POPs are semi-volatile chemicals. After their release into the environment, they travel in multiple cycles of evaporation, transport by air and condensation. Called the grasshopper effect, this process allows POPs to travel great distances quickly. In the cold climate of the Arctic, low evaporation rates trap POPs, and so they enter the food chain. In Canada, the highest concentrations of POPs are found in the Arctic, the Great Lakes and in the St. Lawrence basin.
POPs tend to concentrate in colder climates such as Canada's north.
The geographic location and socio-economic activities of Aboriginal Northerners make them particularly susceptible as they eat country food that has been contaminated. Scientific evidence shows levels of PCBs in the blood of some Inuit women are higher than Health Canada guidelines, and levels of certain POPs in breast milk have been found up to nine times higher than in women who live in southern Canada. Canada chairs the negotiating committee for this agreement. A key issue at the session was the importance of assistance for developing countries to monitor, evaluate and control POPs. Canada is the first country to announce a commitment of capacity building resources to respond to the needs of developing countries in implementing the impending UNEP Convention on POPs.