1. Let us Save Lives!
By Dr.P.S.Navaraj, Science Communicator, Madurai
An eleventh standard boy, Mar. Ramu has visited the busiest fish market on a
particular Sunday. He inquired about the types of Fishes available for sales with the
seller. The shop owner described each and every name of the available fishes in the
local language. Ramu anxiously asking from where the fishes are being caught.
Interestingly, the fishermen replied that these fishes were taken from the Vagal,
River near Thiruppuvanam, Madurai. Being a native of this place, he observes the
spraying of pesticide that is drained into the particular river daily. On knowing this, he
raised another question; doesn’t the pesticide in the river spoil the fish? For this, the
sales man replied that after thorough washing, fishes are sold here. A student of
science, Ramu is not able to digest this answer. He left the place without purchasing
the desired food.
The next day he met his science teacher and asked about the same doubt. The
science teacher is not aware of this. Hence he told him that he will consult his
neighbour who is working in the Biology Dept. of Madurai Kama raj University and let
inform him tomorrow. The mind disturbing boy googled some information in the net
on the same night. As well he expects much to get interacted with the local scientist.
The teacher has informed him that he will take him to the Scientist's next day. Ramu
is familiar with the Cypermethrin that has been sprayed in the agricultural field very
often and so he wants to know the ill effect of this chemical on fish.
After getting an appointment with Professor cum Scientist in the University, both of
them visited his laboratory. The encouraging scientist received this little boy, took
him around the lab and enquired about his burning doubts. After saluting the
Scientist, he simply put the question, Sir; I have googled some information regarding
the chemicals impact on fish. I want to know some more information from you, Sir.
Could you please help me? Definitely, Scientist replied with a smile.
Whether the fish eaten by us is safe? I cannot vouch that all fishes are in safe
mode, he smiled. Which damages the health of fish in water, Sir? Pesticides,
Industrial effluents, Domestic sewages and other waste materials that are dumped in
the water body will damage the fish population.
Sir, in my place Cypermethrin, is sprayed by the farmers in the field and that drained
into the water body, from where the fishes are being caught and sold in the market!
What you think about the Cypermethrin effect on fish? Sir.
Yes, my dear! Cypermethrin is used as an insecticide in large-scale commercial
agricultural applications as well as in consumer products for domestic purposes. It
behaves as a fast-acting toxin in the nervous system of insects.
2. How this pesticide is derived? These are derived from the Chrysanthemum flowers. The
wide use of these pesticides will be a major problem as they pollute the lands and water
resources and finally affect fish and humans.
Can you explain how this chemical spoil the fish? Cypermethrin can easily enter into the fish
body as it is fat-loving substances. Even in low concentration, it will do its actions in the host
animal. When it enters through the buccal or gills route, it will get settled down in the tissues
and organs and pose a threat to the normal functioning.
Any scientific evidence for this Sir! A lot of evidence, here in Madurai, a research scholar
from Yadava College is doing the toxic evaluation of Cypermethrin on Tilapia fish. She has
designed the study in her laboratory and found out some interesting results.
Could you please tell, if time permits? I am here to clear your doubts. Listen! She exposed
the chemical in the selected fish at the selected range. Initially, she has to find out the range
of toxicity on which the fish responds to the chemical toxicity without losing its life. These
responses then recorded and explained.
What type of tests did she perform Sir? Before stepping into the research, she surveyed the
literature and found out the gap, and she tried to fill up the gap with a new finding. In the
literature survey, it is indicated that cypermethrin is an endocrine-disrupting chemical. This
idea provokes her to study the impact of this chemical on the endocrine-
disrupting the activity of the selected fish. You might have been studied hormones in your
class. These hormones are endocrine secretions. Are you clear!
Yes Sir, we have studied in our biology section! Good, Initially when the fish is exposed to
the chemical, the fish shows the disturbances in the respiration, movement as well as some of
the last their breath. It indicates how the cypermethrin is toxic to the fish.
You may ask me whether all fish will die or how many chemicals to be used for this killing
or how long it will take to kill! Depend upon the volume of the pesticide exposure to the fish,
the death will occur. The researcher has to find out the best concentration of the chemical at
which all tests could be conducted without losing the fish.
Normally the 96hour toxicity test will be carried out by the researcher to find the best toxic
concentration for the study. Suppose if it 9, then the researcher has to take either 1/3 of the
value or 1/10 of the value based on the nature of the testing. This concentration will be kept
as a base to find the result of the experiment.
What next Sir! After finding the concentration, the researcher has to set up the experiment in
four concentrations below the selected one and controlled water. The experiment will be
conducted in 21 days and during this period she has observed the results.
Interesting, What results Sir? She observed whether this chemical will affect the organ and
for which she analyzed the selected organ tissues. She identified the various vital parts of the
cell and understood the changes!
Is it! Which organs are normally damaged, Sir? Since her work is to find the endocrine
disrupting activity, she will concentrate on the cells and tissues that involve in the
hormone secretion.
3. Is any damage to Female Fish Sir? Yes, she observed the damage in the ovum cells, ovary,
etc. All these changes inform to the researcher that the vital organs are affected as well as the
hormone secretion is also affected.
Moreover, she observed the fish of either male or female due to the chemical action. Thus it
is concluded that the cypermethrin disrupts the endocrine function of the fish.
What happened to the fish consumers? Good question. When you consume the chemical
loaded fish, you will be in trouble in the long run. The chemical accumulated in the tissues,
organs will penetrate into your body and cause a serious setback in the endocrine function of
the body. When your hormones are in trouble, then it will be very difficult for you to grow,
control sugar, conduct metabolic activities, etc. It is a pity that neither a seller nor a buyer
knows the seriousness of this development in the water body.
As a student, what I should do to help my fellow being and fish? Since you seem to be a
science-loving student, the prime duty is to tell the farmers that before spraying chemicals
they have to have a consultation with the Agriculture experts available in the agriclinic in
every village. Farmers should not be blamed as they do not know the ill effect, but the
literates like us should create awareness regarding this. We can put the banner like this Stop
killing Fish and Man through your Spraying! Consult before adding Chemical into the
field!
Really am feeling guilty to note that I am the son of the farmer who sprays such chemicals in
the field, he apologized for his father’s mistake! I am taking a pledge to spread this message
to the community. As a son of the farmer and a science student, I will rest till all community
know the ill effect of this spraying.
You have opened our eyes, Sir! Thanks! Nice Ramu, the nation needs such volunteers to save
the earth! You are the real model to the community, good luck!
After thanking the teacher, the boy returned home and sat in a gloomy mood. His parents
approached him and enquired for his silence. He told the information that he gained from the
scientist to the farmer parent that pesticide is not safe to use, Daddy! please stop using
pesticide hereafter ! he bent before the knees of his father. The rolling tears from the eyes of
the father falling on the head of Ramu makes him feel that the father has accepted his request.
P.S. Story submitted to AWSAR
