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Xenobiotics (Part II) - Coggle Diagram
Xenobiotics (Part II)
Analysis of pollutants
Sampling
- Discrete sample: specific timepoint / short period
- Composite sample series: over a long period
- Low conc -> high sample volume
Specific detection/ quantification in liquids
- Separation + MS
- Molecular weight + polarity
- GC
Solid-phase microextraction (SPME)
- Isolation based on equilibrium between sample matrix and extractive coating phase (Silica fiber eg)
- Reduce unwanted compounds
- DI - Direct immersion
- HS - Head space
- Advantages
- Usable for thermally labile compounds
- Derivatization not necessary for high polar compound
- Less solvents needed
Solvent microextraction (SME)
- Liquid phase microextraction
- Equilibrium between sample matrix and liquids
- Lipophilic solvent in aqueous phase
- SDME: Single-drop microextraction
1. AhR - Aryl hydrocarbon receptor
- Cytosolic transcription factor
- Cytochrome P450 enzymes
- Immune cell regulation
- Cellular differentiation and maintenance
- Affinity to big planar lipophilic ligands
-
Natural ligands
- Poly cyclic hydrocarbons
- Derivates of tryptophane
Expression in
- Liver, adipose tissues, pancreas
- Connection to insulin secretion and glucose metabolism
2. Fate of xenobiotics in the liver cell
- Hydrophobic organic pollutants -> activ. metabolizing enzymes -> compounds more water soluble
Route I
- Mechanisms of detoxification/toxification
Route II
- Mechanisms for induction of enzymes
Current topics
PFAS - Per- and polyfluoroalkyl substances
- Organofluorines
- Fluorine atoms to alkyl chain
- Teflon
- Coatings, resist heat, oil, water
- Water proof fabric, cooking surfaces,
Effects
- Not chemically inert..?
- Long half times -> accumulation
- Carcinogenic
- Endocrine disruptors
- Thyroid diseases
- High cholesterol
Early stage solutions
- Unsaturated bonds -> bacterial remediation
- Bacteria/fungi/plants degrade/detoxify compounds in environments
- May be native MO or isolated and transported to the contaminated site
- Chemical/physical water treatment
- Ion exchange, water oxidation
Microplastics
- Clothing
- Industrial processes
- Packaging
Primary microplastic
- Purposely manufactured small
- Plastic pellets
Secondary microplastic
- Degraded from larger plastic
- Bottles etc
Occurence
- 75% of marine waste
- 80-90% from land people
Toxic effects
- Cytotoxicity
- Immune response
- Barrier attributes
- Oxidative stress
- Adsorption of other chemical pollutants
- AMR = anti microbial resistance
-
Biodegradability
Type of reaction
- Primary degradation
- Physiochemical changes of properties - ions, H bond
- Secondary degradation
- Loss of undesirable properties, toxic activity
- Ultimate degradation
Metabolic capacity of organisms
- MO: Mineralization -> CO2
- Fish: Metabolism + excretion, broad pattern -> slow rate
- Mammals + birds: Metabolism + excretion, broad pattern -> high rate
Trophic pyramid
- Bottom-up cascades
- Lower trophic level affecting higher tropic levels - resource restriction
- Top-down cascades
- Higher trophic level affecting lower tropic levels - predation