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I Tell

Publications and source records attributed to I Tell.

5 recordsLinked to original sources
PubMed1993

Indoor radon-daughter concentration and gamma radiation in urban and rural homes on geologically varying ground.

The radon (Rn)-daughter level (track film, 3 months) was lower in 129 urban than in 197 rural houses (geometric means, (GM) 18 versus 40 Bq/m3; P < 0.001; range 3-416). In rural dwellings higher levels were found in those built over deposits of alum shale occurrences (P = 0.04; 12 on porous glaciofluvial cover 94 Bq/m3; 127 others 43 Bq/m3; significant interaction, P = 0.01), than in 158 others (37 Bq/m3). There was no systematic effect of the type of water supply, neither of indoor smoking. One hundred twenty three homes with a complete cellar were lower than 200 with no or part cellar (18 versus 40 Bq/m3; P < 0.001). There was only a weak association between log-transformed gamma radiation (GM 10, range 33-50 microR/h) and Rn-daughter levels (r = 0.18; 95% confidence interval 0.07-0.28). Our results show the importance for indoor Rn-daughter levels of the bedrock and cover beneath the house, and the need for Rn-daughter measurements in epidemiological studies.

Air Pollution, Indoor↗
PubMed1992

Chelated lead and bone lead.

In this study a close correlation [correlation coefficient (r) = 0.86, P less than 0.001] was found between the blood lead level of 20 lead workers and their urinary excretion of lead for 24 h after intravenous infusion with 1 g of the chelating agent calcium disodium edetate. In addition, there were significant associations between lead levels in different bones (tibia/calcaneus: r = 0.93, P less than 0.001; tibia/phalanx: r = 0.67, P less than 0.002; calcaneus/phalanx: r = 0.80, P less than 0.001), as measured by in vivo X-ray fluorescence. Chelation produced no significant change in the lead level in either tibia or calcaneus. There was a significant correlation between chelated lead and bone lead (eg, for calcaneus, r = 0.62) in currently exposed workers. However, there was no significant relationship when a retired worker and an inactive worker were included (r = 0.14). It was concluded that chelatable lead mainly reflects the blood and soft-tissue lead pool, which is only partly dependent upon the skeletal lead content that comprises the biggest share of the total body burden.

Adult↗
PubMed1989

In vivo measurements of bone lead--a comparison of two x-ray fluorescence techniques used at three different bone sites.

In vivo bone lead measurements have been made on a group of about 120 people, most of whom were lead exposed workers. Two different x-ray fluorescence (XRF) techniques were used to make measurements at three bone sites. Finger lead was measured using 57Co sources, and lead measurements were made in both tibia and calcaneus with a technique based on 109Cd sources. The results of the bone lead measurements correlated strongly with each other and with the index of cumulative exposure, thus confirming the value and reliability of these in vivo measurements as a tool in the study of chronic lead exposure. Measurement precision, +/- 1 standard deviation, was highest for tibia +/- 7.4 micrograms (g bone mineral)-1, +/- 16.6 micrograms (g bone mineral)-1 for the calcaneus and lowest for phalangeal lead +/- 25.0 micrograms (g bone mineral)-1. Maximum absorbed doses to the skin were comparable for all three measurements (1-3 mGy). The mean whole body dose equivalents were all low, but that for the finger measurement, 0.1 microSv, was significantly less than for the calcaneus and tibia measurements 3-5 microSv.

Bone and Bones↗
PubMed1987

Chelatable lead versus lead in human trabecular and compact bone.

In active and retired lead workers there was a close correlation between urinary excretion of lead during 6 h after intake of a single oral dose of 0.5 g penicillamine, and the excretion during 24 h. In chelation tests it is thus sufficient to collect urine for only a few hours. There was a close correlation between the amount of chelatable lead and the blood-lead level, as well as the lead level in biopsies of trabecular bone from vertebrae, but there was no association with lead in compact bone, as measured in finger-bone by in vivo X-ray fluorescence. The chelatable lead probably mainly reflects the soft tissue lead pool and a fraction of the trabecular bone lead pool, which has a relatively rapid turnover. It is not a valid indicator of the pool of lead which has slowly accumulated in the compact bone, and it is thus not useful as a time-integrated index of the exposure over a long period of time.

Bone and Bones↗