Environment: Our surroundings are called environment.
- The environment includes our physical surroundings like air (or atmosphere), water bodies, soil (land) and all the organisms such as plants, animals, human beings and micro-organisms like bacteria and fungi (called decomposers).
- Living organisms live in different surroundings. Some plants and animals completely live in water and some others live on land.
- Human beings also lead life in different surroundings. Some live in cities, some in towns and some in villages.
- Plants, animals, human beings survive with the interaction between them and the non-living things like air, water and land.
- Human beings depend on the resources of nature. These resources include soil, water, coal, electricity, oil, gas, etc.
Environmental science can be defined as the study of organisms in relation to their surrounding.
Pollution: Any undesirable change in the physical, chemical or biological characteristics of air, land and water that affect human life adversely is called pollution.
Pollutant: A substance released into the environment due to natural or human activity which adversely affects the environment is called pollutant. e-g. Sulphur-di-oxiode, carbon-monoxide, lead, mercury, etc.
CLASSIFICATION OF WASTES
All the waste materials produced by the various activities of man and animals are poisonous to some extent and can be divided into two main groups :
1. Biodegradable wastes
2. Non-bio-degradable wastes
- Substances that are broken down by biological processes of biological or microbial action are called biodegradable waste. e.g. Wood, paper and leather.
- Biodegradable wastes usually do not pollute the environment.
- Substances that are not broken down by biological or microbial action are called non-bio- degradable wastes. e.g. Plastic substances and mineral wastes.
- Non-biodegradable wastes are the major pollutants of the environment.