WATER POLLUTION: POLLUTANT LOADS IN STREAMS OF HEAVILY
POPULATED AND INDUSTRIALISED URBAN DWELLINGS
Felix Ntengwe
Department of Environmental and Chemical Engineering, School of Technology,
Copperbelt University, Jambo Drive, Riverside, Box 21692, Kitwe, Zambia. Email:
fntengwe@cbu.ac.zm
Tel: ++260 2 228212/229780
Fax: ++260 2 228212/229780
Abstract
Water is a commodity that many of us take for granted and allow it to be polluted to some extent.
The industries, settlement areas, farming areas, markets, leaking sewer lines, poor hygiene
practices are all potential sources of pollution. A study conducted in Kitwe Stream, revealed
high levels and loads of Total Suspended Solids (TSS), Coliform, Nitrates, Nitrites and
Chlorides.
These parameters exceeded the maximum contaminant level (MCL).
The
conductivity was also found to be high. The benthic and phytoplankton study revealed a normal
diversity of invertebrates and phytoplankton. The finger size Fish (Tilapia) was found upstream
and at the mouth of the stream where it joins the Kafue River and not at other points. The
stream water quality was therefore found to be poor based on high levels of coliform, nitrates,
nitrites and chlorides.
1
Key Words: Human; Engineering; Water; Quality; Pollution
Introduction
The birth of industrial revolution and the rapid increase in human population has led to a large
transformation of natural environment. The environment has become hostile, posing many
threats to health and welfare because of pollants released into the environment.
It should
therefore be made safe and turned to good use for better standards of living and wealth creation
(Thomas, 1972).
Pollution is a very general term and is defined as the befouling of the environment by man’s
activities particularly by the disposal of solid, gaseous and liquid wastes (Velz, 1970). It can
also be defined as any environmental change, which alters the species diversity in a particular
location as defined by Cairns and Lanza (1973). Inevitably, unsustainable and wasteful use of
resources leads to the production and accumulation of unwanted materials which require disposal
on land, sea and air.
A subject that is becoming important to day is achieving a balanced ecosystem. A balanced
ecosystem is that in which living things and the environments interact for beneficial use to one
another. Obviously water quality plays a critical role in this relationship. Often overlooked is the
need to have a clean supply of water to centres of recreation like fountains, ponds and pools.
Natural water bodies like Lakes, Rivers and Streams should contain water of good quality
because they are the only natural water sources (Mann and Williamson, 1986). The application
of disinfectants to kill organisms presents a solution only to piped water where the rate of kill of
2
organisms is dependent on the number of viable organisms (Tebbutt, 1992). Water quality is
therefore critical in order to maintain a well-balanced environment.
The water quality is usually affected by human and engineering operations which release
material wastes that eventually interfere with water quality when they decay or dissolve into
stream or river water. It is important to appreciate that all natural waters contain a variety of
contaminants arising from erosion, leaching and weathering processes (Nemerow, 1985). Such
pollutants can only have their concentrations reduced by normal water and wastewater treatment
processes so that their presence in a particular water source may limit its use (Tebbutt, 1992).
Study Area
Kitwe Stream is in Kitwe District in Zambia.
It has its catchments area in the northwest of
Kitwe Town.
It traverses from the mine
dumps through the Industrial area at points
P3, P4 and P5, the sugar cane growing area
between points P7 and P8 to the Kafue River
at point P10 (Fig. 1). The major effluents
discharged into the stream are from Mine
Dumps, Market at P4, Water Works at
Fig.1 Kitwe Stream From the source to
upstream of P9 and that from Sewage Works
confluence at Kafue river
near point P10.
3
Objective of the Study
The main objective of the study was to establish whether engineering and other human activities
affect the state of water quality in the stream. The state of water quality can be defined in terms
of poor water quality where the water ecosystem is disturbed or good water quality where the
ecosystem interacts effectively for the benefit of one another. The specific objectives were to
assess loads of metals and inorganic nutrients, measure pH in order to determine whether
compounds that contribute hydrogen ion concentrations accessed stream water and assess the
presence of Algae, Coliform, Vertebrates and Invertebrates in order to determine whether the
water quality was conducive to the well being of organisms.
