Question 1.
Explain Dichlorobiphenyl-trichloroethane (DDT) as a persistent or non-biodegradable pollutant.
DDT is a synthetic pesticide that was widely employed to manage agricultural pests and diseases in the
past. Its use was prohibited in the United States in the 1970s due to environmental concerns. Because it
does not degrade quickly in the environment, DDT is classified as a persistent or non-biodegradable
contaminant. It may survive for lengthy periods of time in soil, water, and even animal bodies. DDT's
compounds are extremely stable and difficult to degrade through natural biological processes.
In the middle of the 20th century, this synthetic pesticide was widely used in agriculture and to manage
vector-borne illnesses like typhus and malaria. DDT, however, has been shown to have negative
consequences on both the environment and human health.
The persistence of DDT in the environment is one of its main features. Natural processes, like microbial
breakdown, are unable to break down DDT. This implies that DDT can accumulate in the soil, water, and
living things after being released into the environment and stay there for a long time. The reason for this
persistence is that DDT's chemical makeup prevents it from degrading naturally.
DDT can bioaccumulate and biomagnify in the food chain due to its persistence. DDT can enter the soil
and water after being applied to crops, where it can be absorbed by plants and aquatic organisms. These
organisms are then consumed by higher-level organisms, causing DDT to move up the food chain. As a
result, higher trophic levels may be subjected to higher DDT concentrations.
DDT's persistence and bioaccumulation pose significant environmental and human health risks. DDT has
been linked to a number of negative outcomes, including reproductive and developmental toxicity,
endocrine disruption, and carcinogenicity. It has been linked to decreased fertility, birth defects, and
hormonal disruptions in both wildlife and humans.
Many countries have banned or severely restricted the use of DDT due to its persistence in the
environment and harmful effects. DDT is listed as one of the persistent organic pollutants that must be
eliminated or restricted due to environmental and health concerns in the Stockholm Convention on
Persistent Organic Pollutants, an international treaty.
Finally, because of its resistance to degradation and ability to accumulate and magnify in the food chain,
DDT is classified as a persistent or non-biodegradable pollutant. Because of its persistence in the
environment and negative effects on human health and wildlife, it is regulated and restricted in many
countries.
Question 2.
Explain the difference between bioaccumulation and biomagnification with reference to
dichlorobiphenyl-trichloroethane (DDT).
Both bioaccumulation and biomagnification entail the accumulation of harmful compounds in the
environment and organisms, such as dichlorobiphenyl-trichloroethane (DDT). There are, however,
significant distinctions between the two processes.
The steady buildup of a material in the tissues of an organism over time is referred to as
bioaccumulation. It happens when an organism absorbs a chemical from its surroundings faster than it
can expel or digest it. When organisms are exposed to DDT-contaminated air, water, or food sources,
bioaccumulation can occur. DDT, if ingested, can accumulate in fatty tissues of organisms such as the liver
or adipose tissue. As a result, the concentration of DDT within the organism can rise over time.
In contrast, biomagnification refers to the process by which the concentration of a drug increases at
higher levels of the food chain. It happens when creatures at lower trophic levels consume species or
substances with lower quantities of the chemical, and the substance is difficult to metabolize or expel.
Because of its durability and difficulty in degradation, the concentration of the chemical can increase
dramatically over time as species at higher trophic levels devour these lower trophic level organisms.
DDT, for example, has been shown to bioaccumulate in certain creatures, such as small fish, which are
then devoured by larger fish or predatory birds.
As a result of biomagnification, the concentration of DDT in the tissues of these higher trophic level
creatures might grow significantly.
To recap, bioaccumulation is the slow accumulation of a chemical in an organism, whereas
biomagnification is the increase in concentration of a material at higher levels of the food chain. In the
case of DDT, it can bioaccumulate in organism tissues and then be biomagnified as it is consumed by
higher trophic level species.
