Cling film may have cancer risks

A study by researchers into the presence of potentially dangerous chemicals in eight brands of cling wrap, which is used to package food has revealed that one brand had a high concentration, which may result in adverse health effects and cancer risks.

The study was conducted by the University of Pretoria’s (UP) Environmental Chemical Pollution and Health Research Unit, and was led by UP Dean of the Faculty of Health Sciences, Prof Tiaan de Jager and Director of the Unit, Dr Natalie Aneck-Hahn. It had collaborators from Stellenbosch University and the Council for Scientific and Industrial Research. It selected eight of the most common cling film brands in South Africa, that are used domestically and commercially for food packaging. They investigated the presence, concentration and potential health risks of the EDCs, para-Nonylphenol (p-NP); Bisphenol A (BPA); Di (2-ethylhexyl) adipate (DEHA) and selected phthalates.                                                                          

The study found that one of the cling film brands had a very high concentration of DEHA, which may result in adverse health effects and carcinogenic risks. Cancer risks resulting from exposure to DEHA equated to about five in 1000 people, which is 50 times higher than the acceptable cancer risk, said Prof de Jager.

Only two of the eight brands were below the detection limit for all target chemicals and also had the CANSA-smart choice seal on them.

High levels of DEHA and di-2-propyl heptyl phthalate (DEHP) were found in the commercial brands tested, posing significant health risks (such as reproductive and developmental effects and liver toxicity), while exposure to the EDC DEHP results in carcinogenic risks that are regarded slightly higher than the acceptable level (1 in 100 000). These risks represent a worst-case scenario and are based on using cling film daily over a 30-year period, said Prof de Jager.

He explained that exposure to EDCs during highly sensitive life stages such as foetal development and early childhood can result in the development of non-communicable diseases, problems with metabolism, as well as immune system dysfunction, problems with neurodevelopment, and reproductive function. ‘It is also possible that there can be an effect in children at an epigenetic level (heritable changes that affect gene expression and activity, but do not involve changes in the DNA sequence) in their adult years, as well as the potential carcinogenic effects to long term exposure,’ said Prof de Jager.

EDCs, which are mostly man-made, have significant effects on the environment, as well as on human and animal health.  They are found in pesticides; metals and electronics; pharmaceuticals and personal care products; as well as in additives in food and food packaging materials.

Cling film contains plasticizers, which are additives that increase the plasticity and flexibility of a material and decreases its viscosity and brittleness. Some plasticizers are EDCs and may be released from the material with time, use and under certain conditions.

Prof de Jager explained that EDCs can leach from the cling film used to package food. This leaching process, whereby chemicals are transferred from the plastic to the food is known as migration. ‘Migration depends on the chemical properties of the packaging and the type of food. Migration of EDCs into foods that are particularly high in fat, such as cheeses, fatty fish and meat are said to be more likely. Migration is also dependent on temperature, exposure to ultraviolet light and the duration that the product is stored.’

Previous studies on the migration of plasticizers (and therefore EDCs) into foods wrapped in PVC film showed substances do occur when packaged foods are defrosted or cooked in the microwave.  Food wrapped in cling film is a source of human exposure to EDCs. Since these studies, plasticizers which contain Phthalate esters DEHP and Dibutyl phthalate (DBP) have been prohibited or regulated in some countries because of their EDC effects.

While levels of BPA and p-NP were detected in cling film samples of this study, Prof de Jager stressed that the levels of these EDCs were lower when compared with a previous South African study in 1997. ‘This means that manufacturers of cling film are using safer alternatives compared to the materials previously used,’ he said.

According to Prof de Jager, as the awareness of EDCs slowly rises among the general public, ‘we should all try take it upon ourselves to become more informed of the materials that contain EDCs and the potential health risks that they can have on us and the environment.’

‘A start would be to make small changes to our daily choices. Perhaps, for example, if we all try to reduce the amount of food packaging – both in what we buy and in our own homes, we will not only be trying to reduce our exposure to EDCs, but we will also be making a bonus effort of reducing the amount of plastic on the planet.’

