Environmental problems – An overview - Environmental Deterioration and Contamination: Problems and their Management - page 22

Table 1.3 Time frame and spatial scale of ecological characteristics and processes.

Characteristic/process Time frame Spatial scale

Genetic and molecular events second-hour-day nm- µ m-mm

Microbial processes hour-day mm-m

Cell-scale processes hour-day-year mm-m-km

Organ and tissue level hour-day-year mm-m-km

Physiology and behavior day-year-10 years m-km-1,000 km

Population and its dynamics day-year-100 years m-km-1,000 km

Ecosystem and its dynamics year-100 years km-1,000 km

Landscape dynamics 100 years-100,000 years km-10,000 km

Global-scale processes and dynamics 100 years-millions of years World wide

Table 1.4 Time frame and spatial scale of the appearance of anthropogenic impacts and contamination

Characteristic/process Time frame Spatial scale

Production and local use of chemicals minute-hour-day m-km

Waste disposal hour-day m-km

Diverse point sources hour-day-year m-km

Wastewater day-year-10 years m-km-100 km

Contaminant spills day-year-10 years m-km-100 km

Diverse diffuse sources day-year-10 years m-km-100 km

Pollutants of emerging concern year-10 years-100 years m-km-100 km

Eutrophication hour-year-100-1,000 years km-1,000 km

Atmospheric deposition 10 years-1,000 years km-10,000 km

Climate change 100 years-1,000,000 years km-10,000 km

Diverse global-scale deteriorations 100 years-millions of years World wide

but also a dynamic approach with a good support for the ecosystem to be able to
maintain its regulating abilities.

4 EXTENSION ANDTIME FRAME OF ENVIRONMENTAL RISKS
ANDTHEIR MANAGEMENT

If the environment is to be effectively managed, in addition to the hierarchy of organ-
isms or genetic and functional groups of organisms in the ecosystem, one has to
know and take into consideration the time frame and spatial scale of natural envi-
ronmental processes (Table 1.3) and deteriorating processes such as contamination
(Table 1.4).
The management of point and diffuse sources needs different models and engi-
neering tools, as introduced in detail in Chapter 9. Many of the adverse effects of
chemicals occur on multiple time and spatial scales because of the differences in short-
term and long-term adverse effects of the same contaminant. For example, in addition
to acute toxicity, many toxicants such as pesticides may have long-term carcinogenic