Definition - What does Synergistic Effect mean?
A synergistic effect is the result of two or more processes interacting together to produce an effect that is greater than the cumulative effect that those processes produce when used individually. The concept is an important consideration in occupational health and safety whenever multiple hazards are present in the workplace.
Two hazards may pose an acceptable risk on their own; however, if they are synergistic with each other the level of risk they pose may rise to an unacceptable level. Occupational exposure limits for a given hazard may not be appropriate if the chemical is used in concert with another hazard that exacerbates its negative effect. Synergistic effects can also occur between hazards that an employee is exposed to separately but which have long-lasting effects on the body.
Safeopedia explains Synergistic Effect
A "synergistic effect" refers to two or more hazards having a multiplicative effect on the level of risk they pose to worker health and safety when used in concert. Synergistic effects contrast with additive effects—where the effect of two or more substances used together is equal to the sum of those substances used separately, and with antagonism—where the effect of two or more substances used together is less than the effect of the two substances used separately.
Potentiated effects are related to synergistic effects. Potentiation refers to a substance that does not have any negative effect by itself but which does have the potential to greatly increase the negative effect of another substance. Some sources consider potentiation to be a type of synergism.
Occupational health and safety experts recommend that occupational exposure to hazards be minimized to the greatest extent possible because occupational exposure limits do not account for potential synergistic exposures. For instance, exposure limits for asbestos and radon daughters do not account for the fact that exposure to those substances is much more hazardous to cigarette smokers than non-smokers due to synergism. The safety data sheets (SDS) used for chemical mixtures do account for synergistic effects and describe the combined hazards from all components in a mixture; however, they do not address potential synergism with other workplace hazards. Synergistic effects may also involve physical phenomena; there are significant indicators that chemical substances associated with hearing loss (ototoxins) may by synergistically exacerbated by noise exposure.