PLANT DOSE ASSESSMENT

The limited information on the plant uptake of other actinide elements (U, Np, Am, Cm) indicates that higher CR values can be expected relative to those observed for Pu. Values for Am based on uptake by roots and from deposition on foliage approach or exceed the 10-1 value used in the LMFBR assessment thus, the value used in dose assessments is probably realistic but not conservative. Price (32) reported CR values of 10-1 to 10-2 for 237Np assimilated by the root pathway. Based on these data and on the low K. for Np (Table II), it appears that this element exhibits a higher mobility than the other actinides. A potential CR > 10-1 due to uptake from soil and from direct contamination of foliage is hypothesized for Np. Curium-244 uptake by the root pathway yielded CR values of 10 3 to 10-1, according to pot culture experiments (32, 52). 

AR559 8.19 Occupational radiation dose assessment in light-water reactor power plants Design stage... 

Yu, C.C., Tung, C.J., Hung, I.F., Tseng, C.L. (1993). Analyses of radioactive aerosols to support accurate internal dose assessments at Chin-Shan Nuclear Power Plant. Health Phys. 65. 

Dose assessments in nuclear power plant siting 1988... 

In another study carried out at a different nuclear establishment, the isotopes and were determined (along with calculated concentrations) in a series of human urine samples, using a concentrated aqua regia wet oxidation method to dissolve the uranium and destroy the organic matter. The uranium was selectively separated from the matrix using anion exchange, eluted with dilute nitric acid, and then aspirated into the ICP mass spectrometer. Using this method, a detection limit of 6 ng/L was achieved, with excellent spike recoveries at the 200 ng/L level, which met both plant and industry standard (American National Standards Institute 13.30) internal dose assessments for total uranium. ... 

This method is also used to measure ex vivo low-density lipoprotein (LDL) oxidation. LDL is isolated fresh from blood samples, oxidation is initiated by Cu(II) or AAPH, and peroxidation of the lipid components is followed at 234 nm for conjugated dienes (Prior and others 2005). In this specific case the procedure can be used to assess the interaction of certain antioxidant compounds, such as vitamin E, carotenoids, and retinyl stearate, exerting a protective effect on LDL (Esterbauer and others 1989). Hence, Viana and others (1996) studied the in vitro antioxidative effects of an extract rich in flavonoids. Similarly, Pearson and others (1999) assessed the ability of compounds in apple juices and extracts from fresh apple to protect LDL. Wang and Goodman (1999) examined the antioxidant properties of 26 common dietary phenolic agents in an ex vivo LDL oxidation model. Salleh and others (2002) screened 12 edible plant extracts rich in polyphenols for their potential to inhibit oxidation of LDL in vitro. Gongalves and others (2004) observed that phenolic extracts from cherry inhibited LDL oxidation in vitro in a dose-dependent manner. Yildirin and others (2007) demonstrated that grapes inhibited oxidation of human LDL at a level comparable to wine. Coinu and others (2007) studied the antioxidant properties of extracts obtained from artichoke leaves and outer bracts measured on human oxidized LDL. Milde and others (2007) showed that many phenolics, as well as carotenoids, enhance resistance to LDL oxidation. 

Assessment starts with a general calculation based on assumed service conditions and identification of the critical parameters and components, with particular regard to risk. Although relatively crude, this ranking of components is probably correct. It is followed by assessment of the actual service conditions experienced - data that should be available for process plant. This can identify the accumulated exposure or dose , or confirm that parameters lie below a threshold level. It can also identify unexpectedly large values, due for example to rapid transient variations, which would not be found in the planned service history. Such large parameters can have an exceptional effect on service lifetime. This is followed by inspection (materials, dimensions, etc.) of the critical components either on the plant or, if allowed, of the dismantled component, to provide a more confident... 

FIGURE S.6 Schematic illustration of the traditional setting of an acceptable level of exposure (ADI) by dividing the NOAEL from an animal study by an assessment factor (AF). The two dose-response relationships have identical NOAEL. If a uniform assessment factor is applied, there will be an adequate MOS at the ADI for effect b but not for effect a. (Modified from KEMI, Human health risk assessment. Proposals for the use of assessment (uncertainty) factors. Application to risk assessment for plant protection products, industrial chemicals and biocidal products within the European Union. Report No. 1/03, Solna, Sweden, 2003. 

Toxicity assessment. Ethanol (50%) extract of the entire plant, administered intraperitoneally to mice produced lethal dose (LDljf, 316 mg/kg . Ethanol (95%) extract of the leaf, administered by gastric intubation to mice, produced LDg, 10 g/kg. Intraperitoneal administration produced CD, 0.7g/kg<= . 

Since risk analysis plays an important role in public policy decision making, efforts have been made to devise a means by which to identify, control, and communicate the risks imposed by agricultural biotechnology. A paradigm of environmental risk assessment was first introduced in the United States by Peterson and Arntzen in 2004. In this risk assessment, a number of assumptions and uncertainties were considered and presented. These include (1) problem formulation, (2) hazard identihcation, (3) dose-response relationships, (4) exposure assessment, and (5) risk characterization. Risk assessment of plant-made pharmaceuticals must be reviewed on a case-by-case basis because the plants used to produce proteins each have different risks associated with them. Many plant-derived biopharmaceuticals will challenge our ability to define an environmental hazard (Howard and Donnelly, 2004). For example, the expression of a bovine-specihc antigen produced in a potato plant and used orally in veterinary medicine would have a dramatically different set of criteria for assessment of risk than, as another example, the expression of a neutralizing nonspecihc oral antibody developed in maize to suppress Campylobacter jejuni in chickens (Peterson and Arntzen, 2004 Kirk et al., 2005). 

The hazard assessment identifies the adverse effects that a chemical may cause and investigates the relationship between their magnitude and the dose to which an organism is exposed. A major source of uncertainty is the use of data from tests on laboratory animals (or plants) to investigate toxicity to other species (including humans). There are at least four reasons why there is uncertainty in the application of test data to exposures of humans and wild animals (RCEP, 2003, pp21—22 Rodricks, 1992, ppl58-179) ... 

Interestingly, the levels of all the extractable flavonoids in the leaves of B. napus plants are decreased in a dose-dependent manner in response to UVA exposure. Additionally, the accumulation of the extractable flavonoids was examined by a shift from the photosynthetically active radiation (PAR) + UVA to PAR + UVB to assess whether the preexposure of the UVA affects the UVB-induced flavonoid accumulation. The UVA preexposures inhibited the UVB-induced accumulation of some flavonoids. This down regulation was particularly evident for quercetin-3-O-sophoroside and quercetin-3-O-sophoroside-7-O-glucoside of two anthocyanins. This is very interesting because the induction of quercetin by UVB is correlated with the UVB tolerance in some plant species. The photobiological nature of these UVA-mediated effects on flavonoid accumulation might suggest complex interactions between the UVA and UVB responses [66]. 

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