Posted By Jacquie Wills
Does anyone know of a good reference source for information on the synergistic effect of chemicals please? My basic knowledge of chemistry tells me that certain chemicals should not be mixed with other substances but this is not good enough for the work I am currently undertaking. Is there anything out there that quantifies the problem? I have found section 10 - Stability and Reactivity - of most Material Safety Data Sheets completely useless.

Posted By Mike
Table 1 is even more up to date today. A few missing vapour ppm to mg/m3 conversions were added on 11 January.

Posted By Adrian Watson
Jacquie,

Part 10 of a MSDS does not deal with synergism; it deals with chemical incompatibility (i.e. don't mix A with B - it goes bang!).

Synergism is the ability of a chemical to increase the toxicological effects of a substance, to greater than the sum of the affects of the two chemicals if applied independently. (i.e. E > 1 + 1

Regards Adrian Watson

Posted By Robert K Lewis
Jacquie

The problem with synergistic effects is that they are not known until identified some time after the event, ie there have been deaths and injury as a result. I do not personally know of a single book or other text which deals with the problem for all known effects. The HSE document does provide some guidance to obtain the OEL for mixtures but these do not necessarily reflect synergies that can occur. Having said that one can assume that potentially tobacco smoke has synergistic effects with many inhaled substances.


The only real solution is to reduce all exposures the the lowest level- which is actually what COSHH is all about.

Bob

Posted By Phil Grace
Careful guys.....

Synergism only produces an effect that is greater than the sum of the individual effects (dictionary definition).

Synergism does not result in a lessening in effect.

However, synergism is not the issue under consideration when one is considering the effects of mixtures. There has long been concern that occupational health standards consider substances in isolation - whereas in real life scenarios the employee is often exposed to more than one potentially harmful substance. There is limited knowledge on the effects of mixtures. In the USA, some years ago, there was guidance on a method of reducing limits when there was multiple exposures. Not sure whether is is still current.

Phil