MATERIALS AND METHODS
A physical survey of the area in which Kitwe Stream flows was carried out. The stream was then
divided into ten points from which samples were collected. The samples were analysed for
temperature, conductivity, alkalinity, dissolved oxygen, biochemical oxygen demand, total
suspended solids, pH, chlorides, sulphates, nitrates and metals using standard methods. The
sampling programme involved collecting of samples every two weeks and the results were
averaged monthly.
The pH and conductivity readings were measured using pH and conductivity meters. Filtration
Method was used to determine the total suspended solids (TSS). The DR/700 Colorimeter was
used for the analysis of Nitrates, Nitrites, Sulphates, Iron and Phosphates. Chlorides were
4
analysed using a Titration Meter where a volume of water sample was placed in a conical flask
and a powder reagent was added. The probe was placed into the sample mixture and the reading
was recorded in mg/L. The Membrane Filtration Method was used to detect and enumerate
Faecal Coliforms (Hammer, 1986; Viessman et al, 2000). The Dissolved Oxygen (DO) was
determined by the use of a DO meter. The value of DO was then used in equation (1) in order to
find BOD (Viessman et al, 2000).
BOD 520 
D1  D2
P
(1)
Where D1 is dissolved oxygen before incubation, D2 is dissolved oxygen after incubation, P is
volumetric fraction of sample used, 5 is the number of days of incubation and 20 is the
temperature of incubation. Zinc, Cadmium, Lead, Manganese and Cobalt were analysed by
using Atomic Absorption Spectrophotometer (AAS). The phytoplanktons were detected in a
counting chamber under a microscope.
The Benthos were detected by placing pieces of
calabashes put together and tied by a rope to which a heavy stone was attached and left in water
for one month at several points. The results were recorded as present or absent (Yes or No). The
Tilapia Fish were detected by observation as present or absent by placing lumps of cooked maize
husks into the stream. The loading (PL) of each pollutant was evaluated using equation (2) while
the total loading (PTL) at any point was evaluated using equation (3). The total external loading
(PTEL) of pollutants entering the stream was calculated using equation (4). The subscripts M,
WW and SW represent Market, Water Works and Sewage Water respectively. In each of the
cases, Q is the flow rate (m3/s) and C is the level of pollutant (mg/L). The external loads could
also be evaluated using the increases at points P4, P9 and P10.
5
PL  QC
(2)
PTL  Q(C1  C2  C3  ....  Cn )
(3)
PTEL  QM CM  QW WCW W  QSW CSW
(4)
RESULTS AND DISCUSSION
The pH is a scale based on hydrogen ion concentration by which water and other substances are
measured in order to determine if they are acidic, neutral or alkaline (Skoog and West, 1976).
The midpoint or neutral point of the scale is pH 7.0. Readings from 0 to 7.0 are acidic and the
lower the pH value the more strongly acidic the material. Readings from 7.0 to 14.0 are alkaline
and the higher the reading the more strongly alkaline the material. Highly acidic or alkaline
waters are undesirable because many microorganisms become inactive. The pH is used to
determine effluent, stream and river water quality. The stream or river water quality is affected
by the pH of the effluents coming from industries because they make metals more soluble in
water and make them become more toxic than normal (Chambers et al, 1999). For example, fish
that can stand pH4.8 will die at pH5.5 if water contains 0.9mg/L of iron (Chambers et al, 1999).
Chambers et al (1999) also reported that, “If one mixes an acid water environment with small
amounts of Lead, Mercury and Aluminium, one will have a similar problem”.
A study
conducted in Nigeria supports this view (Ogunfowokan et al, 2005). Therefore, pH is useful
parameter to monitor water and ecosystem quality. The pH at most of the points in the stream
6
was found to be in the range of 7.00 to 7.60 (Fig. 2). This indicates that the water was neutral at
the time of sampling. The point with the highest pH was point P4 having a pH of 8.56. This
indicates that the water at this point was slightly alkaline at the time of sampling. The next point
also had a slightly higher pH than the rest of the points (pH 7.59). This could also be attributed
to microbial decomposition of organics and dissolution of minerals.
