ACKNOWLEDGMENT
I would like to dedicate this work to
all stake holders who have given me support. I would like to thank entire
Egerton University, especially to the department of Environmental Science.
Special gratitude goes my field attachment supervisors at K.M.F.R.I kisumu
especially Mr. E.J. Odada and Dr. Lewis Sitoki for availing their time to
ensure my success during the attachment period
ABSTRACT
The
field/industrial attachment period is a critical period for students and it
seeks to help them get exposed and familiarize themselves with the working
environment in their areas of specialization, the attachment period also helps
one to get to understand the application of all that which he has learnt in
class and thus equips him/her with the ability to apply this knowledge. KMFRI
Kisumu is a research Centre of KMFRI and its main role is to undertake research
on aquatic resources in inland waters. Main areas covered include Ecosystem
dynamics (Plankton and Fisheries), Environmental pollution, fish quality and
mariculture. This report focuses on the activities carried out at this Centre
especially on the areas of water quality management, natural products
management, fish quality activities, biodiversity conservation in the Lake
Victoria basin and the mariculture aspect of it. Recommendations
on the institution and on attachment programme are also highlighted in the
report.
Table of Contents
ABSTRACT
……………………………………………………………………………………………………………………………………….2
INTRODUCTION
TO KMFRI……………………………………………………………………………………………………………….4
KMFRI
ORGANISATIONAL STRUCTURE……………………………………………………………………………………………..5
GEOGRAPHICAL
LOCATION………………………………………………………………………………………………………………7
NATURAL
PRODUCTSPROGRAMME…………………………………………………………………………………………………8
AQUARIUM
DIVISION……………………………………………………………………………………………………………………14
WATER QUALITY RESEARCH
LAB…………………………………………………………………………………………………….21
CONCLUSION………………………………………………………………………………………………………………………………….36
RECOMMENDATION………………………………………………………………………………………………………………………37
REFERENCES………………………………………………………………………………………………………………………………….38
CHAPTER ONE
1.0.0
INTRODUCTION TO KMFRI
Kenya
Marine and Fisheries Research institute (K.M.F.R.I) is a state corporation in
the ministry of fisheries development. It’s mandated to conduct aquatic
research on covering all the Kenyan waters and the corresponding riparian
areas. The institute was established by an act of parliament (Science and
Technology Act Cap 250 of the laws of Kenya) in 1979. The activity of this
institute is governed by a service charter that seeks to create awareness of
the organization to its client and this includes:
1.0.0.1
VISION
To be a Centre of excellence in aquatic research and
promotion of sustainable utilization of marine and freshwater resources
1.0.0.2
MISSION
To contribute to the
management and sustainable exploitation of aquatic resources and thus alleviate
poverty, enhance employment creation and food security through
multidisciplinary and collaborative research in both marine and fresh water
aquatic systems
1.0.0.3
CORE VALUES
So as to fulfill its mandate and realize its mission, KMFRI
is guided by the following values:
v Integrity
v Excellence
v Team work spirit
v Innovativeness
v Commitment
v Timely delivery
v Information sharing
v Gender equity and social
fairness
1.0.0.4
RESEARCH PROGRAMMES
Ø Aquaculture research and
development programme
Ø Environment and ecology
programme
Ø Fisheries programme
Ø Information and database
programme
Ø Natural products and post-harvest
programme
Ø Socio-economic programme
1.0.1 KMFRI
ORGANISATION STRUCTURE
M&C- marine and
coastal PC- programme
coordinator PLT- principal lab
technologist
MF- master fisherman SC- station coordinator CA- chief accountant
CAO- chief accounting officer
CSO- chief supplies officer
KMFRI’S headquarters is in Mombasa, with a liaison office in Nairobi.
The institute has two research centers based in Kisumu and Mombasa. The Mombasa
Centre coordinates Marine and coastal research in the coastal hinterlands, the
territorial waters and the 200 nautical miles Exclusive Economic Zone (EEZ) in
the Indian ocean. The kisumu Centre coordinates research on Lake Victoria and
other inland waters through five Research stations at: Lake Baringo, Lake
Turkana and Lake Naivasha, Kegati and Sangoro for aquaculture.
The inland waters research center Kisumu deals is mandated to
carry out research on:
Fisheries programme
·
Catch and effort assessment survey
·
Stock assessment of inland water fisheries
·
Fish biology and ecology
·
Fish kills, diseases and infestations
Aquaculture programme
·
Hatchery development
·
Production of quality seed
·
Development of cost effective cultural system
·
Participatory technology development and transfer
Environmental and ecology programme
·
Pollution status of inland waters
·
Impact of water hyacinth infestation
·
Water circulation around Mbita causeway in relation to
fisheries and water quality
·
Relationship of fish quality, occasional fish kills and the
quality of the aquatic environment
Natural products programme
·
Total quality assurance of fish and fishery products
·
Reduction of post-harvest losses
·
Identification of bio products from aquatic resources- plants
and animals
Socio-economic programme
·
Sustainable management of inland aquatic resources with
greater community participation
·
Improved living standards of communities dependent on aquatic
resources through better management of fish farming, marketing and development
projects
The
offices hours begin are from Monday to Friday from 8.00am to 5.00pm in the
evening. A reporting register is used to keep record of the time of entry and
exit, signature and name of all attaches that are within the institute and one
has to sign it as he enters or leaves the institute
1.0.2 GEOGRAPHICAL LOCATION
Kisumu
Research Centre is situated on the shores of Lake Victoria at an altitude of
1140m. It is located next to Kisumu International Airport and it’s directly
opposite the National Cereals and Produce Board Kisumu depot on the road to the
Kenya Pipeline Kisumu depot
CHAPTER TWO
2.0.0 NATURAL PRODUCTS PROGRAMME
This
chapter highlights all the activities that are carried out by the Natural
Products department of KMFRI Kisumu. The major activities carried out in this
department includes
·
Fish processing and preservation
·
Determination of fish quality
·
Fish feed formulation
·
Fish processing techniques
·
Pond management and disaster
2.0.1 FISH PROCESSING AND
PRESERVATION
Processing
is the treating of raw materials so as to come out with a different/partial
product. Processing can also be used to mean that those processes where raw
materials are commercially, physically, biologically treated and transformed
into slightly different products
Preservation
on the other hand means the process in which foods are chemically,
biologically, physically treated to
prevent spoilage or to improve their shelf life
2.0.2 OBJECTIVES OF PROCESSING AND
PRESERVATION OF FISH
1) Helps to improve the
product quality
2) Prevents spoilage of the
product and increases the shelf life of that product
3) Reduces bulkiness of the
final product e.g. a Lates niloticus
(Nile perch) can be up to 2metres long and weigh up to 500kgs but after
processing we can be able to have small fillets that can be sold over the
counter in supermarkets etc.
