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Perfluorinated compounds in landfill leachate from discarded carpets

University of British Columbia

Perfluorinated compounds (PFCs) are a class of anthropogenic chemicals incorporated over six decades into a wide range of industrial and consumer-use products including surface treatments for carpets and textiles, paper and packaging, non-stick cookware, firefighting foams and insecticides. The extremely strong carbon-fluorine bond, "the strongest in organic chemistry", makes them thermally and chemically stable, and resistant to degradation. Several studies on toxicology of PFCs demonstrate negative health effects of these compounds. Some PFCs were added to the Stockholm convention on Persistent Organic Pollutants (POPs) in 2009, due to their persistence, toxicity, and widespread occurrence in the environment. Stain-resistant carpets comprise a major part of global historical PFC production and use. Landfills are a major source of PFC emissions to the environment as final destinations for discarded consumer articles, including carpets. This thesis explores how various PFCs leach from carpets to landfill leachate, and how factors like temperature, pH and contacting efficiency affect the transfer of PFCs into aqueous media. Experiments were conducted in which a number of carpets manufactured in ~2000 to 2005 were contacted with landfill leachate and distilled water. Transfer of different PFCs into the aqueous phase increased with contacting time, with differences between 1 and 24 h much greater than between 24 and 168 h. A temperature increase from 5 to 35oC resulted in a significant increase in PFC leaching. Increasing the pH from 5 to 8 resulted in an increase followed by a decrease in leaching of most PFCs. The overall leaching rates of PFCAs into distilled water were somewhat greater than into landfill leachate. The majority of PFC exchange between carpets and leachate was more dependent on some factor (e.g. adsorption or desorption) rather than external mass transfer.

Text

2012-06-20

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/42522

Civil Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/