Parameterization of a dynamic specific activity model of 14C transfer from surface water-to-humans

Impacts of 14C discharges from a nuclear fuel reprocessing plant on surrounding vegetation: Comparison between grass field measurements and TOCATTA-χ and SSPAM14C model computations

“…In SSPAM 14 C, the volatilization rate of carbon from the soil is considered as a constant value, and is based on Sheppard et al (2006).…”

Carbon-14 transfer into potato plants following a short exposure to an atmospheric 14CO2 emission: observations and model predictions

“…Both PLANT-W and PLANT-S models are based on the following principles: (a) the specific activity of 14 C transferred to plant in a given time interval is the same as the average specific activity of the source over that time interval; (b) in normal conditions, more than 90% of the plant carbon comes from the atmosphere and this was assumed to be the case for the potato experiments; (c) in biochemical reactions occurring in plant, the discrimination factor between 14 C and 12 C is closed to 1 (0.96 AE 0.02, Sheppard et al, 2006) and consequently, the modelling of 14 C transfer is the same as the modelling of stable carbon transfer ( 12 C). The processes considered in both PLANT-W and PLANT-S models were: the initial incorporation of 14 C in the total plant, the loss of 14 C through maintenance and gross respiration, the distribution of dry matter to plant parts and further growth dilution and potential translocation.…”

Measurement of the fate of acetic acid form carbon in soil solution of flooded soils using high performance liquid chromatography coupled with isotope ratio mass spectrometry

“…Only a small portion of carbon from added acetic acid would remain in the soil solutions. The other portion that was transformed to inorganic forms from acetic acid may be fixed to the soil or released to the air (Ishii et al, 2010;Sheppard et al, 2006); the presence of inorganic carbon initially in the soil may prevent more inorganic carbon from being kept in the soil solution.…”

“…There are many data on carbon fate in soil in relation to the global carbon cycle and as agrochemicals, thus the soil-soil solution distribution of organic forms of carbon has been studied using 14 C as a tracer (Christensen and Sørensen, 1985;Ishii et al, 2010;Johnson-Logan et al, 1992;Rhodes et al, 1970;Sallih and Pansu, 1993;Sheppard et al, 2006;Yang et al, 1994). However, 14 C is a radioisotope so that it cannot be used in open fields without restrictions.…”

“…However, 14 C is a radioisotope so that it cannot be used in open fields without restrictions. It is also difficult to manage radiotracer experiments even in a controlled area because part of the added organic carbon can be discharged to the air as CO 2 (Ishii et al, 2010;Sheppard et al, 2006) and such carbon discharge is a well known occurrence in open fields (Dawson and Smith, 2007). Therefore, due to the difficulty in measuring 14 C in different chemical forms, the fate of LMWOCs in the soil solution is still not well known, including answers to the questions of how long the added LMWOCs remain in the soil solution and what chemical forms the added LMWOCs change into.…”