ABSTRACT
This study dealt with analysis of physicochemical parameters, heavy metals in bottom and plankton characteristics of earthen ponds in Michael Okpara University of Agriculture, Umudike Nigeria. The ponds were constructed on low land and therefore prone to runoffs loaded with degradable and non-degradable materials deposited at different degrees in different sections of the farm. For the purpose of this study, the farm was divided into three sections in relation to flooding as; flood free area, low flood area and high flood area. The analysis was carried out to provide empirical data that could be informative in management of earthen ponds in flood prone environment for production of fish for human consumption. Lead, zinc, iron, cadmium were analyzed using atomic absorption spectrophotometer (AAS), dissolved oxygen (Do), Biological oxygen demand(BOD), total dissolved solids(TDS), electrical conductivity (Ec), nitrate, phosphate, temperature, pH, and transparency were analysed using DO meter, TDS meter, conductivity meter, pH meter, thermometer and secchi disc respectively. Plankton was analyzed by filtering water samples through a fine plankton net of mesh size 55um and viewed under microscope for identification. Results obtained showed that DO, BOD, EC, phosphate, temperature, pH were significantly different at 5% probability level (p<0.05) among the different sections of the farm with the following mean values DO had the highest value in sections as 4.78. section 2 4.63 and sectionl 4.19. BOD was highest in Sectionl as 2.08, section2 2.05 and sections 1.78. EC was highest in sectionl as 156.08, sections 114.58 and Section2 83.42. phosphate was highest in sectionl as 1.44, Sections 0.95 and section2 0.13. However, TDS, N03 and transparency were not significantly different among ponds in different sections of the farm. TDS had the highest mean value 73.08 in section3, 70.19 in section2 and 63.41 in sectionl. Nitrate was highest in section3 as 22.04, section2 21.33 and sectionl 19.37. Heavy metals results showed that Pb, Zn, cd, Fe were significantly different at 5% probability level among the various ponds. Results on plankton abundance showed that some ponds were more productive than others which agree that impartation of runoff is at different degree. Sectionl ponds recorded the highest number of plankton which could be linked to the low values of cd, nitrate, TDS. EC values were also high in same section which means that nutrients are better circulated in it. It was recommended that physicochemical parameters should be monitored regularly to make sure they are within the recommended range.
1.1
Justification of the study 5
1.2 Aim of
study 6
1.3 Specific
objectives 6
CHAPTER TWO
2.0
Literature Review 8
2.1
Physicochemical parameters 9
2.2 Plankton 16
CHAPTER THREE
3.0 Materials
and method 22
3.1 Study
area 22
3.2 Duration
of study 22
3.3 Analysis
of water characteristics 23
3.3.1
Collection and treatment of water samples for physicochemical characteristics 23
3.3.2 Methods for
Analysis of physical and chemical parameters 23
3.3.2.1
Temperature of water (°C) 23
3.3.2.2 Transparency
(cm) 23
3.3.2.3
Dissolved Oxygen (D.O) 24
3.3.2.4 pH (Hydrogen
ion concentration) 24
3.3.2.5 Nitrates
(NO3) 24
3.3.2.6
Electrical conductivity of water (EC) 24
3.3.2.7 Total
Dissolved Solids (TDS) 25
3.3.2.8
Biological Oxygen Demand (BOD) 25
3.3.2.9 Water
Phosphate (PO4) 25
3.4 Plankton
characteristics 26
3.4.1
Phytoplankton characteristics 26
3.4.2
Zooplankton characteristics 26
3.5 Heavy
metals analysis at bottom sediments of ponds 27
3.5.1 Experimental
Procedure 27
3.5.2
Analysis 27
3.5.2.1
Atomic Absorption Spectrophotometer (AAS) 27
3.5.3 Lead 28
3.5.4 Iron 28
3.5.5 Zinc 28
3.5.6 Cadmium
29
3.6
Statistical Analysis 29
CHAPTER FOUR
4.0 Results and
Discussion 30
4.1 Heavy metals 33
4.2 Planktons 37
4.2.1 Zooplankton 37
4.2.2 Phytoplankton 46
4.3
Relationship between sediment condition and plankton species samples in the
various ponds 57
CHAPTER
FIVE
5.0 Conclusion and
Recommendation 65
5.1 Conclusion 65
5.2 Recommendations 66
References 67
LIST OF TABLES
Page
1: Mean±SD of physicochemical
parameters of the different ponds throughout the study 33
2: Mean±SD of heavy metal content of
the different ponds throughout the study 36
3: WHO standards for
fresh water 36
4: Total Mean±SD species number
(count) of planktons that occurred in the different ponds throughout the study 38
5: Total Mean±SD taxonomic number
(count) of planktons that occurred in the different ponds throughout the study 48
6: Relationship between heavy metals
and Zooplankton in Pond 1 throughout the period of study 59
7: Relationship between heavy metals
