Monitoring results
Since the closure of the site in September 2003 lead in air and metal concentrations in water have fallen dramatically. Around 90 percent below the levels pre-September 2003. For the first month after closure, lead in air at Fourth Street averaged 0.07 ug/m3 compared to the annual average prior to closure of approximately 0.88 ug/m3. Metals in discharge water are also down significantly with average concentrations of lead now 0.01 mg/m3 from 0.08 mg/m3. In additional cadmium concentrations have fallen from 0.11 mg/m3 to 0.06 mg/m3.

Pasminco continues to monitor the Lead-in-Air in the community surrounding the PCCS site. Instruments are used which act like vacuum cleaners, pulling a known volume of air across a filter. The particles in the air are filtered out, collected, weighed and then analysed for lead.

Historically, there have been 8 monitoring sites. These sites were placed at locations shown on the adjacent map.

Different locations were sampled at different times, but effectively monitoring occurred 24 hours a day, 7 days a week. Some locations were monitored every day while others produced a single daily sample every 6 days.

The lead in air results since the closure of the smelter in November 2003 have decreased dramatically as are shown in the graph below.

Because of these decreases, and with approval of the DEC, PCCS is changing the sampling regime to a single 24 hour sample taken once every 6 days. The 6 day cycle is chosen so sampling results are obtained for all conditions over different week days and weekends.

When the demolition of the smelter buildings commences, the Lead-in-Air monitoring regime will again return to a 24 hour, 7 days a week program. However sampling will only take place at 4 of the locations closest to the PCCS site.

The filter papers are prepared and changed by PCCS staff with the analysis of the filter paper now being performed by a fully accredited external laboratory. The results are forwarded to the DEC on a weekly basis.

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