Unit 3 - Practice Quiz

Sulphur dioxide (SO₂) and nitrogen oxides (NOx) released from burning fossil fuels react with water in the atmosphere to form sulphuric and nitric acids, which fall to the ground as acid rain.

Biochemical Oxygen Demand (BOD) is a measure of the amount of dissolved oxygen needed by aerobic biological organisms to break down organic material present in a given water sample.

Composting is a natural process where microorganisms break down organic matter like food scraps and yard waste in the presence of oxygen, creating a nutrient-rich soil conditioner.

Decibels (dB) are the standard unit used to measure the intensity or loudness of a sound. Higher decibel levels correspond to louder sounds.

Using public transport, carpooling, walking, or cycling reduces the number of individual vehicles on the road, thereby decreasing the emission of pollutants from vehicle exhausts.

While pesticides and fertilizers are used to increase crop yield, their excessive and improper use can contaminate the soil with harmful chemicals, leading to soil pollution.

Thermal pollution is primarily caused by the discharge of heated water from industrial plants and power stations into a body of water, raising its temperature and harming aquatic life.

Incineration is a waste treatment process that involves the combustion of waste materials at high temperatures, converting them into ash, flue gas, and heat.

Plastic waste, including bottles, bags, and microplastics, is the most common type of debris found in the marine environment, posing a significant threat to marine life.

Nuclear power plants produce radioactive waste during their operation. Improper handling and disposal of this waste is a primary source of nuclear pollution.

Carbon dioxide (CO₂) is a major greenhouse gas. It traps heat in the Earth's atmosphere, and its increased concentration from human activities is the main driver of global warming.

Eutrophication is the process where a body of water becomes overly rich in nutrients, typically from fertilizer runoff, causing dense growth of plant life like algae, which depletes oxygen and harms aquatic animals.

The 3Rs - Reduce, Reuse, and Recycle - form a waste hierarchy. The goal is to first reduce the amount of waste generated, then reuse items, and finally recycle materials.

Excessive artificial light at night can confuse nocturnal animals, affecting their feeding, mating, and migration patterns, which disrupts entire ecosystems.

Biogas is primarily composed of methane (CH₄), which is a flammable gas, and carbon dioxide (CO₂). The methane is what allows biogas to be used as a fuel source.

Industrial waste is generated by manufacturing or industrial processes. Fly ash, a byproduct of burning coal in power plants, is a classic example of industrial waste.

Biodegradable waste, such as food scraps, paper, and yard trimmings, is organic material that can be decomposed by bacteria and other living organisms.

Litmus paper provides a basic indication of whether a substance is acidic or alkaline, while a pH meter gives a precise numerical measurement. Both are used to test the pH level, an important indicator of pollution.

Pyrolysis is the thermal decomposition of materials at elevated temperatures in an inert atmosphere, meaning in the absence of oxygen. Unlike incineration (burning), it doesn't involve combustion.

A catalytic converter is a device installed in the exhaust system of vehicles that converts toxic pollutants like carbon monoxide and nitrogen oxides into less harmful substances like carbon dioxide and water vapor.

Ground-level ozone is not directly emitted but is a secondary pollutant formed when primary pollutants like nitrogen oxides () and volatile organic compounds (VOCs) react in the presence of sunlight. This reaction creates photochemical smog, of which ozone is a key component.

Eutrophication begins with excess nutrients (like nitrates and phosphates from fertilizers) entering the water. This fuels a massive algal bloom. When the algae die, bacteria decompose them, consuming large amounts of dissolved oxygen in the process and creating a hypoxic (low-oxygen) or anoxic (no-oxygen) 'dead zone' that cannot support fish life.

The key difference is the presence of oxygen. Incineration is combustion in the presence of oxygen, producing ash, heat, and flue gas. Pyrolysis is decomposition in the absence of oxygen, breaking down organic materials into commercially valuable products like bio-oil, syngas, and char.

The decibel (dB) scale is logarithmic. Doubling the sound intensity or energy results in an increase of approximately 3 dB. Adding 80 dB and 80 dB does not result in 160 dB; instead, the intensity doubles, leading to a level of about 83 dB.

Bioremediation is an effective and less invasive (in-situ) method for treating organic contaminants like petroleum hydrocarbons. It uses naturally occurring microorganisms to break down the pollutants into less harmful substances like carbon dioxide and water.

While Isotope A is acutely dangerous for a short period, it decays relatively quickly. Isotope B, with its 30-year half-life, will remain in the soil, water, and food chain for a very long time, posing a chronic, long-term threat to the health of the ecosystem.

Gases, including oxygen, are less soluble in warm water than in cold water. The discharge of heated water from a power plant raises the river's temperature, reducing the amount of dissolved oxygen available for fish and other aquatic life, which can lead to hypoxic conditions and fish kills.

