The compostable and biodegradable material landscape is covered in what can only be described as an alphabet soup of terms such as ASTM, EN, ISO, BPI … and the list goes on. In a market where organizations can make claims about compostable and biodegradable products without full knowledge of how a material will break-down, third party certifications are key to product credibility. So what do these certifications mean, and which ones are relevant to you and your customers? Well, as often is the case, this depends on your business. 

Biodegradability vs. Compostability
There is one point in particular to clarify before discussing compostable and biodegradable packaging certifications and that is the difference between “biodegradability” and “compostability”. Biodegradability refers to the ability of a material to break down in the presence of micro-organisms. This is a natural biological process and can occur in the presence of air (aerobic) to produce carbon dioxide and water or in the absence of air (anaerobic) to produce methane. Something that biodegrades in a landfill, for example, will produce large amounts of methane, a greenhouse gas that has 25 times the climate impact of carbon dioxide and has a harmful environmental impact. Compostability, on the other hand, refers to the ability of a material to break down to humus, carbon dioxide and water under a prescribed set of conditions. Part of the requirement for compostability is that a material readily biodegrades under aerobic conditions but there are additional requirements that ensure this occurs without harmful effects on the environment. Therefore, compostability is often a more appropriate descriptor for environmental performance than biodegradability alone.

Performance First
First and foremost, it is important to remember that no matter how many compostable or biodegradable certifications a packaging solution has, if the solution does not perform and provide product protection, it is not a sustainable solution. The environmental impact of a damaged product that must be returned, replaced (rebuilt or repaired) and redistributed is far greater than the impact of efficient and performing packaging materials when you take into account the energy expended on manufacturing and return/redistribution transportation.

Location, Location, Location
Aside from performance, an additional consideration for degradable packaging certification is the regions/markets served. There are a number of national/regional third-party organizations that have established certification programs, most of which have their own logos. In the U.S., the Biodegradable Products Institute (BPI) is the most common organization associated with degradable certification. In Europe there are two main groups, Din-Certco and Vincotte. By starting with an understanding of the organizations and certifications relevant to customers’ markets, businesses can easily narrow down the pool of certifications to consider. Also, climate should be a variable as well. If, for example, degradable packaging is being sent into humid climates, make sure the material has been exposed to tropical bombardment testing to ensure it will not break down in conditions common to these environments.

Products are Key
Companies should look at the products being packaged as well. If products containing liquid are being shipped, performance of the material is even more important, as product breakage could result in moisture bombardment and degradation of the packaging material. In most cases, compostable or biodegradable packaging is not an efficient solution for products that could produce moisture. Also, when shipping electronics, you should confirm that the compostable packaging solution does not create static levels that can damage sensitive electronic components.

Degradable Standards and Testing
As mentioned before, there are a number of internationally recognized standards used to evaluate biodegradation, disintegration and compost quality of degradable packaging. The three most recognized international standards include:
• American Standard ASTM D6400-04, known as “Standard Specification for Compostable Plastics”
• European Norm EN 13432 (2000), termed “Requirements for Packaging Recoverable Through Composting and Biodegradation”
• International Standard ISO 17088 (2008) known as, “Specifications for Compostable Plastics”

These standards require materials to pass a list of stringent requirements that test four main product attributes; heavy metal content, biodegradation, composting & disintegration and ecotoxicity.

Biodegradation tests are used to determine aqueous biodegradation, or water solubility of degradable materials. To pass this test, the material must show at least 90% biodegradation within 180 days, which is determined by measuring oxygen demand in an enclosed respirometer (a device used to measure the rate of exchange of oxygen and carbon dioxide). Both ASTM and ISO include standards for biodegradation testing.

Composting & Disintegration 
The purpose of composting and disintegration testing is to ensure that a majority of the degradable material breaks down. The methodology involves running the degraded material through a sieve after it has composted and disintegrated in municipal compost conditions for a 12-week period. The sieve is designed to filter out residue larger than 2 mm, and in order to achieve certification, at least 90 percent of the residue must be able to go through the sieve. Composting and disintegration testing is a part of both ISO and EN composting test procedures.

Heavy Metal Content
Just as it sounds, the heavy metal content testing determines the level of heavy metals within the material. To pass this test, the metal content must be below levels specified by the specific standard. This is done to prevent oxodegradables from leaving traces of metal in the soil when the product breaks down (this can even occur in landfills or municipal composting facilities). These traces could ultimately affect soil quality and pull nutrients from the soil. Both ASTM and EN compostable standards include heavy metal content testing.

Ecotoxicity Test
Finally, ecotoxicity tests are performed to make sure that the degradable materials do not hamper plant germination once they go into the soil. These tests are conducted by planting seeds in soil with the degradable material and planting seeds for a control group in soil without the composted material. Both groups are exposed to the same environment and hydration regimen. The soil with the degradable material residue must show a 90 percent germination compared to the control group to pass ecotoxicity testing. If the soil does not meet the 90 percent germination level, it likely means the degradable material is removing nutrients from the soil once it breaks down.

Being Critical of Claims
It is important for companies considering adopting compostable or biodegradable packaging materials to question product claims. Specifically, it is important to ask if a certain level of inoculants (organisms in nature that can break down materials) are needed to assist with the degradation of a material. While the standards and certifications mentioned above do not depend on inoculants to break down materials, some tests do. Unfortunately, inoculant involvement can be inconsistent in landfills and municipal composting facilities, reducing the reliability for a product to completely break down every time.

Also, it should be noted that the degradable testing procedures discussed do not measure performance outside of compostable and biodegradable attributes. For this reason, package performance testing or certifications are still necessary to ensure that degradable packaging solutions are performing properly to protect products.

With so many elements to consider around compostable or biodegradable packaging materials, certifications and standards play a key role in the integrity of this market. When looking for a degradable packaging material, look for logos or certifications that provide credible third-party endorsement. Also, if companies are still uncertain on where to start looking at compostable and biodegradable products, they should reach out to a knowledgeable packaging or sustainability partner who can offer direction around the solutions that best fit their business needs.

Dr. Ron Cotterman is vice president of sustainability – Sealed Air Corporation.