A & A ENVIRONMENTAL SERVICES INC.
3 Industrial Drive., P.O. Box 604,
KIRKLAND LAKE, Ontario, P2N 3J5
Tel:(705) 567 4996 Fax:(705) 568 8368
email: accuracv@onlink.net
webpage: www.aandaenv.com
President: Dr. George Duncan, M.Sc., Ph.D., M.C.I.C., M.R.S.C., C. Chem., C.E.S.
Offices in: Burlington, North Bay, Timmins, Thunder Bay, Woodstock, Winnipeg.

December 1, 2000

ATT: Mr. Gino Chittaroni
PolyMet Resources Inc.,
I Presley Street, Box 699,
Cobalt, ON
POJ1CO

Dear Mr. Chittaroni,

Re: w/o polymet011091. Review of Site Specific Risk Assessment for the Evaluation Of Remedial Options for the Temiskaming Testing Laboratory, Cobalt, Ontario

I have reviewed the following documents you supplied to me:

1. "Geotechnical Assessment of the Temiskaming Testing Laboratory Site, Cobalt, Ontario RFP-92-020-NDM" dated March 22, 1993 and authored by Trow Consulting Engineers Ltd., Sudbury.

2. "Annex A Evaluation of Remedial Options for the Temiskaming Testing Laboratory: Site Specific Risk Assessment" authored by Beak Consultants, ref 20163.1 and dated March, 1995.

Review

Document 1., above describes an environmental assessment of the former Temiskaming Testing Laboratories' site located in Cobalt, Ontario. This site was used for decades for metallurgical investigations and as an Ontario Government assay laboratory and over the years suffered environmental impact from the on-site dumping of lead-bearing wastes and other materials. 
The Document 1 report describes a borehole-drilling/test-pitting program which identified areas of lead wastes both on- and off-site and a groundwater study which showed the groundwater on site to be flowing eastwards towards Cobalt Lake. Regulation 347 acid leach tests on the sub-soils showed high levels of leached lead, and other metals such as arsenic and cadmium but the groundwater analysis showed no significant impact from these. However, the soils are leachate toxic under Regulation 347.

Document 2 describes a site-specific risk assessment evaluation of several remedial options for the
site. Twelve individual contaminants were considered in the risk assessment: antimony, arsenic, cadmium, cobalt, copper, iron, lead, mercury, nickel, silver, boron and nitrite since these were the parameters that exceeded the MOE's clean-up guidelines. The were examined under the following headings:

Exposure assessment

- Contaminant dispersion
- Narrative exposure scenarios
- Exposure equations and parameters

Toxicity assessment for the twelve parameters named above.

The results from these were used to characterize the risks. For the natural environment, the risks are reported to be negligible. For human health, the risks are unacceptable for children coming into contact with the soils and so a recommendation has been made to isolate the wastes/soils by asphalting the surface. The human health risk factors associated with the site after implementation of the recommendations are less than the present risks to children coming into contact with existing Cobalt soils or to recreational swimming in Cobalt Lake.