Global Water Quality Conditions in the World
People have specific water quality requirements for drinking water, recreation, agriculture and industry; although the specific water quality requirements vary by sector. Degradation of water quality erodes the availability of water for humans and ecosystems, increasing financial costs for human users, and decreasing species diversity and abundance of resident communities.
These changes in environmental quality can be associated with changes in water quality parameters such as sediment load, nutrient concentrations, temperature, dissolved oxygen levels, and pH. The addition of excessive levels of naturally occurring or synthetic compounds, such as oil and grease, pesticides, mercury and other trace metals, and non-metallic toxins can harm wildlife and people that depend on these aquatic resources.
This unit outlines how water quality is affected by different processes and the ways in which human activities in different economic sectors influence these processes.
Global Water Quality Conditions in the World
Table 4 shows the generally identified causes of degradation of water quality in many water resources in the world, and their sources.
Table 4: Sources and Causes of Water Contamination in Many Parts of the World
Source: USEPA National Water Quality Inventory 2000 Report
Read Also : Objectives of Water Treatment and Water Treatment Processes
Figures 2 – 3 show that Africa has the least percentage of cities served by good water supply in the world while the highest population in the continent either do not have modern toilet facilities or do have the local variety and it is of low quality
Fig. 2: Water Supply in the Largest Cities: Mean Percentage of the Population and each Type of Service by Region
Source: WHO and UNICEF “Global Water Supply and Sanitation Assessment 2000 Report
Fig. 3: Sanitation in the Largest Cities: mean Percentage with each Type of Facility, by Region
Source: WHO and UNICEF “Global Water Supply and Sanitation Assessment 2000 Report”
Africa also has the highest percentage of contaminated drinking water available for her population. See Figure 4.
Fig. 4: Percentage of Water Supply which is effectively Disinfected (Free Residual Chlorine over 0.1 mg/l), and Percentage of Drinking Water Quality Test results that Violate National Standards (Microbiological, Chemical, Physical, Aesthetic)
Source: WHO and UNICEF “Global Water Supply and Sanitation Assessment 2000 Report”
Read Also: Meaning and Difference between Palatable Water and Potable Water
