The New Nation - Internet Edition

Environmental pollution is really a social problem. Pollution may be defined as the unfavorable alteration of our surroundings, wholly or largely as a direct or indirect consequence of man's actions. Pollution of air is the most concern today. Air pollution is the contamination of air by different harmful (physical, chemical, biological) substances. These substances are called pollutants, can occur naturally or can be produced by human activities. Natural pollutants include dust, smoke, particles. Different types of gases like carbon dioxide (CO2), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen's oxides (NOx), hydrocarbons etc. are also responsible for air pollution. Sources of air pollution are combustion fired power plants, emission from industries, burn practices in agriculture and forestry management, burning fossil fuels, wood, fireplaces, stoves, furnaces and incinerator use in hospital, oil refinery power plant operations, fumes from paint, varnish, aerosol sprays and other solvents, military uses nuclear weapons, waste disposal in landfills which generate methane. Natural sources such of as pine trees which emit Volatile Organic Compounds (VOCs), volcanic activities, wild fires etc. There are various types of effects of air pollution such as damage to materials, vegetations, farm animals, darkening of sky and reduction in visibility, effect on human health and human activities. It can contribute to respiratory diseases like bronchitis, asthma, lung cancer lead poisoning in inhalation and ingestion and allergies and effects on materials like soil clothing, corroding metals, eroding building surfaces, discoloring. It also causes acid rain. To reduce air pollution we should take such steps like as- to develop infrastructural facilities of vehicles, to stop the improper land use planning, reduce the use of aerosols in households, reduce impure fuel. Car should as far as possible be fitted with catalytic converters. Use only unleaded petrol and awareness of people etc.

Strategies taken for reducing air pollution in Dhaka City: Phase out of two stroke engine vehicles which really causes air pollution. Ban on leaded gasoline. Provision for catalytic converter and diesel particulate filter to the new vehicles as well as existing vehicles. Vehicles inspection stations have been constructed. Construction workshop for CNG conversion vehicles in both private and public sector. Instillation of CNG filling station. CNG operated bus, taxies and three wheelers. Development of vehicular emission standards for new and in-use vehicles. Establishment of continuous air monitoring state etc. Then we can save our air from air pollution.

Niloya Paul

Mawlana Bhashani Science & Technology University, Tangail

Landslide

A landslide is a geological phenomenon which includes a wide range of ground movement, such as rock falls, deep failure of slopes and shallow debris flows, which can occur in offshore, coastal and onshore environments. We can say it "the downward sliding of a relatively dry mass of earth and rock". Although the action of gravity is the primary driving force for a landslide to occur, there are other contributing factors affecting the original slope stability.

Landslides are caused when the stability of a slope changes from a stable to an unstable condition. A change in the stability of a slope can be caused by a number of factors, acting together or alone:

Natural causes are groundwater pressure acting to destabilise the slope; loss or absence of vertical vegetative structure, soil nutrients, and soil structure; erosion of the toe of a slope by rivers or ocean waves ; weakening of a slope through saturation by snowmelt, glaciers melting, or heavy rains; earthquakes adding loads to barely-stable slopes ; earthquake-caused liquefaction destabilising slopes; volcanic eruptions.

Human causes are vibrations from machinery or traffic ; blasting ; earthwork which alters the shape of a slope, or which imposes new loads on an existing slope; in shallow soils, the removal of deep-rooted vegetation that binds colluviums to bedrock ; construction, agricultural, or forestry activities which change the amount of water which infiltrates into the soil.

Afsana Akter Shilpy

MBSTU Tangail

Global warming should stop

Global warming means the increasing of global average temperature of the earth. The average temperature of the earth is about 15-22 oC. But in recent times, the average temperature is increasing due to various reasons which may includes- Green house effects, extensive deforestation, burning of fossil fuels, changes in climatic pattern and atmospheric changes etc.

Mainly human activities are responsible for causing global warming. The activities that are responsible for global warming includes- burning of fossil fuels which contain different gases that are acting in green house effects, cutting or clearing of forest areas that have significant role in the regulation of global temperature and thus the average temperature is increasing.

The effects of global warming will be very dangerous to all living organisms.

The effects of global warming are- melting of ice and glaciers, sea level rising, ecological balance disruption, affecting world food and agricultural production, decreasing of biological productivity, increasing of breeding of pests and diseases, severe and intensive tropical storm etc. Many scientists assumed that if we cannot stop global warming, we have to face many problems which may lead the extinction of different flora and fauna. Human being will also suffer from many problems.

So, we must stop global warming by all means for the survival of human being as well as for the other living beings in the planet earth. The steps and programmes that we must be taken immediately are- conservation of forests, extensive afforestation, encouraging community forestry, reduction in the burning of fossil fuels, Development of environmentally compatible technologies, effective check on the growth of population and imparting of formal and non-formal environmental education.

Thus, we can ensure a better planet and environment for the present generation as well as for the future offspring.

Sharifa Yasmin Shawn

MBSTU, Tangail.

River pollution threat to fresh water

Rivers, the most desirable and essential natural resources of Bangladesh, are major sources of water in various aspects. Approximately 230 rivers are are spreaded over Bangladesh as like as web and networking to one another. Most of the rivers becoming polluted and others are dried and silted. Rivers are now in vulnerable condition. River pollution is the most devastative phenomena that mean any constitutional alteration of rivers water, degradation of water quality. Its generally alteration of physical and chemical parameters such as odor, taste, colour, turbidity, Total hardness, arsenic, chlorides BOD, COD, E. coli, of waters is known as water pollution. Rivers are the most common and important sources of water supply in many cities of our country and are the major survival media for aquatic biodiversity (plants, fishes, and other organism). unfortunately, the water quality are badly altered because of oral disposal of municipal wastes, liquid or semi-liquid lechate from different industries like textile mills, pulp and paper industries, leather tanning, fertiliser and chemical , detergent industry and also dairy industry . Besides that unplanned habitation of slums, over population, rapid increases urbanisation and industrialisation etc. So huge amount of pollutants made the river as a waste sewer, not a container of natural water. As a result of unwanted human activities and industrial discharges, natural water of river reduces capacity of being survival media for aquatic lives, damaging of ecosystem and imbalanced water quality, poisoned water in drinking purpose on water supply. Buriganga, Shitalakha is the remarkable example of it. So, these are. lacking of drinking water. For this aspect DWASA decided to collect water from alternate river. It is not a proper and long live solution for drinking water supply. We should have to protect our river, conserve our water source, safe our aquatic biodiversity for us and future generation. Every relevant organisation and government should have taken protective measure including mass participation to ensure pure and natural simplicity of river water. Every industry, mill, factory and relevant authority should take EEC (Environmental Clearance Certificate), ETP (Effluent Treatment Plant), and EIA (Environmental Impact Assessment). Everybody should remember that pure water is life; life is more valuable than one's commercial sentiment.

Sharifa Yasmin

MBSTU, Tangail