Levels of 131I and Six Natural Radionuclides in Sludge from the Sewage Treatment Plant of Valladolid, Spain

Abstract

The levels of 131 I and six natural radionuclides ( 238 U, 226 Ra, 210 Pb, 228 Ra, 224 Ra, and 40 K) were determined in sewage sludge samples obtained from an urban wastewater treatment plant that services a medium-sized town in Spain. Secondary treatment of wastewater consisting of anaerobic, anoxic, and oxic stages is collectively called A2O processing. Radio analytical determinations were performed by gamma spectrometry using a highpurity germanium detector. This technique has proven useful in identifying local radioactive pollution. This type of pollution was consistently detected throughout the year, with several increases associated with authorized discharges from hospitals. Finally, we examined the radiation dose that workers are exposed to due to the presence of 131 I in the sludge. We found inhalation risk to be negligible, with external radiation as the main source of exposure to 131 I.

Iodine-131 in Sewage Sludge from a Small Water Pollution Control Plant Serving a Thyroid Cancer Treatment Facility

“…The highest 131 I concentration in sewage sludge collected from the Stony Brook WPCP (148 Bq g j1 ) exceeds the previously published maximum value by more than four times (31 Bq g j1 , ISCORS 2003). Specific activities of 131 I in sewage sludge reported in other studies are generally lower than these values (0.004Y2.5 Bq g j1 dry weight, Erlandsson and Mattsson 1978;Erlandsson et al 1983;Barci-Funel et al 1993;Brennan 1997;Dalmasso et al 1997;Puhakainen 1998;Punt et al 2007;Chang et al 2011;Jiménez et al 2011). It is possible that the unique conditions (i.e., a small plant serving a regional thyroid cancer treatment facility) cause the Stony Brook WPCP to have the highest specific activities of 131 I in sewage sludge relative to other facilities.…”

“…Other studies have reported 131 I concentrations in sewage sludge between 0.004Y2.5 Bq g j1 dry weight (Erlandsson and Mattsson 1978;Erlandsson et al 1983;Barci-Funel et al 1993;Brennan 1997;Dalmasso et al 1997;Puhakainen 1998;Punt et al 2007;Chang et al 2011;Jiménez et al 2011). The Interagency Steering Committee on Radiation Standards (ISCORS) published the most comprehensive survey of radioactivity in sewage sludge.…”

“…Several studies have measured 131 I in sewage sludge (Erlandsson and Mattsson 1978;Prichard et al 1981;Erlandsson et al 1983Erlandsson et al , 1989Barci-Funel et al 1993;Stetar et al 1993;Larsen et al 1995;Brennan 1997;Dalmasso et al 1997;Martin and Fenner 1997;Puhakainen 1998;ISCORS 2003;Punt et al 2007;Carolan et al 2011;Chang et al 2011;Jiménez et al 2011). Fewer values of 131 I in sewage effluent have been reported (Sodd et al 1975;Erlandsson et al 1989;Puhakainen 1998;Smith et al 2008;Fischer et al 2009;Kleinschmidt 2009;Carolan et al 2011;Chang et al 2011;Rose 2011;Rose et al 2012).…”

Determination of 90Sr and 210Pb in sludge samples using a LOV-MSFIA system and liquid scintillation counting

“…In the case of 210 Pb, there is more literature as more studies focusing on the determination of radionuclides of natural origin have been reported (ISCORS, 2003;Kleinschmidt and Akber, 2008;Jiménez et al, 2011). Jiménez et al (2011) analyzed sludge samples from a urban sewage treatment plant located in Valladolid (Spain), where there are only local pollution influences.…”

“…Jiménez et al (2011) analyzed sludge samples from a urban sewage treatment plant located in Valladolid (Spain), where there are only local pollution influences. This work reported 210 Pb concentrations in 21 sludge samples ranging between 25 Bq kg À 1 and 69 Bq kg À 1 and these 210 Pb activities levels are similar to the values obtained in our study.…”