Find here some 5 effects of pesticides on pollution in Nepal. We are going to discuss here about effects of pesticides in Nepal, types of pesticides, alternatives of pesticides. let’s have closer look in pesticides on pollution in Nepal. We know that there are many uses of pesticides in Nepal.
Effects of Pesticides on Pollution in Nepal
Pesticides are the poisonous chemicals used by human to control or destroy the harmful organisms like pests. The use of pesticides is mainly associated with agriculture and horticulture. It is also widely used for domestic purposes to control human and animal disease vectors or pests (as malaria). The pests may be insects, nematodes, rodents, weeds, fungus, etc. and thus pesticides are insecticides, nematocides, rodenticides, herbicides, fungicides, etc. respectively used to destroy respective type of pests. image source:
Types of Pesticides
Pesticides may be natural (plant origin) or synthetic (prepared in the industries). The pesticides are categorized as follows –
- Organochlorides – The pesticides which contain organic chlorides are DDT, BHC, aldrin, dieldrin, chlordane, toxaphene, etc.
- Organophosphates – The pesticides which contain organic phosphates like parathion, malathion, diazion, phenothate guthion, etc,
- Carbamates – These pesticides are pyrethrins, baygon, temik, zectran, etc.Organophosphates – The pesticides which contain organic phosphates like parathion, malathion, diazion, phenothate guthion, etc,
- Pyrethroids – Pesticides of plant origin are pyrethroids from Chrysanthemum flower, nicotine from tobacco leaf and other like neem plant, Artemisia leaf, etc.
Insecticides and rodenticides are Zinc phosphide, Arsenic compounds, Thallium sulphate, etc Nematicides are aliphatic halogen compounds, organophosphates and carbamates. Herbicides are phenoxy acids (2-4D and 2,4,5-T), Paraquat, Diquat and Triazoles. Fungicides are HCN, ethylent oxide, acetaldehyde and methyl bromide
5 Effects of Pesticides on Pollution in Nepal
1. Polluting the environment
Although pesticides save about 10% of the world food supply from the pests but these cause senous environmental and health threats to the various organisms. The organochlorides have longer lifetime (longer residual property), therefore, persist and accumulate in environment. These pesticides are generally non- biodegradables, therefore, get incorporated into the food chain and ultimate!; deposited in the fatty tissue of different animals including man.
2. Kills broad spectrum of organisms
The use of pesticides in the farms, gardens and houses may also kill the useful organisms such as natural enemies (predators, parasites and pathogens) of the pests as well as earthworms and detrivores in the soil. Nitrogen fixing bacteria are also destroyed by the use of pesticides.
3. Affect the biology of organisms
Pesticides might be the major cause of decline of reproduction in some animals. Some pesticides like DDT interfere the Ca-metabolism. Therefore, Ca-deficiency symptoms like thinning of egg-shells of birds, weakening of bones, etc. are observed. Hormonal imbalance is also resulted which cause; delayed ovulation and inhibition of gonad development.
4. Results development of resistance
Due to continuous use of pesticides, pests develop resistance or immunity against pesticides, e.g mosquito and housefly against the DDT, BHC. Hence, farmers have to use higher dose of pesticides to protect the crops of the same area hence environmental pollution occurs.
5. Threats to wildlife and human health
Man is more prone to be affected by pesticides as they are more exposed to chemicals in the farms, factories and at homes, etc. They can inhale or ingest the chemicals. These pesticides also harm birds, livestock, wildlife, fishes as well as soil and aquatic organisms. N2 fixing bacteria in the roots may also be harmed.
Alternatives of Pesticides in Nepal
- Biological control – The biological control of pest has traditionally meant regulation by natural enemies such as predators, parasites and pathogens. It represents a form of population management preventing unchecked exponential growth of pest species.
- Cultural control – It is the method to control the plant pests by the rotation of crop.
Article emailed by Durgesh Bhattrai, Kathmandu, Nepal