Hydrophobic and Hydrophilic Properties of Organic Pollutants As a Factor Influencing Their Redistribution during Snowpack Melt (High Arctic)

HYDROPHOBIC AND HYDROPHILIC PROPERTIES OF ORGANIC POLLUTANTS

AS A FACTOR INFLUENCING THEIR REDISTRIBUTION DURING SNOWPACK

MELT (HIGH ARCTIC)

Żaneta Polkowska1*, Krystyna Kozioł1, Katarzyna Kozak1

1 Department of Analytical Chemistry, Faculty of Chemistry, Gdansk University of

Technology, 11/12 Narutowicza St., Gdansk 80-233, Poland;

* Author to whom correspondence should be addressed: E-Mail: zanpolko@pg.gda.pl (Ż.P.);

Tel.: +48-58-347-2110; Fax: +48-58-347-2694.

Keywords:, Snow cover, Elution Persistent organic pollutants, Glacier, High Arctic,

Superimposed ice

Abstract

Glaciers have been recognised as global reservoirs of organic matter and secondary

sources of pollutants to downstream environments. However, the short- and long-term

dynamics of the organic chemical release depends on the glacial snow cover, the most

dynamic part of this hydrological system. The snow cover of the High Arctic undergoes rapid

changes due to the shifts in temperature trends. The consequences of those changes include

the occurrence of more frequent melt events in the winter, altered snow cover structure, and

the modification of pollutant release dynamics from snow. Laboratory-based modelling of

pollutant behaviour provide an important basis for real-life studies of elution behaviours for

different pollutant types. Here, we test these idealised patterns in an environmental setting of

a High Arctic glacier, looking inside the snow cover rather than into the already released

chemicals. As a result, potential effects of the changed pollutant release dynamics inside the

melting snow covers of high latitude glaciers are recognised: an important step forward in

recognising the role of glaciers as secondary sources of pollutants, as well as the chemical

composition of their future snow layers.

The aim of this work is to explore the potential of modeled and known properties of

organic chemicals in snow cover in the explanation of their actual distribution in melting

snowpack in the field. This will help recognise other processes that may also be important in

shaping the snowpack and meltwater chemical signature, thus placing the elution process in a

wider context. It can also be a starting point for recognition of the way in which a certain

chemical’s properties lead to its behaviour in melting snowpack, since the mechanism of

interaction between the elution type and snow properties has yet to be fully established.

From the above considerations, we conclude, that the changes in partly melting

snowpack, the remainder of which could then be incorporated into glacial ice, the POC and

the components attached to it become enriched. On the other hand, the water soluble and

reactive compounds are the least reliable components of ice records, but their general share in

glacial ice should decrease in times of increased melt. The photodegradation rates of those

would be an important driving factor for their concentrations also. It is likely that hydrophilic

compounds represent majority of TOC present in the surface snow of a glacier, while the

superimposed ice is already significantly enriched in hydrophobic organic matter. The melt in

a snow profile is capable of significantly skewing the pollutant composition pattern, and

refreezing has different chemical signatures in small ice lenses compared to superimposed ice

layers, hence the two cannot act as a proxy for one another. Perhaps the hydrophilic to

hydrophobic matter ratio is a promising characteristics for assessing past melt rates from ice

records.

This study was solely funded by the National Science Centre of Poland (NCN), grant

number 2012/05/N/ST10/02848.