Daily urinary excretion of uranium in members of the public of Southwest Nigeria

Abstract

The main aim of this study was to determine and evaluate urinary excretion values of uranium in members of the public of Southwest Nigeria living in areas of low environmental uranium. As several uranium mines are running in Nigeria and the operations could be a risk of contamination for the workers as well as for the members of the public, biomonitoring of urine could provide information about the exposure to uranium for the subjects. Therefore, baseline values of uranium in urine are needed from subjects living in areas without mining activities. Volunteers of both genders (age range 3 to 78 years) were asked to collect 24h-urine samples. The concentration measurements of uranium in urine were performed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). In addition, urinary creatinine values were determined for normalization of the renal uranium relative to the creatinine concentrations. The urinary uranium concentrations and their creatinine normalized values ranged from <10.4 to 150 ng L(-1) (median 13.8 ng L(-1)) and from 2.52 to 252.7 ng g(-1) creatinine (median 33.4 ng g(-1) creatinine), respectively, for adult subjects above 15 years of both genders. An increased uranium excretion value of 61.6 ng L(-1) (median), and of 76.0 ng g(-1) creatinine, respectively, were found in young subjects below 15 years. The median of daily excreted uranium was estimated to be 14.2 ng d(-1) for adults and of 45.1 ng d(-1) for children, respectively. The uranium excretion from males and females living in Nigeria in a non-mining area was comparable to reference values reported from other countries with low level of environmental uranium. The data can be considered as baseline values of urinary uranium in unexposed subjects in Nigeria.

A survey of uranium levels in urine and hair of people living in a coal mining area in Yili, Xinjiang, China

“…The ICRP uranium model (ICRP, 1995a,b) also predicted such an increase under conditions of a continuous level of intake. In contrast, Hoellriegl et al, (2011) and Oeh et al, (2007) concluded that there was no dependency of uranium excretion with age, which is consistent with our conclusion.…”

“…Urine monitoring is the preferred method to determine human exposure to soluble { PAGE \* MERGEFORMAT } uranium since the amount excreted per day via urine is related to the total level of uranium in the body (Hoellriegl et al, 2011). In order to make an assessment on an individual's possible exposure, knowledge of background uranium levels is indispensable.…”

A systematic review and meta-analysis of 24-h urinary output of children and adolescents: impact on the assessment of iodine status using urinary biomarkers

“…Due to the wide age range of participants of the included studies, studies were grouped into three groups according to the age of the participants; 2-5 years (17 studies) [26,28,36,[43][44][45] [25,26,29,36,49,53,54,63,65,67,69,81]. These cut-points were chosen based on the WHO criteria for assessing population iodine deficiency, which defines school-aged children as between 6 and 12 years of age [6].…”

“…The cut-offs used by the remaining three studies [43,48,55] were based on the distribution of volume in the sample, enabling the exclusion of extreme outliers (e.g., 4SDs below the geometric mean [48]). Of the 26 studies which reported the urine exclusion criteria, 6 did not report the number of urine samples excluded from the final analysis [25,54,[73][74][75]82]. As a result of the inconsistency in the criteria used to assess the completeness of the urine samples between studies, 23 studies (54%) scored low on the NOS quality scale [44-46, 49-51, 53-55, 57-59, 62, 63, 65, 69, 71-76, 82] ( Tables 3 and 4).…”

Atomic spectrometry update. Clinical and biological materials, foods and beverages

“…5.4.23 Uranium. Nigeria is a principal area for mining of U. Hollriegl et al, 126 therefore, considered it important to establish a baseline value for urine U in non-exposed Nigerian populations in order to better assess cases of environmental exposure from mining activity. They determined U in 24 h urine samples collected from adult and child volunteers in a low environmental U region of SW Nigeria.…”