Dr Dev Kambhampati | EPA Proceedings- Hydraulic Fracturing Study- Water Resou...
Rampedi Ike_mini thesis
1. i
Facility of Science
Department of Earth Science:
Environment and water Science
Supervisor: Prof L. Raitt
{Biodiversity and Conservation Department}
Heavy metals in water and plants of the Sout River and Groen River (Hopefield), West
Coast, Western Cape Province
By
Rampedi Sephothoma Ike
Email: 2864783@uwc.ac.za
November 2012
2. A
Table of Content
DECLARARTION ------------------------------------------------------------------------- i
Title page ------------------------------------------------------------------------------------ ii
Acknowledgements ----------------------------------------------------------------------- iii
Abstract--------------------------------------------------------------------------------------iv
Chapter 1 ------------------------------------------------------------------------------------ 1
1 Introduction------------------------------------------------------------------------------- 1
1.1 Background ------------------------------------------------------------------------------------------------------------ 1
1.2 Research questions---------------------------------------------------------------------------------------------------- 2
1.2 Hypothesis-------------------------------------------------------------------------------------------------------------- 2
1.3 Amis and objectives ------------------------------------------------------------------- 3
1.3.1 General Aims-------------------------------------------------------------------------------------------------------- 3
1.3.2 Research objectives ------------------------------------------------------------------------------------------------ 3
Chapter 2 ------------------------------------------------------------------------------------ 4
2 Literature review ------------------------------------------------------------------------ 4
2.1 Heavy Metals ---------------------------------------------------------------------------------------------------------- 4
2.1.1 Cadmium (Cd) --------------------------------------------------------------------------------------------------- 5
2.1.2 Copper (Cu)------------------------------------------------------------------------------------------------------- 5
2.1.3 Lead (Pd)---------------------------------------------------------------------------------------------------------- 6
2.1.4 Zinc (Zn) ---------------------------------------------------------------------------------------------------------- 6
2.2 Bioindicator----------------------------------------------------------------------------- 7
2.3 Water quality parameters ----------------------------------------------------------- 7
2.3.1 Electrical conductivity--------------------------------------------------------------------------------------------- 7
2.3.2 pH---------------------------------------------------------------------------------------------------------------------- 8
3. B
2.3.3 Temperature --------------------------------------------------------------------------------------------------------- 8
2.3.4 Dissolved Oxygen -------------------------------------------------------------------------------------------------- 8
Chapter 3 -----------------------------------------------------------------------------------10
3. Site description and overview of research methodology -----------------------10
3.1 Site description ------------------------------------------------------------------------------------------------------ 10
3.2 Methods and Materials-------------------------------------------------------------------------------------------- 12
3.2.1 Field procedure ------------------------------------------------------------------------------------------------ 12
3.2.2 Laboratory procedure----------------------------------------------------------------------------------------- 12
3.3 Statistical Analyses ------------------------------------------------------------------------------------------------- 13
Chapter 4 -----------------------------------------------------------------------------------14
Results Discussion and conclusion-----------------------------------------------------14
4.1 Results----------------------------------------------------------------------------------------------------------------- 14
4.2 Discussion ------------------------------------------------------------------------------27
4.2.1 Water quality parameters---------------------------------------------------------------------------------------- 27
4.2.2 Heavy metals concentration in water ------------------------------------------------------------------------- 29
4.2.2.1 Cadmium (Cd) Concentration ---------------------------------------------------------------------------- 29
4.2.2.2 Copper (Cu) concentration -------------------------------------------------------------------------------- 30
4.2.2.3 Lead (Pb) concentration ----------------------------------------------------------------------------------- 31
4.2.2.4 Zinc (Zc) concentration------------------------------------------------------------------------------------ 32
4.2.3 Heavy metal concentration in plants in relation to water samples -------32
4.2.4 Conclusion and Recommendation ----------------------------------------------34
References Cited --------------------------------------------------------------------------35
Appendix 1: Analytical parameters in the Berg River, Sout River and Groen
River: raw data----------------------------------------------------------------------------38
4. C
Appendix 2: Analytical elements in the Berg River, Sout River and Groen
River: raw data----------------------------------------------------------------------------39
Table
Table 4.1: water element showed no significant difference (p ≤ 0.05) overtime and
over sites .................................................................................................................14
List of Figures
Figure 3.1 A map of the study area showing the location of the 8 study sites, B1 (Berg River),
S1-S4 (Sout River) and G1 to G3 (Groen River), Western Cape, South Africa, imagine
downloaded from Google Earth.................................................................................................... 11
Figure 4.1: Variation in temperature in water of the study areas over the sampling sites in March
to September showed 95 % variation…………….………………………………………………15
Figure 4.2: Variation in temperature in water of the Berg River, Sout River and Groen River
study areas over the sampling period in March to September showed 95 % of variation……….15
Figure 4.3: The mean DO of the Berg River, Sout River and Groen River sampling sites.......... 16
Figure 4.4: The mean DO of the Berg River, Sout River and Groen River over sampling period
from March to September 2012.................................................................................................... 16
Figure 4.5: The mean pH of the Berg River, Sout River and Groen River at sampling sites....... 17
Figure 4.6: The mean pH of the Berg River, Sout River and Groen River at sampling sites....... 17
5. D
Figure 4.7: The mean EC of the Berg River, Sout River and Groen River sampling sites. ......... 18
Figure 4.8: The mean EC of the Berg River, Sout River and Groen River sampling period from
March to September 2012............................................................................................................. 18
Figure 4.9: The mean Na of the Berg River, Sout River and Groen River over sampling sites... 19
Figure 4.10: The mean Na of the Berg River, Sout River and Groen River over sampling period
from March to September 2012 ................................................................................................... 19
Figure 4.11: The variation in cadmium concentrations in water from the Berg River, Sout River
and Groen River study area over the sampling sites..................................................................... 20
Figure 4.12: The variation in cadmium concentrations in water from the Berg River, Sout River
and Groen River study area over the sampling period March to September 2012....................... 20
Figure 4.13: The variation in copper concentrations in water from the Berg River, Sout River and
Groen River study area over the sampling sites............................................................................ 21
Figure 4.14: The variation in lead concentrations in water from the Berg River, Sout River and
Groen River study area over the sampling sites............................................................................ 22
Figure 4.16: The variation in zinc concentrations in water from the Berg River, Sout River and
Groen River study area over the sampling sites............................................................................ 23
Figure 4.17: The variation in zinc concentrations in water from the Berg River, Sout River and
Groen River study area over the sampling period March to September 2012.............................. 23
Figure 4.18: The mean EC of the Berg River, Sout River and Groen River sampling period from
March to September 2012............................................................................................................. 24
6. E
Figure 4.19: The mean Na of plants the Berg River, Sout River and Groen River over sampling
period from March to September 2012......................................................................................... 24
Figure 4.20: The variation in cadmium concentrations in plants from the Berg River, Sout River
and Groen River study area over the sampling sites..................................................................... 25
Figure 4.21: The variation in cadmium concentrations in plants from the Berg River, Sout River
and Groen River study area over the sampling period March to September 2012....................... 25
Figure 4.22: The variation in copper concentrations in plants from the Berg River, Sout River
and Groen River study area over the sampling sites..................................................................... 26
Figure 4.23: The variation in copper concentrations in plants from the Berg River, Sout River
and Groen River study area over the sampling sites..................................................................... 26
Figure 4.24: The variation in zinc concentrations in plants from the Berg River, Sout River and
Groen River study area over the sampling period from March to September 2012..................... 27
7. i
DECLARARTION
I declare that the mini thesis heavy metals in water and plants of the Sout River and Groen River
(Hopefield), is my own work, that it has not been submitted for a degree or examination at any
other university and that all the sources I have used and quoted have been acknowledged by
complete references.
Full names: Rampedi Sephothoma Ike
Signed this day 25 of November 2012, at University of the Western Cape
Signature: ………………………………………
8. ii
Title page
Rampedi Sephothoma Ike
2864783@uwc.ac.za
Bsc (Honours) Mini-thesis, Department of Environment and Water Science, University of
the Western Cape
A mini thesis is submitted as honours research project in partial fulfillment of the
requirements for the degree of Honours in the Department of Environment and
Water Science, University of the Western Cape
Supervisor: Prof LM Raitt (Department of Biodiversity and Conservation Biology,
University of the Western Cape)
November 2012
9. iii
Acknowledgements
Firstly I’ll love to thank God through, Jesus Christ and thank Jesus Christ through His Grace
Our Comforter, for His Grace to enable me to complete this mini-thesis, MOEMEDI GOD
TO US.
