**2.1 Water quality indicators**

To determine the quality of a water body, the chemical, biological and physical conditions of a water body must be measured. Chemical measurements, biological surveys, and visual observations (physical) provide a "big picture" of what's happening in a water body. The following is a list of indicators (physical, chemical and biological) that are often measured to assess the quality of water.

a. Physical indicators

Some physical indicators of the quality of a water sample from any source include,


Some chemical indicators of the quality of a water sample from any source include,

*Application of Water Quality Index for the Assessment of Water from Different Sources… DOI: http://dx.doi.org/10.5772/intechopen.98696*


Some biological indicators of the quality of a water sample includes,

• Bacteria (fecal coliform, *Escherichia coli*, Cryptosporidium, *Giardia lamblia*), � Viruses - Fungi protozoa - Parasitic worms - *Pimephales promelas* (fathead minnow) -*Americamysis bahia* (Mysid shrimp) - Benth ic macroinvertebrates (Ephemeroptera or mayfly, Plecoptera or stonefly and Trichoptera or caddisfly – Sea Urchin – Mollusca (Bivalve mollusks – *Americamysis bahia* (Mysid shrimp)

## **2.2 Water quality standards**

Water quality standards imply statements and numeric values that describe water quality and fall within the following three components:


The standard used for particular water is a function of the expected use of the water. **Table 1** presents some of the established standards of some water quality parameters. What this means is that the established standard used for drinking water is used only in determining the Drinking Water Quality Index while the Aquatic Water Quality Index standards are used to protect aquatic life. Basically, the index can be calculated for three different uses:


#### **2.3 Water quality index**

The general norm for reporting water quality parameters by comparing the different analyzed parameters with their respective permissible limits and standards set by regulating bodies at local, regional, national or international levels has
