Unit-iv unit-iv environmental Hygiene

Physico-chemical characteristics

Two major groups
Particulate pollutants:

• Dust particles,
• Mist,
• Fly ash
• Droplets,
• Fog,
• Smoke,
• Fumes & soot

Gaseous pollutants:

• Oxides of Sulphur & Nitrogen,
• Carbon monoxide
• Hydrogen sulphide
• Vapours of gasoline & trichlorethylene

Toxic to animals & man
Organic decomposition of waste
Methanogenesis: methane (gobar gas) & Carbon dioxide
Carbon dioxide: respiration

Effects of pollutants

• Direct bearing on the health of animals & man, & planetary bio-diversity
• Toxic gases & substances present in the atmosphere cause:
• Retardation of growth,
• Promote ageing,
• Bleaching of leaves
• Necrosis in plants
• The degree of damage:
• Dose of pollutant &
• Duration of exposure
• Loss of valuable plant materials especially around industrial areas
• damage to physical structures, monuments and buildings.

Ex: damage of Taj Mahal

Effects of pollutants

• Nonirritant pollutants (carbon monoxide) may not always be associated with overt clinical manifestations.
• Studies have shown that zinc & lead pollution of air: marked fatalities in cattle & horses in Germany
• Arsenic: Bloody diarrhea, vomiting & excessive thirst in animals
• Smog pollution: Variety of respiratory problems in animals
• Lead pollution: Teeth grinding & laryngeal paralysis (roaring sound) in cattle
• Fluorosis: Cattle & sheep reared near brick kilns and iron/steel aluminum plants & ceramic factories
• In soil (0.1-1.0 g/kg)
• Water (in some areas in India, 25 mg/litre)
• Air (Volcanic eruptions & in the dust particles originating from soil)
• Conditions: lameness, mottled teeth, fragile bones & loss of milk yield in dairy cattle
• Metallic pollutants: Induce anaemia & emaciation in animals