There are two main areas where biodegradation is important, one where it is controlled within the waste stream, and secondly in cases of uncontrolled, environmental release.
Hydropol™ in thin film form will compost. Tests with third party test is on-going in this area following internationally recognised protocols (EN13432, ASTM D6400, ASTM D6868 ISO 17088, ISO14885, ISO 18606, AS4736). Results so far indicate that 15 microns is the upper limit (bear in mind that because of tensile strength that is the equivalent to a 35 micron PE film).
Anaerobic Digestion (AD)
Unlike most plastics, Hydropol™ is compatible in AD systems. Tests so far at an AD plant showed that a 30 micron thick Hydropol™ film passed the AD system and post analysis showed no fragments in the biodigestate or residence in the digester. Further tests are in progress. This method of biodegradation is common to waste water treatment processes and there is historical evidence that PVOH is safe in these systems.
A major concern given the amount of toxic plastic waste in the oceanic environment. Clearly no one wants to deliberately release plastics into the environment but unfortunately it is present and a major global concern.
The accretion of toxins into the plastics causes long term effects on marine flora and fauna and ultimately ourselves. All of our commonly used plastics are hydrophobic (water hating) which necessarily means they resist the water they are in and attract other hydrophobic materials to them such as pesticides and other toxins. This allows for these plastics to concentrate toxins.
The longevity of the common plastic material causes direct macro pollution as seen in the many cases of marine mammals entanglement and digestive blockages.
Hydropol™ is hydrophilic (water liking) and has no propensity to attract toxins or form micro plastics and has been certified to be non-toxic to marine fauna. Ocean conditions vary, and it is too early to say how quickly Aquapak material will break down but the fact it is non-toxic and safely digestible reduces the problem significantly.
For plastic films in agricultural and land management, tests are on-going to see how Hydropol™ meets current test methods (ISO 17556) to determine the breakdown and biodegradation in a variety of applications.
Clearly littering is a much more difficult issue and any material deliberately littered has a disproportionate impact mainly because of visibility. It is likely given the nature of Aquapak materials that they will not dwell in the environment as long as standard plastics and do not have the toxic hydrophobic microplastic formation. Aquapak will continue to work with regulators and NGOs in this area.