HA7 Phthalate Esters: Fate and Effects
201 Oregon Ballroom
8:00 AM - 12:00 PM, Thursday
() Degradation pattern of phthalates in landfill leachates.
Jonsson, S1, Ejlertsson, J2, Svensson, B1, 1 Water and Environmental Studies, Linköping University, Linköping, Sweden2 Tekniska Verken i Linköping AB, Linköping, Sweden
ABSTRACT- Phthalic acid diesters are present in a variety of different products and may leach from these products, as they are not chemically bound the resin matrix. The alcohol moieties of the diesters comprise of one or several carbon atoms and thereby the diesters cover a broad range of different physico-chemical behaviours, e.g. solubility. Also, the different products into which they are originally added differ from each other, e.g. from liquid fragrances to rigid polyvinyl chloride (PVC) plastics. The diesters may be degraded to their corresponding monoester and further to phthalic acid. This topic presents an up to date summary of how concentrations of both diesters and monoesters of phthalic acid, as well as phthalic acid itself, vary in leachates from landfill simulation reactors and young full-scale landfill cells, both developing from acidogenic to methanogenic conditions. It also discuss the concentrations of phthalates observed in groundwater samples down-stream an unlined landfill with respect to the results observed from acute toxicity tests with different aquatic species. The release and degradation of the diesters in landfills are dependent on the properties of both the diesters and the resin matrix. In landfills, the most water-soluble diesters are leached from waste to a higher extent than the less water-soluble, but they are only degraded/transformed to their corresponding monoesters and further to phthalic acid by methanogenic bacteria. Therefore, concentrations of these diesters decrease in leachates as the landfill develop methanogenic conditions. The concentrations of total organic carbon in leachates from landfill simulation reactors follow the pattern of the diesters, showing that a general degradation of organic material takes place during establishment of methanogenic conditions. Modelling confirms and explains the transformation processes studied in landfill simulation reactors. A landfill with no or unsatisfactory liner may contaminate the under-laying aquifer as the leachate penetrates the soil. Phthalates have shown to be potential groundwater contaminants, but also that they may be degraded within the leachate plume down-stream an unlined landfill.
Key words: anaerobic degradation, phthalates, landfill