4) Reduces wastage, this is
in that the whole components of a fish are put into good use and as such no
parts of the fish are able to go into waste e.g. a Lates niloticus (Nile perch) can produce fillets
from the flesh: the skin can be used to make leather products ; the intestines
and bones can be dried and crushed to make fish feeds etc. such that by the end
of the process no parts of that fish goes to waste
5) Encourage farmers to
produce more, due to the fact that processing of fish guarantees a higher yield
in terms of financial gains as almost all the parts have monetary value, more
farmers will want to get into this sector so as to get the financial benefits
of processing the fish rather than just the traditional methods of eating and
throwing the wastes
Apart
from these, we also found out that processing is also done so as to reduce the
microbial spoilage of fish e.g. by mold, yeasts, bacteria etc. that attack the
fish. Processing is also done so as to
reduce the physical degradation of the fish in terms of its physical
appearance, it also reduces the chemical activity that is likely to go on
inside the fish’s body once its exposed to agents that promote spoilage like air,
bacteria, yeast and insects. Because during processing no water is present in
the final output the possibility of enzymatic action is reduced and this goes a
long way to ensure that the shelf life of the product is improved since water
is a host for most of the agents causing spoilage
2.0.3
METHODS OF FISH
PRESERVATION
a)
THERMAL METHOD
This
method involves the application of heat in preservation of fish. In this
process the groups/classes of microorganisms that are killed include:
1.
Psychrophiles :these microbes are capable
of growing in fish below the temperatures of 5*c. its capable of surviving
refrigeration temperatures so in a way refrigerating your fish doesn’t help in
making it fresh rather acts as an activator for this microorganisms. Examples
here includes ,streptococcus: pseudomonas
2.
Mesophiles: these microorganisms are
found in the soils, in water, human bodies. They grow in temperatures of about
25.45*c. examples here includes gotalinium; Bacillus coagulant
3.
Thermophiles: they grow in temperatures above 60*c-80*c. in this
case the concern to the local should be to cook the fish in adequate
temperatures conditions as any milder temperatures just seek to activate the bacteria’s
instead of getting rid of them. Examples here include Streptococcus phycalis,
clepsiele,
acetobacta
4.
Thermodurics: these are microbes capable
of growing in temperatures above 80*c, they are also called spore formers. They
are killed by the diurnal organoleptic change (thermodynamo) e.g. raise it in
high temperatures then change it to a very cold temperature environment so as
to shock the sample or stress it
b)
BRINING
In
this method, the sample/product is put in a large can partially filled with
concentrated salt solution (this is after processing of course). In the case of
the Rastrineobola argenta(dagaa/omena) or any other small fish
one can also be able to use the dry method, where you take salt and sprinkle on
fresh omena. The disadvantage of this method is that some of the salt may
remain on the surface of the fish thus absorbing moisture from the atmosphere
and as such creating an ideal environment for mould growth. Another method that
can be used is the washing of the high quality dagaa/omena and then mixing them
with salt in the ratio of 1:20 (salt: fish) then drying.
N/B: in the case of dagaa, only high
quality dagaa should be salted using pure salt. The storage
containers used should be adequately secured to avoid any moisture from
getting in as salted dagaa absorbs
moisture and absorbs moisture that is an ideal site for mould growth
c)
INJECTION METHOD
This
method is usually preferred in big fishes where salt penetration is low. This
is achieved through a process where a concentrated brine solution is passed to
the product through the arteries. Its advantages are that: it saves time and is
faster to do; is used to handle large quantities of fish; more efficient for
salt penetration to the inner parts. The disadvantages of this method includes
the cost, its expensive in terms of the equipments needed; there is also the
possibility of one injecting too much salt into the fish that would lead to
toughness
d)
SUN DRYING
In
this method the fish is aired and on the ground or on any other technology and
it’s exposed to the solar radiation that dries it till all moisture is gone
from it. So as this method to be very effective it’s recommended that the fish
if big be split so as to increase the surface area exposed to the solar
radiation and to improve penetration. This method has been promoted by KMFRI
Kisumu so as to help the people treat the local delicacy “obambla”(gutted fish
that’s sun dried) well and avoid chances of fish spoilage and also because it’s
cheaper to apply.