He cautioned that when purchasing cling film, people should always check for the CANSA-smart choice seal. 

Researchers

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  Professor Tiaan de Jager

  Professor Tiaan de Jager is serving his second term as Dean of the Faculty of Health Sciences at the University of Pretoria (UP). He is a professor in Environmental Health at UP’s School of Health Systems and Public Health (SHSPH) and holds an Extraordinary Professorship in the section Andrology at the University’s Department of Urology, School of Medicine.
  
  Prof De Jager, who completed his undergraduate studies at Free State University, says his research interest was piqued in 1993 when he became a medical natural scientist at UP’s Department of Urology in the Faculty of Health Sciences and its academic partner Steve Biko Academic Hospital. His research career officially kicked off when he enrolled for a PhD in Reproductive Biology at UP in 1995.
  
  He is doing research at the University because it is a leading research institution that is not only graduating the leaders of tomorrow but has as its vision the creation of new knowledge with the aim of making a difference locally and globally. Prof De Jager says he is proud to be part of this visionary institution and fortunate to be able to lead and conduct research within this framework. “We focus our activities and contribution to making an impact on society above all else,” he says. “It is important to me that we graduate students who are not only good at their jobs and well educated, but who also understand that they have a responsibility to be life-changers and that they need to impact society and contribute positively to change in Africa.”
  
  The attainment of the 2030 Agenda for Sustainable Development Goals (SDGs) is a common thread throughout Prof De Jager’s research, which places a specific focus on SDG 3 (Good Health and Well-being). “My primary research focus is on male reproductive health, specifically related to environmental health and toxicology,” he explains. “I investigate the effects of environmental endocrine-disrupting chemicals (EDCs), including insecticides used for malaria vector control, such as dichlorodiphenyltrichloroethane (DDT), on male reproductive health.”
  The link between male reproductive health and malaria control has resulted in several international research projects that deal with the impact of malaria and associated malaria control on communities where the disease is prevalent, including South Africa, Botswana, Zimbabwe, Mozambique and Malawi. These novel research concepts are fed into safer malaria control strategies, which include drug discovery solutions; policy and regulatory framework intervention; prevention with public health partners; and education and awareness raising.
  
  Prof De Jager is the Director of the UP Institute for Sustainable Malaria Control (UP ISMC), which is a prime example of cross-faculty research. This transdisciplinary institute involves all nine UP faculties as well as the Gordon Institute of Business Science school. The UP ISMC coordinates and promotes collaborative research on safer, more sustainable malaria control and management strategies, generates new knowledge and supports new activities pertaining to safe malaria control in Africa.
  
  “Our interactions and collaborations, however, are not limited to the confines of UP, but includes partners from all spheres,” Prof De Jager says. “This includes communities, government, private industry, and international partners based at research institutions, higher education institutions and science councils.”
  
  As Director of the UP ISMC, Prof De Jager’s main agenda is researching and coordinating efforts to bring about sustained control, eventually leading to the elimination of malaria, starting in South Africa and extending to neighbouring countries like Botswana, Mozambique, Zimbabwe and Malawi.
  
  “Communities affected by malaria need to take responsibility for the control of mosquito vectors and the prevention of bites, while healthcare providers need to take responsibility for early-warning systems and treatment to alert communities to the presence of possible outbreaks,” says Prof De Jager.
  Vector control efficacy and malaria treatment services rely on the commitment of and buy-in from provincial and national governments, as poor communities are unable to carry the costs themselves.
  
  In South Africa, malaria is most prevalent in the Vhembe District in Limpopo. Here, malaria control policies rely on indoor residual spraying, using chemicals such as DDT and pyrethroids to control mosquito vectors. “Based on the evidence of the danger that DDT poses to both human (Bornman et al. 2018) and natural ecosystems, we have started developing and exploring alternative methods of control,” Prof De Jager explains. “In the Vhembe District, we have tested indoor polyethylene wall linings impregnated with long-lasting insecticides, with great success (Kruger et al. 2015), and in Botswana and Zimbabwe, we have field-tested the efficacy of microbial larvicides to control mosquito larvae (Mpofu et al. 2016). Both these methods have the potential to be effective if local communities are supported by municipal and provincial agencies based on sound research methodologies.”
  
