Comparison of radioactivity sources in the ocean

The background level of radiation in oceans and seas varies around the globe. Measured in atomic disintegrations per second (Becquerels) of cesium-137 in a cubic meter of water, this variation becomes readily apparent. The primary source of cesium-137 has been nuclear weapons testing in the Pacific Ocean, but some regions have experienced additional inputs. (Illustration by Amy Caracappa-Qubeck, © Woods Hole Oceanographic Institution)