e)
SMOKING
Smoking
is a method of preserving fish where fish is smoked in a kiln, KMFRI advocates for this since it has been
proven scientifically that smoke has
chemical compounds that kill spoilage causing bacteria since it dries the fish
up and thus leaving no room for any agent that could attack the product. The
heat from the kiln also means that the fish is totally dried up. During the
procedure a lot of smoke is generated and can be quite irritating to the eye
and one can find it difficult to breathe in that atmosphere and as such we were
advised not to stay in the room for long periods of hours
f)
MILLING:
In
this method the fish is milled to flour for human consumption especially fed to
infants e.g. “omena” flour. Another method of fish preservation can be through
deep frying, fermentation, filleting, splitting, gutting. These methods above
seek to add value to the fish product, improve its storage life and also is
geared towards reducing the processing costs etc. we were shown the procedure
for filleting as we prepared samples for showcasing during the annual kisumu
regional show
g)
COOLING/REFRIGERATION:
These encompass a wide array of
technologies used to decrease the fish temperature to levels where metabolic
activities - catalyzed by autolytic or microbial enzymes - are reduced or
completely stopped. This is possible by refrigeration or freezing where the
fish temperature is reduced, respectively, to approximately 0 °C or < -
18°C. Fish refrigeration can use cool air circulating around the fish
(mechanical refrigeration) or icing. Fish icing and boxing on-board
fishing vessels is not always possible in the case of small pelagics that are
caught in large quantities. These are chilled using refrigerated seawater (RSW)
or chilled seawater (CSW). Chilled or frozen fish products require additional
cooling in cold store to avoid an increase in temperature. The design (size,
insulation, palletization) and management of cold stores are key for fish
quality and energy saving. A major environmental issue relates to the
development of alternative refrigerants to replace the chlorofluorocarbons
(CFCs) which are damaging to ozone layers. KMFRI has thus come up with wooden
box cooler boxes that are cheaper, easier to make and yet still as efficient as
the other commercial cooler boxes to encourage local fishermen to use them to
minimize catch spoilage.
2.0.4 DETERMINATION OF FISH QUALITY
Most often "quality" refers to the
aesthetic appearance and freshness or degree of spoilage which the fish has
undergone. It may also involve safety aspects such as being free from harmful
bacteria, parasites or chemicals. It is important to remember that
"quality'' implies different things to different people and is a term
which must be defined in association with an individual product type. For
example, it is often thought that the best quality is found in fish which are
consumed within the first few hours post mortem. However, very fresh fish which
are in rigor mortis are difficult to fillet and skin and are often unsuitable
for smoking. Thus, for the processor, slightly older fish which have passed
through the rigor process are more desirable. The methods for evaluation of fresh fish quality may be conveniently divided into two categories: sensory and instrumental. Since the consumer is the ultimate judge of quality, most chemical or instrumental methods must be correlated with sensory evaluation before being used in the laboratory. However, sensory methods must be performed scientifically under carefully controlled conditions so that the effects of test environment, personal bias, etc., may be reduced.
a) SENSORY
METHODS
Sensory evaluation is defined as
the scientific discipline used to evoke, measure, analyze and interpret
reactions to characteristics of food as perceived through the senses of sight,
smell, taste, touch and hearing. Most sensory characteristics can only be measured meaningfully by humans. However, advances are being made in the development of instruments that can measure individual quality changes.
Instruments capable of measuring parameters included in the sensory profile are the Instron, Bohlin Rheometer for measuring texture and other rheologic properties. Microscopic methods combined with image analysis are used to assess structural changes and "the artificial nose" to evaluate odour profile (Nanto et al., 1993). Some of the features that one should look out for are:
Excellent quality fish
The gills should be dark red with a marine smell with a thin clear slime from it; the eyes of the fish should be bright, metallic, clear pupils, convex in shape. The general appearance of the fish should be such that the belly is firm, the skin bright and shining, firm scales and fresh smell with little or no slime
Poor quality fish
The gills are almost brownish in colour, have a lot of slime and produces a slight off smell; the eyes are dull, with cloudy pupils, slightly concave eyes, bloody eyes or bulging out eyes; the general appearance of the fish is some red brown colour in body colour, it has few or no scales, very soft belly that if you press in does not go back to its original shape, the kin is dry and has a lot of thick yellow slime and has a foul smell
b) INSTRUMENTAL
METHODS/MICROBIOLOGICAL METHODS
The aim of microbiological examinations
of fish products is to evaluate the possible presence of bacteria or organisms
of public health significance and to give an impression of the hygienic quality
of the fish including temperature abuse and hygiene during handling and
processing. Microbiological data will in general not give any information about
eating quality and freshness. But it seeks to give data on the approximated
shelf life of processed fish like the filleted Nile perch. Some of the methods
we used included the total count method, spoilage reaction method where a
sample of fish was exposed to the agents of spoilage and the rate of spoilage
recorded and how it did spoil. Some of the test also carried out on fish
includes the testing of levels in heavy metals of the fish body. Another method
used by the KMFRI researchers is the texture method where an accurately cut
fish sample is compressed by a plunger, and the stress-strain curve recorded. A
modulus of deformability is calculated from the recorded graph. The results
from such measurements may, however, be difficult to interpret and as such
only the well trained researchers were able to make sence of the data we
collected2.0.5 FISH FEED FORMULATION
This is one of the main activities of the natural products division of KMFRI as part of its way of educating the local communities who are going into the aquaculture sector, because the kisumu centre is not an aquaculture centre, they do not do more on this line rather they produce just a small amount for use within their research aquariums and for demonstration purposes.
During one of the preparation exercises that we were involved in, we used different ingredients for the fish feeds preparation, we had milled dagaa, cut vegetables (kale), the remains got from sifted maize from the NCPB . the ingredient are mixed in a trough like container by hand but if it’s in large scale they recommend using a more better efficient mechanical method, the mixture is the added with water to make a paste like mixture, after mixing with already cut vegetables, its passes through a mincer to produce long lengths of feed that are then left to dry on the sun and cut to smaller pellets to enhance drying. After they dried they were kept in an open area to avoid them going bad but we were told that it’s advisable not to be stored in a moist place as this will enhance spoilage
In fish feeds formulation, the locals are taught that depending on the type of fish kept, the feed varies, for fish like the Oreochromis esculentus which are vegetarians, the pellets can be used to feed them, but for carnivores like the Nile perch one should feed them on small fish. The farmers were advised to have both the vegetarian fish and the carnivore fish in one pond as this would lead to economic efficiency as they only have to feed only the vegetarian and the other feed on the Tilapia, creating a food chain reaction in the pond. In so doing the farmer has to ensure to balance.
