Biogeochem - halogenated carbon

Question 1

properties of halogenated hydrocarbons

Answer 1

• non-metals
• high electronegativity
• mostly synthetic
• very toxic and reactive
• commonly used as disinfectants

Question 2

What is the structure of a halogenated hydrocarbon

Answer 2

Essentially methane but with 1 H replaced with a halogen (eg Cl, Br, I)

Question 3

What halogenated hydrocarbon depletes the ozone layer?

Answer 3

Methyl Bromide

Question 4

Characteristics of halogenated hydrocarbons

Answer 4

• volatile (meaning they can switch from one state to another easily)
• persistant
• easily adsorb onto clays

Question 5

Give an example of a halogenated hydrocarbon

Answer 5

DDT

Question 6

What was DDT used for?

Answer 6

Was used as a pesticide to control malaria outbreaks

Question 7

What did DDT do in borneo

Answer 7

DDT killed the wasps which controlled caterpillar populations.

Caterpillars ate the thatched roofs of houses causing a socio-economic problem

DDT got into cockroaches, got into geckos. DDT altered the geckos speed, causing them to get eaten by wild cats. The wild cats died from DDT, increasing rat populations that brought fleas with a plague, impacting human mortality rates.

Question 8

Example of how biomagnification of halogenated hydrocarbons has impacts ecosystem

Answer 8

Birds of prey in north america declined due to DDT.

DDT bioaccumulated through the food chain. DDT inhibits the uptake of calcium into bird of prey egg shells. This caused the eggs broke as there was no calcium to strengthen them, resulting in the young dying. this removal of the predators caused the population of other animals in the food webs to cascade into disarray.

Question 9

where does DDT get stored?

Answer 9

in fatty tissues and then gets biomagnified up the food chain

Question 10

What bird populations has DDT presence caused a decline in

Answer 10

• falcons
• bald eagles
• ospreys
• peregrine falcons

Question 11

List an example of a low-molecular weighted halogenated hydrocarbon?

Answer 11

Vinyl chloride
- toxic
- flammable, carcinogen

Carbon tetrachloride
- used in fire extinguishers
- cleaning agend
- nerve and liver toxin
- carcinogen
- depletes ozone layer

Question 12

state the storage, bioaccumulation and biomagnification issues associated with chlorinated hydrocarbons

Answer 12

• difficult to excrete results in accumulation
• lipid soluble so accumulate in fatty tissues

Question 13

what are the issues associated with the storing of halogenated hydrocarbons in fatty tissues?

Answer 13

Lipids are protected and are good reserves. If starvation occurs, the fats are consumed to release energy and the toxins get released

Question 14

what does DDT stand for

Answer 14

Dichloro-diphenyl-trichloroethane