and prescription drugs, cosmetics, and solvents comprise 
the most frequent human toxic exposures.The resulting 
biologic effect of combined exposure to several agents can be 
characterized as synergistic, additive, Potentiation & 
antagonistic 
Synergism-when the effect of two chemicals is greater than the 
effect of individual chemicals e .g carbontetrachloride + alcohol= 
more toxic to the liver than the sum of the individual drugs 
Additive effect- when the total pharmacological action of two or 
more chemicals taken together is equivalent to the summation of 
their individual pharmacological action.Route of entry of exposures reported was by mouth 
in most cases: 77% were the result of ingestion, 7.0% were 
transdermal, 5.9% were ophthalmic; and 5.5% were by 
inhalation.In 
general, nearly everyone is at risk of acute and chronic toxic 
exposures to hazardous substances in the ambient 
environment.During adolescence 
and young adulthood the exposures are more likely to be 
intentional, either through suicide attempts or 
experimentation with drugs or alcohol.It can be acute (toxic event which occurs soon after acute or 
limited exposure), or chronic (apply to an event which occurs 
many weeks, months or years after exposure).Hazard - is the likelihood that injury will occur in a given 
situation or setting: the conditions of use and exposure are 
primary considerations.Risk - is defined as the expected frequency of the 
occurrence of an undesirable effect arising from exposure to 
a chemical or physical agent.Exposures are equally reported in 
males and females.It is a qualitative term which depends on the amount of 
chemical absorbed, severity of the exposure, dose & others.Acute exposure is a single exposure - or multiple 
exposures occurring over 1 or 2 days.Chronic exposure is multiple exposures continuing over a 
longer period of time.Site of exposure was a residence in 91.9% of all, 
followed by the workplace, schools and health facilities.B) Presence of mixtures
Humans normally come in contact with several (or many) 
different chemicals concurrently or sequentially.Young children 
and elderly are most likely to be accidentally exposed to 
drugs or household chemicals at home.More than 72.4% of 
all poison exposures occur in children and adolescents less 
than 17 years of age.However, adult men have been reported 
to be more at risk of occupational exposures than adult 
woman.Most poison exposures do not result in clinical toxicity.Poison (Toxicant) - a chemical that may harm or kill an 
organism
Toxicity - is the ability of a chemical agent to cause injury.Toxin- a poison of natural origin.3.?????