2.0.6 FISH PROCESSING TECHNIQUES
KMFRI has invested in some of the state of the art technologies used in the process of processing fish. Some of the machines that we were exposed to include the SOXHLATE UNIT that is used to measure the fat content, the ash content in various food products especially in fish species; we were also shown and learnt how to use the MULLER BANDSAW that uses electricity and is used to split large masses of fish like the Nile perch, a lot of caution should be applied when using this machine to prevent one from causing bodily harm to self; they also had a “multipurpose fish processing machine” that is used to process fish where a whole fish is put in and its capable of filleting the fish, giving out the bones and even the wastes; smoking kiln that we used to smoke with fish that was taken for display at the Kisumu agricultural show; there are drying racks that have been made to be used for demonstration purposes to fishermen as appropriate ways of handling fish after harvest and how to dry the fish safely without contamination on the fish
We got to learn that in fish processing techniques one does not have to go just for the high end products but can also employ the local available resources to good efficiency e.g. the use of wooden cooler boxes, wooden drying racks, use of knife and board to fillet etc. they are funding projects aimed at finding local solutions for the local fishermen to deal with the problems of ensuring that fish quality getting to the community is good. In so doing they get to exchange ideas and in the process both groups get to gain knowledge wise
CHAPTER THREE
3.0.1
AQUARIUM DIVISION
This is a
division of the KMFRI structure at the kisumu centre that is used to conduct
research on fish under captivity, it is also used to conduct research on the
biodiversity status of the inland waters of Kenya especially on Lake Victoria,
and in extension it also provides the aesthetic value to the institute. I was
attached to this department for two weeks as one was supposed to rotate through
at least three departments in the institute. The two technicians who were in charge
of this division are Mr. Akama James and Mr. Achia Henry. In this department
were to get hands on experience on the fooling activities/expertise
1)
Classification
of aquariums
2)
Construction
of aquarium tanks
3)
Care and maintenance
of aquarium
4)
Methods of
obtaining fish for captivity to aquarium
5)
Fish
diseases
6)
Fish
taxonomy and classification
KMFRI KISUMU AQUARIM DEPARTMENT
INTRODUCTION
An aquarium is an artificial pool tank used to culture a living aquatic organism, thus it should be able to simulate the natural aquatic environment of the aquatic organism under captivity
3.0.2 CLASSIFICATION OF AQUARIUM TANKS
We have different and diverse types of aquarium tanks depending on the choice and preference and also on the purpose of its use. Some of the types of aquarium tanks in use include:
Ø Glass-water aquarium tank: this is the most
common type of aquarium tank in the market. It comes in different shapes and
design and it’s made of glass. Most common type since one is able to see
through the tank and see the aquatic organism under captivity
Ø Asbestos tanks: these are tanks that are made
of asbestos and are normally used by people who want to have tanks used to
culture organisms or having their tanks outside the house or for use as a
hatchery. It’s made totally of asbestos
Ø Aluminum tanks: made of aluminum material
Ø Plastic tanks: made from plastic materials
and come in different shades of colour according to your want
3.0.3 CONSTRUCTION OF AN AQUARIUM TANKWe were involved in the construction of a Glass-water aquarium in groups of two each. In order for to construct an aquarium one needs to have the following components in place:
1.
Glass
2.
Silicon-
sealant used to join the glasses permanently at an angle
3.
Silicon- sealant
gun/choking gun: used to push the silicon out of the sealant tube
4.
Masking
tape: used to hold the glasses temporarily as you work on them
5.
Detergent:
used to smoothen and remove excess applied sealant
6.
Sharpening
stone: used for making the edges of the glass blunt
7.
Tape
measure: used to take the required measurements
8.
Diamond
pencil/marker pen: to mark the line for cutting
9.
Styrofoam:
this is the soft material on which the glass lies or is rested on to prevent
breakage
3.0.4 CONSTRUCTION PROCEDUREYou are required to ensure that all the surface where you intend to work are clean and dry and should be free from grease, this is because when working with glass you want to prevent any thing that may cause the glass to break or cause injury to you either through slipping or falling.
i.
You should
lay the Styrofoam on the ground and place the glass on top
ii.
using the
tape measure, draw out the size of the tank you want on the glass and make
markings of where you are to cut later using a marker pen, before cutting you do
your math well to ensure you have the correct measurements for the desired
tank.
iii.
At this
point, take the glass cutter and cut the glass along the marked line of the
maker pen, use a meter rule as a guide to help you have a straight line, you
should have five pieces of glass for each side of the aquarium if you intend to
make a single tank.
iv.
Using a
sharp knife cut the tip of the sealant and screw the nozzle on the tip, the
sealant with the fitted nozzle should then be fit into a chocking gun.
v.
Using a masking
tape hold the glasses together in the shape of the tank you wish to make at
right angles until it forms a shape of your desired tank.
vi.
Apply the
silicon-sealant to the inside edges in a steady flow, ensuring that all the
edges are applied with the sealant thoroughly until all the glasses are joined
together.
vii.
Then using a
spatula dipped in a mild detergent, smoothen the applied sealant until
uniformity is achieved and then leave the aquarium tank to cure for a period of
about 48 hours.
viii.
Fill the aquarium
tank with water three quarter way for a period of 7 days, during this period
you are supposed to monitor if any leakage exists so as to seal any. The water
bath also removes any toxic from the sealant (acectoxy xylene).
ix.
Empty the
aquarium tank and refill it with fresh water to be able to culture an organism
NOTE
Ø The procedure should be done in a well
ventilated room so as to avoid any toxic irritation from the use of the sealant
and the detergents and the glass.
