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article imageEssential Science: CFC replacements still pose environmental risk

By Tim Sandle     May 18, 2020 in Environment
While CFC gases, commonly used in cold temperature devices and to propel aerosols, have largely been phased out, a number of so-termed ‘greener’ replacement products are still harmful to the environment as data from the Arctic indicates.
The new research indicates that several CFC replacements are actually a trigger for persistent organic pollution in the Arctic. In-depth data suggests that degraded, toxic compounds, which derive from CFC replacements, have been detected from ice in the Canadian Arctic.
CFCs
Chlorofluorocarbons (CFCs) refers to any of a class of compounds of carbon, hydrogen, chlorine, and fluorine, typically gases used in refrigerants and aerosol propellants. Identified in the 1960s as source of environmental pollution and contributors of global pollution, measures were taken from the late 1980s to phase them out and to introduce less-harmful alternative products.
In 2016   CIRES scientist Lei Hu and NOAA scientist Stephen Montzka investigated the concentrations ...
In 2016, CIRES scientist Lei Hu and NOAA scientist Stephen Montzka investigated the concentrations of CFC's in the stratosphere. Their latest findings show CFC's levels are in fact, rising.
Source: NASA / NOAA
Canadian situation
Canada has taken strong steps to reduce the impact of so-termed ‘greenhouse gases’ upon the environment, dating back to the 1980s. In 1987, the Canadian government enacted the Montreal Protocol. This morphed into a global treaty intended to protect Earth's ozone layer through the banning of substances like CFCs. Since then, it has undergone nine revisions, in 1990 (London), 1991 (Nairobi), 1992 (Copenhagen), 1993 (Bangkok), 1995 (Vienna), 1997 (Montreal), 1998 (Australia), 1999 (Beijing) and 2016 (Kigali).
This led to the phasing in of CFC-replacement substances. However, the types of products that have been introduced to replace them are being shown to have an adverse environmental impact.
New research
Recent data from the University of Alberta shows a rising level of degradation products from replacement CFC products being recovered from the Canadian Arctic. Specifically, climate scientists have taken samples from the Devon Ice Cap, which is located in the Canadian high Arctic. The data indicates a tenfold increase in short-chain perfluorocarboxylic acid (scPFCA) deposition between 1986 and 2014.
a  Measured global surface rates for N2O (grey line)  CFC-12 (thin blue lines)  and CFC-113 (thin gr...
a, Measured global surface rates for N2O (grey line), CFC-12 (thin blue lines), and CFC-113 (thin green lines) from flasks analysed by GC–ECD and also, for the CFCs, by GC–MS. b, Hemispheric differences measured for CFC-12 and N2O. c, Hemispheric differences measured for CFC-113. Multiple CCM simulation results appear in a, b, and c for CFCs as thick dark lines and are updated only annually.
M. Rigby, el. al.
These compounds are organofluorine analogues of ordinary carboxylic acids. Longer chain perfluorinated carboxylic acids, e.g. with five to nine carbons, are used as fluorosurfactants and emulsifiers which form part of the production of Teflon and related fluoropolymers.
The scPFCAs compounds develop by a process termed atmospheric oxidation. With this, CFC replacement compounds are converted into persistent organic pollutants. These fall into the grouping referred to as "forever chemicals", which do not break down. Concerningly, these types of chemicals have proven toxicity to plants and animals.
Commenting on the research study, principal scientist Alison Criscitiello states: “In many ways, the degradation products from these substances may be just as concerning as the original chemical they were meant to replace."
The researcher adds further: “We are seeing significant levels of these short-chain acids accumulating in the Devon Ice Cap, and this study links some of them directly to CFC replacement compounds."
Concluding opinion
The research conclusion is clear: substances designed to replace ozone-depleting chlorofluorocarbons are as problematic as CFCs and either new alternatives are required or humanity’s dependency upon these gases needs to be considerably reduced.
Image of Arctic sea ice taken by  NASA Goddard researcher Linette Boisvert of the holes and openings...
Image of Arctic sea ice taken by NASA Goddard researcher Linette Boisvert of the holes and openings in the sea ice cover that expose the warm ocean below where more heat and moisture are put into the atmosphere, helping to warm the Arctic.
NASA - Operation IceBridge
Research paper
The research has been published in the journal Geophysical Research Letters. The research paper is titled “Ice Core Record of Persistent Short‐Chain Fluorinated Alkyl Acids: Evidence of the Impact From Global Environmental Regulations.”
Essential Science
This article is part of Digital Journal's regular Essential Science columns. Each week Tim Sandle explores a topical and important science subject.
In Australia  Europe and the US  many of those collecting plastic and other recyclables were left sc...
In Australia, Europe and the US, many of those collecting plastic and other recyclables were left scrambling to find new places to send it after China stopped importing plastic waste for recycling
Brenton EDWARDS, AFP
Last week, the subject of plastic pollution in the oceans was examined, noting some alarming increases in pollution levels.
The week before the topic was the coronavirus. Here, researchers have found that two types of cells found in the nose are a mechanism that the SARS-CoV-2 virus harnesses as a mechanism to enter the body and trigger an infection.
More about Aerosols, CFCs, Pollution, Ozone layer, Arctic
 
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