These declining numbers are due to the slew of deadly toxins that have entered their waters over recent years.
PCBs (polychlorinated biphenyls) are man-made organic chemicals that were once used to make insulating liquid, adhesive, paint, plastic, rubber, and even flame retardants that were applied to children's clothing. Even though PCBs were banned in North America in 1979, they can still be found in products that were manufactured prior to the ban. These toxins have made their way into the ocean and into the fish and mammals that orcas feed on.
PCB levels found in wild orcas are several hundred times greater than levels deemed safe for humans. PCBs in orcas can cause impaired reproduction, lowered sperm count, immune deficiency, cancer, and premature death.
A recently published scientific study has estimated that the PCB levels in Pacific Northwest waters will not drop below the risk threshold until 2030. It is predicted that the levels of PCBs found in resident orcas will not drop to a safe level until 2060.
PBDEs (polybrominated diphenyl ethers) are a class of flame retardants that are chemically similar to PCBs. PBDEs can be found in items that you currently own from your furniture to electronics. PBDEs are used in a wide variety of products in North America.
When items containing PBDEs are not properly disposed of, they end up in the environment and cause severe harm to animals.