FOUNDATIONS of Medicine: Environment

((foundations of medicine)) 

environment:

eco = place of living

examples: forest, ocean, small lake, etc.

ecosystem constitutes from abiota and biota components.

food chain:  system of transferring energy from one level to another.

any ecosystem contains three biotic structures:

1.                                      producers: autotrophs which produce energy by photosynthesis process

plankton + plants

2.                                      consumers: 

a-                                                                                                                      primary consumers: animals feed on plants which vary from mite to elephant.

b-                                                                                                                      secondary consumers: sheep eat plant. wolves eat sheep.

secondary consumers are called carnivores or predators.

those who eat both plants and animals are called omnivores.

man is omnivorous (primary, secondary, and tertiary consumer)

              3.              decomposers: fungus and bacteria eat fecal wastes by rotting of organic materials. this type of feeding is called absorptive nutrition.

environmental balance: is a sort of harmony between different components of environmental system.

biodegradable material: any material that can be degraded by microbes.

non-biodegradable material: any material that can not be degraded by microbes.

bioaccumulative material: is the material that can accumulate the body, e.g. ddt^*, lead, mercury, etc.

biomagnification: increase the concentration of a given substance as we go up in food chain.

biodiversity: in any system we have different species of organisms.

simplification of ecosystem: changing complex system with good biodiversity to a simple system with very few species.

atmosphere: 

¨                                      troposphere                        14km

¨                                      stratosphere                        90km

¨                                      mesosphere                          350km

¨                                      thermosphere

community air pollution: presence of unwanted or undesirable materials in the air. air pollution also affect animals, plants, and well-fare.

air pollutants: those impurities which present in sufficient concentration enough to produce adverse health effects.

e.g.: so_x, no_x, total suspended particles, o₃, lead.

threshold limit value (tlv): is the concentration of air pollutant below which there is no harmful effect on human beings.

t.l.v:

                                                                                          §                so2        = 0.03 ppm

                                                                                          §                co            = 9  ppm

                                                                                          §                no          = 0.05 ppm

                                                                                          §                lead      = 1.5  ?gm / m³

                                                                                          §                ozone  = 0.12 ppm

main climatic factors which affect the concentration of air pollutants:

¨                                      humidity.

¨                                      speed and direction of the wind.

¨                                      geography of the area.

sources of air pollution:

1.                                      combustion: smoke contains carbon sulfur, aerosol of tar dropinglets, and polycyclic  hydrocarbons.

2.                                      photochemical pollution

3.                                      smog: smoke polluted fog.

4.                                      industrial sources: chemical industries.