Internal exposure

Various cases of internal exposure to americium have been reported in which the exposures resulted from skin punctures with materials also containing plutonium. Information on the distribution of americium in these cases has been derived from the analysis of autopsy tissues. In most cases, the largest fraction of the 241 Am activity measured in the body was associated with tissues near the puncture wound. In one case,... 

Epidemiological and Human Dosimetry Studies. Epidemiological studies of radiation dose typically involve estimates of exposure that are based on whole-body measurements of internally-deposited americium. A need remains for epidemiological data that can provide quantitative human dose-response information while supplying additional information on the health effects of exposure to ionizing radiation and americium in particular, for cases of known internal exposure. 

IARC. 1989. Tumour development following internal exposures to radionuclides during perinatal period. Richland, WA International Agency for Research on Cancer. 

The internal dose of propoxur was measured by assessing the total amount of 2-isopropoxyphenol (IPP) excreted in the urine, collected over a period of 24 hr from the start of exposure, and described in detail in previous studies (Brouwer et al., 1993 Meuling et al., 1991). Volunteer kinetics studies revealed a one-to-one relationship of absorbed propoxur and excreted IPP on a mole basis. Based on the results by Machemer et al. (1982), a pulmonary retention of 40% was used to calculate the relative contribution of the respiratory exposure to the internal exposure. To estimate the contribution of the dermal exposure, the calculated respiratory portion was subtracted from the total amount of IPP excreted in urine. 

Table 4 Internal Exposure (Dose) of Propoxur Expressed as Excreted Amount of 2-Isopropoxyphenol (nmol IPP)...

The design of a study by Davies et al. (1982) for mixers and applicators was similar to that of Nigg and Stamper (1983). "Between-days" variances of exposure were not given. Mean urinary metabolite concentrations were used to show reduction of internal exposure by protective clothing. The design of the study by van Rooij et al. (1993) was similar to our study (i.e., "within-worker" comparisons of internal exposure). Because no potential dermal exposure was assessed in this study, "within-worker" variances of potential exposure are not known. 

As discussed in the introduction to Section 2.2, the bulk of the human data on the health effects of lead are expressed in terms of internal exposure, or PbB levels, rather than external exposure levels (i.e., mg/m3 or mg/kg/day). For the general population, exposure to lead occurs primarily via the oral route with some contribution from the inhalation route, whereas occupational exposure is primarily by inhalation with some oral. Therefore, it is difficult to distinguish specific routes and levels of exposure. For this reason, the human health effects data for lead will be presented in terms of PbB levels in this section. Health effects associated with human exposures to lead and internal lead doses are shown in Table 2-1. 

Dose (blood lead)-effect data are available in the study by Fowler et al. (1980). Rats exposed to lead acetate in the drinking water through the dams during gestation and lactation and then directly until 9 months of age had the following external exposures (ppm lead), internal exposures ( pg lead/dL in blood), and renal effects 0 ppm (controls), 5 pg/dL, no lesions 0.5 ppm, 4.5 pg/dL, no lesions 5 ppm,... 

Effects at even lower external and internal exposure levels were reported by Hayashi (1983). Lead acetate at 0.7 mg lead/kg/day in the drinking water of rats for the first 18 or 21 days of pregnancy resulted in decreased ALAD activity in the fetal and maternal erythrocytes and increased ALAD activity in fetal but not maternal liver. Fetal, but not maternal, hematocrits and hemoglobin levels were decreased in the group treated for 21 days. Fetal PbB levels were 27 pg/dL and 19 pg/dL in the 18-day and the 21-day treated groups, respectively. Maternal PbB levels were approximately 4 pg/dL in treated and control groups. The study is limited by the use of one dose level, which precluded assessment of dose response. 

Koch HM, Rossbach B, Drexler H, Angerer J (2003) Internal exposure of the general population to DEHP and other phthalates - determination of secondary and primary phthalate monoester metabolites in urine. Environ Res 93 177-185... 

The main problems of the study of chromosome aberrations, caused by radon and daughters at their most frequently existing dose levels, i. e. boardering the natural burdens, ares (i) to get statistical significance at very low doses, and (ii) to study their induction by internal exposure to alpha emitters only. 

The hazards to human health for properties contaminated by tailings surrounding or beneath a structure is principally from the inhalation of Rn-222 and its daughters. In addition, tailings in the soil may contribute to external exposure and, in the case of residence, internal exposure from Ra-226 deposited in the body via the food chain. 

