Evaluate parent kinetics using the NAFTA guidance

+ + +

The function fits the SFO, IORE and DFOP models using mmkin +and returns an object of class nafta that has methods for printing +and plotting.

Print nafta objects. The results for the three models are printed in the +order of increasing model complexity, i.e. SFO, then IORE, and finally DFOP.

+ +

nafta(ds, title = NA, quiet = FALSE, ...)
+
+# S3 method for nafta
+print(x, quiet = TRUE, digits = 3, ...)

+ +

Arguments

+ + + + + + + + + + + + + + + + + + + + + + + + + + +

ds	A dataframe that must contain one variable called "time" with the +time values specified by the `time` argument, one column called +"name" with the grouping of the observed values, and finally one column of +observed values called "value".
title	Optional title of the dataset
quiet	Should the evaluation text be shown?
...	Further arguments passed to `mmkin` (not for the +printing method).
x	An `nafta` object.
digits	Number of digits to be used for printing parameters and +dissipation times.

+ +

Source

+ +

NAFTA (2011) Guidance for evaluating and calculating degradation +kinetics in environmental media. NAFTA Technical Working Group on +Pesticides +https://www.epa.gov/pesticide-science-and-assessing-pesticide-risks/guidance-evaluating-and-calculating-degradation +accessed 2019-02-22

US EPA (2015) Standard Operating Procedure for Using the NAFTA Guidance to +Calculate Representative Half-life Values and Characterizing Pesticide +Degradation +https://www.epa.gov/pesticide-science-and-assessing-pesticide-risks/standard-operating-procedure-using-nafta-guidance

Value

+ +

An list of class nafta. The list element named "mmkin" is the +mmkin object containing the fits of the three models. The +list element named "title" contains the title of the dataset used. The +list element "data" contains the dataset used in the fits.

+ +

Examples


+  nafta_evaluation <- nafta(NAFTA_SOP_Appendix_D, cores = 1)
#> The SFO model is rejected as S_SFO is equal or higher than the critical value S_c
#> The representative half-life of the IORE model is longer than the one corresponding
#> to the terminal degradation rate found with the DFOP model.
#> The representative half-life obtained from the DFOP model may be used
  print(nafta_evaluation)
#> Sums of squares:
+#>       SFO      IORE      DFOP 
+#> 1378.6832  615.7730  517.8836 
+#> 
+#> Critical sum of squares for checking the SFO model:
+#> [1] 717.4598
+#> 
+#> Parameters:
+#> $SFO
+#>               Estimate   Pr(>t)    Lower   Upper
+#> parent_0       83.7558 1.80e-14 77.18268 90.3288
+#> k_parent_sink   0.0017 7.43e-05  0.00112  0.0026
+#> sigma           8.7518 1.22e-05  5.64278 11.8608
+#> 
+#> $IORE
+#>                     Estimate Pr(>t)    Lower    Upper
+#> parent_0            9.69e+01     NA 8.88e+01 1.05e+02
+#> k__iore_parent_sink 8.40e-14     NA 1.79e-18 3.94e-09
+#> N_parent            6.68e+00     NA 4.19e+00 9.17e+00
+#> sigma               5.85e+00     NA 3.76e+00 7.94e+00
+#> 
+#> $DFOP
+#>          Estimate   Pr(>t)    Lower    Upper
+#> parent_0 9.76e+01 1.94e-13 9.02e+01 1.05e+02
+#> k1       4.24e-02 5.92e-03 2.03e-02 8.88e-02
+#> k2       8.24e-04 6.48e-03 3.89e-04 1.75e-03
+#> g        2.88e-01 2.47e-05 1.95e-01 4.03e-01
+#> sigma    5.36e+00 2.22e-05 3.43e+00 7.30e+00
+#> 
+#> 
+#> DTx values:
+#>      DT50    DT90 DT50_rep
+#> SFO   407    1350      407
+#> IORE  541 5190000  1560000
+#> DFOP  429    2380      841
+#> 
+#> Representative half-life:
+#> [1] 841.41
  plot(nafta_evaluation)

+

+ +