On June 9th and 10th our now-annual meeting with Industry Partners, interested consultants, and government representatives was held at Irwin Inn. The weather was most cooperative for this meeting with the largest ever attendance and a special afternoon session entirely organized by Anne McConnell of Procter & Gamble. It is hoped that this industry initiative will be the first of many others in subsequent meetings. We were also pleased to welcome special guest Kai Millyard to this year's meeting. As always, informal discussions continued through lunches and over dinner. These provided an excellent opportunity for individual industry representatives to raise potential new directions for the research group. We were gratified by the overwhelmingly positive reaction to our work so far. The encouragement we receive on these occasions provides much of the enthusiasm and impetus to carry us through the year ahead.
Meeting Participants (from left to right) Front Row: Rick Brown, Reed Harris, David Kane, Don Mackay, Eva Webster, Trevor Scholtz. Second Row: Jeanette Southwood, Michael Leggett, Jerry Coyle, Lynne Milford, Katherine Gillan, Ray Beauchamp, Brendan Hickie, Ellen Bentzen and Aiden. Third Row: Jeff Ridal, Anne McConnell, Ken Taylor, Stacey Fernandez, Jack Soule, John Gannon, Roger Sutcliffe, Pam Kloepper-Sams. Back Row: Gord Cluett, Matthew MacLeod, Lynn McCarty, Brian Dimock, Holger Hintelmann, Rajesh Seth, Bob Bailey, Don Lush, Joe Muldoon, David Pennington, David Lean. Missing from Photo: Steven Sharpe, Grant Feasby, Liz Sahsuvar, Kai Millyard, Martha Lush.
The meeting opened with the usual round of
introductions and a brief overview by Don Mackay of
the activities at the Centre over the past year.
Matthew MacLeod described his work on a
comprehensive environmental fate and exposure
assessment for benzene and the chlorobenzenes in
Canada. The assessment follows a five stage process
of (1) chemical classification, (2) quantifying
discharge rates and environmental concentrations, (3)
evaluative assessment of fate, (4) regional mass
balance modelling, and (5) human exposure
estimation. Both the EQC and ChemCAN models
were applied during the study, and predictions of the
ChemCAN model were found to be in satisfactory
agreement with observed environmental
concentrations. Last year Jim Argo raised the idea of
combining exposure and location data to form an
"accumulated exposure index" prompting this
investigation into human exposure as a first step to
developing such an index. A novel, probabilistic,
multiple pathway model was developed to estimate
human exposure to environmental contaminants, and
applied to the chlorobenzenes. Results suggest that
benzene and 1,4-dichlorobenzene are present in the
environment at levels sufficient to cause near allowable
daily intake (ADI) exposures for the general
population, but the other substances are present at
levels which represent exposures ranging from 1/10 to
1/1000 of the ADI. It was recognized that this simple
approach is confounded by such complications as
imported foods and the need for better data on
background levels for inflow estimates. Soil
monitoring in remote regions could supply improved
background information however no such monitoring
program exists in Canada. A paper on this work has
been submitted to Chemosphere.
The Equilibrium Lipid Partitioning (ELP) method for
examining ecosystem contamination was presented by
Eva Webster. This method expresses the contaminant
concentration in each medium of an ecosystem in
terms of the concentration which would exist in lipid
at equilibrium with the monitored medium.
These ELP concentrations can be expressed in the
common units of g/m3 and plotted on a single graph.
Such a graph immediately reveals biomagnification
up the foodchain, and clearly shows time trends within
the ecosystem as a whole. Changes which effect a
single species but do not reflect the state of the
ecosystem, can also be identified. The time trends in
Lake Ontario and Lake Superior PCB contamination
for 1977 to 1993 were used to demonstrate the
usefulness of the ELP method. A further refinement
was necessary to reduce the concentration data onto a
single broad band indicating ecosystem contamination.
This "adjustment" involved multiplying each ELP
concentration by the average ratio of concentration in
water and the concentration in each medium. The
results for Lakes Ontario and Superior can be seen in
the figures above.
The clear decline in PCB levels in these ecosystems
can be seen, but there are differences between the two
lakes.
While this method is proposed as a useful tool to assist
in the interpretation of monitoring data and can be
used to estimate concentrations in media below
detection limits, it does not take the place of a
comprehensive monitoring program.
The ELP method generated much interest and
discussion among participants. A paper will be
submitted to the Journal of Great Lakes Research.
