The R package pfm provides some utilities for fate modelling, including dealing with FOCUS pesticide fate modelling tools, (currently only TOXSWA cwa and out files), made available under the GNU public license. This means:

This program is free software: you can redistribute it and/or modify it under
Foundation, either version 3 of the License, or (at your option) any later
version.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
details.

You should have received a copy of the GNU General Public License along with
this program. If not, see <http://www.gnu.org/licenses/>

Installation

The easiest way to install the package is probably to use drat:

install.packages("drat")
install.packages("pfm")

Alternatively you can install the package using the devtools package. Using quick = TRUE skips docs, multiple-architecture builds, demos, and vignettes.

library(devtools)
install_github("jranke/pfm", quick = TRUE)