Observing the Environment Degrades It: Antarctic Research Stations and Persistent Organic...

[NNadir]

Last edited Sat Jan 2, 2016, 01:32 PM - Edit history (2)

...Pollutants.

I spent the day off leafing electronically through some back issues of one of my favorite journals, Environmental Science and Technology and came across an interesting paper that caught my eye concerning leaching of certain halogenated persistent organic pollutants from the McMurdo and Scott Research Stations in Antarctica.

A link to the article is here:

An Antarctic Research Station as a Source of Brominated and Perfluorinated Persistent Organic Pollutants to the Local Environment (Environ. Sci. Technol., 2015, 49 (1), pp 103–112)

A great deal has been written in the scientific literature in recent years about these classes of compounds, and no blog post could do the subject any justice, but the paper gives a nice brief overview of the issues for anyone unfamiliar with the risks these now ubiquitously distributed compounds entail. Quoting from the text:

Persistent organic pollutants (POPs) are typically anthropogenic chemicals and ubiquitous global contaminants. They share properties of persistence, toxicity, bioaccumulation potential and propensity for long-range environmental transport (LRET).1?3 As such, POPs are recognized as posing a threat to environmental and human health and are subject to the Stockholm Convention on POPs that aims to reduce, and ultimately eliminate, these compounds from the environment...

...Human activity in Polar regions, particularly the Antarctic, is undergoing rapid changes and is dramatically increasing.6,7 Easier access to both North and South Polar regions has resulted in enhanced research activity, as well as increasing tourism and marine resource exploration and extraction. Most Antarctic research bases are located in ice-free areas close to the coastline.8 These areas are also of great ecological significance. Because of this, and the fact that background POPs levels are generally relatively low, any consequent local contamination can have a disproportionately large effect on biota. Research bases have already been shown to be sources of PAHs and heavy metals along with Legacy POPs, such as PCBs.9?12...

...Alongside the increasing scale of human activity in Polar regions, the list of industrial and consumer chemicals that satisfy the classification criteria of a POP continues to grow. These factors result in an increased potential for POPs to be directly introduced to the local environment as fresh emissions from consumer products, including electronic equipment, textiles and furnishings, many of which contain POPs recently annexed under the Stockholm Convention. For example perfluorooctanesulfonic acid and its salts together with perfluorooctane sulfonyl fluoride have been added to Annex B (Restriction) and the penta- and octa-commercial mixtures of polybrominated diphenyl ethers (PBDEs) to Annex A (Elimination).

These fluorinated and brominated compounds have different physicochemical properties and hence different industrial and commercial uses. Perfluoroalkyl acids for example are generally manufactured as their salts15 such as perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) that are amphiphilic with low volatility. Such compounds have been extensively used as waterproofing or wetting agents, in many nonstick or polytetrafluoroethylene (Teflon) containing products as well as in fire-fighting foam.15 They may also be formed in situ from degradation of volatile precursors such as fluorotelomer alcohols (FTOHs).16 FTOHs are used extensively as intermediates in the manufacture of poly- and perfluoroalkylated substances (PFASs), have been identified
as residual compounds in consumer products such as stain repellents and other surfactants, and are known to have their own detrimental environmental and health effects.17,18 PBDEs on the other hand are hydrophobic and commonly found in fire retardant mixtures as well as building materials, electronics and textiles.19

The potential for PBDEs to be released from remote polar research stations, due to the relatively high density of electronic equipment and increased fire prevention concerns at these locations, has been recognized.20 PBDEs21?24 and PFASs such as PFOS25,26 may be released from consumer products as these products wear and degrade. Their contrasting physicochemical properties will influence subsequent distribution. As they are persistent they can accumulate in organisms with detrimental effects, including hepato-, immune-, and ontogenetic toxicity.
25?27

Dusts within the research station, as well as surrounding soil and some organisms such as lichen, as well as wastewater discharged from the stations, were analyzed via LC/MS/MS for representative species in these classes of compounds, and the results were quite disturbing. The lower limits of quantitation (LLOQ's) for these compounds was relatively modest given the capabilities of modern mass spectrometers, the low nanogram per gram range - modern instrumentation can detect picograms per gram of many compounds of physiological import in various matrices - but in almost every case not much sensitivity was required. At McMudro, indoor dust was found to have 9,560 ng/g as a sum of the various polybrominated diphenyl ether flame retardants.

This concentration is almost 4 orders of magnitude found in the hair of Chinese electronic waste recycling workers (See Science of The Total Environment Volume 397, Issues 1–3, 1 July 2008, Pages 46–57) where the distribution of these compounds is of high concern and thought to be carcinogenic, as well as neurotoxic.

This is, um, disturbing.

(For a description of possible mechanisms by which PDBE's act as carcinogens, toxins, and mutagens, see New Evidence for Toxicity of Polybrominated Diphenyl Ethers: DNA Adduct Formation from Quinone Metabolites (Environ. Sci. Technol. 2011, 45, 10720–10727))

Graphs in the original paper cited here show the gradients in soil sample concentrations of these compounds with increasing distance from the research stations.

The main sink - a very slow sink - for these compound classes is in fact, radiation, typically UV radiation or higher energy radiation such as x-rays and gamma rays. For the deliberate destruction of these molecules with lower energy ionizing radiation, UV, often catalytic amounts of titanium dioxide either pure or doped are employed, but this catalyst is undoubtedly not distributed over the antarctic surface.

Because of the still prevalent ozone hole in Antarctica - 2011 was an unprecedented year (See Nature 478, 469–475 (27 October 2011)) - we may expect a slightly higher rate of degradation, although the most prominent PBDE is PBDE-209, which during its degradation can form any of the other, potentially even more toxic PBDE's as degradants. This is small comfort.

It is notable that the stations in Antarctica are sources of many other questionable organic compounds, notably PCHs, polycyclic hydrocarbons, from leaks of dangerous fossil fuels transported to the stations.

One of the most famous laws in science, the Heisenberg uncertainty principle is a statement overall that attempts to view the state of something, in the case of the principle sub-atomic particles like electrons, changes it. This law surprisingly has a macroscopic correlation in environmental science.

[KT2000]

1. this is sad

Of note here too is the role of dust as carriers of pollutants. I recall an Italian study in a clothing factory showed acceptable levels of formaldehyde in the ambient air but dust measured 5,000 ppm. We are poisoning the whole planet and the human body as well.