Guidelines for Sustainable Bioplastics
Chemicals of Concern include
The end goal of eliminating chemicals of concern is to affirmatively test chemicals for safety. The Green Screen for Safer Chemicals, developed by Clean Production Action is a protocol for rating chemicals based upon a series of characteristics of persistence, bioaccumulation potential and toxicity and the level of testing available to confirm safety. Ideal chemicals for use in bioplastics will all meet the Green Screen Benchmark 4 with low inherent toxicity to humans and wildlife, no bioaccumulation and rapid and complete degradation to benign degradation products or metabolites. These are chemicals that would meet the Principles of Green Chemistry. Further information on the Green Screen is available at www.cleanproduction.org/Green.Greenscreen.php.
More information on lists of chemicals of concern is available from the Healthy Building Network’s Pharos Project.
Further discussion on these and other issues with high hazard additives to avoid can be found in Rossi and Lent, “Creating Safe and Healthy Spaces: Selecting Materials that Support Healing” in Designing the 21st Century Hospital Environmental Leadership for Healthier Patients and Facilities (www.healthybuilding.net/healthcare/HCWH-CHD-Designing_the_21st_Century_Hospital.pdf 135 pages PDF)
While these Guidelines recommend against usage of genetically modified seed stock in the field, genetically engineered organisms, enzymes and other entities used in processing of feedstocks are conditionally supported. This is under the presumption that they are contained within the processing system and not viable outside of the system. It is important to evaluate viability outside of the process and potential for harm. The UN Cartagena Protocol on Biosafety provides useful guidance to protect biological diversity from the potential risks posed by living modified organisms resulting from modern biotechnology, specifically focusing on trans-boundary movement of any living modified organism resulting from modern biotechnology that may harm the conservation and sustainable use of biological diversity.
The Protocol makes specific reference to the precautionary principle as stated in Principle 15 of the Rio Declaration of 1992. See Annex III for general principles, methodological steps, and points to consider in the conduct of risk assessment. The general principles include, among others, the following concepts: Risk assessment should be carried out in a scientifically sound and transparent manner; Lack of scientific knowledge or scientific consensus should not necessarily be interpreted as indicating a particular level of risk, an absence of risk, or an acceptable risk; Risks should be considered in the context of risks posed by the non-modified recipients or parental organisms; and that Risks should be assessed on a case-by-case basis.
When recycling systems exist and are successful, composting the product or package will lose the front end inputs that were used in its extraction, refining and production although this must be weighed against the costs of transportation and recycling. In addition, in the case of the bottles, polyethylene terephthalate (PET) bottles that are likely to be displaced by PLA bottles are extremely valuable for current recycling programs, generally selling for more than 20 cents per pound. That high value will be completely lost inasmuch as the economics of composting would not assign any value to PLA bottles. Moreover, beyond the lost revenues, in the near term during a transition to PLA bottles before investments in expensive auto sort equipment could be justified, bioplastics would contaminate and reduce the value in the PET bottles that are being recycled.
In the longer term, after auto-sort systems can be justified and become widespread, recyclers would still incur additional sortation costs to remove the PLA contaminant, which can range from around 1 - 2 cents per pound to separate the PLA from other plastic bottles. However, because bioplastics otherwise hold so much promise, research should be encouraged to develop and commercialize means to recycle rather than compost PLA to approximate the net value of PET. If that can be done and is corroborated by major recycling programs, pilot programs may be appropriate to validate such systems in a test. Based upon what is presently commercialized in the market, however, there is much controversy currently about the introduction of bioplastic predicated upon composting at the end of the life for bottles where there is an existing and successful recycling system. Potential PLA bottle manufacturers are urged to develop systems to successfully and economically recycle bioplastic bottles to overcome the challenges posed to the current recycling program before there is widespread production. This is in contrast to other applications such as cutlery, cups and utensils for which there is presently no flourishing recycling infrastructure.
Currently, all biodegradable/compostable bags available on the market contain a large percentage of fossil-fuel-based plastics. They also present similar challenges to existing plastic recycling systems as do bottles. Unless a composting collection infrastructure is in place for these, biodegradable bags for retail applications should be avoided (as should other single-use fossil-fuel based bags). One excellent application for biodegradable bags is to collect food waste for composting. Indeed, food scrap composting programs and use of compostable bags are expanding, most notably in the San Francisco Bay Area and some other key cities. While a lot of traditional plastic film is technically recyclable and demand for this material is high, only a tiny portion is actually being recycled (less than 1% nationally). One reason is traditional plastic film is not economically recyclable or compostable in household curbside collection programs. When this material is mixed with recyclables or organics at curbside, it becomes a major contaminant in recycling and composting programs. As curbside organics collection programs expand to include many types of compostable materials, compostable bags and film products have the potential to reach higher recovery levels than their petroleum-based counterparts.
Farms, manufacturers, recyclers and others in the life cycle of biobased materials should all have policies that reflect international guidelines for the protection of worker health and provision of fair compensation. Issues addressed should at least be:
Useful resources include: