Pesticides application and it effects on the environment #3

Hello steemians. Good day to you all. We've been on this series for some time now. This series addresses effects of pesticides application on environment and man. The links to the last two post are here 1 and most recent is number 2.

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If you have the time and the chance, I will advise you to really read the whole series. I guess it will help you. Pesticides are good truth to be told because pest are in serious challenge or competition with human. I bet it with you that as you need food for survival, the pest do too. They want to survive as you want to survive too. So this leads to competition between human using his chemical agent to hunt down all forms of pest. But sad enough while man is trying this, he hurts himself and the entire ecosystem. I guess you still remember competition as part of relationship in biology where it's the survival of the fittest, this time around, man want to survive and the pest too.

But is man not going too far by employing a means too destructive not just for his competitors but also for himself and his environment?. I don't know if that's actually a rhetorical question. But wether it is rhetorical or not, we must understand that our actions is not just against the pest but against ourselves too.

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Let's now move from where we stopped last time.

Okay let's move on to another example of Organophosphates: Dichlorvos;

This pest killing chemicals called Dichlorvos or better know by chemist as 2,2-dichlorovinyl dimethyl phosphate. I would have love to show us some process follow in the name but the international Union of Pure and Applied Chemist (IUPAC) has done that so I guess no need for me to do that again.

The chemical is very good at keeping residential apartment safe from various Intruders (pest) that makes you hate your apartment sometime. It keeps crops away from insects and it is mixed with feeds given to animal in other to treat them against worms. Farmers had used it in European countries against mushroom flies, caterpillar, aphids and many other insects. It's mode of operation is not different from other Organophosphates as it also affect the activities of acetylcholinesterase enzyme which is known as a driver to transport nervous indicator between nerves cells and the muscles as well as a transporter within neurons housed by the brain.

For it's quick recognition, It's appearance is apparently colorless, and sometimes been exposed gives honey-yellow colouration, and smell nice. It's chemical structure is what we have down here.

Dichlorvos:By Jü - Own work, Public Domain,
The chemical formula is C₄H₇Cl₂O₄P
Dichlorvos has been in the market for several decades and has remained notorious for been persistent in water bodies, because it percolates into the water bed without any noticeable interaction with sediments. This interaction eventually recline after some weeks. Like every of it's conterpart, it effects didn't stop at affecting insects but human and other economically relevant insects and animals.

Effect Of exposure to this compound on human is not different with other pesticides explained before. Most people are exposed to it through inhalation,or swallowing, and at times accidentally or carelessly through direct contact with the skin. Exposure trigger several symptoms such as pupil tightening, cramps in the abdominal regions and many other symptoms depending on the level of exposure. Though it is quickly taken care of almost immediately by the liver because it encounter breaking down through hydrolysis. When it is broken down, it gives less dangerous or toxic substances which the body ejected through faeces and urination

My personal experience, about three years ago, wasn't palatable at all as I was trying to applied a particular pesticides around my house. After the application, I began to have intense chest pain, this happened like two times before I knew what has happened. You asked me what happened next?. I got myself treated. But guess the pain............. treated. For further understanding about symptoms associated with exposure to Dichlorvos please check this Link, it's explicit

No report has been given that this chemical is that deleterious to the environment, neither any record of it overbearing staying in the environment has been recorded. It's physical and chemical properties qualifies it to volatilized into the space and produces less harmful substance in the process.

When this chemical is given orally to animals to treat them against worms, almost 85% is assimilated. It's metabolism by enzymes could be through two major part. One partway results in forming demethyl dichlorvos and the other partway gives rise to dimethyl phosphate which is excreted as it is formed, and dichloroacetaldehyde which decomposed quickly and can't be traced in the tissue. The first partway is glutathione dependent while the second is not.

The structure of dimethyl phosphate is given below.

dimethyl phosphate:By Yikrazuul - Own work, Public Domain,

The structure of dichloroacetaldehyde is shown here.

dichloroacetaldehyde:By Jü - Own work, Public Domain,

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Another Organophosphates is Phosmet.

Phosmet:By klever - Own work, Public Domain,
This is another pest killer which is not brightly colored white, solid and gives a characteristics very bad odor with chemical formula C₁₁H₁₂NO₄PS₂ . It's very active against insects and ticks. It is stable if it is properly stored. But readily break down when stored at temperature 45°C. It's a pesticides that is not absorbed into the system. It's highly recommended for treatment of apple tree to prevent or treats the tree against infestation of codling moth. However, it's application is not limited to apple tree alone but also used on several fruit trees. This chemical is also a good killing agent against pests such as lice,ticks and other pest on cattle, dogs, pigs

It's mechanism of action is not different from other Organophosphates in that it block acetylcholinesterase enzyme there by stop the hydrolysis and immobilization of acetylcholinesterase. The action of this chemical on the enzyme leads to the body been accumulated with acetylcholine. This accumulated acetylcholine also at the junction of the nerve leads to total break down of the nervous system in the body of the insect.
The chemical simply blocks the the enzyme at it's active sight where it supposed to be locked up with ester part of acetylcholine

Like dichlorvos, Phosmet is also quickly assimilated in the body. Similar with dichlorvos, 85% is almost absorbed within a day that it is administered. Within split of an hour into two following dosage, highest level of radioactive activity of the chemical in the blood together with plasma can be monitored.

The elimination of the chemical can occur within few hours of administration and several hours even up to two months!!.

Like I earlier discussed in the previous post, atropine is a good antidote in case symptoms of inhibition is noticed in human, and apart from atropine, pralidoxime is another antidote.

Pralidoxime act as an antidote by simply reviving acetylcholinesterase. This happen when it function as a replacement of hydroxyl group of serine present on the enzyme and that lead to the formation of a complex with a divided part organophosphorus.
Pregnant women should be aware that contact with Phosmet should be avoided by all means because it can through the placenta come in contact with fetus.

Summary

In this post, I discussed two major Organophosphates pesticides Dichlorvos and Phosmet. Mode of operation of the two insecticides is similar in that they both inhibit acetylcholinesterase enzyme, thereby leading to paralysis of the Central Nervous System.

The two chemicals are good at keeping home safe off insects and very good at dealing with ticks and lice affecting pets and meat producing animals.

The two insecticides discussed are not as deleterious when compared with insecticides discussed in the previous post. The two chemicals are rapidly absorbed and excreted out in urine and feces. Dichlorvos remain banned in the European countries while Phosmet is still in use by most countries of the globe.

Thanks for stopping by to read from this blog. Do not forget to leave a comment behind if you find this post interesting. You can join us @steemstem on discord by clicking on discord.

REFERENCES

parasitipedia.net

Wikipedia/Dichlorvos

Pubchem.ncbi.nlm.nih.gov

www.inchem.org/documents

Phosmet#section Chemical vehicle

Bingham, E.; Cohrssen, B.; Powell, C.H.; Patty's Toxicology Volumes 1-9 5th ed. John Wiley & Sons. New York, N.Y. (2001)., p. 7:820