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JORD310 - Soil Pollution and Sustainability > Organic pollutants > Flashcards

Organic pollutants Flashcards

(51 cards)

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1
Q

Pugge: ** Important factors for biodegradation**

A
  1. Microbial community
  2. Contaminant structure
  3. Contaminant concentration
  4. Sorption/desorption
  5. Environmental factors
    a. Redox conditions (aerobic/anaerobic)
    b. pH, temperature, salinity
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2
Q

PAF

A

Potentially affected fraction (of species)

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3
Q

LC

A

Lethal concentration

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4
Q

HC

A

Hazardous Concentration

Negative effect concentration

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5
Q

PNEC

A

Predicted No Effect Concentration

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6
Q

PNEC i praksis

A

Sikkerhetsgrense for eksponering, brukt i risikovurdering av kjemikalier.

konsentrasjonen av et stoff i miljøet som antas å ikke ha skadelige effekter på organismer, selv ikke over lang tid.

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7
Q

PEC

Stands for

A

Predicted Environmental Concentration

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8
Q

PEC in practice

A

Is used to predict exposure (total concentration, mg/kg)

How much of a compound is expected to be in the environment

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9
Q

PEC/PNEC < 1

A

Low to no risk

  • Predicted Environmental Concentration
  • Predicted No Effect Concentration
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10
Q

PEC/PNEC ≥ 1

A

Potential risk

  • Predicted Environmental Concentration
  • Predicted No Effect Concentration
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11
Q

MTR

A

Maximum Tolerable Risk

  • 95 % are protected
  • 5 % die
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12
Q

SR

A

Severe risk

50 % protected (HC50 / LC50)

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13
Q

MTR i praksis

A

Maximum Tolerable Risk
- 95 % are protected
- 5 % die

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14
Q

MTR/100

A

Soil is concidered “Clean”

??? LC5/100 ??

??? Der 100 er en sikkerhetsfaktor, for å justere for usikkerheter i data og for å beskytte sensitive arter???

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15
Q

50 % protected

A

Severe risk !!

HC50 or LC50

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16
Q

Classification system:
Class 1 & 2

A

Class 1: Clean, all uses
Class 2: Weakly contaminated
- Housing, child daycare

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17
Q

Classification system: Class 3

A

MTR (95 % protection) < Class 3

Streets, squares

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18
Q

Classification system: Class 4

A

Significantly contaminated

Industry, railways

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19
Q

Classification system: Class 5

A

Severe risk (50 % protection) <

Urgent cleanup / landfill

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20
Q

Remediation want soil back to which two classes?

A

1 & 2
(blue & green)

Clean / weakly contaminated

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21
Q

Uncertainty factor in the risk classification system?

Study These Flashcards
A

Usually 15-30

22
Q

Stepwise risk assesment:

Study These Flashcards
A
  1. Source analysis
  2. Transport analysis
  3. Recipient analysis
23
Q

Risk assesment:
Source Characterization

Study These Flashcards
A

Step: 1

Purpose: Identify and describe the pollution source.

Key questions:
* What pollutants are present?
* What is their total concentration?
* Are they likely to be mobile (e.g., soluble, volatile, particle-bound)?

24
Q

Risk assesment:
Transport Characterization

Study These Flashcards
A

Step: Step: 2

Purpose: Understand how pollutants move from the test site to other environments.

Key mechanisms:
* Leaching into soil and groundwater
* Runoff into surface waters
* Volatilization into the air
* Particle transport (e.g., via erosion)