This concept has also been applied to help interpret the
multimedia concentrations of dioxins and furans in the
UK. A report on this work is near completion.
Ellen Bentzen presented temporal trend data for PCBs
in Lake Ontario lake trout collected by both American
and Canadian government agencies. After accounting
for differences in age and lipid, results of these surveys
were comparable. PCBs declined rapidly from the
1970's to early 1980's followed by slower declines.
Temporal data for rainbow smelt, slimy sculpin,
Diporeia, Mysis relicta, and net plankton, plus food-web PCB accumulation studies were shown. Forage
fish and invertebrates demonstrated substantial annual
variability and no trend of decreasing contaminants.
Much variability is resolved by fluctuations in lipid
content demonstrating the importance of accounting
for lipid in the interpretation of contaminants both
over time and throughout food-webs.
This work on Great Lakes issues is being assembled
for inclusion in the SOLEC (State of the Lakes
Ecosystem Conference) which will be held in Buffalo
in October of this year. This conference yields a
periodic, authoritative statement on the condition of
the Great Lakes as they respond to, and recover from,
a variety of stresses including contaminants, nutrients,
exotic species, and habitat changes.
The current status of work on the organic carbon
partition coefficient (Koc) for hydrophobic chemicals,
started by Jane Muncke last summer, was presented by
Rajesh Seth who is continuing this investigation. Soils
are the primary sink for hydrophobic chemicals, and
soil sorption, characterized by Koc, has a profound
effect on their fate, bioavailability, and effects.
Unfortunately there is no consensus on the estimation
methodology for Koc and numerous correlations have
been derived. The results indicate that the variability
in Koc is best expressed as a factor of uncertainty in
(Koc/Kow). Rajesh is fianlizing his report which will
include a recommendation for the optimal correlation
approach and an assessment of likely error limits.
Lynne Milford provided an update on her modelling of
the Otonabee River - Rice Lake system. Two models
were presented which predict total PCB fate and
concentrations both spatially and temporally, for water,
sediment and fish (biota). The steady-state model
provides important spatial information with regards to
each of the six segments of the system and the dynamic
model provides insight into temporal variability. Since
historical data for direct emissions of PCBs were not
available, a Gaussian-like distribution was used in the
dynamic model to account for these emissions over a
60 year period (1940-2000). There was reasonable
agreement between concentrations predicted by the
models, and those observed in the field. A sensitivity
analysis demonstrated that changes in the magnitude
of the significant process rates affects the
concentrations at peak years but concentrations
ultimately reached equilibrium at approximately the
same time. The Otonabee River - Rice Lake system is
responding to reduction of PCB emission naturally and
does not require any remedial actions to be taken.
A sequel to this work will be a collaborative project
with David Lean and Jeff Ridal of the St. Lawrence
River Institute of Environmental Science in which the
behaviour of PCBs in the St. Lawrence River Area of
Concern (AOC) will be modelled. This area extends
from below the Moses-Saunders power dam at
Cornwall, Ontario / Massena, New York to the
Beauharnois power dam in Quebec.
This is envisaged as contributing to a future, larger
scale model of the entire Lake Ontario / St. Lawrence
system.
Brendan Hickie provided an overview of a project
funded by Alcan to characterize the mass balance of
PAHs in Lac St. Louis near Montreal, Quebec. It is a
shallow fluvial lake at the confluence of the St.
Lawrence and Ottawa rivers with a very short water
residence time (~15 hours). The QWASI model was
modified to include three lake segments with a single
overlying air compartment. PAH inputs considered
were background advective inputs by rivers and the
atmosphere, Alcan stack emissions, and a small direct
discharge from Alcan to the lake. Overall, only a
small proportion of the stack emissions enter the lake
from the atmosphere but these appear to contribute
about 50% of the PAH inputs. This is probably an
overestimate since the PAH loadings from the greater
Montreal area have not yet been well characterised.
Brendan also reported on the ongoing project to model
contaminant accumulation through the Arctic marine
food-web which is funded by the Department of Indian
Affairs and Northern Development - Northern
Contaminants Program (DIAND-NCP). The NCP is
driven by contaminant-related health concerns of
northern people who rely on local food sources
including marine mammals. The presentation included
an overview of the marine food-web structure and the
potential problems of applying a steady-state food-web
model to this system. These include the extended time
required for marine mammals to reach steady-state
(several years at least), and the extreme seasonal
changes in the system. Of particular interest is the
potential role of the spring ice algae community in the
bioaccumulation process.
