Function to calculate maximum time weighted average concentrations from -kinetic models fitted with mkinfit

- - -

This function calculates maximum moving window time weighted average -concentrations (TWAs) for kinetic models fitted with mkinfit. -Currently, only calculations for the parent are implemented for the SFO, -FOMC, DFOP and HS models, using the analytical formulas given in the PEC -soil section of the FOCUS guidance.

- -

max_twa_parent(fit, windows)
-
-max_twa_sfo(M0 = 1, k, t)
-
-max_twa_fomc(M0 = 1, alpha, beta, t)
-
-max_twa_dfop(M0 = 1, k1, k2, g, t)
-
-max_twa_hs(M0 = 1, k1, k2, tb, t)

- -

Arguments

fit: An object of class mkinfit.
windows: The width of the time windows for which the TWAs should be -calculated.
M0: The initial concentration for which the maximum time weighted -average over the decline curve should be calculated. The default is to use -a value of 1, which means that a relative maximum time weighted average -factor (f_twa) is calculated.
k: The rate constant in the case of SFO kinetics.
t: The width of the time window.
alpha: Parameter of the FOMC model.
beta: Parameter of the FOMC model.
k1: The first rate constant of the DFOP or the HS kinetics.
k2: The second rate constant of the DFOP or the HS kinetics.
g: Parameter of the DFOP model.
tb: Parameter of the HS model.

Value

- - -

For max_twa_parent, a numeric vector, named using the -windows argument. For the other functions, a numeric vector of -length one (also known as 'a number').

References

FOCUS (2006) “Guidance Document on Estimating Persistence -and Degradation Kinetics from Environmental Fate Studies on Pesticides in -EU Registration” Report of the FOCUS Work Group on Degradation Kinetics, -EC Document Reference Sanco/10058/2005 version 2.0, 434 pp, -http://esdac.jrc.ec.europa.eu/projects/degradation-kinetics

Author

Johannes Ranke

- -

Examples


-  fit <- mkinfit("FOMC", FOCUS_2006_C, quiet = TRUE)
-  max_twa_parent(fit, c(7, 21))
-#>        7       21 
-#> 34.71343 18.22124 
-
-

- -