Ø The water used in the aquarium must be from a
well known source e.g. pond, harvested rain water, tap water spring water etc.
however pond or harvested rain water is preferred because it is assumed that it’s
free from chemicals and heavy metals. As for tap water you are advised to leave
it for about 3 days in storage before use so as to allow the chlorine levels to
evaporate and degrade to lower levels
3.0.5 AQUARIUM CONSTITUENTSSo as to simulate the natural aquatic habitat of most aquatic organisms, it’s advisable to have some constituents in the tank that makes the tank have the aesthetic value, simulate the natural environment and also to make the tank not look so empty. The constituents include:
Ø Stones- simulating the natural environment
Ø Gravel/sand-helps in infiltration of toxic
substances
Ø An aquaria decorators- background picture
that makes it beautiful also simulate natural environment
Ø Plants- helps in the oxygen generation
Ø Aerator- provides oxygen to the tank
Ø Water
Ø Filters- sponges that helps in infiltration
Ø Hideouts that help the fish hide from the
view when it wants to
3.0.6 MAINTAINANCE AND CLEANING OF AN AQUARIUM TANK
Just like any surface that’s exposed to water and an organism, plus the agents of the environment, an aquarium tank is bound to get dirty and needs cleaning so as to be able to maintain its aesthetic value and provide the fish with sanitary conditions. Cleaning a tank involves the following processes two processes:
a) Full
cleaning
This is done where the whole tank
is washed and all its constituents washed. It’s usually done after a month
because a full cleaning that’s done well ensures the tank will remain neat for
about those weeks. The procedure is as follows
Ø Remove all the aquaria contents except the
water and the fish
Ø Transfer half of the water into a clean
bucket, this will act as a temporary home for the fish, the bucket should be
deep such that the fish can’t jump out
Ø Scoop out the fish from the tank using a
scooping net and put it into the bucket
Ø Scrub the walls of the tanks using fine sand
and a scrubber
Ø Drain off the water used for cleaning the
walls
Ø Put the sand on one side of the tank and
rinse the tank two times with clean water, each time rubbing the sand together
to remove any toxins from it
Ø Using a sponge rinse the water completely out
of the tank
Ø Spread back the sand in the tank
Ø Create space for filters in the tank; arrange
the heights and all the constituents in their original position
Ø Fill the tank with water but not to the brim
to prevent breakage due to the atmospheric pressure being applied on it
Ø Aerate the tank for about 4 hours, this
allows the chlorine in the water to be minimized and also disperses the
chemicals in the water
Ø After four hours scoop the fish out of the
bucket and return to the tank
b) Partial
cleaning
After a full cleaning the tank
may need just a small cleaning exercise, probably to keep it fresh, done at an
interval of about two weeks. It also helps to improve the water quality in the
tank and eradication of toxic substances in the water. The procedure is:
Ø Don’t remove any constituent in the tank
Ø Siphon out the water to halfway
Ø Use the sponge to clean the walls taking care
not to injure the fish
Ø Leave the water to settle, using a siphon
pipe pick out the dirt from the visible areas till clean completely
Ø Refill the water unto the desired level
3.0.7 FISH TAXONOMY
This is the science of classification, ordering of organizing in groups on the basis of their relationship, structure, and way of life. As part of its mandate the aquarium department has classified the fishes of Lake Victoria so as to provide education/ knowledge base for the visiting teams and also to aid in research activities. In the aquarium they have categorized the fishes into two groups i.e. the exotic breed and the native species of Lake Victoria
a) EXOTIC
BREEDS OF LAKE VICTORIA
These are those breeds of fish
that have been introduced to the lake ecosystem or have been acquired for the
aquarium for research purposes and also for their aesthetic value. We got to
learn that their introduction to the lake has both positive and negative
effects including the loss of biodiversity. An example of this effect is the
economic extinction of the “ngege” Oreochromis esculentus
(singida tilapia) from the Lake Victoria waters due to the volatile competition
in the lake for food by the introduced specie of tilapia, the Nile Tilapia (Oreochromis
niloticus) “nyamami”. This particular specie of tilapia is a better
competitor for food and a better feeder, and this competition for food and with
the concept of natural selection and competition that states that two organisms
competing for the same natural resource will fight for that resource until one
is pushed into extinction. Due to this fact and the fact that they feed on
algae mainly, the Singida tilapia has been pushed to economic extinction and
the specie is not found in most of the lake’s waters.Examples of exotic fish species in Kenyan waters include:
|
Scientific name |
Common name |
Local name |
|
Carassius auratus |
Gold fish |
………………. |
|
Haplochromis spp. |
……………… |
fulu |
|
Lates niloticus |
Nile perch |
mbuta |
|
Gambusia affinis |
Mosquitoe fish |
………….. |
|
Oreochromis niloticus |
Nile tilapia |
nyamami |
|
Tilapia zillii |
Red belly tilapia |
opat |
|
Tilapia rendalli |
Red breast tilapia |
…………… |
b) NATIVE
SPECIES OF LAKE VICTORIA
These are those fish that were
originally found in these lakes. Lake Victoria used to have a species diversity
with over five hundred know fish species. The Haplochromis spp.
For instance were of about over twenty types but of late it’s about only three
(Sitoki et al.) the problem of overfishing, introduction of exotic species,
deleterious land use practices, pollution etc have all contributed to the
oxygen depletion of the lake and the mass extinction of the native species is
now taking place. Example of Lake Victoria native species:|
Scientific name |
Common name |
Local name |
|
Oreochromis esculentus |
Singida tilapia |
Ngege |
|
Barbus cercorp |
Barb |
Adel |
|
Labeo victorianus |
Gregorian labeo |
Ningu |
|
Clarias alluadi |
Catfish |
Dhira |
|
Rastrineobola argenta |
Victoria sardine |
Omena |
|
Synadontis victoriae |
L.Victoria squeeker |
Okoko rachar |
|
Aethiomastacembelus frenatus |
Longtail spiny eel |
Okunga |
I got to learn about the proper feeding of fish in captivity. We found out that fish feeds are mainly enriched feeds that are a compilation of several nutrients that are needed by the fish and the ratio given to the fish depends on the size of the fish and the fish species as some eat more than others. The fish can be classified as either vegetarian or carnivorous. The carnivorous feeds on small fish, converting the smaller biomass to a much bigger biomass, that is more valuable economically. A full grown Nile perch can be up to 193cm as compared to a small haplochromis sp. Or the labeo victorianus that grows a mere 41cm. as such we had to fish on the KMFRI pond every 2 days for small fish to feed the Nile perch in the institute while we fed the other vegetarian fish on the feeds. When you give them excess food and they don’t consume them all, the feeds on the presence of the water will start to decompose faster releasing toxins and eating up the oxygen supply in the tank that can end up killing the fish and it also produces a foul smell, in case this scenario occurs, one is supposed to immediately do a full cleaning of the aquarium tank to avert any harm to the fish.