Secondary microplastics are not manufactured to be small; they are created from the physical, chemical, and biological breakdown of larger plastic items (macroplastics) that have entered the environment. Options A, B, and D are all examples of primary microplastics, which are intentionally produced in small sizes.

Lichens are highly sensitive to air pollutants, especially sulfur dioxide, which is a common byproduct of burning fossil fuels. Their absence is a classic biological indicator of poor air quality, specifically high concentrations of .

Microorganisms that drive decomposition require both carbon (for energy) and nitrogen (for building proteins and reproducing). An ideal C:N ratio is around 30:1. When there is too much carbon (a high ratio), the microbes lack the necessary nitrogen to build their populations, slowing the entire composting process significantly.

Waste is classified as hazardous if it exhibits characteristics such as toxicity, corrosivity, reactivity, or ignitability. The presence of high concentrations of heavy metals like mercury and lead makes the sludge toxic and harmful to human health and the environment, requiring special handling and disposal procedures as hazardous waste.

The waste hierarchy prioritizes actions in the order of Reduce, Reuse, Recycle. 'Reducing' consumption and waste generation is the most effective step because it prevents the environmental impact of manufacturing, transport, and disposal altogether. Recycling and reusing are important but address waste that has already been created.

Sea turtle hatchlings have an instinct to move towards the brightest horizon, which historically has always been the moon and stars reflecting off the ocean. Artificial lights from buildings and streets can be brighter, disorienting the hatchlings and leading them away from the sea, where they often die from dehydration or predation.

Biogas is a mixture of gases, but its primary energy-rich, combustible component is methane (), typically making up 50-75% of the volume. The other major component is carbon dioxide (), which is not combustible.

An ESP works by charging the incoming particulate matter with a high-voltage electrical field. The charged particles are then attracted to and collected on plates with the opposite charge. This method is highly efficient for removing very fine particles that are difficult to capture with other mechanical methods like cyclone separators.

BOD measures the amount of dissolved oxygen needed by aerobic bacteria to break down organic matter in a water sample. A high BOD value indicates a large amount of organic pollution (e.g., from sewage or industrial effluent), which will lead to a severe depletion of dissolved oxygen as bacteria consume it during decomposition.

The combustion of organic matter in the presence of chlorine (found in plastics, paper, and salt) can create dioxins and furans. These compounds are highly toxic, persistent in the environment, and can bioaccumulate in the food chain, posing significant health risks.

Biomagnification is the increasing concentration of a substance in organisms at successively higher levels in a food chain. This process affects pollutants that are persistent, mobile, and fat-soluble. Heavy metals like mercury are classic examples, as they are not easily broken down and accumulate in the tissues of organisms.

Pyrolysis is the thermal degradation of carbon-based materials in the absence of oxygen. When applied to plastic waste, it breaks down long polymer chains into smaller hydrocarbons, producing a liquid product called pyrolysis oil or bio-oil, which can be refined into fuel. Incineration produces heat/electricity, while composting is for organic waste.

Gasoline cars are a major source of nitrogen oxides () and volatile organic compounds (VOCs), which are precursors to photochemical smog. They also emit carbon dioxide (), a primary greenhouse gas. By choosing to cycle, the individual eliminates these direct emissions, thus reducing their contribution to both urban air pollution and climate change.

A temperature inversion acts like a lid, trapping primary pollutants like NOx and VOCs close to the ground. With strong sunlight, these precursors react to form high concentrations of secondary pollutants like ozone. While NOx and VOCs are the primary ingredients, the meteorological condition of a temperature inversion is a critical exacerbating factor that traps them and allows the reaction to proceed to a high degree.

COD measures the total amount of oxygen required to chemically oxidize all organic matter, both biodegradable and non-biodegradable. BOD measures only the oxygen consumed by microorganisms to decompose biodegradable organic matter. A high COD/BOD ratio indicates that a significant portion of the organic pollution is resistant to biological degradation, which is characteristic of industrial chemicals and pesticides.

The core difference lies in the presence of oxygen. Incineration is combustion in the presence of excess oxygen, an exothermic process that produces ash and flue gases. Pyrolysis is the thermal decomposition of material at high temperatures in an anoxic (oxygen-deficient) environment. It is an endothermic process requiring an external heat source and produces a mix of solid (biochar), liquid (bio-oil), and gaseous (syngas) products.

Phyto-extraction is the only one of these mechanisms that results in the removal of heavy metals from the soil matrix. Plants known as hyperaccumulators take up metals through their roots and concentrate them in their above-ground biomass (stems and leaves). This biomass can then be harvested and treated, effectively removing the metals from the site. The other methods immobilize or degrade contaminants but do not remove inorganic metals.

The danger of and lies in their biochemical behavior. Cesium-137 mimics potassium () and gets distributed throughout soft tissues. Strontium-90 mimics calcium () and is incorporated into bones. This bio-accumulation and long biological residence time, combined with their relatively long radioactive half-lives (~30 years), lead to prolonged internal radiation exposure.

