Water Quality and Pollution

Yes, flowing water dissolves many soluble minerals present in the soil. These minerals are generally soluble in water.

Algae have green colour as they contain chlorophyll.

Chlorella is a genus of single cell green algae, which belongs to the phylum Chlorophyta. Our body is contaminated with heavy metals from dental fillings, after receiving a vaccine by the use of certain types of cookware or eaten fish.

The coliform bacteria, if present in water, contaminates water and the water is not safe to drink.

Thermal pollution makes water gain or lose temperature, which affects the aquatic life in a bad way. Thermal pollution is the result of release of very hot water or very cool water from industries into water bodies.

'Eutrophication' is a process in which the water body becomes enriched with nutrients. This can be a problem in marine habitats as it can cause algal blooms. The algae may use up all the oxygen in the water leaving none for other marine life. This results in the death of many aquatic organisms such as fishes, which need the oxygen in the water to live.

'Sewage' is the term used for waste water that contains human waste, faeces, urine, laundry waste, etc.

Oligotropic lakes have low nutritional content and productivity due to higher pollution content in water, thereby decreasing its productivity.

Biochemical oxygen demand is more in polluted water and less in potable water. A low BOD is an indicator of good quality water, while a high BOD indicates polluted water. There are generally no standards for an absolute BOD value of drinking water. However, a sample with a BOD between 1 and 2 mg/L indicates a very clean water.

Total coliforms are a group of bacteria commonly found in the environment, for example in soil or vegetation as well as the intestines of mammals, including humans. Total coliform bacteria are not likely to cause illness, but their presence indicates that your water supply may be vulnerable to contamination by more harmful microorganisms present through animal or human waste.

Biochemical oxygen demand is more in polluted water and less in potable water. A low BOD is an indicator of good quality water, while a high BOD indicates polluted water. There are generally no standards for an absolute BOD value of drinking water. However, a sample with a BOD between 1 and 2 mg/L indicates a very clean water.

Oil spills and industrial effluents affect the water bodies by increasing the temperature of water bodies.

The chemicals released in water during industrial processes include arsenic, lead and fluorides. They contaminate the water and cause toxicity.

Statement 1 is incorrect. BOD - Standard method for indirect measurement of the amount of organic pollution in a sample of water. Thus, high BOD means high pollution. Statement 2 is also incorrect.             Eutrophication - The process by which a water body acquires high concentration of nutrients, especially phosphates and nitrates. It promotes growth of algae and the decomposing organisms deplete the available oxygen in water. Thus, there is a decrease in concentration of oxygen and increase in concentration of carbon dioxide.

 Aquatic animals use dissolved oxygen in water for respiration.