This article throws light upon the five major environmental agents which lead to health problems. The environmental agents are: 1. Infectious Organisms 2. Chemicals 3. Radiations 4. Noise 5. Diet.
Environmental Agent # 1. Infectious Organisms:
Disease causing organisms like parasites, worms, microbes, viruses in contaminated water, food and air cause diarrhoea, vomitting, jaundice, dysentery, typhoid, pneumonia, filariasis etc.
Environmental Agent # 2. Chemicals:
A large number of hazardous (e.g., explosives, inflammables) and toxic (poisonous) chemicals are introduced into the environment by anthropogenic activities. Many chemicals like polychlorinated biphenyls, nitrosamines, vinyl chloride cause cancer (carcinogenic) while others affect DNA in cells (mutagenic) or cause abnormalities during embryonic growth (teratogenic) and affect nervous system (neurotoxins) and reproductive system. Various gases and particulates laden with chemicals spewed into the environment from industries and cause air pollution and severely affect human health.
Many chemical agents, metals, fluoride, nitrate, phenols, pesticides, nitrosamines present in water adversely affect human health. Several chlorinated pesticides (DDT) bioaccumulate in food chain and show deleterious effects at the top of the food chain. Metals can contaminate food while cooking in utensils made of alloys like steel.
[For details of effects—also refer to air, water, pesticide pollutants in Unit 5].
Environmental Agent # 3. Radiations:
Anthropogenic sources add large doses of radiations to the existing natural radioactive pollution to which our bodies have got accustomed with several ill effects. Cosmic rays, solar rays, ultraviolet rays cause harmful effects on human health.
[Refer to Unit 5 for detailed effects of radiation on man].
Environmental Agent # 4. Noise:
Noise level beyond the permissible limit causes physiological and psychological changes beside hearing loss.
Environmental Agent # 5. Diet:
Diet plays an important role in maintaining health. Malnutrition makes man prone to other diseases. Food contamination can cause various ill effects. There had been cases of dropsy in India due to contaminant of mustard oil with poisonous seeds of Argemone mexicana. Likewise adulterated pulses, condiments, oils etc. sold in the market to earn profit affect seriously human health.