Environmental Toxicants Overview
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Questions and Answers

Which statement accurately describes the difference between acute and chronic toxicity?

  • Acute toxicity results from prolonged exposure to a small dose.
  • Chronic toxicity has immediate health effects while acute does not.
  • Chronic toxicity is related to a single high exposure.
  • Acute toxicity is associated with a single exposure to a large dose. (correct)

What is a common outcome associated with the chronic exposure to aflatoxin B1?

  • Development of liver cancer. (correct)
  • Acute poisoning followed by rapid recovery.
  • Respiratory irritation from air pollutants.
  • Liver failure and immediate death.

Which of the following is considered an anthropogenic air pollutant?

  • Ozone
  • Volcanic ash
  • Automobile exhaust (correct)
  • Dust storms

What component of air pollution is categorized as particulate matter?

<p>Lead particles (A)</p> Signup and view all the answers

What is the predominant health effect associated with air pollution?

<p>Chemical irritation of the respiratory tract (B)</p> Signup and view all the answers

Which of the following substances is known to cause lung cancer?

<p>Asbestos (C)</p> Signup and view all the answers

Which of the following cancers is strongly associated with the bacterium Helicobacter pylori?

<p>Stomach Cancer (C)</p> Signup and view all the answers

What is a primary goal of cancer treatment focused on 'controlling' the disease?

<p>Stopping the cancer from spreading (A)</p> Signup and view all the answers

Which of the following is NOT considered a method of cancer treatment?

<p>Vaccine Therapy (A)</p> Signup and view all the answers

What is a significant environmental concern regarding the use of pharmaceuticals?

<p>They are recognized as pollutants in surface water. (A)</p> Signup and view all the answers

How do antibiotics primarily enter groundwater and soils from agricultural use?

<p>Through routine application in livestock (C)</p> Signup and view all the answers

Which of the following factors is NOT listed as a goal of cancer treatment?

<p>Minimize healthcare costs (C)</p> Signup and view all the answers

Which type of cancer is linked to Hepatitis B and C infections?

<p>Liver Cancer (A)</p> Signup and view all the answers

What unique characteristic of cancer cells allows them to spread throughout the body?

<p>Ability to invade surrounding normal tissue (C), Ability to grow indefinitely (D)</p> Signup and view all the answers

Which factor is considered non-modifiable in the development of cancer?

<p>Genetic makeup (D)</p> Signup and view all the answers

What is one reason anticancer drugs cannot use the minimum therapeutic dose as a standard for environmental risk?

<p>They exhibit significant toxicities even at minimal doses. (A)</p> Signup and view all the answers

What lifestyle factor has been linked to increased risk for lung cancer?

<p>Tobacco use (C)</p> Signup and view all the answers

Which of the following best describes the concentration of pharmaceuticals in the environment?

<p>Influenced by sewage treatment efficacy (A)</p> Signup and view all the answers

What percentage of deaths in Canada are attributed to cancer?

<p>30% (A)</p> Signup and view all the answers

In which demographic is cancer predominantly diagnosed?

<p>Canadians 50 or older (C)</p> Signup and view all the answers

What dietary component has been strongly linked to colorectal and prostate cancers?

<p>Saturated animal fat (C)</p> Signup and view all the answers

What percentage of unused drugs are typically disposed of by being flushed down the sink or toilet?

<p>25% (D)</p> Signup and view all the answers

Which type of drugs has seen a 60% increase in usage over the past decade?

<p>Neuroreactive drugs (B)</p> Signup and view all the answers

What is a major concern regarding steroid hormone compounds found in the environment?

<p>Their deleterious effect on aquatic animal reproduction (B)</p> Signup and view all the answers

What is known about the effects of hypertensive drugs in surface waters?

<p>They are present but at non-toxic levels (A)</p> Signup and view all the answers

What is a concern regarding the antibiotics used in aquaculture?

<p>They promote rapid growth and can lead to high local concentrations (A)</p> Signup and view all the answers

What happens to a percentage of all pharmaceuticals consumed by humans?

<p>They enter the environment as unchanged drugs or active metabolites (C)</p> Signup and view all the answers

Which class of drugs is notably linked to potentially causing negative effects on the reproductive and physiological development of fish in water bodies?

<p>Selective serotonin reuptake inhibitors (A)</p> Signup and view all the answers

What is a significant environmental concern related to pharmaceutical discharges from manufacturing plants?

<p>They can lead to long-term degradation of surface and groundwater (A)</p> Signup and view all the answers

What is the primary effect of organochloride insecticides on the nervous system?

<p>It increases neuronal sensitivity leading to convulsions. (B)</p> Signup and view all the answers

What major problem led to the ban of DDT in the 1970s?

<p>It resulted in resistance in insect populations. (B)</p> Signup and view all the answers

Which statement is true about organophosphorus insecticides?

<p>They irreversibly inhibit acetylcholinesterase in humans. (A)</p> Signup and view all the answers

What health risk is associated with exposure to environmental tobacco smoke?

