54 Questions
What is the main function of surfactants/detergents in rivers and lakes?
Increase solubility of organic compounds
Which of these is true about PCBs according to the text?
They can stay in the environment for more than 100 years
What is the significance of the left and right in the nomenclature of PCBs?
Left side indicates the percent chlorine by weight
What causes the ozone hole according to the text?
Chlorinated hydrocarbons and acids
Which substance among the mentioned '12 dirties' can cause thinning of the ozone layer?
Aldrin
What type of products are formed from burning chlorinated products according to the text?
Highly toxic dioxins
What is a natural source of Polychlorinated Aromatic Hydrocarbons (PAHs)?
Volcanic eruptions
Which type of dyes require mordants for application and suffer from low color fastness?
Azo dyes
What causes the cancer-inducing effects of tobacco smoking according to the text?
Polychlorinated Aromatic Hydrocarbons (PAHs)
Which type of colorants are commonly used in staining but have poor resistance to light and chemical bleaching?
Triphenylmethane dyes
How can Methyl orange be synthesized according to the text?
By coupling with hydronium and amino groups
What is a common characteristic of Polychlorinated Biphenyls (PCBs), Dioxins, and Dibenzofurans?
Classification as organic pollutants
Which of the following is a property of polycyclic aromatic hydrocarbons (PAHs)?
They can cause alkylation and intercalation
What is the purpose of using anthracene in wood?
To prevent termite attacks
What is the main reason for the cancer-inducing effects of tobacco smoking?
Exposure to polycyclic aromatic hydrocarbons (PAHs)
Which of the following is a natural dye that requires no pretreatment?
Both b and c
What is the main advantage of synthetic dyes over natural dyes?
They have more consistent hues and high fastness
What is the purpose of using a mordant in dyeing?
To help the dye bond with fibers
What is a common use of PCBs?
In food packaging materials
Which substance is considered the most toxic dioxin?
TCDD
How do PCBs enter the body?
By inhalation or dermal contact
What do the first two digits in the nomenclature of PCBs represent?
Number of carbons
Which process is a source of environmental contamination of Dioxins?
Combustion processes
What is the main source of contamination by PCBs?
Food
Which structural feature characterizes the MC Type PCBs?
Presence of at least 2 chlorines at the ortho position
What characteristic makes PCBs resistant to oxidation?
Low aqueous solubility
How are Dioxins accidentally synthesized?
Burning of chlorinated carbons
Which category does not represent a usage category of PCBs?
Industrial processing
What is the most toxic dioxin among the mentioned substances?
TCDD
Which substance is commonly used as an insulator or lubricant?
PCBs
What category did 90% of PCBs fall into in the US in 1971?
Controllable Closed System
What is the natural source of Polyaromatic Hydrocarbons (PAHs)?
Volcanic eruptions
Which mechanism of action does 2,3,7,8-TCDD use to cause toxicity?
Binding to aryl hydrocarbon receptor (AhR)
Where do dioxins and furans accumulate in the body?
Adipose tissue
What is the main target organ affected by dioxins?
Liver
Which substance is NOT among the identified 'dirties' under the Stockholm Convention and Montreal Protocol?
Endrin
Which substances are most likely to cause skin cancer due to thinning of the ozone layer?
PCBs and Dioxins
What property makes PCB congeners with chlorine in non-ortho positions more toxic?
Presence of chlorine substituents in particular positions
What is the main reason for using Anthracene in wood?
To prevent termite attacks
What are the properties of Polycyclic Aromatic Hydrocarbons (PAHs) with respect to water?
They attach strongly to soil and other particles
What is the main reason behind the cancer-inducing effects of tobacco smoking according to the text?
Exposure to PAHs, especially benzo(a)anthracene
How are Dyes different from Pigments in terms of solubility?
Dyes are soluble in water and organic solvents
Which classification of Dyes is based on the interaction of organic molecules like aniline and benzene?
