Nomenclature of environmental chemistry

 2) Explain the Nomenclature of environmental chemistry?

A. Pollution

The living organisms, which are exposed to harmful substances that affect

directly or indirectly to alter the physical, chemical and biological properties of

the atmosphere, including air, water, land, humans, animals and plants. Such a

phenomenon is known as pollution.

Soil and Water bodies like seas, lakes and rivers are polluted by chemical

and other factory effluents and the air pollution is caused by gases of

automobile exhausts, industries, and thermal power plants etc.

Main reasons for pollution: (1) over human Population (2) Rapid

industrialization (3) Mining activities & technology development..Etc.

B. Pollutant

\Any form of a substance which causes pollution is called a pollutant. or a

substance which is already present in nature and the concentration of the

substance increases in the environment due to natural or human activity and

adversely affects the life on earth and ecosystem is called a pollutant. Some of

the main pollutants that affect air, water, and land are

Gases like halogens, Carbon monoxide, Nitrogen Oxides, and Sulphur

Oxides.

c) Acid droplets are of Nitric Acid (HNO3), Sulphuric Acid (H2SO4), and

others.

d) Metals are of Chromium, Cadmium, Lead, Iron, Zinc, Nickel, Tin, and

Mercury.

e) Agrochemicals like biocides (such as insecticides, herbicides, fungicides,

nematicides, bactericides, weedicides, etc.) including fertilisers.

f) Organic oxidant Benzene, Ether, Acetic Acid, and Benzpyrene ..etc.

C. Contaminant

A substance which is not present and enters newly into environment and

adversely effects the environment is called contaminant.

Example: Chemical contaminants are Methyl Isocyanide

(MIC), DDT, BHC, salts, pesticides, metals etc. Radioactive

contaminants include Caesium, Plutonium and Uranium etc.

D. Receptor

The medium which is affected by the pollutant is called receptor. Humans,

trees, animals and fish are the examples for receptors.

Ex: Eyes become red when they are exposed to smoke of automobile exhaust,

here Eyes are the receptors

E. Sink

A chemical medium or species that retains and interacts with the pollutant is

called Sink.

Example: 1. Sea water & plants/trees are big sinks of CO2.

2. The Tajmahal, one of the 7 wonders of the world, is mostly affected by acid

rain. Here Calcium Carbonate is a sink for Acid Rain (Sulphuric Acid).

CaCO3 + H2SO4 -----> CaSO4 + CO2 + H2O

[Marble]

F. Pollution pathway

The process by which the pollution is transferred from the point of origin to

the environmental components is called the pollution path.

Example: Tetraethyl lead [TEL] in petrol enters into soil in the form of Lead

Chloride and into atmosphere in the form of Lead Bromide and finally comes

into food as Contaminants.

G. Threshold Limit Value (TLV)

The amount of a harmful contaminant that can be present in air without

causing harm to a healthy individual working there for 8 hours a day. Every

pollutant has a different TLV value. Example: TLV of Be is 0.002 mg/m3 &

Zinc is 1.0 mg/m3.

H. Dissolved Oxygen (DO)

The amount of Oxygen dissolved in water. It is vital for aquatic life.

 Optimum level of fine quality water range from 4 – 8 mg per litre.

Water with levels < 4 mg per litre is considered polluted and not suitable for

human or animal consumption.

I. Biological Oxygen Demand (BOD):

"The amount of oxygen used by bacteria or microorganism present in water

under aerobic conditions for 5 days at 20oC is called milligrams of Biological

Oxygen Demand (BOD)..

Generally it can be represented in ppm or mg/litre.