Secondly, I would deeply like to extend my sincerely gratitude to Prof Lincoln M. Raitt for his
support and guidance throughout the period of the degree.
My sincerely gratitude to the following people for their enthusiasm support and encouragement,
as well as technical support and advice as I worked on this mini-thesis: From the Biodiversity
and Conservation Biology Department:
Mr. L Cyster (Technical support and data analysis) He is passionate and enthusiast
Dr Marÿke Meerkotter (advices and research resources) she is polite at all times
Mr NB Hlungwani (Honours colleagues and friend). Arnold H. Glasgow once said: "A true
friend never gets in your way unless you happen to be going down” Thank you mchana
Finally, I would like to express my heartfelt appreciation to my mother (Rapolometse M.
Rampedi), sister (Daphney R. Rampedi) family and friends for their love and unwavering
support and encouragement during my studies. May God Bless above mentioned abundantly.
10. iv
Abstract
Heavy metals in water and plants of the Sout River and Groen River (Hopefield)
The Sout River runs from near Moorreesburg through the little town of Hopefield and is one of the
Berg River’s 16 tributaries. The River is suspected to be eutrophic and it supposedly has had a major
increase in Phragmites australis which is a potential problem to the town. This investigation involved
an initial evaluation of the vegetation and water quality of the Sout River and Groen River. The reed
species Phragmites australis was chosen as the bioindicator. Sampling was conducted once per month
at various selected sites along the Sout River and its tributary the Groen River from 22 March 2012 to
25 September 2012. The Berg River was used as a control during the study.
The plant samples were digested with a sulphuric-peroxide mixture (Moore and Chapman, 1986). The
digested plant specimens were filtered and diluted to volume in a 100 ml volumetric flask. Water
samples and digested plant specimens were tested for heavy metals content i.e. cadmium (Cd), copper
(Cu), lead (Pb) and zinc (Zn) using an Atomic Absorption Spectrophotometer. The analysis of variance
was professionally determined using method of the General Linear Models (GLM) procedure of SAS
statistical software version 9.2 (SAS Institute Inc., 2000, Cary, NC, USA). The Student’s t-least
significant difference was calculated at the 5% level to compare treatment means (Ott, 1998).
The results showed that most of element concentrations (Cd, Cu and Zn) in plants were higher than
those in the water samples. Heavy metals were accumulated by plants from the water and thus
Phragmites australis is better bioindicator of micronutrients. Anthropogenic activities had an
influenced on the water quality parameters possibly from agricultural runoff.
Key Words
Heavy metals: copper (Cu), cadmium (Cd), lead (Pb) and zinc (Zn)
pH
Electrical Conductivity
Phragmites australis
Sout River and Groen River
11. 1
Chapter 1
1 Introduction
1.1 Background
The Sout River and Groen River are seasonal rivers and to date little work has been done on seasonal
rivers in Southern Africa. The Sout River runs from near Moreesbury through the little town of Hopefield
and the Groen River joins the Sout River about 20 km south east of Hopefield and runs from near
Malmesbury. According to a study by Swaine et al., (2006), the distribution of plant species and the
composition of vegetation have been widely used (both formally and informally) to provide evidence of
the environmental conditions in which they grow. This central principle of applied ecology has been used
in the assessment of water quality, by relating river plant composition with the chemical characteristics of
the water. The rivers support survival of ecosystems and according to Ngwenya (2006), rivers are
considered to be important and fragile freshwater ecosystems.
The water quality of the river is determined by the diverse range of variables and by the local
environmental condition near the sampling point and land use activities (Swaine et al., 2006; Ngwenya,
2006). The water quality varies with space distance and many variables may show strong temporal
variation due to seasonal differences and storm events (Swaine et al., 2006).
Anthropogenic activities such as agricultural activities, watering of livestock and crop farming are sources
of contamination. Through these and other activities, heavy metals, pesticides, and fertilizers many find
their way in to the running water system and significantly increasing the chemical concentrations of river
water (Mokaya et al., 2004). These cause a decrease in water quality of rivers which presents a major
challenge to South Africa (Ngwenya, 2006). It is important to further the knowledge through research, for
effective sustainable management of the less studied South African Rivers in this case the Sout River and
the Groen River.
Study by Windhama et al., (2001) found that P. australis grows seasonally, whereby greater concentration
of Cu and Zn were found to be in summer. An assessment of the quality of the Sout River and Groen River
was essential to understanding the ecological risk of heavy metals to the area and the river. This
investigation involved an initial evaluation of the vegetation and water quality of the Sout River and the
12. 2
Groen River. The aim was to investigate and analyze the water quality and vegetation with reference to the
selected heavy metals copper (Cu), cadmium (Cd) lead (Pb) and zinc (Zn) and other water quality
parameters that were investigated include electrical conductivity (EC), pH, dissolved oxygen, and
temperature.
South Africa is a semi-arid country and the decline in the quality of available water is one of the major
problems currently facing the country (Davies and Day, 1998). Over the past decades, environmental
regulations have become more stringent, requiring an improved quality of treated effluent. South Africa
has developed water quality guidelines for protection and management of water quality (DWAF, 1996 a).
In recent years, a wide range of treatment technologies such as chemical precipitation and adsorptions
have been developed for heavy metals removal from contaminated wastewater (Barakat, 2010). There are
several factors that contribute to the deteriorations in rivers water quality in South Africa, the most critical
being industry, effluent discharge of waste water (WWTM), intensive and careless agricultural practices
and the population explosion, the study focuses on selected potential pollutants of water.
1.2 Research questions
1. How does the heavy metal content in the Phragmites australis compare with typical values?
2. How does the heavy metal content of the river compare with the standards?
3. Are there any sudden increases in the heavy metals along the river showing any problematic inputs?
4. Which are the main dominate heavy metals in the water and plant of the Soult River and the Groen
River
1.2 Hypothesis
Hypothesis
Heavy metals accumulate in the Phragmites australis leaves in the Sout River and the Groen River.
Null hypothesis
There is no heavy metals accumulation in the Phragmites australis leaves in the Sout River and the Groen
River.
13. 3
1.3 Aims and objectives
1.3.1 General Aims
The aims of the study are:
1. To investigate and assess whether water quality has an influence on the reeds species
Phragmites australis.
2. To investigate the heavy metals content of the water.
1.3.2 Research objectives
Research objectives of the study are:
1 To determine the content of the heavy metals in Phragmites australis and the rivers.
2 To determine as whether heavy metals are problematic to the area.
14. 4
Chapter 2
2 Literature review
2.1 Heavy Metals
Heavy metals are inorganic pollutants (Marschner, 1995), often waste products of anthropogenic activities.
Heavy Metals often originate from biosolids, pesticides, herbicides and their emission often results in the
contamination of the surrounding environment (Eeva & Lehikoinen, 2000; Meerkotter, 2003). Heavy
metals are generally considered to be those whose density exceeds 5 g per cubic centimeter (Barakat,
2010). Heavy metals among other include copper (Cu), cadmium (Cd), lead (Pb) and zinc (Zn)
(Marschner, 1995).
Industrial wastes, agricultural activities and mines are potential sources of heavy metals pollution in the
aquatic environment (Wang et al., 2010; Ying, 2005). Mines are the most obvious source of trace metals in
the environment and often release metals in soluble form (Dallas & Day, 2004). According to Davies &
Day (1998) pollutants may enter water bodies in a way that can be said to be non-point source such as,
seepage, runoff from the agricultural activities and decaying of organic materials. Rivers serve as a
transport medium, the soil as a reservoir of heavy metals and the plants take heavy metals up as
micronutrients such as copper (Cu) and zinc (Zn) (Marschner, 1995). Concentration of metals within a
plant structure may increase as plant grows through a process of biological accumulation. Under certain
environmental conditions, metals may accumulate to toxic proportions and can cause ecological damage
(Mokaya et al., 2004).