25
Risk assesment: Recipient Characterization
Step: 3 Purpose: Assess who or what may be exposed and at risk. Key considerations: * Who/what are the receptors? (e.g., aquatic life, humans, soil organisms) * PEC/PNEC ratios: Good < 1 ≤ Further assesment needed * Passive samplers: Measure bioavailable concentrations in porewater (i.e., what organisms can actually absorb) * Uptake in organisms: Data from monitoring tissue concentrations in organisms
26
Passive samplers
Measuring the bioavailable fraction of pollutants, **without the need for pumps or power sources**. - Rely on diffusion or partitioning (natural processes) - Focus on the dissolved or gaseous phase—what is most relevant for exposure and toxicity - Mimic how pollutants are taken up by organisms - Provide time-integrated measurements (vs. snapshot samples)
27
Sampling devices that **actively draw in air, water, or other media using a pump or other mechanical system to collect pollutants for analysis** - Require power or pressure systems (e.g., pumps, vacuums, flow controllers) - Provide snapshot or instantaneous measurements - Allow for precise control over the volume and duration of sampling - Often used when regulatory-grade, high-resolution data is needed
28
Two main problems with risk assesment
- Safety factors are very uncertain - Kd: Solubilty is very uncertain
29
Toxicity tests should be taken from
the porewater
30
Why do we need safety factors in risk assesment?
We have few data There may be other species in the biota
31
Why is risk assessment of pollutants statistical?
- Complex and variable effects of pollutants *Pollutant effects vary by exposure, duration, susceptibility, and conditions. Statistics help identify and quantify these patterns.* - Population data (not individuals) *We study groups, not individuals, to detect health trends linked to exposure, using statistics to determine if effects are due to the pollutant or random variation.* - Limited or indirect data (e.g., epidemiology, simulations) *Direct experimental data (especially in humans) is often limited or unethical, so we rely on epidemiological studies, animal experiments and simulations* Uncertainty and probability estimation *Risk assessment estimates harm probabilities at certain exposure levels, using statistics to calculate confidence intervals, safety margins, and distributions.* Dose-response modeling
32
"Soil risk derived via soil-water distribution"
Assessing the risk of pollutants or contaminants in soil by considering how they are distributed between the soil and water. It involves understanding how a pollutant moves or concentrates in the soil and the water that interacts with it.
33
"Equilibrium" passive samplers
Uses thin plastic strips to sorb pollutants (various thickness)
34
Why test porewater?
Because freely dissolved concentration is a good correlation with actual risk.
35
Partitioning
How pollutants or chemicals move between different mediums (such as sorption vs. desorption)
36
Passive samplers are useful for
Providing estimates of contaminant concentrations water / freely dissolved contamination.
37
Ways to test risk-relevant free concentrations
Lab - Bring sediments to lab and shake with passive samplers (pore water) In field: - Dig passive samplers directly into sediments (porewater) - Hang passive samplers in water to test "overlaying water"
38
Strong sorption can reduce risk by a factor of
10 to 100
39
What is this called: contaminated soil is removed from a site and then disposed of (dumped) in a landfill
Dig & dump often used when pollutants or hazardous substances in the soil are too difficult or costly to treat in place, or it is too costly to assess actually risk instead of just measuring total concentration
40
How is pollutants taken up?
Diffuse through skin Inhalation Ingestion
41
How are pollutants removed from body?
- Urine - Feces - Breast milk (fat solubles) - Evaporation - Fish gills
42
# **** Xenobiotic compounds
Compounds that are foreign to the biological system - not naturally produced by living organisms
43
How much more soluble is phenol, compared to benzen? Why?
50 x more soluble Due to a -OH group
44
Which elements make organic compounds soluble?
N, O, S
45
Why does N, O, S make organic compounds soluble?
High electronegativity → form H-bridges
46
Aliphatic hydrocarbons
hydrocarbons based on chains of C atoms 3 types: - Saturated, single bonds (alkanes) Unsaturated - Double bonds (alkenes) - Triple bonds (alkynes)
47
Mass =
Volume × density V × ρ
48
ρ
Density
49
Compounds fate in enviroment is determined by:
- Density - Vapour pressure - Solubility - Octanol-water distribution - Air-water partitioning - Sorption - Degradation
50
Compounds fate in enviroment is determined by (**environment & compound specific**, 3 points)
- Air-water partitioning - Sorption - Degradation
51
Air-water partitioning
Distribution of a substance between the gas phase (air) and the liquid phase (water) at equilibrium

JORD310 - Soil Pollution and Sustainability (15 decks)

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