Difference Between Bioaccumulation and Biomagnification

Bioaccumulation vs Biomagnification
 

Food chains are important interrelations in the eco systems. It starts with a producer (vegetative plants), which can produce food for themselves. The second level is occupied with herbivores and the upper levels are occupied with carnivores. The food produced at the bottom level is passed to the upper levels. Therefore, whatever the substances in the lower tropic levels can be passed onto the upper levels along with the nutrients. Bioaccumulation and the biomagnification of substances are considered to be important if those substances are harmful to organisms. If the substances are not harmful, their accumulation won’t do any problem to them. With the industrial development and high population density, a lot of pollutants are released into the environment. Some of them are not easily degradable, and they are toxic. When they enter into the food chains and circulate inside organisms, it is a huge problem. So it is important to have an idea about the concepts of bioaccumulation and biomagnification as well as about the substances which are likely to be bio accumulative.

Bioaccumulation

Bioaccumulation is the accumulation of substances in living organisms. This happens over time. These substances could be heavy metals, pesticides, or organic chemicals. These substances can enter into the systems via water or food. Bioaccumulation is resulted via food chains. The lower tropic levels of the food chain accumulate less concentration of substances than the higher tropic levels. Usually, body has mechanisms to remove all the unwanted and toxic products away from the body. Bioaccumulation results when the accumulating rate is much higher than the removal rate. So, if the life time of the substance is higher, the impact of it also gets higher. Usually, kidneys are responsible for removing the majority of the unwanted substances from the body. Blood carries them into the kidneys and then through filtration and selective reabsorption urine is produced. In order to remove toxics with urine, they should be water soluble. Bioaccumulative substances are normally fat soluble and cannot be broken down into smaller molecules. Therefore, they tend to remain in the body.

Biomagnification

Biomagnification is the increase in the substance concentrations as you go higher in a food chain. The pollutants must be long-lived in order to cause biomagnification. Also, it should be mobile, so that it easily enter into biological systems in means of food or water. If it is not mobile, it may stay inside one organism and will not be passed into the next tropic level. If they are soluble in fat, they tend to remain in bodies of organisms for a longer period. Further, in order for biomagnification to occur, the pollutant must be biologically active. For example, DDT is a chlorinated hydrocarbon which can be bioaccumulated. It is toxic for insects and has a half-life of 15 years. Heavy metals like mercury, lead, cadmium, zinc are also toxic and can be biomagnified.

Bioaccumulation vs Biomagnification

  • Bioaccumulation is increasing the concentration of a substance in one organism whereas biomagnification is increasing the level as you go up in a food chain.
  • Bioaccumulation occurs within a tropic level and biomagnification occurs between tropic levels.