The study by Ma (2005) indicated that most of element concentrations (Cd, Cr, Ni, P and Zn) in plants are
higher than those in the sediments, and much greater than those in the water. However in the case of some
metals such as lead, manganese and vanadium, the greatest concentration levels were found in the
sediments. This suggests that most heavy metals were accumulated by plants from the sediments. Ma
(2005) found out that accumulation of heavy metals by plants varies, Typha capensis would be useful for
monitoring the heavy metals such as; iron, manganese and zinc associated with river flows. The lead levels
in Phragmites australis were found to be much higher than in T. capensis and therefore P. australis could
be more appropriate biomonitor or bioindicator of lead (Pb) (Ma, 2005). This study has shown that not all
plant species respond to same metals, some plant species completely exclude certain metals from their
structure and while other may accumulate them.
15. 5
2.1.1 Cadmium (Cd)
Cadmium occurs naturally in freshwater it is present in the earth curst at an average concentration of 0.2
mg/kg (DWAF, 1996 b). However a significant variety of wastewaters contain heavy metal such as
cadmium (Barakat, 2010). Cadmium can enter soil or a water body through agricultural use of sludge,
fertilizers and pesticides containing cadmium (DWAF, 1996 d). Salinity affects cadmium toxicity, and
higher concentration of cadmium is found in water below pH of 4.0. Cigarette smoke also contains
cadmium, as tobacco intensively extracts cadmium from soil and accumulates it in leaves (WHO, 2008).
Cadmium may enter a human body through contaminated water, but the main source of cadmium is
through the consumption of contaminated foodstuff, especially staple grain and garden crops that have
grown on contaminated soil (Meerkotter, 2003). Plants may take up cadmium that has been chelated by
phytochelatins, but it is not an essential plant nutrient (Marchners 1995; Larcher 2001). Cadmium releases
to the environment are associated with burning or processing of cadmium containing products, particularly
plastic items as well as combustion of solid and liquid fuels (WHO, 2008). Cadmium levels for water used
in agricultural irrigation are 10 μg/l according to SA Water Quality Guideline (DWAF, 1996 d).
2.1.2 Copper (Cu)
Copper is a common metallic element in the rocks and minerals of the earth's crust. Sources of this heavy
metal in the aquatic environment are due to weathering processes or from the dissolution of copper
minerals and native copper (DWAF, 1996 d). Many sources of wastewater contain heavy metal such as
copper (Barakat, 2010). Copper enrichment like that of all other heavy metals may occur as result of
anthropogenic activities such as liquid effluent, sewage treatment plant effluents, runoff and ground water
contamination from the use of copper as fungicides and pesticides in the treatment of soils (DWAF, 1996
a). Aquatic plants take up minerals nutrients over their entire submerged surface whereas terrestrial specie
acquires their mineral via a root system from a soil (Larcher, 2001). Copper is important micronutrients
required by plants for growth in specific tolerable amounts, it is up taken as Cu2+
. Plants differ in their
susceptibility to copper deficiency, however copper deficiencies are rare in plants because they require
very little thereof (Meerkotter, 2003). Plants species differ considerably in sensitivity to copper deficiency,
copper deficiency mostly affects grain and seed formation much more than vegetative growth (Marschner,
1995). The Target Water Quality Range for copper in aquatic ecosystems is less than 0.3 µg/l in soft water
and below 0.8 mg/l in medium soft water.
16. 6
2.1.3 Lead (Pd)
Lead occurs as metallic lead, inorganic compounds, and organometallic compounds (Margorn, 1996).
Lead is principally released into the aquatic environment through the weathering of sulphideores,
especially galena. However most of the lead entering aquatic ecosystem is associated with suspended
sediments, while lead in the dissolved phase is usually complexed by organic ligands (DWAF, 1996 d).
Anthropogenic activities are major sources of this heavy metal in the atmosphere and aquatic environment
(DWAF, 1996 d; Notten et al., 2008), these include precipitation, fallout of lead dust and street runoff
(associated with lead emissions from gasoline-powered motor vehicles); industrial and municipal
wastewater discharge (DWAF, 1996 d). Lead may enters natural water bodies due to application of leaded
petrol as fuel of motor boats and with surface washout from urbanized areas (WHO, 2008). Despite the
legal prohibition of human induced leaded fuel, contamination with this metal is still a problem in the
atmosphere (Notten et al., 2008). Lead is bioaccumulated by freshwater plants and aquatic organisms, and
dependents on the action of calcium; therefore, hardness is an important factor determining the toxicity of
lead in aquatic systems (DWAF, 1996 c).
2.1.4 Zinc (Zn)
Zinc occurs in rocks and ores and is readily refined into a pure stable metal. Leaching soil with sodium
carbonate solution converts zinc to dross and skimmings into zinc oxide, which can be reduced to zinc
metal (USEPA, 2000). Zinc can enter aquatic ecosystems through both natural processes such as
weathering and erosion, and through human induced activities such as industrial activity i.e.
pharmaceuticals, fertilizer and insecticide (DWAF, 1996 d).
Zinc is an important micronutrient required by plants for growth and development in small amounts, it is
up taken as Zn2+
and Zn-chelates which is accumulated in to the roots and shoots system of the plant
(Larcher, 2001). However adsorption of zinc by clay minerals and organic materials is an important
process in aquatic ecosystems since it affects the bio-availability and toxicity of zinc (DWAF, 1996 d).
When the zinc supply is large, zinc toxicity can readily be induced in non tolerant plants, toxicity of zinc
lead to chlorosis in young leaves (Marschner, 1995).
17. 7
2.2 Bioindicator
Biomonitors or Bioindicators organisms are species that provide quantitative information on
environmental quality (Markert et al., 2003). Substances are released in to natural ecosystem and some are
accumulated by plants species i.e. pollutants, heavy metals and micronutrients. Biocentration involves the
direct uptake and accumulation of a substance from the surrounding media i.e. physical environment,
plants take up substances mainly through roots, but also through the leaves (Markert et al., 2003).
However according to Mertens et al., (2005) metal bioavailability and uptake are dependent on the plant
specie and suitable biomonitors can be selected to address a particular environmental problem.
Bioindicators have been used to show the content of micronutrient in plants. For example, Ma (2005) used
T. capensis and P. australis as indicator in the Bottelary River. Through the study there was evidence that
plants can accumulate heavy metals and further play a central role to estimate the content of micronutrients
available in the surrounding environment absorbed by plant.
2.3 Water quality parameters
According to classification system of DWAF (1996 d) pH and electrical conductivity are classified as
Group A indicators. This Group A indicators are those that are considered extremely important and should
always be monitored for water quality studies and domestic water supplies (DWAF, 1996 c). Water quality
parameters such as pH and electrical conductivity are essential indicators of water quality (Golterman et
al, 1997).
2.3.1 Electrical conductivity
Electrical conductivity (EC) is a measure of the ability of water to conduct an electrical current made
possible through the presence of ions and dissolved material (Dallas & Day, 2004; Ngwenya, 2006). The
Total Dissolved Salts (TDS) concentration is directly proportional to the electrical conductivity (EC) of
Water and EC is much easier to measure than TDSalts. The quantity and concentration of ions influences
the water ability to conduct electrical current and therefore acts as a parameter for water quality. A high
EC value is indicative of a higher content of (TDS) in water (DWAF, 1996 a; Morgan, 1996). Domestic
and industrial effluent discharges and surface runoff from urban, industrial and cultivated areas are
examples of the types of sources that may contribute to increased TDS concentrations. Evaporation also
leads to an increase in the total salts (DWAF, 1996 a). The conductivity of most freshwaters ranges from
10 to 1,000 μS cm-1
but may exceed 1,000 μS cm-1
, especially in polluted waters, or those receiving large
quantities of surface runoff (WHO, 1996).
18. 8
2.3.2 pH
The pH is a measure of the acid balance of a solution and is defined as the negative of the logarithm to the
base 10 of the hydrogen ion concentration (DWAF, 1996 d; WHO, 1996). The pH is a good indicator of
acidification in a sample of water (Ngwenya, 2006). The pH scale runs from 0 to 14 (i.e. very acidic to
very alkaline) with pH 7 representing a neutral condition (WHO, 1996). Most raw water or mineral water
pH lies generally within narrow range of 6.5 - 9.5 (Morgan, 1996; DWAF, 1996 d).
