Environmental Science MCQ – Asked in Previous Years, WBCS Mains

Answer – A. Air
Explanation-
▪ Photochemical smog is a type of air pollution that is formed by the reaction of sunlight with pollutants such as nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the presence of oxygen. It is primarily associated with urban areas and is characterized by a brownish haze and the presence of harmful pollutants like ozone. Photochemical smog can have detrimental effects on human health and the environment.

Answer – Coliform Bacteria
Explanation-
▪ Coliform bacteria, specifically Escherichia coli (E. coli), are commonly used as microbial indicators of water contamination. These bacteria are found in the intestines of warm-blooded animals, including humans, and their presence in water indicates the potential presence of fecal contamination. Monitoring coliform bacteria levels in water helps assess the safety and quality of drinking water and the potential risks of waterborne diseases.

Answer – B. Bioremediation
Explanation-
▪ Bioremediation is the process by which microorganisms, such as bacteria and fungi, break down or transform pollutants in soil, water, and other environments into less harmful substances.

▪ These microorganisms use the pollutants as a food source or catalyst for metabolic processes, leading to their degradation or conversion into less toxic forms. Bioremediation is an eco-friendly approach to remediate contaminated sites and restore environmental quality.

Answer – B. Rhinoceros Unicornis
Explanation-
▪ Kaziranga National Park, located in the state of Assam, India, is known for its conservation efforts for the Indian one-horned rhinoceros (Rhinoceros unicornis). This species is protected within the park to ensure its survival and prevent it from becoming extinct. Kaziranga National Park is home to a significant population of Indian rhinoceroses and is recognized as a World Heritage Site.

Answer – D. organic pollutants
Explanation-
▪ BOD (Biochemical Oxygen Demand) is a measure of the amount of organic pollutants present in water. It represents the amount of oxygen required by microorganisms to decompose the organic matter in the water through aerobic biological processes. BOD is an important parameter for assessing the level of organic pollution in water bodies, such as rivers and lakes, and it indicates the potential impact on oxygen levels and aquatic life.

Answer – B. Textile
Explanation-
▪ Byssinosis, also known as “brown lung disease,” is an occupational lung disease that affects workers in the textile industry. It is caused by exposure to dust and fibers from raw cotton, flax, and hemp during textile processing. Prolonged inhalation of these particles can lead to respiratory symptoms, including coughing, wheezing, chest tightness, and impaired lung function. Proper ventilation and protective measures are necessary to prevent the occurrence of byssinosis among textile workers.

Answer – A. methane
Explanation-
▪ Methane (CH4) is the most abundant hydrocarbon pollutant in the atmosphere. It is a potent greenhouse gas and contributes to the enhanced greenhouse effect and climate change. Methane is released from various sources, including natural processes, agricultural activities, fossil fuel production, and waste management. Efforts to reduce methane emissions are crucial for mitigating global warming and promoting environmental sustainability.

Answer –D. Fluoride
Explanation-
▪ The Nalgonda method, named after the region in Telangana, India, where it was developed, is a water treatment technique used to remove excessive fluoride from drinking water. It involves adsorption of fluoride ions using a combination of alum (aluminum sulfate) and lime (calcium hydroxide). The Nalgonda method is a low-cost and effective solution to mitigate the adverse health effects of high fluoride levels in drinking water.

Answer – A. Aluminium Sulfate
Explanation-
▪ Aluminium sulfate, also known as alum, is commonly used as a coagulant in water treatment processes for the removal of phosphates. It helps to form larger particles by neutralizing the electric charges on suspended particles, facilitating their precipitation and removal from water. The addition of aluminium sulfate promotes the formation of aluminum phosphate complexes, which can be easily separated from water through sedimentation or filtration.

Answer – A. Biochemical Oxygen Demand
Explanation-
▪ BOD (Biochemical Oxygen Demand) is a measure of the amount of oxygen required by microorganisms to decompose organic matter in water through aerobic biological processes. It quantifies the oxygen-consuming capacity of organic pollutants present in water. BOD is an essential parameter in assessing the organic pollution level and the potential impact on the oxygen levels and aquatic life in water bodies.