CSS Environmental Science Paper 2019

Table of Contents

ENVIRONMENTAL SCIENCES

No. 2. How is hazardous waste classified? What are the various options for handling hazardous waste? (20)

No. 3. What are the various mechanisms involved in atmospheric SO2 removal? (20)

No. 4. Eutrophication is a phenomenon caused by the abnormal growth of algae in a water body. What are the reasons for algal bloom and how can this phenomenon be controlled? (20)

No. 5. Describe and differentiate between stated and revealed preferences methods used for valuing the environmental resources. (20)

No. 6. What is the importance of public participation in an Environmental Impact Assessment (EIA) process? What is the difference between EIA and Strategic Environmental Assessment (SEA)? (20)

No. 7. Pakistan is located in a semi-arid region of the world, hence is more prone to climate change effects. Explain what adaptation measures will be feasible in the situations of worst climate change in regions like Pakistan. (20)

No. 8. What are the five major air pollutants coming out of fire burning process? Smog formation occurs due to certain air pollutants. What means and ways can be used for its control? (20)

Summaries of Questions:

No. 2. How is hazardous waste classified? What are the various options for handling hazardous waste?

Hazardous waste is classified based on its characteristics: ignitability, corrosivity, reactivity, and toxicity. These wastes can be further categorized into types such as chemical, biological, and radioactive wastes. Handling options include source reduction, recycling, treatment (such as neutralization, incineration, or chemical treatment), and disposal through landfilling or underground injection. The proper handling depends on the nature of the waste and the environmental risks it poses.

No. 3. What are the various mechanisms involved in atmospheric SO2 removal?

Sulfur dioxide (SO2) removal from the atmosphere is accomplished through several mechanisms, including absorption, adsorption, and catalytic reduction. Absorption typically involves scrubbers using alkaline solutions (like lime or sodium hydroxide) to neutralize SO2. Adsorption uses materials like activated carbon to capture the gas. Catalytic reduction involves chemical reactions, often in industrial settings, to convert SO2 into less harmful substances, such as sulfuric acid or elemental sulfur.

No. 4. Eutrophication is a phenomenon caused by the abnormal growth of algae in a water body. What are the reasons for algal bloom and how can this phenomenon be controlled?

Algal blooms occur when excessive nutrients, mainly nitrogen and phosphorus, enter water bodies, often from agricultural runoff, wastewater, and industrial discharge. These nutrients promote rapid algae growth, depleting oxygen and harming aquatic life. Controlling eutrophication can involve reducing nutrient inputs through better agricultural practices, wastewater treatment, using biofilters, and restoring wetlands to absorb nutrients before they reach water bodies.

No. 5. Describe and differentiate between stated and revealed preferences methods used for valuing environmental resources.

Stated preference methods involve directly asking individuals about their willingness to pay for environmental goods or services, typically through surveys (e.g., contingent valuation). Revealed preference methods, on the other hand, infer value from individuals’ actual behavior, such as travel costs to visit a park (e.g., travel cost method) or market prices for goods linked to environmental services (e.g., hedonic pricing). Stated preferences are hypothetical, while revealed preferences are based on real-world data.

No. 6. What is the importance of public participation in an Environmental Impact Assessment (EIA) process? What is the difference between EIA and Strategic Environmental Assessment (SEA)?

Public participation in an EIA process ensures that local communities, stakeholders, and experts have a say in environmental decision-making, leading to better outcomes and transparency. EIA focuses on assessing the impact of specific projects, while SEA is broader and evaluates the environmental effects of policies, plans, or programs, allowing for early identification of potential impacts and enabling more sustainable long-term planning.

No. 7. Pakistan is located in a semi-arid region of the world, hence is more prone to climate change effects. Explain what adaptation measures will be feasible in the situations of worst climate change in regions like Pakistan.

Adaptation measures in Pakistan may include improving water management through efficient irrigation systems, constructing water reservoirs, and enhancing drought-resistant agricultural practices. Reforestation, flood control infrastructure, and disaster risk management strategies (such as early warning systems) can mitigate climate impacts. Strengthening healthcare systems to deal with climate-related diseases and promoting climate-resilient infrastructure are also essential in minimizing the adverse effects of climate change.

No. 8. What are the five major air pollutants coming out of fire burning process? Smog formation occurs due to certain air pollutants. What means and ways can be used for its control?

The five major air pollutants from fire burning are carbon monoxide (CO), carbon dioxide (CO2), particulate matter (PM), nitrogen oxides (NOx), and sulfur dioxide (SO2). Smog formation results from the interaction of these pollutants, especially NOx and VOCs, with sunlight. To control smog, measures such as promoting clean energy sources, using low-emission fuels, implementing stricter vehicle emissions standards, and enhancing industrial regulations can be adopted. Additionally, public awareness and urban planning to reduce open burning can help minimize smog.