Table 4.6: Spatial and time scales within which pollution occurs and can be
remediated
| Major Cause / Issues |
Major Related Issues1 |
Scale2 |
Time to pollute3 |
Time to Remediate4 |
Major Controlling Factors |
| Local |
Region |
Global |
< 1 |
1 to 10 |
10 to 100 |
< 1 |
1 to 10 |
10 to => 100 |
Byophysical |
Human |
| Notes: |
| The nutrional status of most regions of the world has improved
in all developing regions. Sub-Saharan Africa and South Asia have also
improved their nutrional level, b ut they lag behind and are host to the
majority of the undernourished people in the world. |
| 1 Relevant primarity to * surface water, ** groundwater |
| 2 Local < 10000 km2, region
->104 to 106 km2, global
->106 to 108 km2 |
| 3 Lag between cause and effect. |
| 4 Longest time scale if for groundwater, followed by lakes, and
shortest for rivers and streams. |
| |
|
Category Shading
|
| Scale - the colour intensity increases as impact dimension
becomes greater. |
| Time to pollute and Time to remediate are highlighted in red
for most critical, orange for moderately critical, and yellow for the least
critical situations. Green is shown for the situation where remedial actions
could be less than one year (pathogens). |
| |
| Source: Modified from Peters and Meybeck, 2000. |
|
Population
|
Pathogens |
|
|
|
|
|
|
|
|
|
|
Density & Treatment |
| Eutrophication(*) |
|
|
|
|
|
|
|
Treatment |
| Micro-pollutants |
|
|
|
|
Various |
|
Water Management4
|
Eutrophication(*) |
|
|
|
|
|
|
|
|
|
Hydrodynamics |
Flow |
| Salinization |
|
|
|
|
|
Water Balance |
| Parasites |
|
|
|
>100
|
Hydrology |
|
Land Management
|
Pesticides |
|
|
|
|
|
|
|
|
|
|
Agrochemicals |
| Nutrients |
|
|
|
|
|
|
Fertilizer |
| Suspended solids |
|
|
|
|
|
|
Construction / clearing |
| Physical Changes |
|
|
|
|
>100
|
Cultivation, Mining, Construction, Clearing |
|
Atmospheric Transport
|
Acidification (*) |
|
|
|
|
|
|
|
|
|
|
Cities, melting and fossil fuel emissions |
| Micro-pollutants |
|
|
|
|
Cities |
| Radionuclides |
|
|
|
|
|
>100
|
Industry |
| |
Mega Cities |
Pathogens |
|
|
|
|
|
|
|
|
|
|
Population & Treatment |
| Micro-pollutants |
|
|
|
| Mines |
Salinization |
|
|
|
|
|
|
|
|
|
|
Types of Mines |
| Metals |
|
|
|
| Nuclear-Radionuclides |
|
|
|
|
|
|
|
|
>100
|
|
|
|
Global Climate Change
|
Salinization |
|
|
|
|
|
|
|
|
|
Temperature & Precipitacion |
Fossil fue emissions & Greenhouse gases |
|
Natural Ecology
|
Parasites (*) |
|
|
|
Permanent |
|
|
Permanent |
Climate, Hydrology |
|
|
Natural Geochemistry
|
Salts |
|
|
|
Permanent |
|
|
Permanent |
Climate, Lithology |
|
| Fluoride (**) |
|
|
|
| Arsenic, Metals (**) |
|
|
Lithology |
Source: UNESCO 
The United Nations World Water Development Report 2
Section 2: Changing Natural Systems,
Chapter 4, Part 2. Nature, Variability and Availability, p.142
Related publication:
Other Figures & Tables on this publication:
Table 4.1: Precipitation distribution into surface water and groundwater
components (by climate region)
Table 4.2: Selected large aquifer systems with non-renewables groundwater
resources
Table 4.3: Water availability information by country (AQUASTAT, FAO 2005)
Table 4.4: Major principal sources and impacts of sedimentation
Table 4.5: Freshwater pollution sources, effects and constituents of concern
Table 4.6: Spatial and time scales within which pollution occurs and can be
remediated
Table 4.7: Potential applications for reclaimed water
Figure 4.1: Global distribution of the world’s water
Figure 4.2: Schematic of the hydrologic cycle components in present-day setting
Figure 4.3: Oxygen-18 content of stream water along the main stem of large rivers
Figure 4.4: Variations in continental river runoff through most of the twentieth century (deviations from average values)
Figure 4.5: Typical hydrographs in accordance with climatic settings
Figure 4.6: Acid rain and its deposition processes
Figure 4.7: Five-year mean of the pH level in rainfall in the eastern regions of Canada and the US
Figure 4.8: Primary sources of groundwater pollution
Map 4.1
Map 4.2
Map 4.3: Groundwater abstraction rate as a percentage of mean recharge
Aral Sea
