Groundwater from non-polluted areas is generally safe for domestic purposes - to drink, prepare food, wash clothes, bath and water the garden.
But how can we be sure that the chemical, microbiological and physical properties of water are acceptable for domestic users? In this article, we will look at the need to analyse groundwater samples to determine its quality.
Microbiological Quality: Micro-organisms are filtered out and die off as the water travels through the ground. Very often, because it travels slowly the water in a deep unconfined aquifer or a confined aquifer has been there for many years and is free of harmful organisms.
Microbiological Quality: Micro-organisms are filtered out and die off as the water travels through the ground. Very often, because it travels slowly the water in a deep unconfined aquifer or a confined aquifer has been there for many years and is free of harmful organisms.
Shallow, unconfined aquifers are not much safer than surface water sources because the water has had very little filtration or storage time before it is collected for drinking.
Campylobacter, Escherichia coli (E. coli), Cryptosporidium, Giardia and viruses have all been found in groundwater supplies. These microbes are carried into the aquifer from the surface.
The vulnerability of aquifers to microbial contamination is increased by:
1. Shallow aquifer depth.
2. Microbial contamination in the surface water catchment.
3. Water flowing quickly through the aquifer via particularly porous material or fractured rock.
4. The absence of a confining layer.
2.3 Chemical Quality: The chemical quality of groundwater is influenced by the quality of the water entering the aquifer as well as by the minerals in the ground. Minerals in the soil and rocks dissolve into the water as time passes.
In limestone country, for example, the water can become very ‘hard’ as the lime dissolves. In some regions, arsenic is present in volcanic rocks and can be found in groundwater taken from particular aquifers.
Often, because a deep aquifer is devoid of oxygen, the form of the chemicals will
change as they pass through it. As a result, it is common for groundwater to contain
ammonia, sulphides and the soluble forms of many metals such as manganese and
iron. These and other compounds can cause problems with the taste, smell or colour of
the water.
A number of common chemical contaminants that are a particular issue in groundwater
are described in Table 1 below.
Common Contaminants in Groundwater:
1. Arsenic and Boron: Arsenic and boron often occur at potentially harmful levels in groundwater, particularly
in geothermal and hydrothermal areas. The concentration of arsenic can vary
significantly in shallower bores between summer and winter.
2. Calcium and Magnesium: High calcium and magnesium concentrations can cause water to be ‘hard’, which can
lead to problems of scale formation on hot surfaces and difficulty in getting soap to
lather. This often happens in areas where limestone is part of the land formation.
3. Fluoride: Fluoride has not been commonly found at levels that are of concern to health in New
Zealand. However, if fluoride is being dosed, the concentration in the source water
should be taken into account when deciding the dose rate.
4. Iron and
manganese: Iron in drinking-water in high enough concentrations can cause an unpleasant metallic
taste and a rusty colour, which can stain fixtures and clothing.
Manganese can also affect the taste of the water and has potential health effects when
present in the water at higher levels. When oxidised, manganese can be deposited in
pipes. It also causes staining of laundry.
Iron and manganese are often found together in groundwater. The conditions that lead
to the presence of iron and manganese can be localised and may change over time.
High nitrate concentrations can occur in drinking-water sources due to contamination
from farming, septic tank systems and solid waste disposal. A high nitrate
concentration can be toxic to bottle-fed infants.
5. Pesticides: In some boreholes, pesticides may be present. Testing should be undertaken if it is
suspected that pesticides may be present, particularly in shallow unconfined aquifers.
6. Radioactive Elements: Groundwater can contain naturally occurring radioactive elements, such as radon.
Water from new underground sources must be tested for radon before they are
connected to a reticulated drinking-water supply.
7. Salinity: Some aquifers are naturally saline (salty). Bores located near the coast maybe
affected by seawater flowing into the aquifer if excessive water abstraction causes
seawater to be drawn into the aquifer to replace the freshwater.
Nakiso Borehole Drilling: Your Trusted Partner for Safe, Sustainable Water Access
At Nakiso Borehole Drilling, we are your comprehensive partner for unlocking reliable water on your property. Our highly skilled team tackles all drilling projects, from standard boreholes to specialized Blast Hole and RC Drilling. We handle everything in-house for a seamless experience, encompassing expert borehole siting, efficient drilling, and pump installation – solar, electric, or manual – tailored to your specific needs. With Nakiso, your reliable water source is just a drill away.We don't just strive to be the best; we maintain the industry's strictest quality standards and are committed to sustainable practices for the future of Zimbabwe's water security.
For All Your Borehole Drilling Services Contact Us:
Five Facts About Borehole Drilling That You Need To Take Note Of:
1. Know Your Borehole Casings:The Preferred Borehole Casing In Zimbabwe Is Class 9 and 10 (Pressure Classes.)This is because Class 9 and Class 10 Casings are more collapse resistant. The strength of a Casing is often described as collapse resistance.
2. Borehole Drilling Depth: The exact depth, of where the water is located, cannot be established by the drilling contractor nor the Water Surveyor (Borehole Siter).
3. The Is No 100% Guarantee On Water: It is important to note that it is never a 100% guarantee that any hole will yield water, the amount and water quality can also not be guaranteed by the drilling contractor and water surveyor.
4. Borehole Siting or Water Surveying Is Important: Making use of a hydrologist or traditional water diviner will increase your chances of having a successful borehole that will yield a sufficient amount of water.
5. Know The Risks: The risk of the borehole drilling lies with the property owner. The client will still be liable for the drilling costs irrespective of a borehole yielding water or not.
Your smile is our commitment!
Business Offices: 65 Churchill Avenue, Alexandra Park, Harare North, Zimbabwe.
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Office Numbers: +263 867 71 88844
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Email: info@nakisoboreholes.co.zw
Website: www.nakisoboreholes.co.zw