<p>Similar health risks as direct smoking. (B)</p> Signup and view all the answers

What is a common characteristic of both insecticides and herbicides?

<p>They intentionally kill living organisms. (D)</p> Signup and view all the answers

Why are organophosphorus insecticides considered highly toxic to humans?

<p>They cause buildup of acetylcholine in the nervous system. (B)</p> Signup and view all the answers

What demographic is identified as being particularly susceptible to air pollution?

<p>Certain subpopulations. (C)</p> Signup and view all the answers

What common outcome results from the absorption of organophosphorus insecticides through the skin?

<p>Severe poisoning symptoms. (A)</p> Signup and view all the answers

Flashcards

Environmental Toxicant

A chemical released into the environment that can harm living organisms.

Acute Toxicity

Exposure to a large dose of a chemical at once, often causing immediate effects.

Chronic Toxicity

Repeated exposure to small doses of a chemical over a long period, leading to gradual harm.

Particulate Matter (PM)

Tiny particles in the air, including dust, smoke, and biological materials.

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Gaseous Air Pollutants

Gases that pollute the air, such as carbon monoxide, nitrogen oxides, and ozone.

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Air pollution and health

The combined effect of particulate matter and sulfur dioxide is often responsible for health problems, but no one pollutant is solely to blame.

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Susceptibility to air pollution

Certain populations, like those with pre-existing respiratory conditions, are more vulnerable to the effects of air pollution.

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Tobacco smoke

The combination of mainstream smoke inhaled by the smoker and sidestream smoke from the burning end of the cigarette.

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Pesticides

Chemicals deliberately used to kill or incapacitate organisms.

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Insecticides

Chemicals designed to kill insects.

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Herbicides

Chemicals designed to kill plants.

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Organochloride Insecticides

A class of insecticides that work by increasing neuronal sensitivity, leading to tremors, seizures, and death. They persist in the environment and can have long-term effects.

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Organophosphorus Insecticides

A class of insecticides that are very toxic to humans and are absorbed through the skin. They inhibit the enzyme acetylcholinesterase, leading to a build-up of acetylcholine and potentially fatal symptoms.

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Asbestos-related Cancer

A type of cancer associated with exposure to asbestos, a fibrous mineral often found in building materials.

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Benzene-related Cancer

A type of cancer associated with prolonged exposure to benzene, a volatile organic compound often found in gasoline and industrial settings.

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Formaldehyde-related Cancer

A type of cancer associated with exposure to formaldehyde, a pungent chemical used in building materials, glues, and resins.

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Ionizing Radiation-related Cancer

A type of cancer associated with exposure to ionizing radiation, a high-energy form of radiation that can damage DNA.

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Soot-related Cancer

A type of cancer associated with exposure to soot, a black powdery residue produced by incomplete combustion.

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Helicobacter pylori

A bacterium that infects the stomach and can lead to stomach cancer.

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Hepatitis B and C

A virus that can infect the liver and lead to liver cancer.

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Human Papillomavirus (HPV)

A virus that can infect the cervix and lead to cervical cancer.

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Risk Assessment of Pharmaceuticals in the Environment

The minimum therapeutic dose is often used to assess the risk of pharmaceuticals in the environment to humans. However, this method fails for anticancer drugs, where even minimal doses can cause significant toxicity.

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Cancer

A type of cancer characterized by the uncontrolled growth and division of cells.

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Metastasis

A key feature of cancer cells is their ability to invade and spread to other parts of the body.

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Genetics and Cancer Risk

Genetic factors can influence an individual's susceptibility to cancer. For example, people with Xeroderma pigmentosum have a genetic deficiency in DNA repair, making them more prone to mutations.

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Environmental Factors and Cancer Risk

Environmental factors, such as exposure to chemicals, diet, and infections, can contribute to cancer development. These factors can often be modified to reduce risk.

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Tobacco Use and Cancer Risk

Smoking, especially cigarettes, is a major risk factor for various cancers, including lung, esophageal, bladder, and pancreatic cancer. The risk increases with the amount and duration of smoking.

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Diet and Cancer Risk

Dietary factors, such as high consumption of saturated animal fat and red meat, are strongly linked to certain cancers like colon, rectal, and prostate cancer. Conversely, a diet rich in fruits and vegetables may help protect against cancer.

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Pharmaceuticals in Pet Waste

Pharmaceuticals excreted by pets can enter surface and groundwater. This happens as drugs are metabolized and eliminated.

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Drug Disposal and the Environment

A significant percentage of unused drugs end up in the environment, either through flushing or landfill disposal.

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Antibiotics in Aquaculture

Antibiotics used in aquaculture can lead to high concentrations of these drugs in specific locations.

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Pharmaceutical Manufacturing and the Environment

Pharmaceutical manufacturing plants can release large amounts of drugs into the environment, especially in developing countries.

