Chemical Pollution

The arctic has long been considered the "sink" for enviromental contaminants. Organochlorines, such as PCBs and DDT, mercury, and other toxins are carried northward in rivers, ocean currents, and winds where they accumulate at high levels among the food chain. Polars bears have been found to have extremely high amounts of chemical pollutants, putting them at risk of bone mineral density loss, hormonal imbalane, physiological damage, and compromised immune systems. The bone mineral density loss is more devastating with female polar bears than males, becuase females must activate large amounts of calcium phosphate during their pregnancy and nursing.
"As an additional blow, the harmful effects of pollutants can interact negatively with the nutritional stress caused by global warming."-HSI