The key difference between LD50 and LC50 is that LD50 stands for lethal dose, whereas LC50 stands for lethal concentration.
The terms LD50 and LC50 are found mainly in toxicology. These are parameters for different chemical compounds which describe the amount of a substance that can cause death. Both these parameters measure the lethal character of a substance when it is exposed to a population and causes the death of 50% of that population. So, this is the way the denotation of these terms arises. E.g., LD50 means the dose of a substance that can cause 50% deaths when exposed to a certain population.
CONTENTS
1. Overview and Key Difference
2. What is LD50
3. What is LC50
4. Side by Side Comparison – LD50 vs LC50 in Tabular Form
5. Summary
What is LD50?
LD50 stands for Lethal Dose of a substance that can cause 50% deaths when exposed to a population. In other words, the value of LD50 gives the amount of a substance that we need to kill half the population. Here, the substance that we consider regarding the toxicity is usually a toxin, radiation or a pathogen.
Generally, LD50 is a good indicator for the evaluation of acute toxicity. If we have a low value for LD50, then it means the substance has increased toxicity. Similarly, if the value we obtain for LD50 is high, then the toxicity of that substance is low. This is because a low LD50 value means that a little amount of the substance can kill half the population, which in turn makes it more toxic.
Usually, the value for LD50 is given as mass of the substance per unit mass of test subject (i.e. the population of fish in water). Then the unit is used as milligrams of the substance per kilogram of the population. However, the unit may differ according to the type of population we are talking about, i.e. for microorganism culture, we have to use the nanogram scale. Moreover, this lethal does often varies with the way of administration. For example, the toxicity of substances is often low when it is administered orally rather than injecting.
As variations, the parameters LD50/30 and LD50/60 are also important. LD50/30 refers to the amount of the substance that will be lethal to 50% of the population within 30 days of exposure and LD50/60 refers to it being 6o days of exposure.
What is LC50?
LC50 stands for Lethal Concentration of a substance that can cause 50% deaths when exposed to a population. Usually, this parameter is important regarding the toxicities related to water (since we are talking about concentrations).
Moreover, this parameter also is important in determining the level of acute toxicity. The unit of measurement of concentration for the determination of LC50 is usually milligrams per cubic meter or ppm (parts per million).
What is the Difference Between LD50 and LC50?
The key difference between LD50 and LC50 is that LD50 stands for lethal dose, whereas LC50 stands for lethal concentration. LD50 refers to the Lethal Dose of a substance that can cause 50% deaths when exposed to a population while LC50 refers to the Lethal Concentration of a substance that can cause 50% deaths when exposed to a population.
Furthermore, we can determine the LD50 value of any desired substance but usually, the LC50 is determined regarding the toxicity of components in water. Apart from that, the unit of measurement for LD50 is milligrams of substance per kilogram of the population whereas the unit for LC50 is milligrams per cubic meter or ppm (part per million).
The below infographic summarizes the difference between LD50 and LC50.
Summary – LD50 vs LC50
The terms LD50 and LC50 are found mainly in toxicology. These are parameters for different chemical compounds which describe the amount of a substance that can cause death. The key difference between LD50 and LC50 is that LD50 refers to the lethal dose of a substance that can cause 50% deaths when exposed to a population while LC50 refers to the lethal concentration of a substance that can cause 50% deaths when exposed to a population.
Reference:
1. “What is a LD50 and LC50?.” Canadian Centre for Occupational Health and Safety, 27 Oct. 2019, Available here.
Image Courtesy:
1. “Concentration-response curve” By Niranjana Krishnan – The author created this graph (CC BY-SA 4.0) via Commons Wikimedia