Another category of fish feeding habits is the filter feeders, which move in the water at a speed targeting the zooplanktons which they feed on. The apex feeders are predators that feed by hunting and vicious attacks on their prey e.g. Nile perch. The scrappers scrap through the stones, leaves etc e.g. “Gregorian labeo”. The bottom feeders feed on dead matter at the bottom
3.0.9 FISH DISEASES
Just like any living organism, fish also do get sick. We normally use the clinical symptoms to diagnose fish diseases i.e. that which can be seen by the naked eye because its common sense that you cant take a fish out of the water to the lab without killing it or causing it harm.
CLINICAL/GENERAL SYMPTOMS OF FISH DISEASES
Ø Anorexia- lack of appetite
Ø Erosion of the fins- some of the fins are
eaten away
Ø Abnormal swelling of the stomach
Ø Small sugar like spots/cotton like spots
Ø Un directional movement e.g. fish moving in
water with belly upside
Ø Rubbing against the walls of the aquarium
tank or rough contents
CAUSES OF FISH DISEASES
Ø Overfeeding-decomposition of food in the
aquarium tank leads to a loss of oxygen in the water and also toxicity of that
water
Ø Too much fight between the fish in the tank
Ø Poor diet
Ø Overcrowding of fish in a pond/tank
CATEGORIES OF FISH DISEASES
Ø Infectious disease
Ø Congenital diseases
Ø Traumatic diseases
Ø Parasitic diseases
a) Infectious
diseases
These are
diseases caused by disease causing micro organisms’ e.g. fungi, bacteria, protozoa
Ø Fin rot disease- Pseudomonas fluorescence
Ø Gills rot disease- Branchyomyses spp.
Ø White spot disease-Lchthyopthirius multiifillis
b) Congenital diseases
They come as a result of
genetically alterations. E.g. Albinism-lack of formation of melanin in the body
that’s characterized by pink eye colour or light skin
c) Traumatic diseases
These diseases are caused by the
bad injuries to the fish. In the tilapia family when competing for mates a lot
o fighting results leading to injuries. It can also be caused by the chilling
temperatures of the water
d) Parasitic
diseases
These diseases are caused by an
organism that’s relying on another and includes the tape worms in fish, fish
flee, fish flukes.CHAPTER FOUR
4.0.0
WATER QUALITY RESEARCH LAB
(CHEMISTRY/ENVIRONMENTAL LAB)
This is a
division of KMFRI in charge of analyses of water samples from the various field
excursions that the centre does so as to monitor the pollution status of inland
waters. Find the relationship of fish quality, occasional fish kills and the
quality of the aquatic environment.
This
department was headed by Mr. E.J Odada, Mr. Dick and Mr. Moses Umani; I was
attached to this department for about two weeks. This is the busiest department
in the centre where work is always in plenty and accuracy is needed of you as
the results got determine policy made by various government departments relying
on the data from this lab
Some of the
parameters that this lab is tasked to look at are the physio-chemical
parameters e.g. TDS (Total dissolved substances), TSS (Total suspended
substances), TN (total nitrogen) TP (total phosphorous), PH, Alkalinity,
dissolved oxygen, chlorophyll a, etc
Some of the
equipments used in this lab include:
Ø The cadmium reduction column- that is used to
reduce nitrate to nitrites
Ø Secchi disk- used to get the readings of
water clarity
Ø Analytical balances- used to take
measurements of samples to be analyzed
Ø Autoclave- used to digest samples for use in
analysis of total nitrogen in water samples
Ø Spectrophotometer
Ø Ekman grab- used to collect sediment samples
from river/lake beds
Ø Vandon water sampler- measuring parameters
like temperature, ph etc
Ø Centrifuge
Ø Metallic hot plate and stirrer
Autoclave cadmium reduction column analytical balances
During my stay in this lab we received water samples from Lake Turkana, Lake Victoria, and even Lake Baringo for analyses. When new samples come into the lab they should be properly labeled to show the source of the sample and for which parameter it’s going to be analyzed for, and the date the sample was collected. Once all these are found to be in place, the samples are stored in the fridge or the incubator waiting for the time and day it’s to be worked on. The temperatures in the fridge should be such that it keeps the sample cool preventing any further reaction that could affect the outcome of the analysis.
The analysis procedures used in this lab are the international standard procedure so as to give credibility to the research process as a lot of money is pumped into the research projects and the equipments in the centre; this is in line with its vision of being a reputable research centre.
When preparing for analysis for newly arrived sample, we had to prepare certain essential reagents that are used and they include:
Ø acetone solution (90% concentration)
Ø Methyl red indicator (0.002%)
Ø Buffer
Ø Standards
4.0.1 ANALYSIS FOR WATER HARDNESS
(USING EDTA Titrimetric method)
The hardness
of water is the capacity for the precipitation of soap.
The soap is
precipitated by calcium and magnesium ions in water. It can also be
precipitated by other polyvalent metals e.g. Aluminum, copper, Manganese,
Strontium, Zinc and even hydrogen ions but only Magnesium and Calcium are
present in water in high concentration and hence hardness is expressed as the
characteristic of the water to represent total concentration of just Mg and Ca
expressed as carbonate.
A small
amount of dye such as Eriochrome black T is added to an aqueous solution
containing Ca and Mg ion at pH of 10 + 0.1, the solution becomes red. If
EDTA is added as a titrant, Ca and Mg will be complexed.
After a
sufficient EDTA is added to a complex all the Ca and Mg is turned from wine red
to blue- this is the endpoint of the titration.
Principle
EDTA-
Ethylene diamine tetracetic acid and its sodium salt forms a chelated soluble
complex when added to a solution of certain metals.