Natural water should
normally have a pH of 6.5 to 9.
40
34
32
mg/L
30
21
20
10
6.1
4
1.1 2
57
8.6
P3
P4
5.9
6
2.2
4
4
5 5 6.85
P8
P9 P10
2
0
P1
P2
P5
Nitrates
P6
P7
Nitrites
Fig. 2 Levels of Nitrates and Nitrites
Nitrates and nitrites are considered together because of conversion from one form to the other in
the environment. Nitrates present in substantial quantities in soil, waters and in plants including
vegetables. Nitrites generally are at lower levels than nitrates. Nitrates are products of oxidation
of organic nitrogen converted by the bacteria in soils and water where sufficient oxygen is
present.
Nitrites are formed by incomplete bacterial oxidation of organic Nitrogen. Nitrates and some
Nitrites are also produced in the soil by bacterial decomposition of organic material. Very high
7
Nitrate and Nitrite levels are associated with sewage contamination. Nitrate levels in natural
waters seldom exceed a daily load of 0.00622 tones (0.1 mg/L) according to Chapman (1992).
When influenced by man’s activities, surface waters attain nitrate concentration of up to 5 mg/L.
The maximum contaminant level (MCL) is 10mg/L. Nitrate values exceeding 5mg/L were found
at points receiving effluents. High Nitrate level at points P4 (8.6mg/L), P5 (5.9mg/L), and P6
(6.8mg/L) could be attributed to run-offs from some industries and market. At points P9 and
P10, there is a possibility that some sewage found its way to the stream to contaminate its water
(Fig.2). Nitrites levels in natural waters are usually very low (0.001mg/L) and are rarely higher
than 1mg/L (Chapman, 1993). The high Nitrite levels at points P4 (34mg/L), P5 (32mg/L), P6
(21mg/L) and P10 (12.4mg/L) could be due to contamination from human activities. The results
at other points exceeded the level of 1mg/L but were found to be below 6mg/L, which is also
high for natural waters. The average daily load was 0.77tones, which was high when compared
to the acceptable daily value of 0.062tones. The high values could also be due to Nitrates being
reduced to Nitrites by denitrification processes that are natural (Hammer, 1986).
Phosphorus is an essential nutrient for living organisms and exists in water bodies as both
dissolved and particulate matter. The natural sources of phosphorus are mainly the weathering
of phosphorus bearing rocks and the decomposition of organic matter. Domestic wastewaters,
particularly those containing detergents, industrial effluents and fertilizer run-off contribute to
elevated levels in surface waters. Phosphorus is rarely found in high concentrations in fresh
waters as plants actively take it up. In most natural surface waters, phosphorus ranges from
0.005 to 0.20 mg/L (Viessman et al, 2000). The MCL for phosphates is 10mg/L or a daily load
8
of 0.622tones. High concentrations of phosphates can indicate the presence of pollutants that are
largely responsible for atrophic conditions. The highest phosphate levels as compared to the
other points were found at points P4 (8mg/L), P5 (7.5mg/L) and P6 (7.4mg/L). This could be
attributed to the people’s activities. The high phosphate level at point P5 could be due to
detergents from the washing of cars at this point, as well as faecal contamination from the bush.
At point P6, the high level was due to faecal contamination. The values at other points were
found to be below 4mg/L and therefore within the acceptable contaminant level.
Conductivity or specific conductance is a measure of the ability of water to conduct an electric
current. It is sensitive to variations of dissolved solids mostly mineral salts, degrees to which
they dissociate into ions, the amount of electrical charge, ion mobility and the temperature of the
solution. It is used to judge whether metals contaminate the water. A high value indicates
positive result that metals are present and low value indicates low levels.
The points with high conductivities (500μS/cm) were points P4, P5, P6, P7, P8, P9, and P10.
The rest of the points had conductivities in the range of 311 and 498µS/cm.
The high
conductivities could be attributed to high mineral salt concentration which comes from the
dissolution of minerals in the soil or by run-off from dumps at the source of the stream.
