''Plastic bags safe''

By Racheal Nabisubi

Polythene bags in Uganda remain one of the biggest challenges in waste management as a result of poor handling and disposal habits.

Many will agree polythene bags end up in drainage systems, causing major flooding in towns especially when it rains.

The inability of polythene bags to decompose when disposed of has also worsened the situation.

Also in many homes, polythene bags are used for lighting charcoal stoves and in the preparation of food as well despite findings by Makerere University's School of Food Technology Nutrition and Bio-engineering that food cooked in polythene bags is likely to cause cancer as a result of gases and chemicals released from the generated heat.

Dealers in plastics have embarked on marketing some plastic products as biodegradable but consumers have good reason to doubt these claims.

But a research team from Michigan State University USA in a new study published recently in the ACS journal Environmental Science & Technology, found plastics designed to degrade didn't break down any faster than their more conventional counterparts.

In this study, they evaluated the effect of biodegradation-promoting additives on the biodegradation of polyethylene (PE) films and polyethylene terephthalate (PET) sheets. Biodegradation was evaluated in compost, anaerobic digestion, and soil burial environments.

“None of the five different additives tested, significantly increased biodegradation in any of these environments,” said Susan Selke, a  researcher at the University.

But the Oxo-biodegradable Plastics Association claims the tests were largely irrelevant for their products dismissing the findings as flawed.

Brandon Atwood, Director R&D Willow Ridge Plastics, Inc.  Uganda said: “In our opinion, the study author is trying to make the case that ‘one size fits all’ or more appropriately ‘one test method fits all materials tested. The problem with this belief is that various biodegradable technologies have vastly different starting mechanisms.”

“Another problem with this, or any other study, is the lack of fact checking. What should be most alarming is the fact that all of the principle materials involved in the study issued statements about how the entire study is invalid,” he added.

Atwood explained that when one combines this knowledge with the fact that there are a number of published studies validating the oxo-biodegradable technology, questions rise over the methods and results published by the MSU study team.

“The fact that this study has been published and referenced creates confusion and misinformation for those trying to find relevant answers to the question of technology confirmation. A good researcher will look beyond one study and search for multiple opinions on the topic,” he said.

More recently, some manufacturers now make plastics with additives that are supposed to make the products biodegradable. But the effectiveness of this approach has been unclear.

In Uganda, the ban on polythene bags was first implemented in June 2007. Government at the time slapped a ban on the importation, use and production of polythene bags of 30 microns and below, which are usually very thin.

Government also imposed an excise tax of 120% on the importation of all polythene bags. But this did not last long as NEMA was overwhelmed by the manufacturers.

Traders still smuggled polythene bags into the country as the environmental watchdog NEMA looked on.

Last April, NEMA again slapped another ban on polythene bags, drawing mixed reactions from the public.

Plastics manufactures under their umbrella body Uganda Plastics Manufactures and Recyclers Association (UPMRA) petitioned President Yoweri Museveni asking government to halt the ban.

They argued in their petition that the ban on polythene use is not the solution, but rather the establishment of plastic waste recycling plants in the country for waste management.