The pH of natural water is influenced by various factors and processes including acidic precipitation,
industrial effluents and atmospheric deposition of acid forming substances (WHO, 1996). Oxygenation
reaction often leads to the decrease in the pH and processes such as denitirification and sulfate reduction
tend to increase pH (Morgan, 1996). The pH of pure water (that is, water containing no solutes) is 7.0, the
number of H+
and OH-
ions is equal (DWAF, 1996 d). The average pH of water in South Africa is between
6 and 8.5. The pH of water is good indicator of the presence of elements in water. The pH value below
seven favours heavy metals such as lead and manganese, whereas a pH value exceeding seven may convert
non-metallic ions into a toxin (Ngwenya, 2006; DWAF, 1996 d).
2.3.3 Temperature
Temperature may be defined as the condition of a body that determines the transfer of heat to or from
other bodies (DWAF, 1996 d). Temperature plays an important role in water by affecting the rates of
chemical reactions and therefore also the metabolic rates of organisms. The temperatures of inland and
coastal waters in South Africa generally range from 5 - 0 (DWAF, 1996 d). Temperature is affected by
various factors such as climatic condition, clouds cover, wind and precipitation. According to DWAF,
(1996 d), despite climatic condition, there are other factors that may affect temperature, i.e. structural
characteristics of the river and catchment area, topographic features, vegetation cover, channel form, water
volume and depth.
2.3.4 Dissolved Oxygen
Oxygen as it well known is essential to all forms of life both aquatic and terrestrial. Aquatic organism
including those organisms responsible for the self-purification processes in natural waters. Gaseous
oxygen (O2) from the atmosphere enters water body through diffusion and it is also generated during
photosynthesis by aquatic plants and phytoplankton (DWAF, 1996 a; WHO, 1996). The quick method for
determination of dissolved oxygen can be done using oxygen probe in situ (WHO, 1996). Dissolved
oxygen is expressed in terms of percentage saturation, part per million and milligrams per litre.
19. 9
Oxygen is moderately soluble in water and the solubility of oxygen decreases as temperature and salinity
increase (DWAF, 1996 a; WHO, 1996). The reduction of dissolved oxygen concentration in surface water
can be caused by the presence of oxidizable organic matter, originating in waste discharges and the
amount of suspended material (DWAF, 1996 d). If the dissolved oxygen concentrations are high, one can
presume that that pollution level in the water are low and consequently if dissolved oxygen concentrations
are low, one can presume there is high oxygen demands and the water body may not be optimal healthy.
According to DWAF, (1996 a) water quality guidelines, concentrations of less than 100 % saturation
indicate that dissolved oxygen has been depleted from the theoretical equilibrium concentration and
continuous exposure to concentrations of less than 80 % of saturation can be harmful may lead to
physiological and behavioral stress.
20. 10
Chapter 3
3. Site description and overview of research methodology
3.1 Site description
The Groen River flows from near Malmesbury it passes through the Darling farms and joins the Sout
River at about 20 km south east Hopefield, Western Cape Province, South Africa. The Sout River is a
tributary of the Berg River that flows from near Moorreesburg through farming and residential areas
downstream and north of Hopefield finally discharges into the Berg River (Figure 3.1). Sites were selected
along the rivers at specific positions, and the locational points were noted with the use of a Global
Positioning System (GPS). Several sites were identified along the two rivers and spatial georeferenced as
G1-G3 (Groen River) and S1-S4 (Sout River), distributed from Darling through to the Berg River (B1)
which severed as a control (Figure 3.1). These rivers are seasonal and there is little work done as yet on
seasonal rivers in Southern Africa. The two rivers include various riparian plants i.e. reeds, trees and
shrubs, and The Sout River tends to be dominated by P. australis along the river banks.
21. 11
.
Figure 3.1 A map of the study area showing the location of the 8 study sites, B1 (Berg River), S1-S4 (Sout
River) and G1 to G3 (Groen River), Western Cape, South Africa, image downloaded from Google Earth.
22. 12
3.2 Methods and Materials
3.2.1 Field procedure
The study involved field sampling and laboratory analyses to determine water quality parameters and
content of heavy metals in the water and vegetation. A GPS was used to permanently locate the working
stations (S1-S4, G1-G3) and Berg River (B1). Water was sampled point-by-point from March 2012 to
September 2012 once per month using 250 ml plastic bottles. The oxygen content of the water was
measured in mg/l with the YSI Professional Plus multiparameter water quality meter model 12C102662. In
addition, the Pro Plus was used to measure, electrical conductivity, pH and temperature on site (in situ).
Leaves Phragmites australis (as a species common to all sites) were collected, once per month during the
period of March- September.
3.2.2 Laboratory procedure
3.2.2.1 Water Samples
Water samples were stored in a refrigerator at temperature of 4 °C. A 0.5 ml of nitric acid was added
into the water sample to prevent microorganism growth. Samples were first filtered to remove particles
(Meerkotter, 2003). The content of copper (Cu), cadmium (Cd), lead (Pb) and zinc (Zn) were
measured, using a Unicam Mseries Soloar Atomic Absorption Spectrophotometer.
3.2.2.2 Plants samples
Leaves were dried at 60 °C in an oven for approximately 48 hours. The dried leaves samples were
ground in a Wiley Mill, powdered leaves sample were stored in plastic bottles for further analyses. The
plant samples were digested with a sulphuric-peroxide mixture (Moore and Chapman, 1986).
Approximately 0.4g of ground plant sample was accurately weighed in to cigarette paper and then
placed in a digestion tube. A 5 ml of aliquot sulphuric-peroxide was added into a digestion tube and
heated at 180°C for 40 minutes the temperature was increased to 250°C after 40 minutes and then
increased to 320°C, until the solution became clear. The digested plant specimen was cooled then
filtered and diluted to volume in a 100 ml volumetric flask. The method was repeated three times with
blank solutions (excluding ground plant samples). The content of copper (Cu), lead (Pb), zinc (Zn), and
cadmium (Cd) were determined with the use of a Unicam Mseris Soloar Atomic Absorption
Spectrophotometer.
23. 13
3.3 Statistical Analyses
The statistical analysis was based on the raw data attached in the Appendix. The analysis of variance
was professionally determined using method of the General Linear Models (GLM) procedure of SAS
statistical software version 9.2 (SAS Institute Inc., 2000, Cary, NC, USA). The Shapiro-Wilk test was
performed to test for normality (Shapiro and Wilk, 1965). The Student’s t-least significant difference
was calculated at the 5% level to compare treatment means (Ott, 1998). A probability level of 5% was
considered significant for all significance tests.
24. 14
Chapter 4
Results, Discussion and Conclusion
4. Results
The results were based on the raw data in the appendix
The statics showed there was no significant difference observed in the water concentrations of copper over
time during the sampling period (table 4.1). The statics showed there were no significant differences
observed in the plant element concentrations of lead over time and between different sites (table 4.1). Zinc
concentration between different sites did not show significant difference table (4.1).
Elements Over time Over site
Copper (Cu) (mg/l) 0.0016 -
Lead (Pb) (µg/kg) 1.5527 1.5354
Zinc (Zn) (mg/kg) - 41.7182
Table 4.1: The water element showed no significant difference (p ≤ 0.05) overtime and over
sites.
The following figures are represented over sites (BR) Berg River, Sout River (S1-S4) and Groen River
(G1-G2) and represented over time from March to September (0-165 days) 2012.
25. 15
The minimum temperature occurred at Sites (S3 and G1) and the maximum at S4 (Figure 4.1).
Figure 4.1: The variation in temperature in water of the study areas over the sampling
sites. The sites marked with the same latter on the graph do not differ significantly (p ≤
0.05).
The temperature decrease with the change in seasons, maximum temperature is observed from
early (0 to 34) days and decreases gradually with the increase in days (Figure 4.2).
Figure 4.2: The variation in temperature in water of the Berg River, Sout River and Groen
River study areas over the sampling period in March to September does not show
significant difference (p ≤ 0.05).
26. 16
It is observed that the lowest DO occurred at site G3 and highest at S3 (Figure 4.3).
Figure 4.3: The mean DO of the Berg River, Sout River and Groen River over sampling
sites. Sites marked with same letter do not differ significantly from each other (p ≤ 0.05).
The concentration of DO varies seasonally, the highest concentration is noted from 0 to 15 days
and it decreases from 15 to 34 then increases gradually over sampling period from 97 to 165
days (Figure 4.4).
Figure 4.4: The mean DO of the Berg River, Sout River and Groen River over sampling
period from March to September 2012. Days differ significantly from each other (p ≤ 0.05).
27. 17
The samples display an almost uniform pH at sites S1, S3 to G2. The lowest pH values occur
upstream at sites G3. The rivers display an almost uniform pH at sites S1, S3 to G2. The lowest
pH values occur upstream at sites G3 (Figure 4.5).
Figure 4.5: The mean pH of the Berg River, Sout River and Groen River at sampling sites.
Sites with the same letter do not differ significantly from each other (p ≤ 0.05).
The pH value fluctuate through out the season, it dips at 97 days before it increase gradually with
the change in season. The highest peak is observed at 71 days (Figure 4.6).
Figure 4.6: The mean pH of the Berg River, Sout River and Groen River over the sampling
period. Days with the same letter do not differ significantly from each other (p ≤ 0.05).
28. 18
The increase in conductivity was observed upstream at site G1, site S1, S2 S4 and lowest at BR
(Figure 4.7).
Figure 4.7: The mean EC of the Berg River, Sout River and Groen River sampling sites
marked with same letter do not differ significantly from each other (p ≤ 0.05).
From 0 to 71 days electrical conductivity is almost uniform and increases rapidly with the
change in seasons from 71 to 165 days (Figure 4.8).
Figure 4.8: The mean EC of the Berg River, Sout River and Groen River sampling period
from March to September 2012, days marked with same letter do not differ significantly
from each other (p ≤ 0.05).
29. 19
It is noted that highest Na concentration is at S1 and the mean concentration between sites are
almost uniform (Figure 4.9).
Figure 4.9: The mean Na of the Berg River, Sout River and Groen River over sampling
sites. Sites marked with same letter from BR and S2 to G3 do not differ significantly from
each other (p ≤ 0.05).
It is observed that the Na concentration varies seasonally, the concentration decrease rapidly with
the change in seasons (Figure 4.10).
Figure 4.10: The mean Na of the Berg River, Sout River and Groen River over sampling
period from March to September 2012. Days marked with same letter from 97 to 165 days
do not differ significantly from each other (p ≤ 0.05).
30. 20
The concentration of cadmium varies between different sites, with the lowest concentration at
site G2 and G3, the highest concentration is noted at S4 (Figure 4.11).
Figure 4.11: The variation in cadmium concentrations in water from the Berg River, Sout
River and Groen River study area over the sampling sites. Sites marked by the same letter
do not differ significantly (p ≤ 0.05).
The concentration fluctuates through the seasons, the highest peak is observed at 71 days and it
decreases slightly with the change in seasons Figure (4.12).
Figure 4.12: The variation in cadmium concentrations in water from the Berg River, Sout
River and Groen River study area over the sampling period March to September 2012.
Days marked by the same letter do not differ significantly (p ≤ 0.05).
31. 21
The sampling sites have approximately a uniform concentration of copper, however the highest
concentrations of copper is noted at G1 Figure (4.13).
Figure 4.13: The variation in copper concentrations in water from the Berg River, Sout
River and Groen River study area over the sampling sites. Sites marked by the same letter
do not differ significantly (p ≤ 0.05).
32. 22
The concentration of lead is almost uniform at sites BR and S4 to G3. Site S1 and S2 also have
uniform concentrations. The highest concentration is observed at S3 (Figure 4.14).
Figure 4.14: The variation in lead concentrations in water from the Berg River, Sout River
and Groen River study area over the sampling sites. Sites marked by the same letter do not
differ significantly (p ≤ 0.05).
The concentrations of lead fluctuate through out the season. It dips at 34 days before it increases at
71 days and then deceases rapidly from 97 to 165 days.
Figure 4.15: The variation in lead concentrations in water from the Berg River, Sout River
and Groen River study area over the sampling period March to September 2012. Days
marked by the same letter do not differ significantly (p ≤ 0.05).
33. 23
The highest concentration is noted at G1. From BR to S4 the concentrations are approximately
uniform. The highest concentration is noted at site G1 (Figure 4.16).
Figure 4.16: The variation in zinc concentrations in water from the Berg River, Sout River
and Groen River study area over the sampling sites. Sites marked by the same letter do not
differ significantly (p ≤ 0.05).
The concentration increases from 0-71 days and reaches the highest peak at 97 then deceases
gradually till reaching 165 days (Figure 4.17)
Figure 4.17: The variation in zinc concentrations in water from the Berg River, Sout River
and Groen River study area over the sampling period March to September 2012.
Concentrations marked by the same letter do not differ significantly (p ≤ 0.05).
34. 24
The highest concentration of Na is at S3. Sites BR, S1, G1 to G3 have uniform concentrations
(Figure 4.18).
Figure 4.18: The mean Na of plants from the Berg River, Sout River and Groen River over
sampling sites. Sites marked with same letter from do not differ significantly from each
other (p>0.05).
The concentration varies through out the season, the concentration is uniform from 0 -71 and
dips at 97 before it increases till reaching highest peaks at 165 days (Figure 419).
Figure 4.19: The mean Na of plants the Berg River, Sout River and Groen River over
sampling period from March to September 2012. Days marked with same letter do not
differ significantly from each other (p>0.05).
35. 25
The highest cadmium concentration is noted at S2 and the lowest at S3, all the sites have
approximately uniform concentrations (Figure 4.20).
Figure 4.20: The variation in cadmium concentrations in plants from the Berg River, Sout
River and Groen River study area over the sampling sites. Concentrations marked by the
same letter do not differ significantly (p ≤ 0.05).
The concentration peaks is at 34 days and then decreases gradually with the change in seasons
from 34 to 126 says.
Figure 4.21: The variation in cadmium concentrations in plants from the Berg River, Sout
River and Groen River study area over the sampling period March to September 2012.
Days marked by the same letter do not differ significantly (p ≤ 0.05).
36. 26
The sites S3 and G3 have almost uniform copper concentrations and the highest concentration is
observed in the two sits. Site BR and S4 have lowest concentrations (Figure 4.22).
Figure 4.22: The variation in copper concentrations in plants from the Berg River, Sout
River and Groen River study area over the sampling sites. Concentrations marked by the
same letter do not differ significantly (p ≤ 0.05).
The concentration fluctuates from 0 to 71 days and start increasing gradually from 71 days till it
reaches the highest peaks at 165 days (Figure 4.23).
Figure 4.23: The variation in copper concentrations in plants from the Berg River, Sout
River and Groen River study area over the sampling period from March to September
2012. Concentrations marked by the same letter do not differ significantly (p ≤ 0.05).
37. 27
The concentration increases gradually with the change in seasons. The concentration start to
increases rapidly from 0 – 36 days were it reaches its highest peaks then decrease rapidly, and
continue to increase gradually from 71 days (winter) to 165 days (summer) (Figure 4.24).
Figure 4.24: The variation in zinc concentrations in plants from the Berg River, Sout River
and Groen River study area over the sampling period from March to September 2012.
Concentrations marked by the same letter do not differ significantly (p ≤ 0.05).
4.2 Discussion
The Groen River flows from near Malmesbury it passes through the Darling farms and joins the Sout
River at about 20 km south east Hopefield. The Sout River flow from near Moorreesburg through farming
and residential areas downstream and north of Hopefield finally discharges into the Berg River. The
agricultural activities in the study area include livestock farming and crop framing such as wheat. It was
hypothesised that heavy metal accumulate in the Phragmites australis in the Sout River and Groen River.
However the status of heavy metal content in the areas was unknown. The Phragmites australis (reeds)
were the most common plant species occurring in the rivers. The research questions were based on the
comparison of the heavy metal content of the rivers with the South African Water Quality Guidelines for
Agricultural Water Use and Aquatic Ecosystem as set by the Department of Water and Frosty 1996.