The total dissolved solids (TDS) in water comprise inorganic salts and small amounts of organic
matter. The principal ions contributing to TDS are Carbonate, Bicarbonate, Chloride, Sulphate,
Nitrate, Sodium, Potassium, Calcium and Magnesium. Total Dissolved Solids originate from
natural sources, sewage effluent discharges, urban run off, or industrial waste discharges. High
9
levels of TDS means poor water quality and vice versa. Chloride ion increases the conductance
of electrical insulating paper. Other salts increase the hardness of water. High hardness makes
fish not to thrive while highly mineralised water is not good for human consumption (Chambers
et al, 1999). A study by Malik et al (2003) revealed that industrial effluents from Tannery
Industry had no effect on seed germination but had depressive effect on plant growth due to total
dissolved solids that were released into the stream.
A high TDS implies that the water has a
high concentration of mineral salts, which might come from the dissolution of rocks and soils or
from land run-off. The TDS is related to conductivity in that if they are high, the conductivity
will also be high (Table: 1). The point with high TDS value, P4 (296mg/L), also had high
conductivity value of 586µS/cm. The maximum contaminant level (MCL) of TDS is considered
on case by case basis.
Inorganic solids such as clay and silt bring about total suspended solids (TSS). The TSS are
particles of different materials that remain suspended in water. Water with high TSS value is
displeasing to human beings and reduces the growth rate of fish (Viessman et al, 2000). The
TSS also provides adsorption sites for chemicals and biological agents. The TSS is related to
turbidity in that if it is high, turbidity will also be high. The points with a high TSS values were
points P4 118mg/L), P5 (99mg/L) and P6 (140mg/L) representing daily loads of 7.74, 6.16 and
8.71 tones. The first three points were found to have a value of 41mg/L and the rest of the points
had values less than 27mg/L. A lot of domestic waste from the trading area entered at points P4
and P5, which resulted in high TSS values (Fig.3). Increased levels of dissolved solids also
result in reduction of dissolved oxygen in water (Kirk-Othmer, 1984). Fish often die of a sudden
lowering of the oxygen content of a stream or river and solids that settle to the bottom will cover
10
their spawning grounds and inhibit propagation (Martin et al, 1996). An acceptable value of
TSS is 100mg/L or a daily load of 6.22 tones (GRZ, 1990). Therefore the result was outside the
range at some points.
140
mg/L
150
118
100
50
58 57
4841 41 41
70
99
80 87
58
58
56
57
27
20
14
P7
P8
P9 P10
14
0
P1
P2
P3
P4
P5
P6
Chlorides
TSS
Fig. 3 Levels of Chlorides and TSS
Chloride is one of the major anions found in water and sewage. Its presence in large amounts
may be due to natural processes such as the passage of water through natural salt formations in
the earth or it may be an indication of pollution from seawater or industrial and domestic wastes.
Any change in normal chloride content of natural water should be reason for suspecting pollution
from one of these sources. The points with the highest chloride levels were points P4 (70mg/L),
P5 (80mg/L) and P6 (87mg/L) (Fig.3). This represents daily loads of 4.36, 4.98 and 5.41 tones
respectively. At these points, the contamination could be from human waste and washing
activities. The other points had chloride values ranging from 48 to 58mg/L. This could be due
to natural processes such as passage of water over natural salt formations in the soil and rocks.
11
The MCL daily load value for chlorides is 0.03tones (0.5mg/L) while the average daily load was
3.92 tones for Zambian Standard. Therefore chloride level was high in the stream.
The most common mineral sulphates of Sulphur are Iron Sulphide, Lead Sulphide, Zinc
Sulphide, Calcium Sulphate and Magnesium Sulphate. The majority of sulphates are soluble in
water. The exceptions are sulphates of Lead, Barium and Strontium (Hicks, 1977). Dissolved
Sulphate (SO42+) is considered to be a permanent solute of Water (H2O) that reacts with Organic
Matter to produce Sulphur (S), Water and Carbon Dioxide (CO2). It may however, be reduced to
sulphides or volatilised as Hydrogen Sulphide (H2S), in the presence of hydrogen ions (H+),
which has a foul smell. The quality of stream water is affected by sulphates. The results of the
study showed increasing values from point P1 (58mg/L) to point P10 (1415mg/L) representing
daily loads of 3.61 and 88 tones respectively. The average load was 56.42 tones. The other
points had values at points P2 (56mg/L), P3 (57mg/L), P4 (1285mg/L), P5 (1270mg/L), P6
(1275mg/L), P7 (1250mg/L), P8 (1145mg/L) and P9 (1300mg/L) falling within the two
extremes. The Trend Graph shows how the contribution of effluents from the market and other
areas were increasing the level in the stream. The MCL for sulphates is 1500mg/l or daily load
of 93.3 tones for Kitwe Stream while that for Sulphite is 0.1mg/L. Therefore sulphates were
within acceptable limit.
