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ENVIRONMENTAL DEGRADATION – 09

MAJOR TYPES OF WATER POLLUTION

Thermal Pollution 

Thermal pollution is increase in temperature of water body due to discharge of heated water or wastewater into the watercourse. It denotes the impairment of quality and deterioration of aquatic and terrestrial environment by various industrial plants like Thermal, Atomic, Nuclear, Coal-Fired Plants, Oil Field Generators, Factories, And Mills.

Sources of Thermal Pollution

  • Nuclear Power Plant
  • Coal-fired power Plant
  • Industrial Effluents
  • Domestic Sewage
  • Hydro-electric power
  • Thermal Power Plant

The discharged effluents of these sources have a higher temperature than the intake water that reduces the concentration of oxygen from the water which causes the deleterious effects on the marine ecosystem.

Effects of the Thermal Pollution

Reduction in dissolved Oxygen

The pollutant from various industrial plants are heated decreases the concentration of oxygen with an increase in the temperature of water.

Change in water properties

The decrease in density, viscosity and solubility of gases in water increases the setting speed of suspended particles which seriously affect the food supplies of aquatic organism.

INCREASE IN TOXICITY

The concentrated pollutant causes the rise in the temperature of water which increases the toxicity of the poison present in water. The toxicity in water will increase the death rate in marine life

DISRUPTION OF BIOLOGICAL ACTIVITIES

Temperature changes disrupt the entire marine ecosystem because changes in temperature causes change in physiology, metabolism and biological process like respiration rate, digestion, excretion and development of an aquatic organism.

DAMAGE OF BIOTIC ORGANISM – Aquatic organisms like juvenile fish, plankton, fish, eggs, larva, algae and protozoa are extremely sensitive to abrupt temperature changes. They are habitual of warmer water may suddenly face increase or decrease in temperature of water bodies and thus die because of sudden changes in the temperature of water.

Groundwater Pollution 

Groundwater pollution is often caused by pesticide contamination from the soil, this can infect our drinking water and cause Huge Problems, Spilling Gasoline, Oil, Paint Thinners, etc. onto the ground can contaminate groundwater. Groundwater pollution is a low-risk ecological problem but high-risk health problem. Contaminated water in the aquifer will slowly flow, creating a plume of contaminated water. Contaminants in groundwater are not diluted or dispersed because this water moves usually less than 0.3 meter per day, polluted groundwater has very slow cleansing rate due to the low dissolved oxygen and low bacterial count. It can take hundreds of years to cleanse degradable wastes and non-degradable wastes are there permanently Factors affecting ground water pollution- The extent of ground water pollution depends on the following factors:

  • Rainfall pattern
  • Depth of water table.
  • Distance from the source of contamination 
  • Soil properties such as texture, structure and filtration rate.

Sources of groundwater contamination 

  1. Natural: Groundwater naturally contains impurities due to nature of geological formations. Natural arsenic pollution occurs because aquifer sediments contain organic matter that generates anaerobic conditions in the aquifer, thus releasing arsenic. Occurrence of fluoride is close related to the abundance and solubility of fluoride-containing minerals such as fluorite
  2. Agriculture: Intensive use of chemical fertilizers in farms result in leaching of the residual nitrate causing high nitrate concentrations in groundwater. Excessive and improper irrigation practices
  3. Industrial Waste: Industrial effluents and municipal waste seeps through the soil and pollutes the groundwater. Toxic industrial waste releases traces of heavy metals such as Lead, Cadmium, Zinc And Mercury. Brine Disposal From The Petroleum Industry, Mine Wastes, deep-well disposal of liquid wastes leaky underground gas tanks, Sludge disposal
  4. Municipal waste: Pollution by landfills, septic tanks. Indiscriminate disposal of human and animal waste on land; faulty onsite sanitation structures leaky sewer lines
  5. Indiscriminate extraction of groundwater – Indiscriminate extraction of groundwater for irrigation purposes has led to inland salinity problem in parts of Punjab, Haryana Excessive withdrawal of groundwater from coastal aquifers has led to induced pollution in the form of seawater intrusion. For example: In Kachchh, Gujarat. Uranium contamination has aggravated by groundwater-table decline. Decline in groundwater table induces oxidation conditions. As a result, uranium enrichment in shallow groundwater is enhanced.
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