Katherine Gillan presented an overview of her work on
the development of a bioaccumulation model for
amphibians, specifically frogs. The apparent global
decline of amphibian populations as well as high
incidences of limb deformities may make these
animals good indicators of local contamination.
Amphibians spend varying degrees of their lives in
water and on land depending on the species. Uptake
routes for contaminants include food, skin, and lungs
(or gills for tadpoles). Data are being collected
regarding physiological parameters for entirely aquatic
frog species such as the green frog for the
bioaccumulation model and eventually may be applied
to a life cycle-type model.
Stacey Fernandez of SENES Consulting gave a
presentation on a model used to assess risks associated
with a landfill being located in an open-pit mine. The
possibility of mercury contamination of an adjoining
river from leachate was used as an example. The fate
and transport of mercury was determined and the
effects on three local receptor populations, fish, gulls
and mink, were discussed. Mink were found to be the
most sensitive receptors to the potential mercury
contamination.
Jeanette Southwood of Angus Environmental gave a
brief presentation describing application of fugacity
models to various environmental problems. Disparate
examples of agrochemical fate in ponds in
Saskatchewan and the fate of pulp and paper mill
effluent in rivers in Finland were used to illustrate the
flexibility of the basic QWASI fugacity model.
Anne McConnell of Procter and Gamble introduced
the topic and the speakers of this special session
focussing on the assessment of risk associated with
household cleaning products. It was suggested that this
type of session become a regular feature of these
meetings to facilitate industry taking a more pro-active
role in defining the research directions of the Centre.
Pam Kloepper-Sams, Environmental Safety Section of Procter and Gamble, described their approach to environmental risk assessment and modelling for household cleaning products. Since the bulk of these products finally end up in the sewers, she gave a comprehensive overview of the detailed modelling of their fate and transport conducted by P&G as they pass through the sewage treatment system and into receiving US waterways. The EQC model is used as a part of this process to match with regulators' expectations, however, more emphasis is put on other aspects of the product life-cycle since these are down-the-drain products by design. The receiving waterways in Canada are not well parameterized for modelling estimates so values derived from similar American systems are used and expected to give conservative estimates. The results of these models are used to steer product development toward more acceptable, non-harmful products. This echos the report given last year by John Gannon of Dupont who spoke of the use of Level I as an initial screening tool to avoid the development of problematic chemicals. It is very valuable to us to know how the models developed at the Centre are being used by our partners.
A number of industry priorities were identified including:
Ed Berry from the Association of Canadian
Manufacturers of Chemical Specialties outlined the
post-consumer solid waste issues associated with
household chemicals. The banning of solid wastes
associated with household chemicals from municipal
landfills is based on "perceived" hazard and varies
from place to place with regulations coming from
various levels of government with a lack of
uniformity. The example of a toilet bowl cleaner bottle
was used to illustrate the problem; toilet bowl cleaner
is designed to be flushed, but in some jurisdictions, the
residue in an empty bottle is labelled as household
hazardous waste with the associated high cost disposal.
This emphasized the need for a scientific basis for the
assessment of risks associated with the solid waste
disposal of these chemicals and to assist in decision-making and the need to bridge the gap between the
perceived hazard and the actual risk. Two actions were
identified; a need for models of landfill sites with
mixtures of chemicals, and a need for producers to take
a pro-active approach informing the public of a
product's life-cycle.
Thank you, Anne, for your efforts in organising this
interesting and thought-provoking session.
David Pennington from the Systems Analysis Branch
of the Environmental Protection Agency (EPA), USA,
gave a comprehensive overview of the Agency's
initiatives, particularly in the area of application of
computer-based tools for the assessment of chemicals
and their impacts. The use of models by producers to
move beyond compliance was encouraged. He
elaborated on his branch's application of the EQC
model for comparing the relative impact of chemicals
and argued that multimedia models provided a
scientific basis for decision-making. The EQC model
is also being used by the EPA as a part of the
Waste Minimization
Prioritization Tool (WMPT) for the preliminary
assessment of chemicals based on PBT (persistence,
bioaccumulation and toxicity) scores. About 4500
chemicals have been evaluated with WMPT. He
emphasized the need for extending the ChemCAN
model to regions in the USA for a more accurate
evaluation of the regional ecological impact of
chemicals of concern. The need to address inorganics
and metals was raised. A special, spreadsheet version
of EQC was developed by David for use by the EPA.
