Banned toxic chemicals being produced at all-time high
Tens of thousands of tonnes of toxic chemicals are being produced as an industrial by-product despite being banned decades ago, new research says.
Polychlorinated biphenyls (PCBs) have been restricted for more than 40 years, but research from Manchester Metropolitan University shows that we may be producing more PCBs than at any other time in history.
PCBs are man-made chemicals that have been prohibited since 1976 in the United States and restricted from 1981 in the UK, after they were recognised as environmental pollutants and health hazards, leading to them being phased out globally and the introduction of strict regulations on their production, use and disposal.
PCBs were initially produced as a cocktail of 60 to 120 different chemicals that were most widely used in electricity transformers and capacitors but were also used as additives in building materials and other uses. Their stability and resistance to heat meant they were used regularly before their environmental impact was understood.
They can persist in the environment for long periods, as well as being able to travel long distances though air and water.
In 2004, the Stockholm Convention on persistent organic pollutants obliged countries to eliminate the use of PCBs in equipment by 2025.
However, the new research, published in the journal Science of the Total Environment, shows that PCBs are continuing to be produced unintentionally as a by-product of industry on a very large scale.
Dr David Megson, Reader in Chemistry and Environmental Forensics at Manchester Metropolitan University, said: “Our research shows that we may be currently producing more PCBs now than at any other point in history, with our estimates showing that US legislation currently permits the generation of more by-product PCBs than during peak commercial production in the 1970s.
“However, they are being produced unintentionally as by-products in chemical reactions which means small proportions of them are present in many chemicals and products we use today. When we take into account the volumes of these chemicals and the small levels of PCBs within them, this adds up to a massive number, approximately 100 million lb (or 45,000 tonnes) of PCBs per year in the US alone.
“Most people associate this accidental production of PCBs with paints and pigments, but our research shows its much broader than that, with chlorinated solvents dominating the list. These are currently going undetected in many studies, as the specific PCBs produced accidentally are different to the PCBs that were produced intentionally more than 50 years ago.
“We need further research to better establish the quantity of these by-product PCBs that are accidentally manufactured, to identify the main production sources and to take steps to reduce their production, or if that’s not possible to ensure they’re reclaimed, retained and appropriately destroyed, with a view to a legal framework that encompasses all PCBs, not just the ones produced historically.”
The paper was co-authored with Dr Ifeoluwa Grace Idowu and Dr Courtney Sandau of Chemistry Matters in Canada.
