Pollution Water and Air

Leeches are pollution-tolerant organisms that thrive in low-oxygen environments. In contrast, trout, mayflies, and caddisflies are sensitive indicators that require high levels of dissolved oxygen to survive.

Ozone is a powerful oxidizing agent widely used as an alternative to chlorine for disinfecting wastewater because it effectively kills pathogens without leaving harmful chlorinated byproducts.

Cultural eutrophication leads to algal blooms, which eventually die and decompose. This decomposition process consumes oxygen, leading to an increase in anaerobic bacteria that thrive in the resulting low-oxygen conditions.

The Montreal Protocol is an international treaty specifically designed to phase out the production and consumption of ozone-depleting substances, including chlorofluorocarbons (CFCs).

Cl2F2C, also known as Dichlorodifluoromethane or Freon-12, is a chlorofluorocarbon (CFC) that releases chlorine atoms in the stratosphere, which catalyze the destruction of ozone molecules.

Photochemical smog is primarily formed by the reaction of nitrogen oxides (NO2) and volatile organic compounds with sunlight. Nitrogen dioxide is a key precursor in this process.

The human respiratory system uses multiple defense mechanisms, including nasal hairs to trap large particles, mucus to capture smaller particles, and reflexes like sneezing and coughing to expel irritants.

Algae are primarily aquatic photosynthetic organisms that rarely cause human diseases. In contrast, viruses, bacteria, and protozoa include many well-known pathogens responsible for illnesses ranging from colds to malaria. Note: option B has a typo (viruse should be virus).

Underground storage tanks at old gas stations often corrode over time, leading to leaks of gasoline and other chemicals into the surrounding soil and groundwater.

Formaldehyde is a common indoor air pollutant found in many building materials, including pressed-wood products, furniture stuffing, and foam insulation.

Sick building syndrome is associated with acute symptoms like headaches, fatigue, and respiratory irritation. Lung cancer is a long-term chronic disease typically associated with specific carcinogens like asbestos or radon, not the general syndrome.

Thermal pollution increases water temperature, which decreases the solubility of oxygen in water, thereby reducing the amount of dissolved oxygen available for aquatic life.

Sludge generated in water treatment plants is typically dewatered and then disposed of in landfills, incinerated, or sometimes applied as fertilizer if it meets safety standards.

Secondary treatment in a wastewater plant is a biological process that uses microorganisms to break down organic matter, which includes nitrogen and phosphorus compounds, rather than just physical solids.

Leeches are highly tolerant of low-oxygen conditions and pollution. Perch, mayfly larvae, and caddisfly larvae are sensitive species that require high levels of dissolved oxygen.

Cholera, malaria (vector-borne, but often associated with water), and giardia are commonly linked to water. Chicken pox is a viral disease spread primarily through respiratory droplets or contact, not water.

Flocculation is a process in water treatment where small particles are induced to aggregate or clump together into larger 'flocs', which can then be easily removed by sedimentation or filtration.

The Exxon Valdez oil spill occurred in 1989 in Prince William Sound, Alaska, and was caused by an oil tanker owned by the Exxon Corporation.

Normal precipitation has a pH of approximately 5.6 because atmospheric carbon dioxide dissolves in rainwater to form weak carbonic acid, making it naturally slightly acidic.

Agriculture is considered the leading source of nonpoint source water pollution due to runoff containing fertilizers, pesticides, and sediment from large areas of farmland.

Infectious agents refer to pathogens such as bacteria, viruses, and parasites that contaminate water and cause diseases in humans and animals.