Eduard Szöcs

Data in Environmental Science and Eco(toxico-)logy

# Regulatory Acceptable Concentrations (RAC)

## Intro

The German Environment Agency (UBA) recently published a list of regulatory acceptable concentrations (RAC) for 108 pesticides [Link]. I used it already in a previous project (paper is currently under review) and here I show how we can use R to:

2. Digitize the pdf
4. Create summary statistics to explore the RACs

I will use two ROpenSci packages for this tasks:

1. tabulizer to digitize the pdf and
2. my webchem package to retrieve information on the pesticides.

First, we need to get the RAC-list from ETOX.

## Digitize the data

Next we need to get the pdf into a tabular format. I use tabulizer for this task. We digitize the pdf table using extract_tables():

This gives two lists with matrices because there are two pages. We combine both

We see that there are 109 instead of 108 lines. Inspecting the raw pdf and the table we see that there is an addtional for Diuron with 2 CAS numbers and no indentifer in the first column. I simply delete this row:

## Clean the data

Some more cleaning is needed before we can use this data efficiently:

1. Delete unused columns
2. Coerce to data.frame
1. split columns missed by tabulizer.
1. Check CAS numbers

One CAS is wrong (date in stead of CAS), which I set to NA

1. coerce rac to numeric (currently it is text)
1. final cleanup

I search for additional information, like the activity, in Alan Wood’s Compendium of Pesticide Common Names:

This worked very well and we found information for all substances except for a Prothioconazole metabolite

I remove this from the results and the rac list.

Finally, I extract the subactivity and add it to the rac table:

From this I extract the activity and build 4 groups (insecticides, herbicides, fungicides and others):

Next, I search the Physprop database for $K_{OW}$ values.

We could not find data for 20 substances and I set their value to NA.

## Summarize data

All the code above was just done to create few summary statistics…

Here the RACs splitted by type:

We clearly see that insecticides have much lower RACs than the other groups of pesticides. However, there is no strong relationship between the $log~K_{OW}$ and the RAC for the different types.

Written on December 5, 2016