Re: How is pollution in the atmosphere measured by studying bee pollen?

To best answer this question, I have consulted with an expert at 
Agriculture Canada. This is from Jerry Bromenshenk:

"Bees forage a wide area and bring back pollutants in or on their own
bodies, and in or on the substances that they collect (nectar - for honey,
pollen - to feed the brood, resin - to make bee glue or propolis).

In doing this, bees are collecting materials from the air, water, soil, and
plants as well as any pollutants that happen to be present.

Because all of the bees return home to the hive, they also bring the
pollutants back to the hive.  We can then sample at the hive and get an
idea of what contaminants, if any, occur in the area surrounding the hive.

In addition, bees may be harmed by these pollutants.  Therefore, we can
also observe the colony and determine whether it is in good health.

With respect to pollen, the pollen grains are slightly sticky.  Dust
particles settle out of the air onto the pollen.  These dust particles may
contain contaminants.  Also, the plant may take up pollutants in the soil
and transfer them through the stem into the flower and eventually into the
pollen.

Pollutants in pollen usually indicate that the contaminants occur in air or
soil - mainly because most plants that have showy flowers grow on the land,
not in water.    But, there are exceptions.

For pollution monitoring, the bee itself gets "dirty".  The good news is
that pollutants rarely end up in the honey.

Jerry"

c/o Neala MacDonald