Iron (Fe) is the fourth most abundant element by weight in the earth’s crust. In water, it occurs
mainly in the divalent and trivalent (Ferrous and Ferric) states. Iron in surface-water is generally
present in the Ferric (Fe3+) state. The concentration of Iron in well-aerated Water is seldom high
but under reducing conditions, which may exist in some groundwater, Lakes or Reservoirs and in
12
the absence of Sulphide and Carbonate, high concentrations of soluble Ferrous Iron may be
found. Iron promotes the growth of ‘Iron Bacteria’ (Viessman et al, 2000). Iron Bacteria derive
their energy from the oxidation of Ferrous Iron to Ferric Iron. The above problems usually arise
in water distribution systems when the Iron concentration approaches 0.3mg/L.
The highest value of Iron (2mg/L) with a daily load of 0.12 tones, was at points P8 and P9 while
the lowest value was 0.062 tones (Table: 1). The MCL value is 2mg/L and therefore within
range. The metals Zinc (Zn), Copper (Cu), Cadmium (Cd), Manganese (Mn) Lead (Pb), and
Cobalt (Co) were analysed. The MCL for metals Zinc (10mg/L), Copper (1.5mg/L), Cadmium
(0.5mg/L), Lead (0.5mg/L), Manganese (1mg/L) and Cobalt (1mg/L) were found to be within
and higher than 0.5ppm, the value obtained at all the points. This indicates that effluents of very
low metal concentration were disposed into the stream. Unpolluted waters generally contain less
than 1μg/L of Cadmium [Viessman et al, 2000], which is 50% higher than the result obtained in
this study.
Zinc is one of a number of trace elements considered essential to plant growth. It imparts to
water an undesirable taste and in addition, at concentrations in excess of 0.5mg/L may develop a
greasy film on boiling. Zinc has been associated with impairment of river and stream water
quality for many years. For example, the State of Texas (2005) reported rivers as not meeting
their aquatic uses due to toxic metals; Wichita and Middlefork Rivers lost their aquatic uses due
to Selenium, Neches River below Lake Palestine due to Lead, and Neches River above Lake
Palestine due to high level of Zinc. Peplow (2000) and Viessman (2000) reported that elevated
concentrations of Cadmium, Copper, Selenium including Zinc in stream waters and sediments
13
reduced species diversity and abundance in aquatic communities. Lawrence et al (2004) reported
negative effect of Nickel on abundance of phototropic organisms like Algae and Cyanobacteria.
Lead is a natural constituent of the earth’s crust with an average concentration of about 16mg/kg.
It is present in a number of minerals. It has been widely used for many centuries and in many
places. Some contamination of the environment has occurred as a result of the mining and
smelting processes or from the use of products made from it. The natural Lead content of lake
and river water worldwide has been estimated to be between 1 and 10μg/L (Chapman, 1992).
Higher values indicate contamination from industrial sources. Cobalt has been found in mining
areas. The principal commercial sources are the Copper-Cobalt and Iron Sulphide Ores. Cobalt
metal is found in many useful alloys and its compounds find application in colouring of glass and
pottery, electroplating, paint and varnish manufacturing and in animal nutrition. Loads of these
metals were considerably low.
Turbidity in water is caused by the presence of suspended matter, such as Clay, Silt, Colloidal
Organic Particles, Plankton and other microscopic organisms. Turbidity is the scattering and
light absorbing properties of the water sample. A high turbidity value depicts low water quality
level and a low value, good water quality if other parameters are also within acceptable ranges.
