ISO 23517 pdf free download

ISO 23517-2021 pdf free download.Plastics一Soil biodegradable materials for mulch films for use in agriculture and horticulture – Requirements and test methods regarding biodegradation, ecotoxicity and control of constituents.
5.2 Ultimate aerobic biodegradation
5.2.1 Test method and evaluation criteria
The ultimate aerobic biodegradability shall be determined for the whole material or for each organic constituent.
Test samples shall not be subjected to conditions or procedures, such as a pre-treatment by heat and or an exposure to radiation exposure, designed to accelerate biodegradation prior to testing according to
Iso 17556.
The material is considered to have demonstrated a satisfactory rate and level of biodegradation in soil ii, when tested in accordance with ISO 17556, it achieves a minimum biodegradation percentage as specified hereunder:
a) 90 % of the organic carbon shall have been converted to CO2 by the end of the test period (relative to a reference material). Both the reference material and the test item shall be tested for the same length of time and the results compared at the same point in time;
b) as an alternative, 90 % (in absolute terms) of the organic carbon shall have been converted to carbon dioxide by the end of the test period.
lithe level of biodegradation exceeds 90 % (relative to a reference material or in absolute terms), then the biodegradation test can be terminated. However, the test period shall be no longer than 2 years.
The biodegradation test shall be performed at a temperature constant to within ±2 °C in the range between 20 °C and 28 °C, preferably 25 °C.
Use, as reference material, a well-defined biodegradable polymer (microcrystalline-cellulose powder or ashless cellulose filters). If possible, the physical form and size of the reference material should he comparable to that of the test material.
The validity criteria as stated in ISO 17556 shall be fulfilled.
NOTE Biodegradability is assessed by measuring the mineralization level, i.e. the conversion of the organic carbon of a product or a material into CO2 with the consumption of 02 under aerobic conditions, or into CO2 and CH4 under anaerobic conditions. During biodegradation, part of the organic carbon is also assimilated as biomass. This biomass yield typically ranges from 10 % to 40 %. depending on the substrate. As a consequence, the mineralization level rarely reaches 100 % also when the biodegradation is 100 %, because of biomass formation. Standard test methods for the accurate determination of product’s or material’s carbon assimilated in biomass during biodegradation are not available yet.
5.2.2 RequIrements regarding constituents
Organic constituents which are present at concentrations of less than 1 % (dry mass) do not need to demonstrate biodegradability. However, the sum of such constituents shall not exceed 3 % (dry mass).
For organic constituents which are present in the material at a concentration between 1 % and 15 % (by dry mass), the level of biodegradation shall be determined separately and meet the criteria specified in £21.. Organic constituents at a concentration between 1 % and 15 % (by dry mass) that turned out to be readily biodegradable in a ready biodegradation test according to an OECD test guideline (OECD 301, Methods A to FlUJ; OECD 3lOL1J) are considered as biodegradable in the context of ISO 23517.
As an alternative to testing the single organic constituent used between 1 % and 15 % (by dry mass), the level of biodegradation of that organic constituent can be determined using an artificial blend of the same material consisting of at least 15 % by total organic carbon (TOC) content. In case this artificial blend meets the criteria specified in 5.2.1. then the organic constituent in question is considered to be biodegradable in the context of ISO 23517 and can be used at the same or lower concentration in a material on the condition that the co-substrate is present as tested in the artificial blend.
Carbon black which is frequently used in mulch film is an inert solid. Therefore, it is not considered as an organic constituent and shall not be accounted in the calculation of the degree of biodegradation.
NOTE The objective of testing an artificial blend is to demonstrate that a constituent which does not meet the biodegradability requirements of ISO 23517 when tested alone, may become biodegradable in combination with another biodegradable constituents of a material. The concentration of the constituent in the artificial blend was set at a minimum of 15 % in order to avoid false-positive results, as theoretically a material with, for example, 10% of a non or moderately biodegradable constituent may still reach the pass level for biodegradation specified in £Z..1.
5.3 Negative effects on terrestrial organism
5.3.1 Ecotoxiclty testing scheme
Ecotoxicity tests shall be performed in order to investigate possible adverse effects caused by degradation products resulting from the degradation of the material of a mulch film in soil at the end of the intended service life.
The test scheme takes into account:
— all relevant terrestrial organism groups as plants, earthworms (invertebrates) and microorganisms;
— important ecological processes critical due to their role in maintaining soil functions as breakdown
of organic matter, formulation of soil structure and cycling of materials;
— all relevant exposure pathways as soil pore water, soil pore air and soil material.
The link between soil organism groups of major ecological importance covering all significant soil exposure pathways and suitable test methods for the evaluation of ecotoxicity of the materials of mulch films and their degradation products is shown in Table 1.ISO 23517 pdf download.