Reagents
Buffer for
the hardness titration
Dissolve
1.179g of Disodium EDTA (analytical reagent grade) and 0.78g of Magnesium
sulphate in 50 ml of distilled water. Add to this solution to a 250 ml
volumetric flask containing 16.9g of Ammonium chloride and 143 ml of conc.
Ammonium hydroxide. Mix and dilute to the mark with distilled water.
Standard EDTA preparation
EDTA titrant
0.02N
Place 3.723
g of analytical reagent grade of disodium ethylene diamine tetracetate
dihydrate (Na2H2C10H1208N2.2H20)
in 1 litre volume flask and dilute to the mark with distilled water.
Ammonium hydroxide (1N)
Dilute 70
mils of conc. ammonium hydroxide to 1 litre with distilled water
Eriochrome T black
Mix together
0.5g Eriochrome black T and 100g of sodium chloride
Procedure
Take 50-ml
of water sample
Add 1 ml of
buffer (1 ml sufficient to give a pH of 10.1) and 1 ml of (1N) ammonium
hydroxide
Absence of a
sharp point colour change titration means that an inhibitor must be added at
this point or that the indicator has deteriorated
Add a few
granules of the indicator (Eriochrome T black mixture)
Add a standard EDTA titrant
slowly, or with continuous stirring, till the last reddish tinge (pink)
disappear from the solution
Add last few
drops at 3 to 5 seconds interval
Endpoint
solution is normally blue
If
sufficient sample available and interference absence, the accuracy is improved
by increasing sample size.
Calculations:
Hardness
EDTA (mg/l) = (A*B*50,000)/V
Where
A = ml of
titrant EDTA
B = mg
carbonate equivalent 1 ml EDTA titrated (EDTA normality) V = Volume of sample
4.0.2 ANALYSIS OF WATER FOR
ALKALINITY
Alkalinity
is defined as the capability of water to neutralize acids in presence of
carbonates, bicarbonates and hydroxides of calcium, magnesium and sodium, which
are the common causes of alkalinity in natural waters.
The level of
alkalinity is dependent on the source of water. Natural surface and well water
contain less alkalinity than sewage or wastewater
Alkalinity
is normally expressed as P- Phenolpthalein or as total alkalinity
Principle
The natural
water with carbonates is hydrolysed owing to the weakness of the carbonic acid
leading to production of hydroxyl ions and consequently a rise in pH
M+HCO3-
+ H20 = M + H2CO3 + OH-
The concentration
of the carbonate in solution is determined by titration a sample with acid till
the above equilibrium moves completely to the right - all the carbonate present
is un-dissociated carbonic acid and carbon dioxide. This occurs when the pH
reduces to 4.5. The indicator is chosen to give the color change at this pH or
the pH can be monitored using a glass electrode.
Reagents
Standard sodium carbonate (0.02N)
Dissolve
1,059 g of pure anhydrous sodium carbonate dried overnight at 110°C into 1l of
water in flask.
0,02M HCl
Conc. acid
is 12M (by dilution law) 2ml are dissolved in 1000 ml of distilled water)
Indicator
Methyl red
0,002% (0.2g) in neutral 95% alcohol with 0.01% (1g) bromocressal green
Procedure
Transfer 50
ml of sample into a conical flask
Add three
drops of indicator
Run in 0,02N
(0.02M) standard acid from the burette with continuous shaking till the colour
of the indicator assumes a pale pink flush or till measure pH reaches chosen
endpoint value of 4,5
Color
changes from Blue through Grey to Pink
Calculations
Endpoint pH
Alkalinity
(mg/l) = (A*N*50,000)/V
Where;
A is the ml
of acid taken,
V is the sample volume and N is
the acid normality
4.0.3 ANALYSIS OF SAMPLES FOR
DISSOLVED OXYGEN (D.O)
Carefully
fill one of the stoppered bottles. Allow to overflow and avoid entrapment of
air bubbles. Stopper the bottle care being taken not to trap an air bubble
With a
pippette introduced below the water surface;
Add 0.5 ml of manganese sulphate
and 0.5ml of winklers reagent.
Replace the
stopper firmly, again taking care to avoid trapping air and shake well. A
precipitate of manganese hydroxide is formed.
Introduce 1ml of sulphuric acid
to the bottles. Transfer 50 mls of sample into a conical flask. Add
thiosulphate drop by drop till the colour turns yellow
Add a bit of
starch- colour turns blue
Carefully
add the thiosulphate until the colour becomes colourless.
This is one
of the sample collections that require one to be tactful since any slight loss
of concentration leads to one getting the wrong results. It was a challenge
collecting samples for analysis in a lake that has wave motion almost
throughout and still trying to ensure that no air bubbles get into the sample
bottles. With more practice at the KMFRI pier we got to learn the best way to
collect the sample with minimal margin for error
4.0.4 ANALYSIS FOR CHLOROPHYLL a IN
MACROPHYTES
During
the extraction you should work in dim light conditions to prevent chlorophyll
decomposition by light
1.
Set aside 5ml of 96% ethanol in a measuring cylinder for each
sample
2.
Grind 0.1 to 0.3 g fresh weight of plant material in a mortar and
pestle with 2 ml ethanol (preserved frozen samples are easier to grind)
3.
Grind until the green suspension is all that is left of the plant
material
4.
Transfer the suspension quantitatively to a screw capped
centrifuge tube
5.
Use the remaining 3ml ethanol to rinse off the pestle and mortar
and transport this solution also as much as possible to the tube
6.
Fill up the tube with ethanol to the 5ml mark on the centrifuge
tube
7.
Put a cup on the tube to prevent the evaporation of the ethanol
8.
Leave the sample overnight or at least 12 hours n the dark at room
temperature for maximum extraction
The following day
9.
Centrifuge for about for about 10 minutes at 3000 rpm, there be clear
supernatant left. Keep the samples in the dark as much as possible
10.