4.2.1 Water quality parameters
Temperature plays an important role in water it affects the rates of chemical reactions and therefore also
the metabolic rates of organisms (DWAF, 1996 d). The oxygen content and temperature are highly
correlated with one another (Davies and Day, 1998). This is observed at S3 and G1 to G3 where the low
38. 28
temperature correlates with the high dissolved oxygen content (Figure 4.1 and Figure 4.3). The rate at
which aquatic plants and algae produce oxygen in water depend on temperature, since cold water can hold
more dissolved oxygen than warm water. The increase in temperature affects aquatic plants and algae
productivity (DWAF, 1996 a). The maximum temperature of the study areas was (28 C) (Figure 4. ), in
early summer which was in the range of the coastal water temperature (5 - 0 ) in South Africa ( WF,
1996 b). Temperature decreases with the change in seasons which correlate with the high level of
dissolved oxygen (Figure 4.2 and 4.4). Towards winter (71 to 126 days) the level of dissolved oxygen
increases with the decrease in temperature (Figure 4.17).
The raw water pH lies between 6.5– 9.5 (DWAF, 1996 d), through out the seasons the pH range of the
study areas was within this range (Figure 4.5). The pH of natural water is influenced by various factors and
processes including acidic precipitation and agricultural effluents (WHO, 1996). The maximum pH 8.4
value were observed downstream of the Groen River (G1 and G2) and Sout River (S1-S4) (Figure 4.5).
These downstream sites are situated in areas dominated by farming activities. The high values of pH in
these sites might be due to the influence of agricultural activities such as the use of mulches and manure as
fertilizers, this can be cross referenced with the high sodium content (Figure 4.9). The minimum pH 7.4
value were observed in the upstream of Groen River (G3) (Figure 4.5), the surrounding areas does not
have many farming activities (Figure 3.1).
The pH of water is good indicator of the presence of elements in water. The pH value below seven favours
heavy metals such as lead and cadmium (DWAF, 1996 d). The cadmium has a low solubility at neutral or
alkaline pH values and is more soluble under acidic conditions. The pH of the study area ranged from 7.4-
8.4 (Figure 4.5). The highest concentration of cadmium was 0.9 µg/l (Figure 4.11), which is contained
within the level of acceptable cadmium concentration of water used for agricultural irrigation (DWAF,
1996 d). This might be due the pH range (7.4-8.4) of the water (Figure 4.5), which is not favoring the
cadmium solubility.
A high EC value is indicative of a higher content of (TDS) in water (DWAF 1996 a; Morgan 1996).
Domestic discharges and surface runoff from agricultural and cultivated areas are examples of the types of
sources that may contribute to increased TDS concentrations. Evaporation also leads to an increase in the
total salts (DWAF, 1996 d). Figure 4.1.8 indicate that lower concentration of EC occurred from 0- 71 days
through the seasons, during this time there was no overland flow which discharges in the stream. The
temperature was at its maximum level, thus the rate of evaporation was high. The exponential increase in
39. 29
EC concentration is observed from (71 to 165 days) winter to spring (Figure 4.8). Western Cape receives
most of its rainfall during winter towards spring (71 to 165 days), during this seasons overland flow from
agricultural, domestic and cultivated areas in the surrounding study area was at the highest peaks thus an
exponential increase in EC.
The conductivity of most freshwaters ranges from 10 to 1,000 μS cm-1
but may exceed 1,000 μS cm-1
,
especially in polluted waters, or those receiving large quantities of surface runoff (WHO, 1996). This
range was contained in BR site, this occurred due to dilution of water by the Berg River’s tributaries
(Figure 4.7). The EC concentration level over time and over sites is extremely high in both Sout River and
Groen River 10 μS cm-1
to 4600 μS cm-1
which is an indication of highly polluted water (Figure 4.7 and
Figure 4.8). The salinity level is the measure of the salt load of a water body such as a river and lakes
(DWAF, 1996 b). The concentration of sodium over the sites does not show any significant different only
at site S1 the concentration is extremely high (5000 mg/l) (Figure 4.9). Sodium affects heavy metal, which
are soluble under certain acidic condition. Plants require certain level of salinity and when concentration
salinities attain (1 g/l,) the river water is useless for agriculture (DWAF, 1996 b). The concentration of
sodium over time decreases with change in seasons from (0 – 71 days). During these seasons the rate of
evaporation was high and affected the available of water which resulted in high concentration of sodium.
4.2.2 Heavy metals concentration in water
4.2.2.1 Cadmium (Cd) Concentration
The cadmium toxicity in water is influenced by salinity, pH, and water temperature. Cadmium has a low
solubility at neutral or alkaline pH values and is more soluble under acidic conditions below pH of 4.0
( WAF, 1996 d). A cadmium level for water used in agricultural irrigation is 10 μg/l ( WAF, 1996 d).
The mean values of cadmium ranged from 0.0299 to 0.9696 μg/l with the highest concentrations at site S4
(Figure 4.11). The lowest cadmium value was observed at site G3 and G2 (upstream of the Groen River)
(Figure 3.1). The results suggest that the main source of cadmium in the Sout River and G1 of the Groen
River could be attributed to agricultural runoff from the farming and runoff from Hopefield (Figure 3.1).
During the study period the mean values for cadmium concentration were in range of 0.0251 to 1.2115
μg/l, over time. Figure 4.12 indicates that the highest peak was at 71 days during winter to spring from 34
to 97 days. This could be due to increase surface runoff.
40. 30
The Target Water Quality Range of cadmium for moderately soft water should be within 0.25 μg/l
(DWAF, 1996 d). From the results average mean cadmium value over the sites of the Soult River and
Groen River was 0.3223 μg/l and over the study period was 2.5007 μg/l which is not contained within the
0.25 μg/l Target Water Quality Range of cadmium. The concentration exceeded the Chronic Effect Value
in soft water. Therefore cadmium concentration is not suitable for sustainable use of ecosystems and could
be poisonous to the aquatic organisms. However the Berg River site (BR) mean value is 0.0585 μg/l is
contained within 0.25 μg/l Target Water Quality Range of cadmium for moderately soft water. Thus is
favorable for aquatic organisms and ecosystem this might be due of dilution by Berg River’s tributaries.
The SA Water Quality Guideline for cadmium in water suitable for livestock is 0–10 μg/l ( WAF, 1996
c). The results indicate that cadmium concentration is not poisonous to livestock faming it was below
2.5007 μg/l over the study period.
4.2.2.2 Copper (Cu) concentration
Copper is important micronutrients required by plants for growth in specific tolerable amounts.
(Marschner,1995). Aquatic plants take up minerals nutrients over their entire submerged surface whereas
terrestrial specie acquires their mineral via a root system from a soil (Larcher, 2001). The toxicity of
copper increases in aquatic systems with a decrease in dissolved oxygen (DWAF, 1996 d). The mean value
of copper concentrations over sites samples at the Sout River and Groen River ranged from 0.0005 to
0.0131 mg/l (Figure 4.13). The Berg River was used as control hence, the Sout River discharges in to it.
The mean value of copper over site BR was 0.0005 mg/l, low than concentrations of copper at site S1,
which is the site before the discharges in to the Berg River (Figure 3.1). The highest mean value of copper
was displayed in the Groen River site G1 few meters from the livestock farm. The concentrations of
copper over sites did not have significant difference to each other at (p ≤ 0.5), except at site G1 with the
highest concentration 0.0131 mg/l (Figure 4.13). The average copper concentration over time was 0.0016
mg/l and did not show any significant difference (p ≤ 0.5) over sampling period (Table 4.1). The result
suggests that the sampling sites had approximately uniform concentration of copper except at G1 with the
highest concentration. The levels of copper in the study area could be contributed by runoff from the use
of copper based pesticides on the farms or fertilizer.
