0 Introduction

The use of plastics and particularly polyoleﬁn-based plastics has signiﬁcantly increased over the past decades in many applications.[1] Driven by low costs and strong supply chains, polyoleﬁns have become the material of choice for many product applications. The result of this widespread use has meant that the end-of-life scenarios of these materials has come under ever-increased scrutiny. There are four major end-of-life scenarios of plastic materials. [2]

a) landﬁll;
b) incineration/waste-to-energy;
c) mechanical recycling; and
c) litter or leakage into the natural environment.

Whilst well-known standards and/or industry-accepted protocols exist for determining the applicability or performance of a plastic material in scenarios a), b) and c), previous standards in scenario d) have identiﬁed guidelines, but have not speciﬁed outcomes. In addition, they have sought to pre-determine the type of degradation process, rather than producing numerical criteria associated with the performance of the material under the stated test conditions.

NOTE 1 Similarly to standards within scenarios a), b) and c) for end-of-life of plastic materials, which do not overlap with each other when evaluating a plastic material, this PAS does not overlap with standards relating to landﬁll, incineration or recycling of plastics. This PAS provides data on the material only related to the end-of-life scenario as stated in scenario d): littering or leakage into the natural environment.

Within all plastic materials, polyoleﬁn-based plastics are the most littered category (approx. 50% of total). [2] More speciﬁcally, 75% of all fugitive plastic is land based.[3][4] It is widely accepted that fugitive plastic on land goes through a process of weathering, normally resulting in the generation of microplastics, followed by limited soil biodegradation depending upon the environmental conditions.[3]

NOTE 2 A deﬁnition of microplastics can be found in Annex G.

The problem is that polyoleﬁns are hydrocarbon-based materials that are resistant to environmental stimuli and inert to biological attack. Due to the ever-growing problem of plastic pollution and the need to innovate within current polyoleﬁn-based packaging, additive-based solutions are being proposed as biodegradable innovations within polyoleﬁnic materials. Although these additive-based innovations have been known for some time, previous standardization efforts have covered only speciﬁc aspects of polyoleﬁn use, such as durability (via weathering testing), degradation or loss of physical properties due to aging over time or biodegradation under selected conditions. The primary objective of this PAS is to provide a standard speciﬁcation that provides numerical data on the biodegradability of a given polyoleﬁn containing a speciﬁc biodegradable additive under open-air terrestrial conditions. The PAS is speciﬁcally designed to simulate the overarching process of biodegradability in an unmanaged environment, as in the case of littering or unmanaged disposal. It does not provide data on how a polyoleﬁnic material would perform under managed biodegradable end-of-life scenarios such as industrial or home composting, anaerobic digestion, or organic recycling.

NOTE 3 Biodegradability in unmanaged aquatic or marine environments is not considered in this PAS. These environments will be considered upon revision of this PAS depending upon available standards and evidence.

To achieve the objective of this PAS, internationally accepted existing standards in relation to the three key stages of concern with respect to biodegradability in an open-air terrestrial environment will be referenced accordingly. These standards will be further augmented in line with written protocols to specify the conditions and timeframes used for the testing at each stage. The three stages represented are:

1) weathering of the polyoleﬁnic material under speciﬁc conditions and timeframes, after which chemical analysis proves that the polyoleﬁnic material has been transformed into a wax containing a speciﬁed carbonyl index;
2) an assessment of the eco-toxicity of the wax using three sentinel species to determine that the wax presents no hazardous or inhibiting effects; and
3) biodegradation of the wax under mesophilic conditions using exclusively soil as the medium for the test to reﬂect unmanaged disposal conditions.

NOTE 4 An overview of the approach and pass-fail criteria can be found in Annex A.

NOTE 5 Specifying that the biodegradation testing achieves a degree of mineralization greater than 90% avoids the generation of microplastics.

The PAS aims to standardize the effectiveness of technologies that impart biodegradability within polyoleﬁns by providing data on the performance of the tested technology under the stated conditions. Only by meeting the requirements of the standardized testing in all stages of this PAS is a technology within a given polyoleﬁnic material composition deemed to be compliant.

This PAS does not specify the origin of the raw materials used in the polyoleﬁn composition. Claims around bio-based content are to be made in accordance with relevant standards. In addition, the PAS does not specify the use-life or durability aspects of the polyoleﬁnic material under evaluation.

NOTE 6 If an assessment of the bio-based content of a polyoleﬁnic material is desired, further reading of BS EN 16640 and BS EN 16785‑1 is recommended.

NOTE 7 The compatibility of innovative polyoleﬁn packaging entering the market and its current recycling streams is covered by relevant industry recycling protocols.

The PAS is not intended for making claims of biodegradability, nor for product (self-) declaration. Compliance with the PAS would provide the numerical evidence to support claims about the performance of the technology within polyoleﬁns in alignment with BS EN ISO 14021.

NOTE 8 Attention is drawn to the legal requirements of the territory of use of the polyoleﬁnic material.

PAS 9017:2020

Plastics. Biodegradation of polyolefins in an open-air terrestrial environment. Specification

Current

Published:

31 Oct 2021