Q 2: chemical movement in the enviro

Question 1

How Do Chemicals Get Around ?

Answer 1

In the Environment – between different environmental compartments (oil tankers)

In Organisms – how do they get in ? (pestisides)

Question 2

how are humans intervening

Answer 2

Moving substances from inaccessible to accessible compartments
Metal ores
Crude oil (not so bad when its in the ground but when we rtake it out, we concentrate it)
Concentrating previously diffuse sources
Metal refining
Changing Chemical Forms
Converting metal salts into elemental metals
AND THEN DUMPING IT ALL

Question 3

how are non-human processes intervening

Answer 3

Many chemicals have been cycling in the environment since there was an earth
Carbon dioxide – plants – animals – carbon dioxide
Carbon, nitrogen, oxygen, sulphur, iron, etc. all have their natural cycles
So why would a human chemical put in one place stay in one place ?

Question 4

what matters

Answer 4

Is it inorganic – metals – mercury, lead, copper
Is it ‘organic’ – made up of C, H, O, S, N, …
Does the chemical have a charge (+ or -) ? Is it ionized
Most inorganic chemicals that are uncharged are unavailable
There are a few exceptions
Most metal ions have a +ve charge
Organic molecules can also be charged (carboxylic acids, amines)
Organic molecules can be large and
have separate charged and uncharged
regions

Question 5

what elements are in organic metals

Answer 5

C, H, O, S, N,

Question 6

are metals positive or negative charges

Answer 6

mostly positive

Question 7

amines

Answer 7

positively charged

Question 8

carboxylic acid

Answer 8

• charge

Question 9

what are some physico chemical properties

Answer 9

structure, water solubility, thermal conductivity, density, vapor pressure

Question 10

what are some water solubility of chemicals

Answer 10

ethanol is infinite, DDT : 0.0017- will stay in same place for very long time becasue not soluble

Question 11

vapor pressure

Answer 11

EVAPORATION CAUSES AN INCREASE IN VAPOR PRESSURE UNTIL EQUILIBRIUM IS REACHED, things that evaporate rapidly will have a higher vapor pressure
ethanol splil dont have to wipe up because it will evaporate quickly

Question 12

what was found in the antarctic

Answer 12

DDT- A lot got their from the air and snow`

Question 13

low altitude

Answer 13

more evaporation

Question 14

mild latitude

Answer 14

equal deposition and evaporation

Question 15

high altitudes

Answer 15

more deposition

Question 16

Long Range Atmospheric Transport

Answer 16

Compounds need some volatility
Generally molecules that are not charged – i.e. non-polar (things that are charged are usually sticking to something)
Compound needs to be persistent in the atmosphere (uv light destroys them)
Polar compounds such as PFOS may travel as non-polar volatile precursors and degrade at distant locations

Question 17

rubber duckies

Answer 17

15 years to travel over the artic down to florida

Question 18

what is theGreat Pacific Garbage Patch

Answer 18

Ocean currents have resulted in the accumulation of ‘large’ amount of plastic wastes in the open ocean
Physical threat to wildlife
Potential to increase chemical exposures from adhered chemicals

Question 19

how can chemicals move around

Answer 19

Even insoluble things can move in air and water if they are stuck to something like dust or sediment – which are moved around by these media

Many chemicals bind tightly to soil and sediment that can be moved by air and water

Question 20

sedimentation

Answer 20

fanning out results in decreases water velocity so suspended particles are no longer supporter
occurs in freshwater and marine systems
can get some sorting of material depending on density
estarine systems are very important for the sorting of poplutants
enrichment of organic matter results in deposition of many contaminants- metal and organic
estuarine systems are critival marine habitats for the breeding of many aquatic species

Question 21

uptake by organisms depend on

Answer 21

Depends on the chemicals properties
Depends on the organisms properties
Soil binds chemicals relatively tightly and may make them unavailable
Air, water and food are major routes of exposure

Question 22

Bioconcentration

Answer 22

Gills work just as well for accumulating anything else dissolved in the water
Works well for dissolved metals – metals bound to organic matter no so well
Once in the body chemicals can dissolve in fat (organic chemical) or can bind to other components of the body such as protein
Chemicals dissolved in the blood can also be eliminated via the gills
Bioconcentration = the accumulation and sequestration of contaminant materials by living organisms directly from the ambient environment.

Question 23

Bioconcentration-factor (BCF)

Answer 23

Bioconcentration-factor (BCF) indicates the degree to which a chemical may accumulate in organisms, coincident with concentrations of chemical in water.

Question 24

OCTANOL/WATER PARTITION COEFFICIENT (Kow)

Answer 24

OCTANOL/WATER PARTITION COEFFICIENT (Kow)

Ratio of a chemical’s concentration in octanol phase to its concentration in the aqueous phase of a two-phase octanol/water system

octanol phase/ aqueous phase

Question 25

Kow)…

Answer 25

Consider the pesticide DDT. Its Kow = 3.4 x 106, which is well into the high value range for Kow. Kow values above 1000 would predict that it has low water solubility (solubility = 0.025 mg/L), is slowly biodegraded, persistent in the environment (low mobility and biodegradation), strongly adsorbed to soil, and is strongly bioaccumulated.

On the other hand, phenol has a Kow of 30, a low value. Phenol has high water solubility (8.3 x 104 mg/L), biodegrades rapidly, is not persistent, is weakly sorbed to soil, highly mobile and weakly bioaccumulated.

Question 26

Biomagnification

Answer 26

Some contaminants pass thru food chains with high efficiency – chemicals with high Kow

So if all the DDT in 10 kg of fish goes into the final 1 kg of eagle then the concentration of the DDT increases 10 fold.

This is the basis of biomagnification between trophic levels
Not all contaminants are transferred with 100% efficiency

Question 27

biomagnification factor

Answer 27

concentration in organism/ concentration in food

Question 28

concentration vs. accumulation vs. magnification

Answer 28

Bioconcentration - direct uptake from water in aquatic organisms. Most directly related to partitioning coefficient

Bioaccumulation – Uptake from water and from diet in aquatic organisms. Food rather than water may be the major route of exposure

Biomagnification – Increasing concentration of chemical at higher trophic levels. Due to metabolic and biomass considerations