Roger Sutcliffe of Environment Canada, New
Chemicals Evaluation Section, Commercial Chemicals
Branch, gave an overview of the use of fugacity models
for the assessment of partitioning and fate of new
chemical substances. These types of models tend to be
most useful at a screening level since there can be
discrepancies between predicted and observed results.
The generic type models are useful for determining
fate in a multi-media environment, however, it is
important to perform uncertainty analyses on input
parameters. If models are to be used in industry
submissions the version number should be included so
that any discrepancies in model results can be traced.
Concerns were raised regarding models being used to
seek waivers for data submissions. Models should
supplement, not replace, laboratory experiments.
Models are excellent screening tools, but experimental
data must accompany submissions to Environment
Canada.
Ken Taylor also from Environment Canada, Chemicals
Evaluation Division, made a brief presentation on the
use of models in the environmental assessment of
priority substances under the Canadian Environmental
Protection Act (CEPA). The possibility of allowing
future new chemical notifications based on modelled
physical chemical properties was discussed, and some
potential pitfalls identified.
It was generally agreed that models need to be tested
and calibrated in much the same way as analytical
chemists calibrate their methods and instruments.
While more research is needed, the decision-making
process should proceed with the best information
currently available.
Don Mackay briefly reviewed the global modelling
work being done by Frank Wania with Department of
Indian and Northern Affairs (DIAND) sponsorship.
The model has been revised and a description of a new
version has been submitted to Environmental
Toxicology and Chemistry. A sequel paper describes
the application of the model to HCH, a component of
technical lindane which has been widely emitted in
past decades. The results show convincingly the
transport and accumulation of this substance to the
Arctic as well as the overall global response to a
decade-long "pulse" of HCH release. This work is
feeding directly into United Nations programs for
global control of persistent chemicals.
Liz Sahsuvar, a Masters student at York University
under the supervision of Len Barrie of Environment
Canada, presented her work on developing a 1-D
column version of the Northern Aerosol Regional
Climate Model (NARCM) to explain the temporal
variations observed in air-phase PCB congener
patterns in the Arctic. The work includes
parameterization of physical chemical properties of
PCBs for the atmosphere-water/air/soil/vegetation
exchange processes as well as partitioning between the
gas phase and aerosols.
Trevor Scholtz of ORTECH described air-surface
exchange models currently under development at the
Canadian Global Emissions Interpretation Centre.
Air-soil exchange was briefly described, along with a
more detailed discussion of air-ocean exchange
models. Air-plant exchange was discussed at last year's
meeting. The application of air-surface exchange
models such as these in describing the "grasshopper
effect" or global migration of persistent organic
contaminants, was discussed.
These studies are of particular interest to us because
air-surface exchange is a key component of our
multimedia models.
Rajesh Seth reported progress on fugacity-based, mass
balance modelling of the fate and transport of metals
in the aquatic environment. The approach is being
applied to nickel and copper contaminated Alice and
Baby Lakes in the Sudbury region of Ontario in
collaboration with David Woodfine (one of Trent's
first graduating Ph.D. students) and Magda Havas
(David's thesis supervisor). Sediment cores provided
the monitoring data. Potential adsorbents for metals in
these lakes have been identified and their properties
defined. Information on metal speciation and partition
to inorganic and organic sorbents is being derived with
the help of models such as the Windermere Humic
Aqueous Model (WHAM) and USEPA's MINTEQA2
Model. The derived information is being used for
modelling the steady- and unsteady-state fate and
transport of nickel and copper in these lakes.
Holger Hintelmann summarized the findings of the recent workshop "Sources of error in methylmercury determinations" that he co-organized on behalf of the European Community (within the framework of the Standard Materials and Testing program). The major issue of the workshop was the observation by Holger and others that methylmercury is accidentally generated during the analytical procedure while analyzing sediment samples leading to an overestimation of the true values. All papers presented on this workshop will be published in a special issue of Chemosphere with Holger as guest editor.
A study of the bioaccumulation of mercury in caddisfly
nymphs conducted by Elizabeth Haack and John Cole,
two honours chemistry students under his supervision,
was presented by Holger. The rates of uptake and
elimination for methylmercury and inorganic mercury
from water and dietary sources were determined. The
study showed that organic Hg is accumulated at much
faster rates than inorganic Hg. Food was the major
source. Uptake from water was significant, but can not
alone explain the observed natural mercury levels. The
work showed again the potential of caddisfly nymphs
as biomonitors and the importance of biomagnification
of methylmercury in the aquatic food-web.
