The Science of POPs 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, Great Lakes and St. Lawrence basin.
POPs tend to concentrate in colder climates such as Canada's north.
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. The geographic location and socio-economic activities of Aboriginal Northerners make them particularly susceptible as they eat country food that has been contaminated. Country food is economically essential for most Aboriginal Northerners. Data from sediment samples in the Great Lakes and other regions reveal that the concentrations of dioxins and furans have increased steadily since the 1940s, indicating that these substances are generated and released through industrial activities. DDT in the environment causes the eggshells of gulls and eagles to become so thin they break during incubation.