Decline of PCB concentrations in North Atlantic surface water.

Abstract

POLYCHLOROBIPHENYL (PCB) concentrations in North Atlantic surface waters have declined fortyfold since 1972, following the cessation of certain industrial uses of those compounds. Industrial sales of PCB for use in products which would allow leakage to the environment, for example in plastics, inks and paints were stopped in the United States and Sweden during 1970–711; and in 1972–73 other European countries and Japan initiated a similar action2. In 1971 and 1972 average surface concentrations of PCB in the open North Atlantic Ocean were about 30 ng l−1 (ref. 3 and C. E. Olney and J. J. Quinn, unpublished). By April of 1973 the concentration in the Sargasso Sea had been reduced to 1 ng l−1 (ref. 4); five months later we found that the decline had levelled at 0.8 ng l−1, a concentration which was still present in February 1974 in the north-west Atlantic. The accumulated data are presented in Table 1. These observations revealing a reduction in surface water concentrations of PCB compare well with our February 1974 measurements of a tenfold decrease of PCB in the atmosphere over the north-west Atlantic since 1973 (ref. 5), and a fivefold decrease since 1972 in the PCB content of mixed plankton collected along 09°N latitude in September of 1973 (ref. 6).