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(Retired) Compostables in the Marine Environment

Here at Seaside, we want to expand the term “compostable”!

Testing the Legitimacy of Compostable Products 

The term “compostable” refers to a certification given to products that have the ability to biodegrade and that are made of materials that can be returned to the environment.

Currently, in order for a product to be certified compostable, it must be capable of being degraded at elevated temperatures in soil under specified conditions and time scales, usually only encountered in an industrial composter (United Nations Environment Programme, 2016). This means that compostable products may not naturally degrade depending on environmental conditions and disposal methods. In these cases, compostables could actually contribute to pollution! So are compostable products that much better than single-use plastic products?

A report from the UN in 2015 concluded that, “On the balance of the available evidence, biodegradable plastics will not play a significant role in reducing marine litter.” As a result, Seaside Sustainability is working to investigate the biodegradation of certified compostable single-use products in marine environments through systematic testing procedures.

One of Seaside’s field projects tests this rate of degradation to determine a product’s potential harm to the marine environment. Seaside then works with manufacturers to broaden the term “compostable” to include full degradation. The goal of testing the decomposition rates of products such as compostable bags and straws is to determine the legitimacy of compostable products compared to their single-use counterparts. Do compostable products actually decompose at faster rates?

Seaside has conducted a number of evaluations on the numerous certified compostable products on the market to see if any show signs of full biodegradation in marine environments. For the products that do biodegrade, Seaside will look further into their chemical makeup in order to determine if the biodegradation produced toxic byproducts or microplastics. For the products that don’t biodegrade, manufacturers will be informed and Seaside will make suggestions as to what can be changed to ensure that the product will more efficiently reduce plastic in our oceans.

Final Mudflat Acidification Infographic.