Holger also introduced his graduate student, Brian
Dimock, to meeting participants.
Reed Harris of TetraTech Consultants provided an
update on the mercury model he presented at the
previous meeting. This multimedia, steady-state model
allows for dynamic growth in fish examining all fate
pathways and processes within an aquatic ecosystem.
It has been used to predict concentrations in fish with
changes in atmospheric loadings and applied to 21
different lakes in Wisconsin and in the Florida
Everglades. To better understand some of the
processes in the mercury cycle, collaborative work with
H. Hintelmann on a whole lake study has been
proposed.
If by some accident, or in the course of company re-organization, you fail to receive copies of our
newsletters, please remember that we post them on our
website (www.trentu.ca/envmodel). If a newsletter
appears there, and you did not receive your copy,
please contact us. It's not intentional, we've probably
just mis-placed you.
Please suggest other individuals who should receive
our Newsletter. Send the address to
ewebster@trentu.ca
Please visit our website from time to time.
A lunch meeting at SETAC in Charlotte NC for
November 18 (tentatively) is planned following last
year's success. This brief meeting allows many of our
partners who already attend SETAC to be updated on
the Centre's activities and progress.
Next year's meeting is tentatively scheduled for June 8th and 9th, 1999.
While we are quickly filling the conference room at
Irwin Inn, there was a strong general feeling that we
should continue to meet there. If you would like to host
a session as Anne did this year, please let us know so
that we can plan to have sufficient time for discussion.
We can not over-emphasise the importance, to us, of
the participation of our industry partners and we urge
those of you who have not yet attended these meetings
to do so, if at all possible, next year.
In January, David Lean, NSERC-Industry Chair at the
University of Ottawa, and close collaborator with the
Centre, held his first Partners' meeting. Eva Webster
presented an overview of the work of the Centre and
Lynne Milford talked about her work modelling river
ecosystems, especially the proposed application to the
section of the St. Lawrence River by Cornwall. We see
these two research programs as highly complementary
and hope to further strengthen the existing
collaborative efforts.
In February Eva Webster and Matthew MacLeod
attended C4's meeting at Toronto airport to report on
C4 funded projects as well as work in general at the
Centre. It was interesting to learn of the other research
they are funding.
In the Spring, Lynne Milford returned to Cornwall to
attend the Great Lakes Conference with Matthew
MacLeod. Brendan Hickie was an invited speaker and
discussed his modelling of the St. Lawrence beluga
whale population.
Matthew MacLeod and Frank Wania presented posters
on Frank's global model and snowpack modelling at
the DIAND Northern Contaminants Program review
meeting in Calgary, and Brendan presented a poster on
his Arctic marine foodweb modelling.
A large contingent from the Centre attended the
International Association for Great Lakes Research
(IAGLR) conference in Hamilton in May. Don
presented two talks: A Synoptic Indicator of
Contaminant Levels in the Great Lakes Basin; and
Exchange of Organic Chemicals Between Soil,
Vegetation and the Atmosphere.
In March Don Mackay gave a seminar at Trent on the
Two Resistance Theory of Mass Diffusion. Also in that
month he gave a talk at the University of Guelph on
Persistent and Hydrophobic Chemicals in the
Environment. In April Don attended a workshop on
persisent organic pollutants at the Stockholm Institute,
York (UK) and he gave a presentation on global
modelling of chemicals at a conference at Lancaster.
Later he visited the Unilever Environmental Research
Laboratory at Port Sunlight.
Bruce Conard, the representative for INCO which is
sponsoring the Junior Chair, visited Trent in August
1997. A visit which was returned in October 1997
when Holger went to Sudbury to see INCO's mining
operations and wastewater treatment facilities.
Ian Cousins from Lancaster University gave a seminar
on air-soil exchange of toxic organics in the
Applications of Modelling graduate program seminar
series during his visit to the Centre this Spring. We
hope to again benefit from his expertise during his
visit to Canada this summer.
Conny Breitkopf from Gerrit Schuurmann's research
group in Leipzig visited us to collaborate on a
multimedia model which has since been linked with
their QSAR model. It is hoped that this will lead to
collaboration on sensitivity analysis and model
validations.