Azo Dyes
Why are Triphenylmethane Dyes used without consideration of light fastness?
They have multiple pi bonds that make them easily degraded by light
What is the main source of environmental contamination of PCBs?
Food
What is the primary reason for the resistance of PCBs to oxidation?
Use reduction followed by oxidation through microorganisms
Which of the following is a property of PCBs that contributes to their higher solubility in fatty tissue?
High partition coefficient
Which of the following is a source of dioxins?
Chemical processes involving chlorine
What is the most toxic dioxin compound mentioned in the text?
2,3,7,8-TCDD
Which of the following is a chronic effect of dioxin exposure?
Induction of microsomal enzymes
What is the primary target organ for the toxic effects of 2,3,7,8-TCDD?
Liver
Which of the following is a natural source of polyaromatic hydrocarbons (PAHs)?
Volcanic eruptions
What is the mechanism of mutation caused by the planar structure of certain PCB congeners?
Intercalation, leading to deletions of certain codons
Which of the following is a property of the 2,3,7,8-TCDD dioxin compound?
Low partition coefficient (Kow) of 6.8
Study Notes
Organic Pollutants
- All organic substances are toxic
- Types of organic pollutants:
- Polychlorinated Biphenyls (PCBs)
- Dioxins and Dibenzofurans
- Polyaromatic Hydrocarbons (PAHs)
- Surfactants/Detergents
- Pesticides
Polychlorinated Biphenyls (PCBs)
- Commonly used as insulators or lubricants
- Sources of environmental contamination:
- Open burning or incomplete combustion of PCB-containing solid waste
- Vaporization of PCBs in open applications
- Accidental spills or leakages
- Disposal into sewage systems
- Food (main source of contamination)
- Nomenclature: 4-digit code, first two digits represent the number of carbons, and the last two digits represent the percentage of chlorine by mass
- Toxicity: acute and chronic effects, including chloracne, cancer, and biochemical changes
- Physiochemical properties:
- Low aqueous solubility
- Non-flammability
- Resistance to oxidation
- Resistance to hydrolysis
- Low electrical conductivity
- LogKOW ranges from 3.76 to 6.38
Dioxins
- Usually accidentally synthesized as byproducts
- Sources of environmental contamination:
- Chemical processes involving chlorine
- Combustion processes
- Biocompost and sludges
- Most toxic dioxin: 2,3,7,8-tetrachlorodibenzo[1,4]dioxin (TCDD)
- Physiochemical properties:
- Similar to PCBs
- LogKOW of 6.8
- Toxicity: acute and chronic effects, including chloracne, cancer, and immunotoxicity
- Mechanism of toxic action: binds to aryl hydrocarbon receptor (AhR)
Polyaromatic Hydrocarbons (PAHs)
- Natural sources: volcanic eruptions, natural petroleum, fires
- Anthropogenic sources: petroleum spills, wood burning, incinerations, cigarette smoke, coking plants
- Common PAHs: anthracene, benzo(a)pyrene, naphthalene
- Uses: pigments (water insoluble) and dyes (water soluble)
- Toxicity: immunosuppressant, carcinogenic, and mutagenic
- Physiochemical properties:
- Low aqueous solubility
- Non-flammability
- Resistance to oxidation
- Resistance to hydrolysis
- Low electrical conductivity
- LogKOW ranges from 3.36 to 6.04
Dyes
- Colored organic compounds
- Classification:
- Based on source: natural, synthetic
- Based on structure: azo, triphenylmethane, phthalein
- Uses: pigments (water insoluble) and dyes (water soluble)
- Examples: anthracene, benzo(a)pyrene, naphthalene
Test your knowledge on organic pollutants and their harmful effects on the environment. Explore topics like Polychlorinated Biphenyls, Dioxins, Polyaromatic Hydrocarbons, Pesticides, and Surfactants/Detergents. Learn about the impact of these substances on rivers, lakes, and ecosystems.
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