Estimated PCB Loads in the Global Environment

Environment PCB load (t) Percentage of PCB load Persentage of world production Terrestrial and coastal Air 500 0.13   River and lake water 3,500 0.94   Seawater 2,400 0.64   Soil 2,400 0.64   Sediment 130,000 35   Biota 4,300 1.1   Total (A) 143,000 39   Open ocean Air 790 0.21   Seawater 230,000 61   Sedeiment 110 0.03   Biota 270 0.07   Total (B) 231,000 61   Total load in the environment (A+B) 374,000 100 31 Degraded and incinerated 43,000 4 Land-stocked* 783,000   65 World production 1,200,000   100

Pollution of the ocean means that plankton and fish are also polluted. Since PCBs are slow to decompose, they accumulate in the bodies of ocean dwelling creatures, and particularly in those creatures, such as porpoises and whales, that eat large amounts of small creatures, resulting in higher concentrations of PCBs. Mammals in particular have thick layers of fat and PCBs are easily absorbed in body fats, so sea mammals have a tendency to high levels of contamination.

Moreover, it is believed that porpoises and whales are more contaminated than animals on land because of their lower metabolic abilities. In recent years there have been mass seal deaths, and PCBs are suspected as one of the causes. One theory is that PCBs disrupted seals' immune systems, making them vulnerable to viral infections, leading to mass deaths.

We should take these phenomena in the natural world as a serious warning. It will be too late to start taking action after we find similar phenomena in humans.

Comparison of total PCB concentrations (wet wt.)
of PCBs in cetaceans from various regions

Dall's porpoise Bering Sea 1985 13 Dall's porpoise North-eastern North Pacific 1987 19 Common dolphin North-eastern North Pacific 1987 22 Harbour porpoise Hokkaido, Japan 1993 8 Dall's porpoise Japan Sea 1989 34 Northern right whale dolphin Northern North Pacific 1991 30 Pacific white-sided dolphin Northern North Pacific 1991 27 Striped dolphin off Sanriku, Japan 1992 37 Fraser's dolphin off Kii Peninsula, Japan 1991 51 Hump-backed dolphin Hong Kong 1993-1997 31 Finless porpoise Hong Kong 1993-1997 20 Spinner dolphin Mindanao Sea, Philippines 1996 2.5 Fraser's dolphin Mindanao Sea, Philippines 1996 6.2 Spinner dolphin Bay of Bengal, India 1990 2.2 Dall's porpoise Northern North Pacific 1980-1985 8.6 Finless porpoise Seto island Sea, Japan 1985 320 Baird's beaked whale Pacific coast of Japan 1985 2.3 Killer whale Pacific coast of Japan 1986 370 Harbour porpoise Black Sea 1993 22 Striped dolphin Western Mediterranean Sea 1990 390 Bottlenose dolphin Italian coastal waters 1992 590 Risso's dolphin Italian coastal waters 1992 320 Common porpoise Puck Bay, Baltic Sea 1989-1990 31 Beluga whale St. Lawrence river 1987-1990 160 Killer whale British Columbia coast 1986-1989 22 False killer whale British Columbia coast 1987-1989 40 Risso's dolphin British Columbia coast 1988 1.7 Dall's porpoise British Columbia coast 1987-1988 4.5 Harbour porpoise British Columbia coast 1987-1989 8.4