stressaddition

This is the R implementation of the tri-phasic concentration-response model introduced in Liess, M., Henz, S. & Knillmann, S. Predicting low-concentration effects of pesticides. Sci Rep 9, 15248 (2019). It allows modeling of ecotoxicological experiments where the response shows signs of a hormesis effect.

Installation

Stressaddition is not on CRAN. You can install the most recent stable version from GitLab using the devtools package:

# install.packages("devtools")
devtools::install_gitlab("oekotox/stressaddition", host = "git.ufz.de")

Alternatively there are binary and source builds downloadable from the releases page.

Updating

RStudio's integrated package updater won't detect updates in packages installed from GitHub or GitLab. I recommend running

devtools::update_packages()

in regular intervals to check for updates from those sources.

Citation

Please cite this package if you use it in your analysis. See citation("stressaddition") for details.

Example

In the paper we use the model in the context of survival experiments. However, it can also be applicable in modeling other concentration or dose dependent responses. For this reason the more general term "effect" instead of "survival" is used throughout the package.

library(stressaddition)
model <- ecxsys(
    concentration = c(0, 0.05, 0.5, 5, 30),
    hormesis_concentration = 0.5,
    effect_tox_observed = c(90, 81, 92, 28, 0),
    effect_tox_env_observed = c(29, 27, 33, 5, 0)
)

# Plot the effect and the system stress:
par(mfrow = c(2, 1))
plot_effect(model)
plot_stress(model)

# The LC50 of the effect under the influence of toxicant and system tress:
ec(model, "effect_tox_sys", 50)

# The LC10 of the effect under the influence  of toxicant, system and environmental tress:
ec(model, "effect_tox_env_sys", 10)

Copyright and License

Copyright (c) 2020,
Helmholtz-Zentrum fuer Umweltforschung GmbH - UFZ.
All rights reserved.

The code is a property of:

Helmholtz-Zentrum fuer Umweltforschung GmbH - UFZ
Registered Office: Leipzig
Registration Office: Amtsgericht Leipzig
Trade Register: Nr. B 4703
Chairman of the Supervisory Board: MinDirig'in Oda Keppler
Scientific Director: Prof. Dr. Georg Teutsch
Administrative Director: Dr. Sabine König

stressaddition is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software 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 https://www.gnu.org/licenses/.