Monday, September 30, 2013

Gifts from the Netherlands – More UNIFAC and more

Compared to the US, the Netherlands is a relatively small country but it is gigantic in the stature and generosity of its scientists doing human health risk assessment.  Of course, these folks  are not the only other good guys in the world making great contributions to our field from relatively small countries (Demark and the UK come to mind) but one Dutch colleague really highlighted this for me recently because of his kindness.   My friend and colleague, Theo Scheffers (formal title:  Ir. Theo Scheffers RAH) read the last blog and sent me an email.   He asked if I was aware of an Excel sheet (XLUnifac.xls) that has been highlighted as an advanced tool for REACh.    REACh stands for Registration, Evaluation, Authorisation and Restriction of Chemicals.  It is a very big deal in Europe and something I will cover in a future blog or two.

Turns out I had not heard of XLUnifac.xls so Theo sent me a copy along with a pdf manual for the spreadsheet.    The program and manual were written by Preben Randhol and Hilde K. Engelien for their students at the Norwegian University of Science and Technology (NTNU).   It will do 15 mixture components (UNIFACAL does 5) and really goes into the background of the UNIFAC method which the UNIFACAL spreadsheet discussed last week does not.  So if you really like looking under the hood this is the program and document for you.  You can find the program with a Google search but if that gives you trouble just email me ( and I will send it to you along with the manual.

It further turns out that Theo has sent me a link to a site with quite a few very interesting tools for the Industrial Hygiene community.   He apologizes that some of the material is in Dutch but there is enough there for any of us to find of interest.   The site is: 
I will let you folks explore its contents for yourself but wanted to put up two sites that really caught my eye: The first is  This site presents a very extensive database of Occupational Exposure Limits from all over the world.   It includes OSHA and NIOSH limits but not the ACGIH TLVs. 

Another site that I found very interesting and potentially quite valuable:   Below is a cut and paste from this site:

“ChemSpider is a free chemical structure database providing fast text and structure search access to over 29 million structures from hundreds of data sources.
our introduction video.”  
Pretty cool!

Down in the Dutch language part of the TSAC web site is a section entitled:   SKINPERM.    In this section there is a link to the home page of another outstanding contributor from the Netherlands to our science:  Dr. Wil tenBurg.    Wil’s site: has been up for many years and contains a lot of great stuff.    The page is not flashy and has the very modest introduction reproduced below:

   "Main areas of interest are:
  • Estimation of the permeation rate of substances through the skin .
  • Estimation of dose/response relationships for acute inhalation toxicity, controlled by exposure concentration, exposure period and other independent variables"
The “skin” link is the program SKINPERM which estimates dermal exposure to chemicals applied to the skin and in the air over skin.  It does this as well or better than anything else I have seen or I have been able to find after many year of searching.   The “relationships” link presents his ground breaking software to calculate acute dose-response modeling (usually lethality) as a function of both time and concentration.   This is a very big deal in setting Emergency Response Planning Guidelines (ERPGs) and is used all over the world.   Wil provides these remarkable tools for free.   I will be discussing the technical details of all this in future blogs but I just wanted show off some of these links and to tip my hat to our colleagues from the Netherlands.  


  1. Mike

    The more general link to a range of databases by GESTIS is

    This is the portal to the Exposure Limits you have already mentioned, but also a DNEL (Derived No Effect Level - a sort of REACH Exposure Limit) database, criteria documents database and a dust explosion database.

    You can also get apps of the OEL Database for both Android and Apple. There are QR codes for the links to the apps on the link above.


    Richard Brown

    1. Outstanding - the power of the network! Many thanks for sending this!