Feature Article of Wednesday, 14 November 2012
Columnist: Anim-Mensah, Alexander
Water is considered one of the most abundant solvents and is classified as highly complex by virtue of its behavior. It has several properties that make it unique and it is the source of our living. The quality of our developments depends very much on the quality of water we as humans consume. The impurities in water that directly affect our health are termed primary contaminants and the others that are considered non-health threatening are termed secondary contaminants.
This article presents some information on secondary water contaminants, their effects, and clues for diagnosis and identifications to attract the necessary proper water treatment. This would help, I believe, to achieve the water quality of interest. Secondary contamination effect of water is basically the effects of some water contaminants above some standard limits. This shows visible effects and which some could have direct consequences. Secondary contamination effects do not necessitate enforcement and adherence to standard limits but only serve as a guideline.
Although, much emphasis is placed on the primary contaminants effects because it is related to human health; secondary effects have associated consequences if appropriate measures are not put in place or not adhere to could have indirectly consequence to life as well. For instance:
• Loss of lives and properties from exploded hot water/ steam system as results of corrosion.
• Rupturing, leakage or blockage of water distribution lines.
• Increased incidence of Alzheimer’s diseases.
• Greater portions of Ghanaians losing their teeth at a young adult age.
• The graying of our eyes, and
• loss of independent mobility (ambulation) as a result of brittle bones or fractures
What all these consequences have in common is exposure of consumers to poor water quality by secondary contaminants, however safe the water is considered. Though, this might sound hyperbolic to some, it is real. A lot of people in Africa are going through poverty and diseases because of lack of basic understanding of the relationship that exists between human survival and water quality.
Therefore, apart from the health effects of some water contaminants of which are considered primary; there are secondary effects that are categorized as aesthetic, cosmetic and technical. Some of which could be directly or indirectly related to primary effects. These secondary effects includes taste, odour, appearance i.e. colour, and could have varied impacts on life. Corrosion could result in unsuspected explosion if a water or steam vessel under pressure unexpectedly bursts out water. Other consequences include flooding or hot water/ steam gushing out which could affect lives and/or properties.
Water quality is described by physical, chemical and biological parameters. Physical parameters refer to taste, odour and appearance. Appearance includes colour and the clearness of water (turbidity). Chemical parameters involve ions, gases and other dissolved substances in the water while biological by the presence of germs and other living microorganisms. Taste, odour and colour define the cosmetic, aesthetic and technical impacts of water. In some cases the chemical nature of the water above some limit show up as physical which impacts taste, odour and appearance while some biological activities could also show up as chemical and physical above some limit. The interconnection between the physical, chemical and biological nature of water defines such parameters as total hardness, total dissolved solid (TDS), total suspended solids (TSS), conductivity, pH and the rest.
As water quality varies from place to place and so are the properties. Additionally, the nature of surfaces such as plastic, soil type, metal, etc or activities mining, farming, construction, etc water is exposed to on its way could affects the properties. Note that rainfall pattern, geological activities and man’s activities help define water quality.
Though, these secondary standards are not enforceable in Ghana; they are associated with water quality. Aesthetic effects are associated with undesirable taste and odour, while cosmetic is associated with appearance like color/discoloration. Technical effects are associated with damages and/or inefficiencies including reduced heating, etc. of equipments from buildup of scales, dirt and/or corrosion hence cost money to repair. The above shows that the secondary standard limit on water needs to be considered seriously in some situations.
In Africa, huge uncertainty surrounds the quality of our water; considering sanitation issues pestering our part of the world making physical indicators of water quality like colour, taste and odour be a good candidate in relation to the safety of the water. Odour and taste indicate the type of treatment required or the treatment method used. Some contaminants however present in small concentrations in water could results in objectionable or noticeable taste, odour and colour which may be required to be removed.
Some of the ions and compounds that are associated odour and taste in water above some limit include Copper, Iron, Manganese, pH, Chloride, Fluoride, Sulphate, Silver, Total Dissolved Solid (TDS), Zinc, Foaming Agents, and Threshold Odour Number (TON). Colour of water is an indicator of dissolved organic material such as decaying leaves, biological activity in water. And are indications of inadequate treatment or high disinfection demands, and/or potential presence of excess disinfection by- products in water. Others above some limits producing colour in water include Aluminum, Copper, Foaming Agents, Iron, Manganese and TDS. Foaming of water could be associated with water having inherent oily, fishy or perfume- like taste which could have a natural or synthetic origin.
Skin and tooth discoloration, tooth pitting, graying of the white part of the eyes (argyria) and staining are some of the cosmetic impacts of water. Skin discoloration and graying of the white part of the eye is associated with regular consumption of water with silver above a limit. Ingestion of silver in water is not known to cause any impairment to body function however it is a major component in some water treatment products as antibacterial agent, which high levels or daily consumption is a concern. Fluoride in the right concentration in water is known to be good for the teeth and helps prevent decay, however in excess could result in teeth discoloration, pitting and/or crumble especially in children. Others believe the presence of excess Fluoride is linked to brittle bones and improves the body’s absorption for Aluminum. Research has found Aluminum in the brains of many Alzheimer’s patients which could be linked to the cause of disease. In addition, excess Fluoride has been implicated to damage the muscle, skeletal and nervous systems.
To be specific noticeable ions in water or water parameters above some limits associated with metallic taste are Copper, Iron, Zinc, Manganese and low pH. Salty taste of water may be linked to Chlorides, Sulphates and TDS while bitter tastes are associated with Foaming Agents and Manganese. Cloudy water is related to high TDS while deposits on surfaces are related to suspended particles, TDS, high pH and hardness (mostly Calcium and Magnesium). Blue-green staining is associated with copper, tan - black with manganese while red-brown-orange with Iron.
I believe understanding the power of water and its various characteristics could help with the diagnosis of some simple water problems and prompts the required treatment. In addition, this will help apply water effectively and efficiently in the midst of dwindling water resources. Moreover, some of these observations could be used for monitoring of activities upstream of some rivers to prompt the right remedy or attention. I will say pay attention to your tap water. Finally, water has to be treated sufficiently to dim low some of the primary and secondary effects for a given application-consumption, domestic or industrial use. God bless Ghana.
My sincere thanks go to Douglas Oti, PhD (Tampa Florida, [email protected]) for editing this article.
Alexander R. Anim-Mensah, Ph.D.