Antonio Di Guardo, now at the University of Milan,
visited in December of 1997 to continue work on
ChemCAN, improving the handling of aerosols and
preparing a paper.
Hayley Hung has returned to Lancaster where she is
measuring the kinetics and equilibria of PCB uptake
by grasses as part of her Ph.D. program on the air-vegetation-domestic animal foodchain.
The Fugacity Workshop at Trent, on the Monday
preceeding the Partners' Meeting, offered an
opportunity for industry and government
representatives as well as consultants to gain a deeper
insight into the workings of models developed at the
Centre. Computers were available both at the
Workshop and in the evenings at Irwin Inn for
participants to experiment with various models, ask
questions, and offer suggestions for future directions.
International Association for the Exchange of Students
for Technical Experience (IAESTE), recently honoured
Don for his involvement in the program. Since the
institution of his position at Trent, three students have
come to the Centre to work for the summer months
under his direction.
Claudine Kavanagh (1996) who spent much of her
time working on chemical analysis with Chris
Metcalfe.
Jane Muncke (1997) assisted with the KOC project
being continued by Rajesh.
Anders Thygesen arrived June this year and will be
assisting with various projects, but especially snow
modelling.
In addition to these activities a couple of other projects
are noteworthy.
We continue to collaborate with Dr. Jocelyne Hellou of
the Bedford Institute of Oceanography on
bioaccumulation in marine fish.
A project is underway in cooperation with the World Wildlife Fund Canada on a model of human exposure to DDT indoors following spraying for mosquito control.
Mackay D, Paterson, S., Kicsi, G., Di Guardo, A., Cowan, C.E. "Assessing the Fate of New and Existing Chemicals:
A Five Stage Process". Environ. Toxicol. Chem.. 15 No.9 , 1618-1626, 1996.
Mackay D, Paterson, S., Di Guardo, A., Cowan, C.E. "Evaluating the Environmental Fate of a Variety of Types of
Chemicals Using the EQC Model", Environ. Toxicol. Chem. 15 No.9, 1627- 1637, 1996.
Mackay D, Paterson, S., Kicsi, G., Cowan, C.E., Di Guardo, A., Kane, D.M. "Assessment of Chemical Fate in the
Environment Using Evaluative, Regional and Local-Scale Models: Illustrative Application to Chlorobenzene and
Linear Alkylbenzene Sulfonates" Environ. Toxicol. Chem. 15 No.9, 1638-1648, 1996.
Bentzen E, D.R.S. Lean, Taylor W.D., and Mackay D. "Role of Food Web Structure on Lipid and Bioaccumulation of Organic Contaminants by Lake Trout (Salvelinus namaycush)", Can. J. Fish. Aquat. 53: 2397-2407, 1996
Mackay, D., Southwood, J.M., Kukkonen, J., Shiu, W.Y., Tam, D.D., Varhanickova D., and Lun R. "Modeling the
Fate of 2,4,6-Trichlorophenol in Pulp and Paper Mill Effluent in lake Saimaa, Finland". St. Lucie Press, Delray Beach,
Fl. pp. 219-228. 1996.
Wania, F., Mackay, D. "Tracking the Distribution of Persistent Organic Pollutants". Environ. Sci. & Technol., 30
No.9, 390A-396A. 1996.
Mackay, D., Jia, C.Q., Hoff, J., Gregor, D., and Wania, F. "The Behaviour of Organic Chemicals in Snow". Edited
by E.W. Wolff and R. C. Bales. Published in cooperation with NATO Scientific Affairs Division, by Springer-Verlag,
Heidelberg, Berlin, pp 587-593. 1996.
Mackay, D. " Fate and Exposure Modelling". SETAC News Vol. 16, No. 4. July 1996, pp. 15-16.
Falter, R., Hintelmann H., and Ilgen G. "Methylquecksilberbestimmung: Die Fallen der
Wasserdampfdestillationstechnik, oder wie man sich Methylquecksilber während der Probenaufarbeitung selbst
herstellt." CHIMIA 50:304, 1996.
Hintelmann H. "Distillation of monomethylmercury using the MICRO DIST system" Technical report prepared for
Lachat Instruments, 1996.
Shiu, W.Y., Wania F, Hung, H and Mackay D. " Temperature Dependence of Aqueous Solubility of Selected
Chlorobenzenes, Polychlorinated Biphenyls and Dibenzofuran". J. Chem. Eng. Data. 42:2, pp.293-297. 1997.
