. . Sources of Water Pollution Even though water bodies or sources can be polluted by natural causes, water pollution is usually caused by human activities. There are three main types of sources: point sources, non-point sources, leaks and spills.
Point sources: Discharge of pollutants at specific locations through pipelines or sewers into the water body. Factory effluents, sewage, underground mines, oil wells, oil tankers and agriculture are common point sources (Fig. . a) .
Non-point sources: Sources that cannot be traced to a single site of discharge like acid rain, dumping of the plastics in water bodies, agriculture chemical run off are common examples (Fig. . b) . • Increase green cover alongside roads (planting avenue trees) • Promoting Swachh Bharat Abhiyan • Enactment and Enforcement of stricter environmental laws • Maintenance of air standards by proper enforcement and monitoring • Reducing carbon emissions • Encourage use of renewable energy • Limiting the sale of firecrackers and developing eco-friendly crackers • Make Environmental Impact Assessment mandatory Air Quality Index (AQI) is a number used by government agencies to communicate to the public how polluted the air is at a given time.
Air Quality Index AQI Air Pollution Level Colour - Good - Moderate - Unhealthy for Sensitive Groups - Unhealthy - Very Unhealthy + Hazardous Average human consumption of Oxygen per day = L Cost of . L Oxygen cylinder = ₹ Cost of L of oxygen from tree = ₹ , , ----------------------------------------- Oxygen production by one healthy tree per year = , , L Cost of . L oxygen cylinder = ₹ Cost of , , L of oxygen from one tree /year = ₹ , , , XII Std Biology-Zoology Chapter- XII Std Biology-Zoology Chapter- Environmental Issues containing waste water, sometimes in toxic concentrations. These discharges can affect temperatures of the water bodies as well as dissolved oxygen level.
. Agricultural wastes include fertiliser and pesticide runoff from agricultural fields, food processing waste, tree and saw dust from logging operations and bacteria from sewage or livestock operations. Water pollutants reach water bodies like rivers, streams and the marine system by precipitation, run-off and the groundwater by seepage or percolation.