08-16-2017, 09:44 PM
[attachment=3871]
ENVIRONMENTAL POLLUTION
BY
R.M.BANIK
What is Pollution
What is Pollution
Pollution is the action of environmental contamination with man-made waste. This includes mainly land, water, and air.
Pollution is the introduction of contaminants into an environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms
Forms of pollution
Air Pollution
Water Pollution
Soil pollution
Radioactive pollution
Noise pollution
Light pollution (includes light trespass, over illumination and astronomical interference.
Visual pollution
Thermal pollution
Land Pollution
Land pollution the action of environmental contamination with man-made waste on land.
Americans generate five pounds of solid waste every day, furthermore creating one ton of solid waste each year.
In an average day in the United States, people throw out 200,000 tons of edible food .
The main human contributor to pollution are landfills. Approximately half of our trash is disposed in landfills.
Only 2% of our waste is actually recycled.
Air Pollution
These are following gases that are known as the "Big Six" air pollutants":
Carbon Dioxide
Carbon Monoxide
Sulfur Oxide
Nitrogen Oxide
Hydrocarbons (Benzene, Terpene, etc.) Particulates
Water Pollutants
The source of this waste could be raw sewage, chemicals, trash, or fertilizer.
They can be categorized as
1. Inorganic pollutants
2. Organic pollutants
3. Sediments
4. Heat
5. Radioactive pollutant
6. Water pollution by heavy metals
Inorganic pollutants
This group consists of inorganic salts, mineral acids, finely divided metals or metal compounds, complexes of metals with organics in natural water, organometallic compounds, trace elements and acid mine drainage. Several trace elements (few ppm) are found in polluted water. The most dangerous among them are heavy metals e.g. As (V), Cd, Cu, Hg, Cr etc and metalloids As, Se and Sb.
Organic pollutants
This group includes, oxygen demanding wastes, plant nutrients, sewage, synthetic organic compounds, pesticides, detergents and oils. Decrease in dissolve oxygen (DO) value is an index of pollution mainly due to organic matter e.g. sewage, industrial wastes from food processing plants, paper mills and tanneries, meat-packing plants, runoff from agricultural lands etc.
Polluted water causes immense harm to public health. The water borne diseases are typhoid, and paratyphoid fevers, dysentery and cholera, polio and infectious hepatitis. Production and disposal of pesticides, petrochemicals, detergents etc. aggravates the pollution problem.
Sediments
Sediments are important repositories for trace metals. They also contain high level of organic matter in sediments. Detrimental increase in sediments in water is due to natural process of soil erosion. It represents the most extensive pollutants of surface waters.
Heat
Rise in temperature decrease dissolve oxygen in water, which affects fish and other aquatic life adversely. The industrial, municipal and wastes from agricultural practices are major contributor.
Radioactive pollutant
Radioactive pollution includes liquid and gaseous wastes from fuel, elements, low level radioactive wastes, various components of radioactive fall out, fission products, radio nucleotides etc.
Water pollution by Heavy Metals
Heavy metals are widely employed in textile, tanneries and metal plating industries, among others. Use of these metals generates liquids waste, which are usually continuously disposed of without any treatment.
Fuel and power industries generate 2.4 million tons of As, Cd, Cr, Cu, Hg, Ni, As (V), Se, V and Zn annually. The metal industries adds 0.39 million tons/year of the above metals to the environment. Apart from this agriculture contributes 1.4 million tons/year, manufacturing generates 0.24 million tons/year and waste disposal adds 0.72 million tons/year
Sources of heavy metals in waste water
Toxic effect of heavy metals
Antimony--Increase in blood cholesterol; decrease in blood sugar
Arsenic--Skin damage or problems with circulatory systems, and may have increased risk of getting cancer
Asbestos--Increased risk of developing benign intestinal polyps
Cadmium--Kidney damage
Copper--Short term exposure: Gastrointestinal distress
Long term exposure: Liver or kidney damage
Lead--Infants and children: Delays in physical or mental development Adults: Kidney problems; high blood pressure
Selenium--Hair or fingernail loss; numbness in fingers or toes;
Drinking water quality standards
Parameter USEPA (2000) WHO (1993) Bangladesh (GoB, 1997)
(mg/L) (mg/L) (mg/L)
pH 6.5-8.5 7-8.5 6.5-8.5
Iron 0.3 0.3 0.3-1.0
Chloride 250 250 150-600
Hardness as (CaCO3) 100-500 - 200-500
Sulfate 250 250 400
Manganese 0.1 0.05 0.1
Fluoride 2.0 1.5 1.0
Nitrate 10 50 10
Arsenic 0.01 0.01 0.05
TDS 400-500 1000 1000
Drinking water quality standards
Parameter USEPA (2000) WHO (1993) Bangladesh (GoB, 1997)
(mg/L) (mg/L) (mg/L)
pH 6.5-8.5 7-8.5 6.5-8.5
Iron 0.3 0.3 0.3-1.0
Chloride 250 250 150-600
Hardness as (CaCO3) 100-500 - 200-500
Sulfate 250 250 400
Manganese 0.1 0.05 0.1
Fluoride 2.0 1.5 1.0
Nitrate 10 50 10
Arsenic 0.01 0.01 0.05
TDS 400-500 1000 1000
Ganga Pollution: Total coliform count at different points along the Ganga