7Be Levels in Sewage Sludge: A Baseline Study

Abstract There is no serious information in the existing literature on the levels of radioactive 7Be in sewage sludge. Our research took the form of a baseline study to provide suitable information in this respect. In addition, the sludge is converted to fertilizer, which can lead to radioactive contamination of streams and underground water supplies by agricultural run‐off. According to the documented literature, the acceptable level of radioactivity in domestic water supplies is <0.1 Bq/L. The levels in the sludge were up to three orders of magnitude higher. We subsequently investigated the distribution of this radioactivity over a 3‐year period. Our study involved measurement, by gamma ray spectroscopy, of 7Be in sludge and corresponding waste water specimens, and evaluation of its distribution over a period extending from March 2000 to March 2003. The sludge and disinfected effluent samples were collected thrice monthly, and subjected to high‐resolution gamma‐ray measurement with a 28‐cm2 Ge detector....