Environmental Impact of using actinium (228Ac)-contaminated sludge as soil conditioner and sand substitute

Low-level actinium contamination (²²⁸Ac) of petroleum sludge is reported. The sludge is earmarked for road-building and soil enrichment, hence long-term radiation in low doses is not desirable. We subsequently investigated the distribution of this radioactivity over a one-year period. Collection was conducted at different sites, and the sludge was subjected to high-resolution gamma-ray measurement with a Geenlarge this page detector. Samples of 1 kg dry weight were prepared in suitable Marinelli beakers and counted for 12 h. The approximate literature guideline for this radioistope in soil and regular sludge is about 60 Bq/kg. The levels in many of our samples were several times higher, and activities up to 600 Bq/kg were observed. The general distribution was studied; and suggestions for possible preventative remediation to deplete the activity levels in the sludge prior to its use as a building material and on sludge-farms are outlined. The study, therefore, formed an interesting contribution to research associated with radioactivity in the environment.