For monitoring vast, remote areas, satellite-based remote sensing is unparalleled. Instruments like TROPOMI provide daily global coverage, allowing for the detection of pollution plumes from both industrial sources and wildfires over large spatial scales. A ground-based network would be prohibitively expensive and difficult to maintain in a remote forest, while LIDAR has a limited spatial range.

This is a critical synergistic effect. The solubility of gases like oxygen in water decreases as temperature increases. Simultaneously, the metabolic rates of aerobic bacteria that decompose organic waste increase with temperature. This creates a situation where the oxygen supply is reduced while the oxygen demand is increased, leading to a much more severe drop in dissolved oxygen (hypoxia) than either pollutant would cause alone.

The primary non-auditory pathway is the body's stress response. Noise is interpreted by the brain as a threat, activating the sympathetic nervous system. This results in the chronic release of stress hormones like adrenaline and cortisol, leading to sustained increases in heart rate and blood pressure, which are major risk factors for hypertension and other cardiovascular diseases.

Methanogenic archaea are extremely sensitive to pH and thrive in a neutral range. If the system is overloaded, acid-forming bacteria produce volatile fatty acids (VFAs) faster than the methanogens can consume them. This accumulation of acids causes a sharp drop in pH, a condition known as 'souring,' which inhibits or kills the methanogens and stops biogas production.

While all reactions are relevant, the critical one for reducing carbonate availability is the reaction of excess hydrogen ions (), produced from the dissociation of carbonic acid, with available carbonate ions (). This reaction forms bicarbonate ions (), effectively 'stealing' the carbonate ions that organisms need to build their calcium carbonate () shells and skeletons.

The key factor is the spectral composition. Melatonin, a hormone crucial for regulating circadian rhythms, is suppressed by light, especially blue wavelengths. White LEDs have a strong peak in the blue part of the spectrum, making them far more effective at suppressing melatonin and disrupting these critical biological cycles than monochromatic, amber-colored sodium lamps which lack blue light.

While all options are hazards, the open burning of plastic components from circuit boards and wires at uncontrolled low temperatures is a notorious source of dioxins and furans. These are highly toxic, carcinogenic, and persistent organic pollutants that pose a severe and immediate inhalation risk to workers and nearby communities, as well as causing long-term environmental contamination.

The ISWM hierarchy prioritizes strategies that prevent waste from being generated. The universally accepted order, from most to least desirable, is: 1. Source Reduction & Prevention, 2. Reuse, 3. Recycling & Composting, 4. Energy Recovery (e.g., incineration), and finally, as the last resort, 5. Treatment & Disposal (e.g., landfilling). This approach aims to maximize resource efficiency and minimize environmental impact.

The chemistry of a wet limestone scrubber (, then oxidized to ) effectively removes from the air but transfers the pollutant to a solid/liquid medium. This process generates massive quantities of synthetic gypsum sludge, creating a significant solid waste disposal problem for the power plant.

This is a classic example of using indicator species. Different lichen species have varying tolerances to air pollution. The composition of the lichen community and the 'succession' from more complex forms (fruticose) to simpler forms (crustose) directly indicate the long-term average air quality. Their presence, absence, or change in community structure serves as a biological indicator of pollution levels.

Soil colloids have negatively charged surfaces that bind positive metal cations, immobilizing them. In acidic conditions, a high concentration of hydrogen ions () competes for these binding sites, displacing the metals into the soil solution. This increases the metals' mobility, bioavailability for plant uptake, and risk of leaching into groundwater.

Primary treatment removes large solids (A, D) and secondary treatment removes dissolved organics (B). Tertiary treatment targets specific pollutants, most commonly the nutrients nitrogen and phosphorus, which cause eutrophication. Biological Nutrient Removal (BNR) is a sophisticated tertiary process that manipulates oxygen levels to encourage different microbial processes (like nitrification and denitrification) to remove these nutrients from the effluent.

Dioxins and furans are destroyed at very high temperatures (>850°C) but can reform via "De Novo Synthesis" as the flue gas cools. This process is most efficient in a specific temperature window (250-450°C) and requires precursors like carbon, chlorine, and metal catalysts found in fly ash. Modern incinerators are designed to pass through this temperature window as quickly as possible (rapid quenching) to minimize reformation.

Eutrophication is primarily caused by nitrogen and phosphorus runoff. Modern agriculture, particularly for animal feed, is a massive user of these fertilizers. Animal manure is also a major source. Reducing demand for meat directly reduces the amount of fertilizer and manure-based nutrient pollution generated upstream in the food production life cycle. The other options are environmentally beneficial but less directly linked to preventing eutrophication.

While all are sources of natural background radiation, the inhalation of radon gas and its short-lived decay products is, by a significant margin, the largest single contributor for most people. Radon-222 is a decay product of uranium in soil and rock. The gas can seep into buildings and accumulate, and when inhaled, its alpha-emitting decay products lodge in the lungs, delivering a concentrated radiation dose.