  The institute has seen several highlights over the past few years, one of the most recent being a breakthrough in 2020 amid the challenges brought on by the COVID-19 pandemic. “We had a breakthrough relating to drug discovery, where we were trying to find compounds to block the parasite interaction,” Prof De Jager explains. “Our research group, under the lead of Prof Lyn-Marie Birkholtz along with local and international partners, focused their research on the parasite and found specific drug compounds that can be effectively used as part of an intervention. This is a major breakthrough in terms of our malaria research.”
  
  Other highlights span a longer period; a few noteworthy examples include the UP ISMC being designated as one of three South African Medical Research Council-collaborating centres for malaria research in the country; the UP ISMC being host to the DSI/NRF SARChI Chair on Sustainable Malaria Control (Prof Birkholtz); and the institute being named winner of the Communication for Outreach and Creating Awareness of SET and Innovation Award at the 2017/2018 NSTF-South32 Awards.
  
  Some of Prof De Jager’s personal research highlights include successfully graduating several postgraduate students. Also, many of his students have won awards at the annual Faculty Research Day where their research projects were presented. His appointment as an expert peer reviewer of the World Health Organisation’s (WHO) ‘Global assessment of the state of the science of endocrine disruptors’ document was another highlight, as was his appointment by the National Minister of Health to the South African Malaria Elimination Committee.
  
  Over the past 18 months, Prof De Jager says he has dedicated his time to further developing and growing the UP ISMC, with the long-term aim of malaria control and elimination. Various experts and role players from UP and government are currently involved. “The UP ISMC is developing safer alternatives for malaria control, including chemical product design/development, which includes WHO Phase II and III Field Trials on new patents for malaria vector control [Prof Walter Focke, Chemical Engineering], health impact/toxicology/health risk [Prof Riana Bornman, SHSPH, who Prof De Jager credits as his research mentor] and integrated vector management/decision tools and policy [Dr Clifford Mutero, SHSPH and Duke University].
  
  “To take this into the future, and using opportunities created by big data sciences, we have introduced an initiative using remote sensing for malaria control (ReSMaCA) in collaboration with the French and South African national space agencies (CNES and SANSA), and national, regional and other international researchers. This approach takes climate change into account when developing early-warning systems for malaria. The programme will focus on environmental and climate issues, and will include vector and parasite control strategies, with a strong focus on cross-border malaria transmission. With funding from the German Research Foundation, we are also working on assessing the controlled release of volatile mosquito repellents from nanostructured polymers to reduce infectious tropical diseases including malaria. These initiatives focus on innovative approaches to malaria elimination in the African region and will involve researchers from developing countries facilitating capacity building and contributing towards the development of the African continent.”
  
  Prof De Jager adds that an international project on malaria insecticides and reproductive health, funded by the Canadian Institutes of Health Research, laid the foundation for projects in Chiapas in Mexico, Quebec City, Canada, and later in Limpopo, further driving his special interest in malaria-related research.
  
  His research agenda will continue to focus on questions related to the SDGs, particularly on EDCs, malaria control and the environment. “My passion is to continue being a life-changer through my contribution to research, making a difference in society and battling for a better life for our vulnerable, poor communities.”
  

  More from this Researcher
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  Dr Natalie Aneck-Hahn

  Dr Natalie Aneck-Hahn has been in the field of Andrology for more than 26 years and is the Deputy Director Medical Natural Sciences in the Department of Urology and head of Andrology at the Steve Academic Hospital. She is also the Director of the Environmental Chemical Pollution and Health (ECPH) Research Unit at the School of Health Systems and Public Health at the University of Pretoria.

  Dr Aneck-Hahn’s research focus is on the effect of endocrine disrupting chemicals on male
  reproductive health and in the environment. She has authored and co-authored several technical reports
  and peer reviewed publications.

  More from this Researcher

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