Biological Water Quality Parameters

Biological water characteristics are used to describe the presence of microbiological organisms and water-borne pathogens. Many organisms can cause illness when directly consumed by humans and animals. Micro-organisms and waterborne pathogens generally enter rivers and lakes when they are contaminated by human faeces, for example when sanitation is lacking or untreated or partially treated sewage is discharged into it.

Within the Kunene River basin there are no functioning wastewater treatment plants, thus a vast potential for faecal contamination of water resources exists.

Giardia lamblia is a protozoan parasite that can be found in untreated water and cause diarrhoea.

Source: Carr 2006

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Achieving a water quality standard that will not harm aquatic organisms, and is safe for human consumption is a challenge throughout much of the basin. This is especially true for rural areas (e.g., Momba et al. 2006, Hodgson and Manus 2006). Water borne diseases such as dysentery, cholera, typhoid, gastro-entertitis and hepatitis are the primary cause of disease and poor health in the SADC region (SADC 2009).

Bilharzia and malaria are other waterborne diseases that persist in the SADC region. Water polluted with ecoli and fecal coliform used for bathing and drinking are pricipal pathways of infection.

Typical values for water quality parameters for un-polluted and polluted water are shown in the table below.

Typical Values for Water Quality Parameters