and phytoplankton in Pond 1 throughout the period of study 60
8: Relationship between heavy metals
and Zooplankton in Pond 2 throughout the period of study 61
9: Relationship between heavy metals
and phytoplankton in Pond 2 throughout the period of study 62
10: Relationship between heavy metals
and Zooplankton in Pond 3 throughout the period of study 63
11: Relationship between heavy metals
and phytoplankton in Pond 3 throughout the period of study 64
LIST OF PLATES
Page
I:
Cyanophyta 40
IIa:
Chlorophyta 41
IIb:
Chlorophyta 42
III:
Bacillariophyta 43
IV:
Euglenaphyta 44
Va:
Rotifera 48
Vb:
Rotifera 49
Via:
Cladocera 50
VIb:
Cladocera 51
VIc:
Cladocera 52
VIIa:
Copepoda 53
VIIb:
Copepoda 54
The aquaculture industry is a
key factor for increasing the economic income in developing countries, most
notably in the rural areas as it provides limitless employment opportunities to
improve the economic situation for the people in these regions (Maigualema and
Garnet, 2003).
Aquatic ecosystem whether
fresh, marine or brackish is one of the valuable natural resources whose
quality is vital for human welfare and socio-economic development. Aquatic
ecosystems are particularly prone to environmental change and many are at
present degraded (Williamson, et al.,
2008). In recent years, increase in human population, demand for food, land
conversion and use of fertilizer have led to faster degradation of many
freshwater resources (Muchin et al.,
2012 and Jayakumar et al., 2009).
Fresh water ecosystem, of which University
earthen ponds is part of is
characterized with low or no percentage of dissolved salt and is
subjected to the influence of a wide array of physical and chemical factors according to (Achionye-Nzeh and
Isimaikaiye, 2010) The increase and
decrease of these factors frequently affects the water quality thus altering the diversity of the plant and animal organisms dwelling in
this habitat and also affecting the biodiversity of aquatic ecosystem such as
density, buoyancy, temperature, light, dissolved oxygen, carbon-dioxide
content, pH concentration.
In the growing aquaculture
industry, it is accepted that good water quality is needed to maintain good
aquaculture production (King, 1998). Poor water quality can lead to low profit,
low product quality and potential human health risks. Production is reduced
when the water contains impurities that can hinder development, growth,
reproduction, or even cause mortality to the cultured species (Stone and
Thormforde, 2003). Some impurities can accumulate to the point where it
threatens human health (King, 1998).
All biological and chemical
processes in an aquaculture operation are influenced by temperature. Each
species of fish has a preferred or optimum temperature range where it grows
best. At temperatures above or below optimum, fish growth is affected.
Mortalities may even occur at extreme temperatures (Piper et al., 1982). Turbidity determines light penetration in water.
This in turn will have an effect on the temperature of the water and the amount
of vegetation and algae that will do well in the pond, thus affecting the rate
of photosynthesis and primary productivity (USDA, 1996; Environmental Review,
2008).
Chemical characteristics i.e.
water quality parameters that are chemical in nature within an aquaculture pond
are also of immense importance to the local pond environment and overall yield
of propagated fish species. They are considered to be important and critical
water quality parameters in aquaculture as they change continuously and are
affected by physical and biological characteristics that have been mentioned
previously (Boyd, 1990b). Some important chemical parameters include
alkalinity, Biological Oxygen Demand (BOD), Conductivity, Dissolved Oxygen
(DO), and pH (Boyd, 1998; Environmental Review, 2008). A low dissolved oxygen
level is the major limiting water quality parameter in aquaculture systems
(Boyd, 1995). A critically low dissolved oxygen level occurs in ponds
particularly when algal blooms die-off and subsequent decomposition of algal
blooms and can cause stress or mortality of prawns in ponds. Chronically low
dissolved oxygen levels can reduce growth, feeding and molting frequency. Also
a high degree of variability in the concentration of dissolved nitrates,
nitrites and ammonia (Schwartz and Boyd, 1994) could adversely affect fish. The
environmental conditions that create high ammonia concentrations may also cause
increase in nitrite concentration. Both ammonia and nitrite can be directly
toxic to culture organisms or can induce to sub lethal stress in culture
populations that results in lowered resistance to diseases (Boyd, 1998).
