Contrast point source pollution and non-point source pollution

Point sources. A point source is a single, identifiable source of pollution, such as a pipe or a drain. Industrial wastes are commonly discharged to rivers and the sea in this way.

Point source pollutant: My school is situated near a river. A wastewater treatment plant is a few miles away. The plant uses certain chemicals to treat wastewater, but releases effluents into the river. Although the plant regulates the released effluents, the treatment system gets overloaded during heavy rainfall. As a result, untreated chemicals and wastes enter the river. The plant thus becomes a point source pollutant for the river. The wastes and chemicals entering the river adversely affect growth of plants and fishes in the water body.  

Non -point source pollutant: I live in a residential area that has a groundwater reservoir. Last month, the authorities in my area complained that the water in the reservoir was getting polluted. On investigating, they found that rainwater picks up debris and pollutants from roads and sidewalks as it flows on its path. The polluted water enters waterways that are connected to the groundwater reservoir. The debris and pollutants are many in number, and it was difficult to trace exactly where the rainwater picked them up. However, these pollutants affect large areas because the water from the groundwater reservoir reaches many homes. Therefore, the debris and pollutants are non-point source pollutants.

Explanation: i got it from the teacher

b. read the phase at the intersection of any given temperature and pressure.