Tag: soil pollution

Questions Related to soil pollution

The herbicide mixture rich in 2,4-D and 2,4,5-T with TCDD being carcinogenic and teratogenic, used by Americans in Vietnam war in 1961-71, was

  1. Agent orange

  2. Triazines

  3. Organophosphates

  4. Pyrethroids


Correct Option: A
Explanation:

Agent orange was a powerful mixture of chemical defoliants used by U.S. military forces during the Vietnam war to eliminate forest cover for north Vietnamese, as well as crops that might be used to feed them. The U.S. program of defoliation, codenamed Operation Ranch Hand, sprayed more than 19 million gallons of herbicides over 4.5 million acres of land in Vietnam from 1961 to 1972.

Agent orange, which contained the chemical dioxin, was the most commonly used of the herbicide mixtures, and the most effective. It was later revealed to cause serious health issues–including tumors, birth defects, rashes, psychological symptoms and cancer–among returning U.S. servicemen and their families as well as among the Vietnamese population.
Thus, the correct answer is option A.

Consider the following four measures (a-d) that could be taken to successfully grow chickpea in an area where bacterial blight disease is common.
a) Spray with Bordeaux mixture
b) Control of the insect vector of the disease pathogen
c) Use of only disease-free seeds
d) Use of varieties resistant to the disease
Which two of the above measures can control the disease?

  1. b and c

  2. a and b

  3. c and d

  4. a and d


Correct Option: C
Explanation:

Bacterial blight is a serious disease of field peas that is caused by the pathogens Pseudomonas syringae pv. pisi and Pseudomonas syringae pv. syringae

It can be controlled by crop rotation, time of sowing, farm hygiene, sowing disease free seed and using resistant varieties.The disease is characterized by small, pale green spots or streaks which soon appear water-soaked. The lesions expand and then appear as dry dead spots. In severe infections, a milky gray exudate may be squeezed from the cut end of leaf exhibiting symptoms.
It can be prevented by use of only disease-free seeds and use of varieties resistant to the disease.

Which destroys the acetyl choline esterase?

  1. Malathione

  2. CO

  3. KCN

  4. Colchicine


Correct Option: A

Which of the following is a chlorinated hydrocarbon?

  1. Malathion

  2. Pyrethrum

  3. Aldrin

  4. Carbamates


Correct Option: C
Explanation:

Aldrin is an organochlorine insecticide that was widely used until the 1970s, when it was banned in most countries. It is a colourless solid. Before the ban, it was heavily used as a pesticide to treat seed and soil. It is a chlorinated hydrocarbon. Thus, option C is correct. A carbamate is an organic compound derived from carbamic acid (NH2COOH). Thus, option D is wrong. Malathion is an organophosphate parasympathomimetic which binds irreversibly to cholinesterase. Malathion is an insecticide of relatively low human toxicity. It is not a chlorinated hydrocarbon. Thus, option A is wrong. Pyrethrum was a genus of several Old World plants now classified as Chrysanthemum or Tanacetum which are cultivated as ornamentals for their showy flower heads. Thus, option B is wrong. 

Which pesticide is lipophilic?

  1. Triazines

  2. Pyrethroids

  3. Organophosphate

  4. Organochlorine


Correct Option: D

The bioconcentration of DDT in the body fat of Indian people is

  1. 18-36 ppm

  2. 5-10 ppm

  3. 13-31 ppm

  4. 2-5 ppm


Correct Option: C
Explanation:

Most of organochlorine pesticides are highly soluble in fat of animals. Further, these chemicals are resistant to be metabolized, so they start accumulating in the bodies of animals. 

In India due to prolonged use of DDT, 13-31 ppm of DDT can be detected in the body fat of people, which is highest in the world. Thus, the correct answer is option C.

Which of the following is a cholinesterase inhibitor?

  1. Aldrin

  2. Malathion

  3. Endosulfan

  4. $\beta$-hexachlorocyclohexane


Correct Option: B
Explanation:

Malathion is an organophosphate parasympathomimetic, which binds irreversibly to cholinesterase. Malathion is an insecticide of relatively low human toxicity. Malathion is a parasympathomimetic organophosphate compound that is used as an insecticide for the treatment of head lice. It inhibits acetylcholinesterase activity of most eukaryotes. Malathion is toxic to aquatic organisms, but has a relatively low toxicity for birds and mammals. 

Cholinesterases catalyze the hydrolysis of the neurotransmitter acetylcholine into choline and acetic acid, a reaction necessary to allow a cholinergic neuron to return to its resting state after activation. Because of its essential function, chemicals that interfere with the action of cholinesterase are potent neurotoxins, causing muscle spasms and ultimately death. Thus, the correct answer is option B.

Bottom-feeding fish from the Great Lakes often contain

  1. Lead

  2. Dioxin

  3. Urethane

  4. Polychlorinated biphenyls

  5. B and D


Correct Option: E
Explanation:

Polychlorinated biphenyls are a group of man-made chemicals useful in a variety of industrial processes, including the insulation and cooling of electrical equipment. But PCB pollution continues long after its source is cut off. PCBs are still found in the Great Lakes through a process called atmospheric deposition. Pollutants like dioxins and PCBs enter from the air into the water through rain and snow, falling particles, and absorption of the gas form of the pollutants into the water.  Dioxins are chemically similar to PCBs. Lake and river sediments are especially good at holding onto PCBs, so bottom-dwelling fish tend to have higher levels.

Therefore, the correct answer is option E.

Herbicide carbamates are

  1. Dithiocarbamates

  2. Thiocarbamates

  3. Phenyl carbamates

  4. Both (b) and (c)


Correct Option: D
Explanation:

Herbicide carbamatets are asulam (thiocarbamate), carboxazole, chlorprocarb (phenyl carbamate), dichlormate, fenasulam, karbutilate, terbucarb.

Which of the following is a herbicide?

  1. Allethrin

  2. Triazine

  3. Aldrin

  4. BHC


Correct Option: B
Explanation:

The allethrins are a group of related synthetic compounds used in insecticides.

Triazine, is an important herbicide for quackgrass control and other perennial weeds. 
Aldrin is an organochlorine insecticide.
BHC is an organochloride.