What role do shape and slope play in environmental toxicolog

What role do shape and slope play in environmental toxicology?

Solution

Environmental toxicology is the study of adverse nature of physical and chemical agents on a living organism existing in a specific environment. Theopharstus stated that all substances are poisons only the dose that distinguishes them from normal to poisonous substance. The dose is very important measure. The response observed at the minimum dose is known as threshold dose level. The plot drawn between individual response and lowest to highest dose of toxicant is always a bell shaped curve and depicts about adverse effect of a chemical, lowest dose at which the effect is observed and rate at which the effect is maximum (slope).

The dose - response curve is sigmoid shape when the percent of population affected is plotted against dose concentration in mg. The sigmoid curve always shows the threshold level or effect observed at lowest level. Below threshold level the effect is nil or nigligible. The shape and slope of dose response curves is much important in providing information about the threshold levels of various toxic substances and also the percent of population affected by change of unit dose (predicted by the slope).