The points with high turbidity values were points P3 (18NTU), P4 (20NTU), P5 (15NTU), and
P6 (10NTU), while the rest of the points had a turbidity less than 5NTU. The high turbidity
could be attributed to inorganic and organic matter because the points with high values received
waste from human activities (market and car washing). Turbidity can also be developed naturally
14
by particles of Clay, Silt and Algae Bloom. The acceptable level of turbidity is 15NTU.
Therefore turbidity was out of the range at points P3 and P4.
The biochemical oxygen demand (BOD) is an approximate measure of the amount of degradable
organic matter in water.
It is defined as the amount of oxygen required by aerobic
microorganisms to oxidize the organic matter to stable inorganic form (Viessman et al, 2000).
Unpolluted waters typically have oxygen demand value of 2mg/L or less and those receiving
wastewater may have values up to 10mg/L. The acceptable BOD in streams and rivers is 50mg/L
in Zambia representing a daily load of 3.11tonnes. The BOD load was highest at points P4
(63mg/L, 3.92 tones/day), P5 (70mg/L, 4.35tones/day) and P6 (90mg/L, 5.6tones/day). The
results showed that the effluent from the market and activities at point P5 contributed to the
increase. It means that there was a high loading of nutrients; nitrates, phosphates and faecal
matter (Table: 1). The other points had BOD level of less than 9mg/L representing a daily load
of 0.56tones. The average BOD load was 1.62 tones per day, which was below the acceptable
loading of 3.11tones a day. Therefore BOD was acceptable.
Table: 1 Pollution loads into Kitwe Stream
Parameter
Unit
Sulphate
P1
P2
P3
P4
P5
P6
P7
P8
P9
P10
tone/day 3.61 3.48 3.55
79.9
79.0
79.3
77.8
71.2
80.8
88
Chlorides
tone/day
3.0 3.61 3.55
4.36
4.98
5.41
3.61
3.61
3.48
3.55
TSS
tone/day 2.55 2.55 2.55
7.34
6.16
8.71
1.68
1.24
0.87
0.87
TDS
tone/day 5.72 9.33 9.83
18.4
16.9
15.6
14.8
14.5
14.2
14.3
BOD
tone/day 0.12 0.24 0.54
3.91
4.35
5.60
0.36
0.36
0.30
0.30
15
Nitrates
tone/day 0.07 0.12 0.31
0.54
0.37
0.25
0.14
0.12
0.31
0.42
Nitrites
tone/day 0.38 0.25 0.44
2.12
2.00
1.31
0.37
0.25
0.31
0.31
0.12
0.50
0.47
0.46
0.16
0.17
0.14
0.25
Zinc
tone/day 0.03 0.03 0.03
0.03
0.03
0.03
0.03
0.03
0.03
0.03
PTL
tone/day 15.7 19.8 21.1
117.
115
117
99.2
91.8
101
108
PTEL
tone/day
96.3
9.02
7.40
Phosphates tone/day 0
0
Coliform bacteria, as typified by Escherichia coli and Faecal Streptococci residing in the
intestinal tract of humans, are excreted in large numbers in faeces of humans and other warmblooded animals. Consequently, water contaminated by faecal matter is identified as being
potentially dangerous because the indicator organisms co-exist with Escherichia coli, which
cause cholera [Hammer, 1986]. Some examples of diseases caused by drinking or swimming in
faecal contaminated water are Diarrhoea, Cholera, Dysentery, skin, eye, ear and nose and throat
infections (WHO, 1993; Shuval, 1977). The Faecal Coliform at all points were due to faecal
contamination. However, the points that exhibited highest counts were points P9 (2099), P10
(2558) followed by P4 (1149), P5 (1256) and P6 (1370) as shown in Fig.4. Therefore, all the
points that showed high values could have received faecal matter from non-point and point
sources. The acceptable level of E. coli in Iowa United States of America is 126/100ml or
235/100ml per sample. The compliance level in Zambia is 500/100ml.