In the same vein, high
stocking density of fish or crustaceans in ponds usually poses problems with
water quality, sediment deterioration and pond bottom characteristics. Wastes
generated by aquaculture activity (faces and unconsumed feed) first settle in
the bottom, as a consequence of organic waste and metabolite of degraded
organic matter is accumulated in sediment and water and could present some
challenges for fish health (Boyd, 1990).
There are more than twenty
heavy metals, but four are of particular concern to human health and the
environment namely; Lead (Pb), Cadmium (Cd), Mercury (Hg), and Arsenic (As)
(ATSDR, 2011). They are toxic and can cause damaging effects even at very low
concentrations. The Agency for toxic substances and Disease registry (ATSDR) in
Atlanta; Georgia, (a part of U.S Department of Health and Human Services)
compiled a priority list called the “Top 20 Hazardous substances”. The heavy
metals arsenic (I), Lead (2), Mercury (3), and cadmium (7) appear on this list.
Human activity inevitably
affects the environment, it causes changes in plant cover and natural
landscapes, and transforms water systems by making different hydraulic
quantities of products from human activity are gradually accumulating in water
bodies, in soils and on the earth’s surface. This is already an obstacle for
socio-economic development in many regions and countries.
Human activity affects to an
extent all basic components of the hydrological cycle: precipitation,
evaporation and also water runoff. Moreover, any change in any component leads
to a change in the other components. It should be noted that the scale and type
of change in hydrological cycle components greatly depend on the size of the
area concerned. As a rule, the larger the territory the more stable the natural
ratios between individual components of the hydrological cycle. Nevertheless,
they are subject to the effects of an anthropogenic factors.
However, water management is
still a major developmental challenge as human
activities have resulted in the dwindling of freshwater resources,
increased pollution load, health and transportation problems and reduced ecosystem
resilience which pose significant threat
to sustainable development.
Industrial activities such as
mining activities results in increased revenue for all parties involved in the
communities, country and the miners themselves. However, irrespective of this
financial advantage, the different environmental pollution effects must be
considered for the health of the people.
Pollution occurs in different form; soil pollution, water pollution and
air pollution depending on the type of activity.
1.1 JUSTIFICATION OF THE STUDY
Run offs from different
sources, carry degradable and non-degradable materials into most of the ponds during
heavy rain which can cause changes in water quality parameters and bottom
sediment chemistry which may affect pond productivity. As fish is a
cold-blooded animal, its growth, reproduction, maturity and survival mostly
depends on water temperature. Inadequate maintenance of water quality might
cause severe problems in fish pond production. Sometimes lack of maintenance of
water quality may cause great loss to the farmers. Therefore, fish farming
requires a regular management of water quality for maintaining a suitable
environment and to maximize their production. The main water quality parameters
(physicochemical) are; transparency, temperature, dissolved oxygen, pH, ammonia
etc. All of these parameters are essential for cultured organisms. The maintenance
of good quality of water is essential for both survival and optimum growth of
culture organisms. Good water quality is characterized by adequate oxygen and
limited levels of metabolites.
The need to analyze heavy
metals in bottom sediments and water characteristics of ponds which may be
imparted by runoffs at different degrees precipitated this study this will also
provide useful information to farmers in raising fish in a site for long period
of time while minimizing impact to the environment.
1.2AIM OF STUDY
The earthen ponds in MOUAU
fish farm were constructed on low land. Runoffs from different sources carry
degradable and non-degradable materials into most of the ponds during heavy
rainfall. It is therefore necessary to evaluate the possible effects of the
runoffs on the pond aimed at reducing the levels of its impartation of the
runoffs in the ponds.
1.3 SPECIFIC OBJECTIVES
1. To access heavy metal accumulation in bottom sediments of the
earthen ponds in MOUAU Fish Farm.
2. To estimate the ponds water quality variables.
3. To describe the distribution patterns, species composition and
biomass of plankton in different earth ponds in the university fish farm.
4. To relate sediment condition with the plankton community of the
ponds in MOUAU fish farm.
Login To Comment