RE: ENVIRONMENTAL POLLUTION
||ENVIRONMENT & POLLUTION
ENVIRONMENT & POLLUTION.doc (Size: 8.3 MB / Downloads: 844)
Presence of matter (gas, liquid, solid) or energy (heat, noise, radiation) whose nature, location, or quantity directly or indirectly alters characteristics or processes of any part of the environment, and causes (or has the potential to cause) damage to the condition, health, safety, or welfare of animals, humans, plants, or property.
There are two types of the cause of pollution, natural and man-made. Natural pollution occurs naturally and won't cause excessive harm to our lives due to its regeneration ability. While the man-made pollution is caused by human activities, and hard to get rid of. The backbones of man-made pollution are human population and technology. Naturally human needs contact to the environment, we get resources from nature. This is for the sake of living. By the increase of human population, the contact is getting more intensive, because needs are increasing. And by the findings and development of new technologies, human can apply them to get the resources. And it's common that new technologies would bring their respective side effects besides their advantages.
Soil and Water Pollution
• Causes cancers including leukaemia
• Lead in soil is especially hazardous for young children causing developmental damage to the brain
• Mercury can increase the risk of kidney damage; cyclodienes can lead to liver toxicity
• Causes neuromuscular blockage as well as depression of the central nervous system
• Also causes headaches, nausea, fatigue, eye irritation and skin rash
They combine with Mg2+ of chlorophyll and hence inhibit photosynthesis, cause leaf abscission and of fruit. Maize is the sensitive indicator of fluoride pollution. In human beings mottling of teeth (fluorosis) is an indication of fluorination. Bone fluorosis results in weak bones, boat shaped posture and knocking of knee.
Nitrogen fertilization (nitrates + nitrite)
Toxic concentration in leaves and fruits enters into food chain. In alimentary canal, activity of bacteria changes nitrates into nitries. The latter entres blood and combine with haemoglobin to form met6-haemoglobin so oxygen transport is reduced. It give rise to disease called methanaemoglobinaemia. In infants it cause cyanosis (blue babies due to bluish tint of skin). Nitrate poisoning is fatal unless methylene blue is injected (in infants) while in adult it produces breathlessness.
They are usually metabolic inhibitors which stop photosynthesis and other metabolic activities killing the plant. Some causes death due to proliferation of phloem cells to block transport of organic food.
Water pollution is contamination of water by foreign matter that deteriorates the quality of the water. Water pollution covers pollutions in liquid forms like ocean pollution and river pollution. As the term applies, liquid pollution occurs in the oceans, lakes, streams, rivers, underground water and bays, in short liquid-containing areas. It involves the release of toxic substances, pathogenic germs, substances that require much oxygen to decompose, easy-soluble substances, radioactivity, etc. that becomes deposited upon the bottom and their accumulations will interfere with the condition of aquatic ecosystems. For example, the eutrophication: lack of oxygen in a water body caused by excessive algae growths because of enrichment of pollutants.
Water Cycle and Pollution
Water cycle is, simply saying, the circulation of water in earth. In fact, the water in the earth's biosphere is used and reused again and again. This is called water cycle or continuous movement of water between the earth and the atmosphere. It involves the following mechanisms:
• Evaporation: changing of water from liquid to gas
• Transpiration: Release of water vapor from plant leaves
• Condensation: changing of vapor to liquid (cooled down)
• Precipitation: Water that returns to the earth (water droplets in clouds become large enough and there comes the rain).