SCHOLARS

Monica N. Danon-Schaffer

Monica N. Danon-Schaffer

University of British Columbia, Ph.D.
EREF Scholar 2005

Polybrominated Diphenyl Ethers in Landfills from Electronic Waste

Where Are They Now?  Monica is currently the Manager of Environmental Compliance at Wardrop Engineering, Inc.  She is also pursuing her Ph.D. in Chemical & Biological Engineering at the University of British Columbia (2010). 

Project Description (while EREF Scholar):
Monica’s research focused on Brominated Flame Retardants (BFRs), including Polybrominated Diphenyl Ethers (PBDEs), largely their concentrations in the environment and their adverse effects on human health.  This thesis explores how these compounds reach the environment, how they are transferred from waste streams to water and soil, and how they are transported to distant locations like Northern Canada.  Landfills, which receive a large proportion of society’s discarded consumer waste products, including electronic wastes (e-waste), are the major focus of attention.

Leachate was collected and analysed from 27 landfills across Canada and 11 dump sites in the Canadian North, for a total of 264 samples.  There was wide variability in the results, both in terms of the total concentrations of PBDEs and in the distribution of congeners.  There was limited correlation with the population of the city or town in which the landfill or dumpsite was located.  Northern sites tended to have lower PBDE concentrations than southern ones, but some levels were significant despite the low population density and lack of industry in the north.  The potential exists for significant transfer of PBDEs from e-wastes to landfill leachate in southern Canada.  The North provides a sink for PBDE contaminants.  Significant differences in PBDE levels in leachate in contact with wastes originating in different 5-year time intervals suggest that the time-of-manufacture of electronic goods plays an important role in determining the rate of PBDE release into the environment.  Electronic components manufactured in the 1985-89 period were found to have especially high PBDE concentrations.

Experiments were carried out in which e-waste was contacted with distilled water and leachate from a major urban landfill in a custom-built contactor.  There was appreciable transfer of PBDEs to the aqueous phase which increased with increasing time of contact and increasing temperature, while mostly decreasing with increasing pH for the range tested.  Exposing e-waste to distilled water in the contactor led to lower, but still appreciable, PBDE concentrations, probably due to dislodgement of fine dust from the surface of e-waste particles.

A comprehensive mechanistic mole balance model was prepared to assist in predicting the concentration of PBDEs in and near landfills.  The balances were applied to different homologue groups and different subsystems - field e-waste, non-e-waste solids, air and aqueous phase, although air was excluded due to lack of data.  Landfill conditions are obtained from field measurements, best available data or estimates.  Key mass transfer parameters were obtained from solid-liquid contacting experiments with crushed e-waste.

Simulations indicate that PBDEs will persist for decades in the environment even if they are no longer manufactured and incorporated in plastics. how landfill microbiology impacts refuse decomposition in landfills.  While a good understanding of the microbial populations involved in refuse decomposition and their basic function had been developed, the mechanics of how specific microbial species vary with time and how this variation might impact the stability and rate of refuse decomposition has not been previously evaluated.  By assessing microbial function and metabolism, it is hoped that new strategies can be developed that will enhance refuse decomposition and methane recovery.


Biography:
Monica has more than 15 years of professional experience with expertise in several disciplines including chemical and environmental engineering, and environmental forensics.  Monica specializes in assessments of environmental, health and safety compliance and liabilities, and has experience conducting due diligence, waste and compliance audits, impact assessments, site remediation; environmental forensic investigations; and project management on local and international projects throughout the Americas.

Her PhD has investigated and quantified migration pathways for Polybrominated Diphenyl Ethers (PBDEs), a family of emerging contaminant used as flame retardants in textiles and plastics, from landfills across Canada, including the North. Monica’s research on fate and transport of PDBEs has generated laboratory and field data on the presence of these substances in Canadian landfill leachate, which has not been previously collected.  The laboratory and field data were used in simulations of contaminant transport and transformation paths to predict release and degradation of PDBEs in landfills over time. In completing her investigation.  Monica has established contacts with researchers, regulators, and NGOs from Canada and abroad who are involved in the study and quantification of emerging contaminants from landfills.

Research Publications:
MN Danon-Schaffer. “Polybrominated Diphenyl Ethers in Landfills from Electronic Waste.”

MN Danon-Schaffer, JR Grace, MG Ikonomou. “PBDEs in Waste Disposal sites from Northern Canada.” Organoh Compounds, Vol. 70 (2008) p. 365-368

MN Danon-Schaffer, JR Grace, MG Ikonomou. “PBDEs in Landfill Leachate and Potential for transfer from Electronic Waste.” Organoh Compounds, Vol. 68 (2006) p. 1759-1762

MN Danon-Schaffer, JR Grace, MG Ikonomou. “Identifying Sources of PBDEs in the Canadian Arctic.” Organoh. Compounds, Vol. 67, (2005) p 513-517

MN Danon-Schaffer, JR Grace, MG Ikonomou. “Modeling of PBDEs in Landfills and Other Systems.” Organoh. Compounds, Vol. 67, (2005) p 1923-1927