A model assessment of the ability of lake water in Terra Nova Bay, Antarctica, to induce the photochemical degradation of emerging contaminants. (November 2016)

• Record Type: Journal Article
• Authors: Minella, Marco; Maurino, Valter; Minero, Claudio; Vione, Davide
• Is Part Of: Chemosphere. Volume 162(2016)
• Page Start: 91
• Page End: 98
• Publication Date: 2016-11
• Subjects: Environmental photochemistry -- Pollutant photodegradation -- Polar regions -- Abiotic attenuation processes -- Emerging pollutants; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2016.07.049
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: The shallow lakes located in Terra Nova Bay, Antarctica, are free from ice for only up to a couple of months (mid December to early/mid February) during the austral summer. In the rest of the year, the ice cover shields the light and inhibits the photochemical processes in the water columns. Previous work has shown that chromophoric dissolved organic matter (CDOM) in these lakes is very reactive photochemically. A model assessment is here provided of lake-water photoreactivity in field conditions, based on experimental data of lake water absorption spectra, chemistry and photochemistry obtained previously, taking into account the water depth and the irradiation conditions of the Antarctic summer. The chosen sample contaminants were the solar filter benzophenone-3 and the antimicrobial agent triclosan, which have very well known photoreactivity and have been found in a variety of environmental matrices in the Antarctic continent. The two compounds would have a half-life time of just a few days or less in the lake water during the Antarctic summertime, largely due to reaction with CDOM triplet states ( 3 CDOM*). In general, pollutants that occur in the ice and could be released to lake water upon ice melting (around or soon after the December solstice) would be quickly photodegraded if they undergo fast reaction with 3 CDOM*. With some compounds, the important 3 CDOM* reactions might favour the production of harmful secondary pollutants, such as 2, 8-dichlorodibenzodioxin from the basic (anionic) form of triclosan. Graphical abstract: Highlights: Elevated photochemical self-depollution potential of lake water in the Antarctica. Photochemistry is dominated by triplet-sensitised processes in the ice-free season. Contaminants undergoing fast triplet sensitisation are quickly degraded. Contaminants that only react with OH are not effectively degraded in some lakes. Secondary pollutants may be formed photochemically from some contaminants.