of products made with biodegradable plastic materials. Biodegradable plastic product lifetime in the field will generally be affected by thickness and shape. The assessment of performance of products made with biodegradable resins is outside the scope of the present specification. 1.5 Plastics that are designed to biodegrade in soil but that do not possess such biodegradability as an innate property are outside the scope of this specification 1.6 Although results may indicate that the tested plastic material will biodegrade under the specified test conditions at a certain rate, it is cautioned that the results of any laboratory exposure in this specification cannot be directly extrapolated to soil environments at the actual site of use or disposal since soil properties, local temperatures and humidity ranges must be considered as they vary widely with geography. Field testing shall be performed to establish a correlation with laboratory methods for specific uses.
Plastics that are biodegradable in soil have many applications such as erosion control, horticulture, agriculture, and so forth. The great value of these products is that they are applied in a natural environment and no effort is needed to remove them after use. There is an increasing demand from the marketplace to differentiate such soil-biodegradable plastics and ensure that plastics used for such applications are safe for the environment.
Keywordsplastics; soil biodegradable; biodegradable
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
Francesco Degli Innocenti
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