Comparison of atmosphere/aquatic environment concentration ratio of volatile chlorinated hydrocarbons between temperate regions and Antarctica
Introduction
Since the Second World War, a massive production and a widely varying and extended industrial use of volatile chlorinated hydrocarbons (VCHCs) has taken place, due to their versatility in several processes. Taking into account the entity of the emissions (estimated in hundreds of thousands of tons per year (McCulloch et al., 1999)) and their physico-chemical properties (in particular volatility and persistence) (Campbell et al., 1985), VCHCs can spread from industrialized and inhabited regions and reach remote zones of the Earth, such as Antarctica. This large-scale diffusion takes place by means of long range transport via atmospheric and ocean currents, in particular by means of a process known as global distillation and fractionation (Wania and Mackay, 1993). According to the latter process, volatile and semi-volatile compounds evaporate into the atmosphere in temperate and tropical regions, where they are used and discharged, and are then carried by atmospheric currents until they reach colder climates, where they condense and are deposited (Wania and Mackay, 1995, Fernandez and Grimalt, 2003). As VCHCs have the peculiar capability of being diffused at planetary level, and being distributed between air and water, they were selected as indicators of global contamination (Zoccolillo and Rellori, 1994, Zoccolillo et al., 1996, Zoccolillo et al., 2004, Zoccolillo et al., 2007, Zoccolillo et al., 2009).
In the present work, the atmosphere/aquatic environment concentration ratio of VCHCs was evaluated in order to understand their transport and deposition mechanisms and the distribution between air and water (or snow). In addition, the VCHC concentration ratio in Antarctic matrices was compared with the concentration ratio in Italian matrices, in order to compare VCHC behaviour in polar and temperate climate. The VCHCs investigated were: chloroform (CHCl3), 1,1,1-trichloroethane (C2H3Cl3), tetrachloromethane (CCl4), 1,1,2-trichloroethylene (C2HCl3) and tetrachloroethylene (CCl4).
A preliminary and essential part of the present research consisted in modifying and improving air sampling equipment, in order to solve the problems associated with air collection operations in Antarctica, taking into account the operating difficulties facing air sampling in remote and cold zones.
Section snippets
Air sampling equipment
The air samplings were performed using a suitably modified diaphragm pump (model 8000-1) and canisters (model 6-L G.O. Stabilizer™) purchased from General Oceanics Environmental, Miami, Florida.
The air contact surfaces of the diaphragm pump were all made of stainless steel in order to avoid any release of organic compounds. The pump was battery operated and oil-free; therefore, in situ samplings can be performed even in absence of electric current and any contamination of the air sample during
Apparatus
For VCHC analysis in air, an ad hoc analytical system was used, based on a cryofocusing-trap-injector coupled to a gas chromatograph with mass spectrometric detection operating in selected ion monitoring mode (SIM) (CTI-GC–MS). For VCHC analysis in aqueous matrices (i.e. water and snow), a highly sensitive and selective technique was used based on a purge and trap injector coupled to a gas chromatograph with mass spectrometric detection operating in SIM (PTI-GC–MS) (Zoccolillo et al., 2005).
Results and discussion
In order to evaluate any drawbacks due to the relatively lengthy storage of the air and aqueous samples collected in Antarctica, some advance tests were made. Air samples with low VCHC concentrations (e.g. those from rural areas) were analysed immediately after collection and after a variable storage time (from 2 weeks to 2 months). In some cases, the canisters were maintained at −20 °C, for a period of time comparable to the duration of the Antarctic expedition, and brought back to room
Conclusions
The environmental monitoring of VCHCs, in particular the determination of concentration values and distribution among compartments, is fundamental for the purpose of determining the extent of the problem on a scientific basis in consideration of the toxicity of VCHCs above all for Antarctic ecosystems. Thus, several sampling campaigns were carried out to collect air, water and snow in both Italy, a typical temperate zone of the Northern Hemisphere, and Antarctica, a cold zone of the Earth. In
Acknowledgements
The authors wish to acknowledge financial support from the Italian National Research Programme in Antarctica (PNRA).
The authors gratefully thank Dr. Carlo Abete for his helpfulness during sampling operations during the Italian Antarctic expeditions.
References (19)
- et al.
Is rain or snow a more efficient scavenger of organic chemicals?
Atmos. Environ.
(2004) - et al.
A method for determination of methyl chloride concentration in air trapped in ice cores
Chemosphere
(2006) - et al.
Investigation of the use of oxygen doping of the electroncapture detection for determination of atmospheric halocarbons
J. Chromatogr. A
(1995) - et al.
A global distribution model for persistent organic chemicals
Sci. Total Environ.
(1995) - et al.
The effect of snow and ice on the environmental behaviour of hydrophobic organic chemicals
Environ. Pollut.
(1998) - et al.
Improved analysis of volatile halogenated hydrocarbons in water by purge-and-trap with gas chromatography and mass spectrometric detection
J. Chromatogr. A
(2005) - et al.
Volatile chlorinated hydrocarbons in Antarctic superficial snow sampled during Italian ITASE expeditions
Chemosphere
(2007) - et al.
Evaluation of volatile chlorinated hydrocarbons distribution along depth profiles in the Ross Sea, Antarctica
Microchem. J.
(2009) - et al.
Idrocarburi alogenati nelle acque da bere
Chim. Ind. Milan.
(2004)
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