“Blind” testing of models for predicting the 90Sr activity concentration in river systems using post-Chernobyl monitoring data

Abstract

Two different models for predicting the time-dependent mobility of (90)Sr in river systems have been evaluated using post-Chernobyl monitoring data for five large Belarusian rivers (Dnieper, Pripyat, Sozh, Besed and Iput) in the period between 1990 and 2004. The results of model predictions are shown to be in good agreement (within a factor of 5) with the measurements of (90)Sr activity concentration in river waters over a long period of time after the accident. This verifies the relatively good accuracy of the generalised input parameters of these models which were derived primarily from measurements of (90)Sr deposited after atmospheric nuclear weapons testing (NWT). For the cases studied here, the simpler AQUASCOPE model performed just as well as the more complex "Global" model which used GIS-based catchment data as an input. The reasons for this are discussed. Exponential decay equations were also curve-fitted to the data for each river to help assess the uncertainties in the predictive models.

Are groundwater nitrate concentrations reaching a turning point in some chalk aquifers?

“…Our first, most complex model (Model 1) is formed from a series of two exponential functions which model a "fast" and "slow" response component to time changes in nitrate concentrations in groundwaters. Such models have been used successfully for a number of applications, including predicting activity concentrations of 90 Sr and 137 Cs in rivers following surface depositions to catchments from atmospheric nuclear weapons testing and the Chernobyl accident (Cross et al, 2002;Sasina et al, 2007;Smith et al, 2000).…”

A review and test of predictive models for the bioaccumulation of radiostrontium in fish

“…Due to the changing 90 Sr activity concentration in water (e.g. Cross et al, 2002;Sasina et al, 2007) and the deposit of 90 Sr in bone, this dynamic accumulation process is to an extent dependent on fish lifespan, but equilibrium is generally considered to have been achieved 8-12 years after radioisotope fallout (Kryshev, 2003). For estimating of 90 Sr accumulation in fish under non-equilibrium conditions, a number of dynamic models are available, (Sazykina, 2000;Kryshev and Ryabov, 2000;Kryshev, 2003Kryshev, , 2006 though all of these dynamic approaches use estimates of the equilibrium CF as one of their input parameters.…”

Kinetic box models for the uptake of radionuclides and heavy metals by suspended particulate matter: equivalence between models and its implications

“…Finally, numerous contributions apply these models to the transport of pollutants in waters and sediments: Benes et al (1994), Smith and Comans (1996), Periañez and Martínez-Aguirre (1997), Periañez and Elliot (2002), Monte et al (2006), Sasina et al (2007), etc.…”