Urticaria following internal exposure to nickel has been reported [418] the urticaria might be due to mechanisms other than delayed hypersensitivity. Precipitating antibodies against nickel sulphate bound to human albumin was found in some patients with widespread erythema after oral challenge. Moreover, patients with immediate patch test reactions to nickel and chronic urticaria have been reported [419]. 

Internal exposure (respiratory protection, hygiene, and monitoring)... 

Edible mushrooms are a significant element of the diet of the local population, and therefore represent a serious source of internal exposure to irradiation. Between 30% and 60% of the local population of Ukrainian Polissya regularly consume forest food products (Strand et al., 1996a), and a close correlation has been established between their consumption and i Cs load (Jacob and Likhtarev, 1996 Strand et al. 1996b). The contribution of forest food products to the internal exposure dose of the population in the forested region varies widely - from 12%-40% of the entire population to 50%-95% in some critical groups (Balonov et al., 1996 ... 

Figure 12. Contribution of different food products into internal exposure dose of population groups A and B of village Khristinovka.

The dynamics of the impact of forest food load on the internal exposure dose of Khrystynivka groups A and B over the period 1996 and 2016 is of significant scientific and practical interest. For group A, the relative contribution of dry B. edulis to the internal exposure dose will have increased over two fold, that of C. cibarius will have fallen by 25%, that of R. paludosa will have slightly increased, and that of X. chrysenteron decreased. The relative contribution of fresh mushrooms will also have changed B. edulis up about two fold, C. cibarius down by 1.3 fold, R. paludosa up by 1.1 fold, and X. chrysenteron up by 1.4 fold. The... 

For the inhabitants of the exclusion zone, situated in a forested region without well-developed economic and social infrastructures, it is of interest to estimate the relative contributions to internal exposure of forest food (berries and mushrooms) and conventional agricultural food (potatoes and milk). Some specialist studies have assumed that forest food represents only a small part of the diet of inhabitants of the exclusion zone, but we would suggest that in fact, it plays a major role. Typically, the consumption of forest food contributes 50% of the internal exposure dose, while for some critical population groups, it can exceed 80%. The definition of the spatial variation in pollution, the prevailing ecological conditions, and the diet should allow a scientifically-based prediction to be made of the internal exposure dose to the local population, and will help to identify the major risk factors within a certain time period following the Chernobyl catastrophe. 

Biuk G.Ya., Shutov V.N., Travnikova I.G., Balonov M.I., Kaduka M.V., Basalaeva L.N., 1999. The Role of the Forest Products in the Formation of Internal Exposure Dose to the Population of Russia after the Chernobyl Accident, in Contaminated Forests. Recent developments in risk identification and future perspectives, eds. I.Linkov and W.R. Schell, Ser. 2, Environmental Security, 58, Dordrecht-Boston-London, Kluwer Academic Publishers, pp. 343-352. 

Kenigsberg Y.E., Buglova E.E., 1994. Dose formation of internal exposure according to the peculiarities of casium radionuclides transfer by food chain and efficiency of countermeasures, in Belarus-Japan Symposium Acute and Late Consequences of Nuclear Catastrophes Hirosima-Nagasaki and Chernobyl (Minsk, Belarus, October 3-5, 1994), Proceedings, Minsk, pp. 82-97. 

Orlov A.A., Krasnov V.P., Prishchepa A.L., 2002. Radioactive contaminated forests as a critical landscapes radioactivity of food products and influence on forming of population internal exposure doses (analytical review), Zhytomyr, ZIET Publ., 202 p. 

Koch HM, Preuss R, Angerer J (2006) Di(2-ethyl-hexyl)phthalate (DEHP) human metabolism and internal exposure - an update and latest results. Int J Androl 29 155-165... 

MieUce H, Partisch F, Gundert-Remy U (2011) The contribution of dermal exposure to the internal exposure of bisphenol A in man. Toxicol Lett 204 190-198... 

Chen M-L, Chen J-S, Tang C-L, Mao IF (2008) The internal exposure of Taiwanese to phthalate—an evidence of intensive use of plastic materials. Environ Int 34 79-85... 

Koch HM, Drexler H, Angerer J (2004) Internal exposure of nursery-school children and their parents and teachers to di(2-ethylhexyl) phthalate (DEHP). Int J Hyg Environ Health 207 15-22... 

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