Mackay D. and Calcott, D.. "Partitioning and Physical Chemical Properties of PAHs", Chapter 3 for Handbook of
Environmental Chemistry, "PAHs and Related Compounds", edited by A.H. Neilson, Published by Springer, Berlin.
1997
Mackay D. "Multimedia Mass Balance Models of Chemical Distribution and Fate", Chapter 8 of "Ecotoxicology"
edited by G. Schuurmann and B. Markert and published by John Wiley. pp. 237-257, 1997.
Shiu, W.Y. and Mackay D. "Henry's Law Constants of Selected Aromatic Hydrocarbons, Alcohols, and Ketones".
J. Chem Engng. Data, 42:27-30. 1997.
Wania, F and Mackay D., "Global Distillation" Our Planet (The United Nations Environment Programme Magazine
for Environmentally Sustainable Development) Vol. 8:6, pp. 15-16. 1997.
MacFarlane, S., Mackay D., Shiu, W.Y.. "Application of Screening Model for Assessing Subsurface NAPL
Contamination and Remediation". Paper 97 RA 132A 132A.06, Air and Waste Management Association 90th Annual
Meeting & Exhibition, June 8-13, 1997, Toronto, Ontario, Canada 12pp.
MacFarlane, S., Mackay, D. "A Fugacity-Based Screening Model to Assess Contamination and Remediation of the
Subsurface Containing Non-Aqueous Phase Liquids" J. of Soil Contamination 17, 17-46, 1998.
Bahadur, N.P., Shiu, W.Y., Boocock, D.G.B., and Mackay D. "Temperature Dependence of Octanol-Water Partition
Coefficient for Selected Chlorobenzenes". J. Chem. Eng. Data 42, 685-688, 1997.
Hung, H., Mackay, D. "A Novel and Simple Model of the Uptake of Organic Chemicals by Vegetation from Air and
Soil." Chemosphere, 35, 959-977. 1997.
Mackay, D., Shiu, W.Y., Ma, K.C. "Illustrated Handbook of Physical Chemical Properties and Environmental Fate
for Organic Chemicals". Vol. 5 Pesticide Chemicals. Lewis Publishers/CRC Press New York, N.Y. 1997
Xie, W.H., Shiu, W.Y., Mackay, D. "A Review of the Effect of Salts on the Solubility of Organic Compounds in
Seawater. Marine Environ. Res.44. 429-444. 1997.
Finizio, A., Mackay, D., Bidleman, T. and Harner T. "Octanol-Air Partition Coefficient as a Predictor of Partitioning
of Semi-Volatile Organic Chemicals to Aerosols" Atmos. Environ. 31: 2289-2296. 1997
Mackay, D., Di Guardo, A., Hickie, B., Webster, E. "Environmental Modelling: Progress and Prospects". SAR and
QSAR in Environ. Res. 1997. 6: 1-17
Barrie, L., Macdonald, R., Bidleman, T., Diamond, M., Gregor, D., Semkin, R., Strachan, W., Alaee, M., Backus, S.,
Bewers, M., Gobeil, C., Halsall, C, Hoff, J., Li, A., Lockhart, L., Mackay, D., Muir, D., Pudykiewicz, J., Reimer, K.,
Smith, J., Stern G., Schroeder, W., Wagemann, R., Wania, F., Yunker, M. " Chapter 2. Sources, Occurrence and
Pathways". In: Jensen, J., Adare, K. and Shearer, R. (Eds) Canadian Arctic Contaminants Assessment Report, Indian
and Northern Affairs Canada, Ottawa 1997.
Wania, F., Pacyna, J.M., and Mackay, D. "Global Fate of Persistent Organic Pollutants". Toxicol. & Environ. Chem.
pp. 1-8. 1997
Hintelmann H., Falter R., Ilgen G. and Evans R. D. "Determination of artifactual methylmercury (CH3Hg+) formation
in environmental samples using stable Hg2+ isotopes with ICP-MS detection: Calculation of contents applying species
specific isotope addition" Fresenius J Anal Chem, 358:363-370, 1997.
Hintelmann H. and Evans R. D. "Application of stable isotopes in environmental tracer studies - Measurement of monomethylmercury (CH3Hg+) by isotope dilution ICP-MS and detection of species transformation" Fresenius J
Anal Chem, 358:378-385, 1997.