The results of phytoplankton, fish and benthos (invertebrates) showed that all were present
in the stream despite high levels of coliform and a considerable level of Iron. However the
16
availability of fish was low down stream but high upstream particularly near the source of the
stream. The benthic organisms were found at all points with a considerable diversity.
3000
2558
Count (No)
2500
2099
2000
13701318 1237
11491256
1500
1000
500
349 320 392
0
P1
P2
P3
P4
P5
P6
P7
P8
P9
P10
Coliform
Fig.4 Level of Coliforms
Aquatic insects are excellent overall indicators of both recent and long-term environmental
conditions (Patrick and Palavage, 1994).
According to Patrick and Palavage (1994), the
immature stages of aquatic insects have short life cycles, often several generations a year, and
remain in the general area of propagation. Thus, when environmental changes occur, the species
must endure the disturbance, adapt quickly, or die and be replaced by more tolerant species.
Aquatic insects and water are used in environmental monitoring (Chapman, 1992; WHO, 1996).
They are also useful indicators of contamination of the sediments and waters that may have gone
unnoticed by routine physicochemical measurements. Uptake of toxic substances, such as heavy
metals and organochlorine compounds causes various kinds of deformities of the larval and
pupal Chironomidae (Lanat, 1993). Based on the presence and absence of fish, one could say
that water quality of Kitwe Stream was poor at the middle points because the fish levels were
low.
17
The high levels of parameters signified that the stream was heavily loaded with nutrients that
have the capacity to deplete oxygen in water. Chambers et al (1999) found that low level
encouraged growth of Algae and Phytoplankton while high level resulted in excessive growth
and interference of sunlight and hence reduction of Dissolved Oxygen (DO) in water. The foul
smell emitted by water of Kitwe Stream, was a product of anaerobic processes, which took place
in the stream. The anaerobic processes used dissolved oxygen and consequently resulted in high
BOD level. Sadar (1996] reported diminishing fish levels in water with diminished dissolved
oxygen. The total load (PTL) was highest at point P4 and lowest at the source, P1. The total
external pollutant loading (PTEL) into the stream was found to be 112.68tones/day. This level of
loading is likely to impact severely on the water quality of the stream if discharges continue.
CONCLUSION
The analysis of results revealed that Kitwe Stream carried high loads of coliform, nitrates and
phosphates. The effluents from the market, water works, car washing activity and sewage plant
were the major causes for the rise in parameters along the stream. The absence and presence of
Tilapia fish could not be used for determining water quality neither was Phytoplankton. The
level of metals was within acceptable ranges for river and stream water quality. The level of
Turbidity and Phosphate loads were normal. There were many benthic organisms along the
stream and therefore the presence and absence criterion could not be used. Further analysis of
the benthos is required in order to make meaningful conclusion. The water quality was found to
be poor based on average loads of Coliform, Nitrates, Nitrites, Total Suspended Solids and
18
Chlorides. The water quality of Kitwe Stream was therefore affected by engineering and other
human activities.
RECOMMENDATIONS
The modes of control and mitigation of pollutants in Kitwe Stream include awareness campaigns
where the public is taught about the importance of water and its uses (Ntengwe, 2004). Hygiene
awareness and education are not about coercion but bringing about of change in the behaviour
patterns of people in order to make them aware of the diseases related to unhygienic practices,
poor water supply and improper sanitation (Almerdon, 1997). The main components of a
hygiene awareness and education strategy include motivation and community mobilization,
communication and community participation, user education, skills training and knowledge
transfer, development of messages, presentation of messages and maintenance of good practice
(Dunker, 1999). Enforcing the Environmental Protection and Pollution Control Act (EPPCA)
legislation will ensure that all industries and mines keep their effluent pollutant concentrations to
the minimum (GRZ, 1990). The use of plants to clean up the stream is another way of reducing
the pollution because plants will reduce the concentration levels of many nutrients (Hossetti and
Kumar, 1998). Allocating idle land to developers, who would construct buildings in some areas
of the stream and improving the market structures could help to reduce pollution.
ACKNOWLEDGMENT
19
I wish to acknowledge the assistance received from the technologist Mundia Silumesi who
analysed the samples during the study. I also would like to acknowledge the assistance received
from the Copperbelt University.
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