Test 3 Chapter 14

Question 1

Heavy metals have to be treated differently why?

Answer 1

They cannot be degraded or destroyed

Question 2

Sources of heavy metals in the environment

Answer 2

Mining activities, industry, agrochemicals, atmospheric deposition, waste disposal

Question 3

Metals bioremediation mechanisms:

Answer 3

Metal immobilization
—Complexation (Bioaccumulation and biosoprtion)
—Precipitation
Solubilization (Bioleaching)

Question 4

Mercury traits

Answer 4

Only common metal that is liquid at room temperature.

Question 5

Where is mercury found in nature?

Answer 5

Cinnabar ore (HgS) in Spain and Italy

Question 6

How does mercury methylation occur?

Answer 6

Mercury polution gets into the water and underwater archaea or bacteria what are then moved up the food chain to fish we eat.

Question 7

Most toxic form of mercury?

Answer 7

methyl mercury

Question 8

Bioaccumulation

Answer 8

the buildup of substances, such as pesticides or heavy metals, in an organism.

Question 9

How does bioaccumulation occur?

Answer 9

when an organism absorbs a substance faster than it excretes it.

Question 10

Results of bioaccumulation

Answer 10

results in the organism having a higher concentration than the surrounding environment.

Question 11

Biomagnification

Answer 11

An increase in concentration of a pollutant from one link in a food chain to another.

Question 12

Bio-magnification effect?

Answer 12

Predators will have more accumulation since they are at the top of food chain.

Question 13

Number of Chromium oxidation states?

Most common ones

Answer 13

6 oxidation states

+3, +6 most common

Question 14

Hexavalent Cr(VI)

Answer 14

Most toxic and most soluble form of Chromium

Question 15

What does Cr (VI) cause?

Answer 15

Induces free-radical formation

Oxidative stress - DNA/membrane damage

Question 16

Chromium (III)

Answer 16

essential nutrient for humans and shortages may cause heart conditions, disruptions of metabolisms and diabetes

Question 17

Chromium (III) overdose

Answer 17

uptake of too much chromium(III) can cause health effects as well, for instance skin rashes

Question 18

Chromium (VI)

Answer 18

Danger to human health, mainly steel and textile industry. And smokers.

Question 19

Bio-immobilization

Answer 19

Direct reductive precipitation - microbes change valency

Indirect reductive precipitation - microbes reduce other Terminal electron acceptor to precipitate heavy metals

Question 20

Indirect reductive precipitation

Answer 20

Microbial reduction of other terminal electron acceptors result in abiotic reduction and preciptation of heavy metals.
Useful in above-ground and in situ treatments.

Question 21

Direct reductive precipitation

Answer 21

using microbes to precipitate heavy metals by changing their valency
Useful in above-ground and in situ treatments