Hintelmann H., Welbourn P. M. and Evans R. D. "Measurement of complexation of methylmercury(II) compounds
by freshwater humic substances using equilibrium dialysis" Environ Sci Technol, 31:489-495, 1997.
Lun, R., Lee, K., De Marco, L., Nalewajko, C. and Mackay, D. "A Model of the Fate of Polycyclic Aromatic
Hydrocarbons in the Saguenay Fjord". Environ. Toxicol. and Chem. 17, 333-341, 1998.
Southwood, J.M., Muir, D.C.G., Mackay, D. "Modelling Agrochemical Dissipation in Surface Microlayers Following
Aerial Deposition". Chemosphere (in press) 1998
Hoff, J.T., Gregor, D., Mackay, D., Wania, F., Jia, C.Q. "Measurement of the Specific Surface Area of Snow with the
Nitrogen Adsorption Technique". Environ. Sci. Technol. 32: 58-62, 1998
Wania, F., Haugen, J.E., Lei, Y.D. and Mackay, D. "Temperature Dependence of Atmospheric Concentrations of
Semivolatile Organic Compounds. Environ. Sci. Technol. 32: 1013-1021. 1998.
Hellou, J., Mackay, D., Banoub, J.H. "Dietary and Aqueous Exposure of Finfish to Organochlorine Compounds: A
Case Study. Environ. Contam. Toxicol., 34: 280-288. 1998.
Scott, S., Mackay, D., and Webster E. "Estimation of Spatially Variable Atmospheric Concentrations Deduced from
Regional Mass Balance Models". Chemosphere 36, 2507-2522 , 1998.
Thomas, G., Sweetman, A.J., Ockenden, W.A., Mackay, D. and Jones, K.C. "Air - Pasture Transfer of PCBs.
Environ. Sci. Technol. 32, 936-942, 1998.
Webster E., Mackay, D., Wania, F. "Evaluating Environmental Persistence" Environ. Toxicol. Chem. (in press ) 1998
Macleod M., Mackay, D. "An Assessment of the Environmental Fate and Exposure of Benzene and the
Chlorobenzenes in Canada" (Submitted to Chemosphere June 1998)
Mackay, D. and Webster, E. "Linking Emissions to Prevailing Concentrations - Exposure on a Local Scale."
Environmetrics, 9: (in press) 1998.
Muncke, J., Seth, R. Mackay, D. "Estimation of the Organic Carbon Partition Coefficient (KOC) for Hydrophobic
Chemicals - A Critique" (Paper in Preparation)
Woodfine, D., Mackay, D., Seth, R. and Havas, M. "Predicting the Fate of Nickel and Copper in Lakes Affected by
Smelter Pollution: Applicability of the QWASI Model " (Paper in Preparation)
Milford, L., Mackay, D., Metcalfe, C.D. "A Model of the Fate of Polychlorinated Biphenyls in the Otonabee River-River Lake Ecosystem, Peterborough Ontario" (Paper in Preparation)
Southwood, J.M., Mackay, D., Kukkonen, J., Lun, R., and Shiu, W.J. "Modelling the Fate of Organochlorine
Chemicals in Pulp and Paper Mill Effluents in Lake Saimaa, Finland. (Paper in Preparation for Chemosphere)
The Centre started on July 1, 1995 and has now been in existence for 3 years. During this period we have built up a
viable group, fashioned a purposeful modelling research program, and established a good working relationship with
our partners. Funding is assured for the next two years, ie. until July 1, 2000.
Our agreement with NSERC requires that we submit a proposal for renewal at 40 months, in November 1998. Our
intention is to maintain the Centre at its present level of effort and with much the same research thrust for a further
5 year period, from 2000 to 2005. Negotiations with NSERC are already underway to clarify exactly what we can
expect from them, but regardless of the outcome, we will prepare a report and proposal by November 1998 with a
possible site visit in early 1999. As part of that proposal we must seek commitments for support and funding from our
partners for the period 2000 to 2005. We recognize that it may be difficult to make commitments so far in advance,
but we must present a proposal for a viable, funded program to NSERC.
Accordingly, in the next month we will be contacting our partners individually with a view to obtaining letters of
support and funding commitments. Please factor this into your plans! Any assistance you can provide regarding new
partners will be most welcome.
It will also assist us if you as a partners or collaborators can write up a letter commenting on your association with the
Centre and pointing out any benefits you have derived from this association.
We hope we can count on your continued support to maintain the Centre as a leader in environmental modelling both
in Canada and internationally.