Accumulation of persistent organochlorine compounds in mountains of western Canada

1. Accumulation of persistent organochlorine compounds in mountains of western Canada Jules M Blais, David W. Schindler, Derek C. G. Muir, Lynda E Kimpe, David B. Donald, Bruno Rosenberg Presented By Matt Kruse

2. Basically • Persistent, semi volatile oranochlorine compounds such as toxic industrial pollutants and agricultural pesticides are found everywhere on Earth. • However we are seeing higher than expected occurrences of these compounds in remote regions as a result of long range transport in the atmosphere. • Basically volatilization in warm locations and condensation in cooler environments • The high elevations of mountains are similar to high latitudes in that they have lower temperatures which then increases condensation and deposition of the organochlorines in the snow pack. • Also the tendency to volatize decreases with temperature, and hence high altitude.

3. Why is this Important? • Accumulation of organochlorine compounds has not yet been documented as a function of altitude, which is what this study set out to do • This study reported a strong increase in the deposition of organochlorines as a result of altitude. (A magnitude of 10 to 100 fold increase between 770 and 3,100 m.a.s.l.) • Organochlorines are toxic so its good to know especially for regions where there are high precipitation levels that are close to pollution sources.

4. What prompted the study? • Fish from high altitude lakes in the Canadian Rockies had high concentrations of chlorinated organic contaminants. • The lakes in the Canadian Rockies don’t have long food chains which would result in biomagnification. • In view of these findings atmospheric deposition must be the root cause of these high concentrations of organic contaminants. • So we look to see if this hypothesis is true. • Hypothesis: Increased atmospheric deposition of organochlorines at high-elevation sites could be caused by the larger precipitation rates and reduced volatilization at high altitudes.

5. Sample Sites • Snowpack samples were collected in the vicinity of 15 Canadian meteorological stations(22 sites) in the coastal mountains of British Columbia • Elevations ranged from Donald (I) at 770 to Sunshine (B) at 2,186 m.a.s.l.

6. Methods • Snow pack samples were taken within a two-week period in late February and early March 1996. • Before melting had occurred • When snow packs were at peak depths • Meteorological data showed a drop in 6 degrees for every 1,000 feet • Snow pack samples were collected • Snow pack depth and snow density were determined • Samples ran through chromatography/mass spectrometry to determine the concentrations of organochlorines.

7. Results1st Main Point • Basically overall we see contaminant concentrations increase with increase in altitude. • Organochlorines in snow defined as the snow depth x the concentration increased by factors of 10 to 100 over the elevation range studied • This is a combination of higher concentrations within the snow pack as well as more snow at high elevations. • Dramatic increase in both above 2,000 m.a.s.l. Snowpack vs. Elevation Snowpack Concentration vs. Elevation

8. Results 2nd Main Point • Main Point we note the increase in more volatile, less chlorinated organochlorines at high elevations • Inversely we see less of an effect on heavier less volatile organochlorines. • Classed by number of chlorine atoms per molecule in snow from four of the study sites Less Volatile More Volatile

9. Implications • It is presently unclear how much of these organochlorines could find there way into surface waters. • In North America much of the water received is from high elevations • Alberta where the study was done supplies 87% of the flow of the Saskatchewan River system while constituting only 12% of the surface area basin • Many Peaks in the Rockies are much higher than the ones done in the study and there is reason to believe that concentrations of organochlorines would continue to increase with elevation • Cities like Denver and Mexico City derive their water supply from snow melt on mountains over 3,000 meters and are much closer to sources of organochlorines. • It is likely that the effects could be much more pronounced in these areas.