The Target Water Quality Range for copper in aquatic ecosystems is less than 0.3 µg/l in soft water and
below 0.8 mg/l in medium soft water. The Chronic Effect Value for copper in water for aquatic
ecosystems is 0.53 µg /l in soft water and 1.5 µg /l in medium soft water, while the Acute Effect Value for
41. 31
copper is 1.6 µg /l in soft water and 4.6 µg /l in medium soft water (DWAF, 1996 d). From the results, the
mean copper values in the water samples from the Sout River, Groen River and Berg River exceeded the
0.3 μg/l for soft water and exceeded 0.8 μg/l Target Water Quality Range for medium soft water. The
concentrations of copper in the water samples from the rivers exceeded the Chronic Effect Value and the
Acute Effect Value for soft and medium soft water. Thus the rivers water is unsuitable for aquatic
ecosystems and could cause adverse effects to aquatic organisms due to copper poisoning. However the
concentration did not exceed 200 µg/l for water used in agriculture irrigation, which is considered
appropriate for irrigation and safe to be taken up by plants. The concentration of copper in the rivers is
favorable for livestock such cattle and sheep, it was below the 500 µg/l. (DWAF, 1996 c).
4.2.2.3 Lead (Pb) concentration
Lead is bioaccumulated by freshwater plants and aquatic organisms (DWAF, 1996 c). The major
Anthropogenic sources of lead in the atmosphere and aquatic environment these include precipitation,
fallout of lead dust and street runoff (associated with lead emissions from motor vehicles) (DWAF 1996;
Notten et al., 2008).
The result indicate that the lead mean value ranged from 0.1472 – 1.1471 μg/l in the water samples from
the Sout River and Groen River (Figure 4.14), whereby highest concentration was noted at site S3 within
farming area and the lowest concentration was observed at site G1. Figure 4.15 shows that the mean
concentration of lead fluctuated through out the seasons with the highest peaks during winter to spring
seasons (34 to 97 day). During spring plants start to grow and the lead concentration decreased gradually
this could be caused by the accumulation of lead by plants (Figure 4.15). The average mean concentration
of lead in plant samples was 1.5527 μg/l did not show any significant difference (p ≤.0.05) over time
(Table 4.1) and it was higher than average mean of water samples 0.7425 μg/l. This suggests that lead was
taken up by plants during spring season as they start to grow.
The lead values in the water samples were found to be above the 0. μg/l Target Water Quality Range for
the soft water and only at sites G1 and G3 was found to be below 0–0.5 μg/l in medium soft water of
standards set by DWAF, (1996 d). Lead concentrations exceeded the standards in the water samples, thus
river water is not favorable for aquatic ecosystems and aquatic organisms. However the lead concentration
did not exceed the SA Water Quality Guidelines 500 μg/l used for livestock (DWAF, 1996 c). Thus the
water can be suitable for consumed by animals and for irrigation.
42. 32
4.2.2.4 Zinc (Zc) concentration
Zinc is an important micronutrient required by plants for growth and development in small amounts
(DWAF, 1996 d). Zinc can enter aquatic ecosystems through natural processes such as weathering and
erosion, and through human induced activities such as industrial activity i.e. fertilizer and insecticide
(DWAF, 1996 d). Figure 4.17 shows that the zinc mean values ranged from 0.0092 mg/l) to 0.0335 mg/l
over time and increased over the sampling period from winter to spring (71 to 97 days). The highest mean
value of zinc was noted in around August and September, during these months Western Cape receives
most of its rainfall. This may be due to increased agricultural runoff washing way leached soil containing
zinc oxide. The Target Water Quality Range is 0–0.002 mg/l for aquatic ecosystem, the Chronic Effect
Value is 0.0036 mg/l, and the Acute Effect Value is 0.036 mg/l (DWAF, 1996 d). These standards for
aquatic ecosystem were exceeded at all sites. The lowest zinc mean concentration in the water samples was
0.0092 mg/l at (site S4) (Figure 4.16). This may be threat to the aquatic ecosystem. Despite aquatic
ecosystem standard, none of the other limits were exceeded. This suggest that Sout River and Groen River
water are suitable for agricultural and livestock farming.
4.2.3 Heavy metal concentration in plants in relation to water samples
Phragmites australis occurred widely within the Groen River Sout River and Berg River. It was found that
the species has ability to accumulate high quantities of cadmium and zinc. Sodium has a negative effect on
plant growth it makes the water saline and thus affects the concentration of micronutrients in the water
(WHO, 1996). The highest Na was noted at site S3 (4348. 44 mg/kg). This seems to affect the Cd
concentration at site S3 (Figure 4.18 and Figure 4.20). Figure 4.24 and Figure 4.19 shows that when Na
concentration is high over time element concentration of Cd and Zn decrease through out the seasons from
71 to 165 days. However the copper concentration was not affect by the sodium concentration (Figure
4.23). This suggests that some micronutrients are not affected by sodium.
Plants may take up cadmium that has been chelated by phytochelatins, but it is not an essential plant
nutrient (Marchners 1995; Larcher 2001). The normal cadmium concentration in plants is 0.1 mg/kg. Plants
in unpolluted environment contain 0.01–0.3 mg/kg cadmium (Larcher, 2001). Phragmites australis
accumulated minimum of 5.0844 mg/kg over site (S3) and minimum of 9.6779 mg/kg over time (Figure
4.20 and Figure 4.21). This indicates that Phragmites australis has exceeded the typical values of cadmium
concentration and therefore the environment which it absorbs the micronutrient is highly polluted (Larcher,
2001). When comparing seasonal concentration trends of cadmium in water and plant samples the results
43. 33
suggest that the cadmium is a dominate heavy metal is water and plant samples of the Groen River, Sout
River and Berg River. This might be due to agricultural use of sludge, fertilizers and pesticides in farms
near Malmesbury and Moorreesburg. The high quantities of heavy metals particularly cadmium and zinc
accumulation over time (71-165 days) could probably have been attributed to the high rainfall intensity,
discharging material containing cadmium oxide and zinc oxide in to the rivers.
The mean average concentration of copper in plants was 4.5694 mg/kg with the highest value at sit S2
(5.5197 mg/kg) and lowest at site S3 (3.3952 mg/kg) (Figure 4.20). The average mean concentration of
copper did not exceed the requirement in plants. This suggest that copper concentration is acceptable to be
up taken as mineral nutrient and does not show any potential threat to aquatic ecosystem. A significant
difference of 50 % in copper concentrations in plants was observed over the course of the study period
(Figure 4.21). The peak in the copper concentration in plants seems corresponding with copper
concentration in water and can be related to the increase rainfall (71- 97 days) flushing runoff in to the
river.
The concentration of lead element in plants did not show significant difference over sites and over time at
(p≤ 0.05) during the study period similar to the concentration of zinc element did not show significant
difference (p≤ 0.05) over the sites (Table 4.1). The concentration of lead in plants had an average of 1.55
27 µg/kg over time and 1.535 µg/kg over sites through the study period (Table 4.1). The normal level of
lead (Pb) in plants is between 5-10 mg/kg (Larcher, 2001) but it is not required. The average concentration
of lead in plants through the study period was below 2 mg/kg. This suggests Phragmites australis is good
bioindicator of heavy metal accumulation. Hence the average concentration of lead in plant samples
correlates with lead in the water samples. The water samples had lower concentrations of lead which do not
pose a threat to aquatic ecosystems and organisms, similar to plants the concentration is below the
requirement standards. This suggests there is no sudden increase in lead in the area. Thus lead does not
pose a threat.
The requirement of zinc in plants ranges from 10 mg/kg -15 mg/kg (Larcher, 2001). This suggests that
Phragmites australis had the ability to accumulate zinc element with the mean average of 41.7182 mg/kg
which exceeded the requirement. Figure 4.24 indicate that the accumulation of zinc reached highest peaks
at 31 days early summer before it dips and increases gradually with the change in seasons. The highest zinc
peaks during summer is questionable, however the increase in zinc concentration from early winter to
spring (71 – 165 days) can be attributed to the increase rainfall thus increase in surface runoff which
44. 34
deposited erodible material contain zinc oxide which can be reduced to zinc metal (USEPA, 2000). The
zinc concentration in water samples during early summer towards winter (0-71 days) was at lowest level
while in plants the concentration was at the highest peaks. This suggests that there is a sudden increase in
the accumulation of heavy metal content in plants.