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Neuroreactive Drugs in Wastewater

Neuroreactive drugs like antidepressants are not effectively removed by sewage treatment plants.

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Estrogen Compounds in the Environment

Estrogen-like compounds from oral contraceptives and animal waste are of concern due to their potential impact on aquatic life.

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Hypertensive Drugs in the Environment

Hypertensive drugs used to treat high blood pressure are prevalent in surface water, but their long-term effects and biomagnification are unclear.

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Analgesics in the Environment

Analgesics like ibuprofen and NSAIDs are found in the environment, raising concerns about their potential impact on humans and wildlife.

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Study Notes

Environmental Toxicants

  • Environmental toxicants are chemicals released into the environment that cause adverse health effects in living organisms.
  • Acute toxicity is associated with a single exposure at a high dose.
  • Chronic toxicity is associated with repeated exposure at low doses over a long period.
  • Examples of environmental toxicants include aflatoxin B1 (common food contaminant) which causes liver failure/cancer.

Common Environmental Toxicants

  • Air pollution is divided into particulate matter and gaseous pollutants.
  • Particulate matter is a mixture of tiny particles (liquid or solid). Sources can be natural (volcanoes, fires, dust) or man-made (combustion of fossil fuels, industrial processes, vehicle exhaust).
  • Gaseous air pollutants include carbon monoxide, carbon dioxide, nitrogen oxides, sulfur oxides, ozone, etc.

Pesticides

  • Insecticides and herbicides are environmental toxicants that kill insects or prevent plant growth, respectively.
  • Organochlorine insecticides (e.g., DDT) work by increasing neuron sensitivity, causing tremors, convulsions, and death.
  • Organophosphorus insecticides are generally unstable in the environment and break down quickly, with lower environmental impact than organochlorine insecticides.
  • Herbicides kill or harm plants.

Cancer Statistics

  • Cancer primarily affects individuals aged 50 or older.
  • Approximately 45% of men and 43% of women will develop cancer.
  • Cancer is a leading cause of death in Canada, with approximately 30% of deaths attributed to this disease.
  • Lung cancer is the most common type of cancer.

Cancer Cell Features

  • Cancer cells can grow and divide indefinitely.
  • They can invade surrounding normal tissue.
  • They can spread throughout the body (metastasis).

Cancer Causes

  • Genetics (e.g., Xeroderma pigmentosum impacting DNA repair) play a role in individual cancer susceptibility.
  • Environmental factors (e.g., chemical exposure, diet, infection) also contribute.
  • Specific environmental factors like tobacco smoke (smoking and secondhand exposure) are associated with increased cancer risk (e.g., lung cancer).
  • Diet (dietary components) is a modifiable risk factor.

Cancer Treatment Goals

  • Preventing cancer involves preventing cancer cell growth or removing precancerous cells.
  • Curing cancer is the main goal of certain treatments.
  • Controlling cancer growth and preventing the spread is another treatment goal.
  • Relieving symptoms is a necessary approach when curing is not possible.

Toxic Effects of Specific Chemicals (Lead)

  • Lead is an ubiquitous,naturally occurring element in the environment and different compounds. Lead oxide and tetraethyl lead are toxic compounds.
  • Exposure happens through old paint (in the 1950s), where a brighter colour was achieved. Lead was also commonly used in batteries.

Toxic Effects of Specific Chemicals (Mercury)

  • Mercury is found in water and air and is used in industries. Contamination sources are water and air.
  • Mercury in water is concentrated in the aquatic food chain.
  • Two toxic forms exist: mercuric mercury (inhaled or absorbed through skin) and methyl mercury (ingested). Methyl mercury is commonly more toxic to people.

Toxic Effects of Specific Chemicals (Bisphenol A [BPA])

  • Bisphenol A (BPA) is an industrial chemical used to make polycarbonate plastics (e.g., water bottles, food containers), and it can leach into the environment.
  • BPA exposure can occur through diet and can increase with heating.

Toxic Effects of Specific Chemicals (Pharmaceuticals)

  • Increased use of pharmaceuticals led to their recognition as environmental pollutants.
  • They are found in surface water, groundwater and soils (most studied in surface waters).
  • Pharmaceuticals can have adverse effects on aquatic species and birds, even at low concentrations;
  • Pharmaceuticals can have adverse effects on humans if exposed and absorbed at high concentrations.

Chemotherapy

  • Chemotherapy is a drug treatment approach to kill cancer cells.
  • Chemotherapy drug classes include alkylating agents, mitotic inhibitors, hormones/hormone antagonists and biologicals.
  • Cancer chemotherapy commonly includes a combination of therapies.

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Related Documents

Module 6 - Environmental Toxicology and Cancer PDF

Description

This quiz covers the fundamentals of environmental toxicants, including their definitions, types, and examples. Learn about acute and chronic toxicity, the impact of air pollution, and the role of pesticides. Test your understanding of how these toxicants affect health and the environment.

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