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Flashcards in chapter 6: Water quality managment Deck (59)
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1

Primary fate and transport mechanisms for contaminants potentially present include the following:

  • Volatilization of chemicals from soil
  • Degradation of chemicals in soil and groundwater
  • Erosion of particulate-bound chemicals from soil
  • Leaching from soil with infiltrating water
  • Transport of chemicals with groundwater flow.

2

Volatilization can significantly affect

the distribution of a chemical in the environment

3

Volatilization can significantly affect the distribution of a chemical in the environment. In soils, the result is

a decrease in the amount of a chemical in soil

4

In soils, the result is a decrease in the amount of a chemical in soil as the chemical

volatilizes to soil gas and ultimately discharges to the atmosphere

5

. In soils, the result is a decrease in the amount of a chemical in soil as the chemical volatilizes to soil gas and ultimately discharges to the atmosphere. Volatilization reactions are most significant in

surface soils that are in direct (or near-direct) contact with the atmosphere.

6

Numerous chemicals in the environment are subject to

naturally occurring biotic (biologically based) and abiotic (non-biologically based) transformation reactions

7

Numerous chemicals in the environment are subject to naturally occurring biotic (biologically based) and abiotic (non-biologically based) transformation reactions that result in

the degradation of the chemical

8

Numerous chemicals in the environment are subject to naturally occurring biotic (biologically based) and abiotic (non-biologically based) transformation reactions that result in the degradation of the chemical. Many organic compounds are subject to

biodegradation reactions

9

Numerous chemicals in the environment are subject to naturally occurring biotic (biologically based) and abiotic (non-biologically based) transformation reactions that result in the degradation of the chemical. Many organic compounds are subject to biodegradation reactions under

aerobic (in the presence of oxygen) and anaerobic (in the absence of oxygen) conditions

10

During biodegradation, naturally occurring microorganisms in the ...................... 

subsurface

11

During biodegradation, naturally occurring microorganisms in the subsurface transform

a chemical to another state as a direct or indirect consequence of their metabolic processes

12

During biodegradation, naturally occurring microorganisms in the subsurface transform a chemical to another state as a direct or indirect consequence of their metabolic processes. Biodegradation reactions often

break down organic chemicals to less toxic forms

13

Several naturally occurring abiotic reactions can significantly affect

the fate of chemicals in the environment

14

Several naturally occurring abiotic reactions can significantly affect the fate of chemicals in the environment. Common abiotic reactions include

photodegradation and hydrolysis

15

Photodegradation is

the process of decomposition of a chemical upon exposure to radiant energy such as the action of light

16

Photodegradation is the process of decomposition of a chemical upon exposure to radiant energy such as the action of light, and is most significant to chemicals in

surface soil that are in direct contact with sunlight

17

Hydrolysis is

the degradation reaction of the chemical with components of water

18

Hydrolysis is the degradation reaction of the chemical with components of water (e.g.,

hydroxyl and hydronium ions)

19

Hydrolysis is the degradation reaction of the chemical with components of water (e.g., hydroxyl and hydronium ions) and is thus most important in

saturated environments

20

Erosion processes can substantially affect the

distribution of soil-bound particulates in the environment

21

Erosion processes can substantially affect the distribution of soil-bound particulates in the environment and thus influence the

distribution of soil contaminants

22

Erosion processes can substantially affect the distribution of soil-bound particulates in the environment and thus influence the distribution of soil contaminants. High winds can scour

fine particles from the soil surface and redistribute these particles downwind

23

Similarly, runoff resulting from heavy precipitation events can scour

fine soil particles from surface soils

24

Similarly, runoff resulting from heavy precipitation events can scour fine soil particles from surface soils, eventually

depositing the particles during sedimentation downstream.

25

Similarly, runoff resulting from heavy precipitation events can scour fine soil particles from surface soils, eventually depositing the particles during sedimentation downstream.

These physical processes often represent the

primary mechanism for transport of otherwise immobile chemicals such as metals.

26

Chemicals in soils have the potential to

migrate to greater depths

27

Chemicals in soils have the potential to migrate to greater depths with

infiltrating water.

28

Chemicals in soils have the potential to migrate to greater depths with infiltrating water. As rainwater infiltrates, chemicals may be

be leached from the soil and carried to greater depths and potentially to groundwater

29

Chemicals in soils have the potential to migrate to greater depths with infiltrating water. As rainwater infiltrates, chemicals may be leached from the soil and carried to greater depths and potentially to groundwater. The degree to which a chemical is leached is strongly influenced by

the chemical’s tendency to partition to the solid or aqueous phases

30

Chemicals in soils have the potential to migrate to greater depths with infiltrating water. As rainwater infiltrates, chemicals may be leached from the soil and carried to greater depths and potentially to groundwater. The degree to which a chemical is leached is strongly influenced by the chemical’s tendency to partition to the solid or aqueous phases, which is largely a function of

the chemical’s solubility and particle affinity.