4.2.4 Conclusion and Recommendation
The study showed that heavy metals are present in the Groen River and Sout River and are accumulated by
the Phragmites australis. Phragmites australis occurred widely within the Groen River Sout River and
Berg River. It was found that the species has ability to accumulate high quantities of cadmium and zinc.
Based on the research questions cadmium seems to be the most prevalent pollutant and dominate heavy
metal in both plants and water samples, followed by zinc. Lead has shown to be less problematic to the
area. Additional research questions included determining the heavy metal content of rivers and compare
with the typical values and strands. The heavy metal content of the rivers was found to be above
acceptable standards. Therefore cadmium (Cd) copper (Cu) and zinc (Zn) concentrations were not suitable
for sustainable use by ecosystems and could be poisonous to the aquatic organisms and thus pose threat.
Anthropogenic activities were thought to have had an influenced to the water quality parameters, possible
from agricultural runoff. The heavy metals that occurred in the highest concentrations were Cd and Zn and
were dominate in the Sout River. These two heavy metals were influenced by excess agricultural runoff
from farming areas near Hopefield. It was hypothesised that heavy metals accumulate in the Phragmites
australis in the Sout River and Groen River, based on the results the hypothesis was supported. The results
showed that most of element concentrations (Cd, Cu and Zn) in plants were higher than those in the water
samples. This suggests that most heavy metals were accumulated by plants from the water and thus
Phragmites australis is good bioindicator of micronutrients and heavy metals.
The Sout River and Groen River are seasonal rivers and to date little work has been done on seasonal
rivers in Southern Africa. The study could be improved by frequent investigation because seasonality
influences the water quality parameters i.e. rainfall intensity and temperature. The Sout Rivers is a tributary
of the Berg River, poor management of river will affect the quality of water in the Berg River in future thus
affect aquatic ecosystem and organisms. Consistent catchment management of the study area will reduce
the chance of Berg River being contaminated by water from the Sout River.
45. 35
References Cited
1. Barakat, M.A. (2010). New trends in removing heavy metals from industrial wastewater
Department of Environmental Sciences, Faculty of Meteorology and Environment, King
Abdulaziz University (KAU), Jeddah 21589, Saudi Arabia: pg 364-374.
2. Buszewski, .B, Jastrzębska, .A, Kowalkowski, .T, and Binkul, A. ( 000). Monitoring of
Selected Heavy Metals Uptake by Plants and Soils in the Area of Toruń. Poland.
Department of Environmental Chemistry and Ecoanalytics. Faculty of Chemistry.
Nicholas Copernicus University: pg 512-514.
3. Dallas, H. F. & Day, J.A. (2004). The Effect of Water Quality Variables on Aquatic
Ecosystems: A Review. WRC Report No. TT224/04.
4. Davies, B., Day, J. (1998). Vanishing waters. University of Cape Toen Press. Cape
Town: pg 194 -195.
5. DWAF, (1996 a). South African Water Quality Guidelines Volume 3: industrial water
use second edition, Pretoria: pg 32, 33, 45,46,69,70 and 116.
6. DWAF, (1996 b). South African Water Quality Guidelines, Volume 4: Agricultural Use:
Irrigation. 2nd ed. Pretoria: Department of Water Affairs and Forestry.
7. DWAF, (1996 c). South African Water Quality Guidelines, Volume 5: Agricultural
Use: Livestock Watering. 2nd ed. Pretoria: Department of Water Affairs and Forestry.
8. DWAF, (1996 d). South African Water Quality Guidelines. Volume 7: Aquatic
Ecosystems. Pretoria: pg 59 - 91.
9. Eeva, .T & Lehikoinen, .E (2000). Recovery of breeding success in wild birds. Nature
403: pg 850–852.
10. Golterman, H.L., Clymo, R.S. & Ohnstad, M.A.M. (1997). Methods for the Physical and
Chemical Analysis of Fresh Waters. 2nd Edition. Blackwell, Oxford. pg 87
11. Larcher, W. (2001). Physiological Plant Ecology, 4th
edition, Institute of Botany, Edition,
Springer, Berlin . ISBN 3-540-43516-6. pg 186 & 194
12. Ma, Y. (2005). Monitoring of Heavy Metals in the Bottelary River Using Typha capensis
and Phragmites australi. [Master Thesis]. Department of Biodiversity and Conservation
Biology, Bellville University of the Western Cape.
46. 36
13. Margorn, J. (1996), Aquatic chemistry, Chemical Equilibria and Rates in Natural Water,
3rd
edition, Environmental Engineering science, California Institute of Technology, New
York ISBN 0-471-51184-6: 88-107. pg 278
14. Markert, B.A., Breure, A.M., Zechmeister, H.G., (2003). Bioindicators and Biomonitors,
Definitions, strategies, and principles for bioindication or biomonitoring of the
environment in trace metals and other contaminants in the Environment, Elsevier: pg 3-
39.
15. Marschner, .H. (1995). Mineral Nutrition of Higher Plants. 2nd
edition. Institute of Plant
Nutrition University of Hohenheim. Germany. London San Diego New York, ISBN 0-
12-473543-6: 333-347. pg 332 -47
16. Meerkotter, .M. (2003). Heavy metals and vegetable farming in Cape Town [Masters
Thesis]. Bellville. University of the Western Cape.
17. Mertens, J., Luyssaert, S., Verheyen, K., 2005. Use and abuse of trace metal
concentrations in plant tissue for biomonitoring and phytoextraction. Environmental
Pollution, 138: pg 1-4.
18. Mokaya, S. K. Mathooko, J. M. and Leichtfried, M. (2004), Influence of anthropogenic
activities on water quality of a tropical stream ecosystem. African Journal of Ecology,
Volume 42: pg 281–288.
19. Moore, P.D and Chapman S.B. (1986), Method in plants ecology Blackwell oxford ISBN 0-
632-00996-9
20. Notten, M.J.M., Walraven, N., Beets, C.J., Vroon, P., Rozema, J., Aerts, R. (2008).
Investigating the origin of Pb pollution in a terrestrial soil–plant–snail food chain by
means of Pb isotope ratios. Applied Geochemistry: pg 24.
21. Ngwenya, .F. (2006). Water quality trends in the Eerste River. Western Cape. 1990-2005
[Masters Thesis]. Bellville. University of the Western Cape.
22. Ott R.L. (1998). An Introduction to Statistical methods and data analysis. Belmont,
California: Duxbury Press: pg 807-837
23. SAS, (2000). SAS/STAT Users Guide, Version 8, First Edition, Volume 2. SAS
Institute Inc., Cary, NC, USA
47. 37
24. Shapiro, S.S and Wilk M.B. (1965). An analysis of Variance Test for Normality
(complete samples), Biometrika 52, pg 591-611.
25. Swaine, M.D, Adomako J, Ameka G, Graft-Johnston K.A.A, and Cheek M. (2006).
Forest river plants and water quality, CSIR Water Research Institute, pg 300-308.
26. USEPA. (2000). Biosolids technology fact sheet: Land application of biosolids. The U.S.
Environmental Protection Agency, EPA 832-F-00-064, Office of Water.
27. Washington, D.C. Wang, .J, Liu .R, Ling. P, Yu .P, and Tang .A. (2010). Heavy Metals
Contamination and its Sources in the Luoyuan Bay. Procedia Environmental Sciences.
Volume 2: pg 1188-1192.
28. Windhama, L. Weisb, J.S, Weisc P. (2001). Uptake and distribution of metals in two
dominant salt marsh macrophytes, Spartina alterniflora (cordgrass) and Phragmites
australis (common reed) Department of Earth and Environmental Sciences, Lehigh
University, Bethlehem, PA 18015, USA: pg 64-71.
29. WHO. (World Health Organisation). 2008. The problem of environmental contamination
by cadmium, lead and mercury in Russia and Ukraine. Pg 9-10
http://www.who.int/ifcs/documents/forums/forum6/eco_accord_en.pdf download 22 July
2012 downloaded 22 July 2012.
30. WHO (World Health Organization). 1996. Water Quality Assessments - A Guide to Use
of Biota, Sediments and Water in Environmental Monitoring - Second Edition
http://www.who.int/water_sanitation_health/resourcesquality/wqachapter3.pdf
downloaded 23 July 2012 downloaded 22 July 2012.
