Q.23. Give a brief account of environmental effects of modern agriculture. (AKTU. - 2009 - 10)
Ans. Because of the increase in the population, modern agriculture is playing a significant role in increasing the crop-yield. It includes the use of chemical fertilizers and pesticides. But with the increase in the production, there occurs some adverse effects on soil productivity and environmental quality.
Fertilizer related problems: - Fertilizers are the chemical substance which increases the fertility of the soil. Fertilizers used in the modern agriculture have nitrogen, phosphorus and potassium (N.P.K) in inorganic form. Farmers use these fertilizers to increase the plant growth and this may cause micro-nutrient imbalance in the soil.
Due to excess nitrogen i.e. concentration above 25 mg/l cause serious health hazard called as blue baby syndrome or methaemoglobinemia in the infants. A large amount of nitrogen and phosphorus used in the crop fields are warned off and reach to nearby water bodies causing eutrophication is excess nourishment.
Pesticide related problems: - Pesticides are the chemical substance used to kill the pest. e.g. DDT (Dichiorodiphenyl trichlorol ethane). Many pesticides are used in agriculture to minimize the destruction by the pests.
Many of these not only kill the target species but also non-target species, which may be useful for agriculture. Most of the pesticides are synthetic compounds. These are non- biodegradable and accumulate in the food chain and increase at successive tropic level, called as biological magnification. It is harmful and lethal to human beings and animals.
Q.24. What are minerals and what is the environmental impact of mining?
Ans. Minerals: -
A mineral is any substance that is naturally present in the Earth’s crust and is not formed from animal or vegetable matter. The Earth’s geological processes have formed these minerals over millions or billions of years and hence they are non-renewable.
Impact of Mining: -
Mining is the process of extracting and processing minerals. Over 100 minerals are mined and these include metals like gold, iron, copper and aluminium and non-metals such as stone, sand and salt. Apart from minerals, another major material that is mined is coal.
Underground mining has little direct effect on the environment, but it can cause long-term problems like subsidence and pollution of aquifers. Moreover, workers are at great risk in underground mines. Accidents like flooding and collapses are common and the work itself causes severe health problems like respiratory illnesses.
Surface mining destroys all vegetation in the area and pollutes the landscape with the dust that is thrown up. Once the available material is mined out, large craters are left behind. When hills that act as watersheds are mined away, the water tables go down, as in the case of the Aravallis in Rajasthan.
Q.25. What is Environmental Impact Assessment? Discuss its importance in planning and implementation of engineering projects. (AKTU. - 2009 - 10, 10-11)
Ans. Environmental Impact Assessment: -
EIA is an assessment of the environment impact of any development project. In 1994, Environmental Impact Assessment (EIA) was made mandatory for certain types of projects. The regulations require the project proponent to submit an EIA report, an environmental management plan, details of the public hearing, and a project report to MOEF (Ministry of the Environment and Forests).
The MOEF (Ministry of the Environment and Forests) has prepare environmental guidelines, to the implementation of engineering. Projects guidelines have been prepared to bring out specific information on the environment required for environmental clearance. The agencies, which are primarily responsible for the respective sectors are closely involved in preparing the guidelines. River, valley projects, thermal power projects, mining projects and industries, ports and harbors, developed of beaches, highway/rail road projects are the sectors for which guidelines have already been prepared. These guidelines basically consist of aspects regarding planning and implementation of development projects. The majority of projects in India, which require EIA’s are large development projects like Nuclear power, river valley, thermal power plants etc, where government plays an important role.
The Ministry’s Impact Assessment Agency evaluates EIA reports. The assessment is to be completed within 90 days of receipt of the requisite documents and data from the Project Authorities and completion of the public hearing and the decision must be conveyed within 30 days thereafter. The clearance granted is valid for a period of five years from the commencement of the construction or operation of the project.