Zero the apparatus (spectrophotometer) with ethanol at all wavelengths
11.
Carefully pipette 3m of the supernatant into a cuvette
12.
Measure at 750, 665 and 649
13.
Add 0.5ml of 0.06 M HCl to the cuvette
14.
Measure at 750, 666, 655 nm
4.0.5
ANALYSIS FOR CHROROPHYLL a IN ALGAE
The
standard procedure: 1 litre of sea water is filtered on a GF/C filter paper
under low suction. We used a suction pump to filter the samples, this speeds up
the filtration process as it creates a vacuum on the lower compartment forcing
the air pressure acting on the samples to drip downwards to fill that resultant
vacuum. The sample size can be adjusted to the phytoplankton in the sample
Reagent
90
% acetone (CH3C0 CH3)- analar is dissolved in distilled
water (1l).
Centrifuge
at 3000 rpm for 10 minute
Procedure
Fill
two cuvettes with 90% acetone (blanks)
Adjust
the wavelength to 750nm
First,
zero the spectrophotometer by putting the blank cuvette in position
Measure
the extinction after the nd blank (correction of the possible difference in the
optical properties of the cuvettes)
Fill the
second cuvette with supernatant of the centrifuged sample
Measure the extinction
Switch to
665nm wavelength, repeat zeroing and measure
Repeat at
665nm and 645 nm
Calculations
Subtract the
reading at 750 nm from the other readings
Units (µg/ml
if the 1 cm cuvettes are used)
C(Chl a)
=11.6E665 -1.31E645-0.14E630
C(Chl b)
=20.7E645 -4.42E630-4.34E665
C(Chl c)
=55E630 -4.64E665-16.3E645
The results
obtained from these formulas are multiplied by a factor f, in order to obtain
the chlorophyll values in mg/m3
F= (V)/(I*v)
where;
I = the
length of the cuvette in cm
V = the
volume of acetone used for extraction (ml)
v
= volume of sample water filtered (in litres)
4.0.6
ANALYSIS OF SAMPLES FOR NUTRIENTS
This
is done in a systematic manner. The field team will go and collect samples from
the field at certain well defined field sample collection points, label the
bottles on what is to be tested for, the date the sample was collected and the
collection point name. The samples are persevered using conc. hydrochloric acid
till they are brought to the lab for analysis. Upon arrival at the lab the
samples are refrigerated till time for analysis reaches. When collecting
samples from a sampling point the common procedure was that one collects about
one litre of sample so as to enable the analysis team test for all the required
parameters i.e.
·
TDS- total dissolved substances
·
TSS- total suspended substances
·
TN- total nitrogen
·
TP- total phosphorous
·
Silicates
·
Ammonia
·
Nitrite
·
Nitrate
4.0.7
ANALYSIS OF SAMPLES FOR TDS AND TSS
TSS
AND TDS are a measure used to calculate the level of water clarity and the
extent of water pollution in a water body. The normal practice was that once
samples arrived we would start with the analysis for TSS and TDS first. Count
the total number of samples to be analyzed and prepare a corresponding number
of GF/C filter papers, twice the number of samples. Measure the weight of each
filtered paper in an analytical balance and record the weight. Each paper is
numbered or labeled.
Using
a suction pump filter about 100mils of the sample. Do this for all the samples,
then take the samples to an oven and dry them at a temperature of about 100*c
for 24 hours. After that time you again measure the weight in an analytical
balance and record the difference in the readings will indicate the TSS IN EACH
SAMPLE
Analysis
of water quality
Some
parameters such as the Ph, temperature, are measured at the collection point
using a Vandon water sampler that gives the readings on the spot. Water clarity
is also measured using a Secchi disk that is calibrated. The disk is dipped
into the water and the sampler is supposed to check on the point at which he
stop seeing the disk any more as he lowers it further so as to record down the
findings for calculations at the lab
4.0.8
ANALYSIS FOR SILICATES
Dissolved
silica (SiO2) usually occurs in moderate abundance in fresh water. Although essentially unionised
and relatively unreactive chemically, disolved silica is assimilated in large
quantities by diatoms in their synthesis of their cell walls or frastules.
since diatoms are major algal components in many lakes, diatom utilisation can
modify greatly the concentration and
flux rates of dissolved silica in lakes and streams. The availability of
dissolved silica can have a marked influence on the productivity and succession
of algal populations
Silicon
in solution as silicic acid (H4SiO2) or silicate (SiO2-2)
reacts with acidic ammonium molybdate to form a yellow silicomolybdate complex.
This complex is then reduced by sodium sulphite to form the silicomolybdate
colour. The extinction is measured at 700nm
Reagents
Hydrochloric acid (0.25M)
Mix
22 ml of concentrated hydrochloric acid (sp. gr. 1.18) with water and dilute to
1l
Ammonium molybdate 5%
Dissolve
52g of Ammonium molybdate (NH4)Mo7O24 4H20) in water and dilute to 1l
Disodium EDTA 1%
Dissolve
10g of Disodium EDTA in water and dilute to 1l
Sodium
sulphite 17%
Dissolve
170 g of NaSO3 in water and dilute to 1l
Analysis
Pipette
25 ml of sample
Ø Add 5 ml of 0.25M Hcl tot
he flask and swirl
Ø Add 5ml of 5% ammonium
molybdate, swirl
Ø Add 5 ml of 1% Disodium salt; swirl
After
5 minutes have elapsed following the addition of the molybdate, add 10 ml of
17% sodium sulphite. Mix and allow standing for 30 minutes. The clour is stable
for 3 hours
Standards
Stock
Solution: (1g SiO2/l)
Weigh
accurately 3.13g of Sodium hexafluorosilicate (Na2SiF6)
and dissolve this in distilled deionised water and make upto 1000ml (1l).
Calculations: 188 Na2SiF2
=60 SiO2
3.13 Na2SiF2 =(3.13*60)/188 =(1g SiO2/l)
Substock or
working solution: (100mg SiO2 / l)
Make a substock solution by diluting the stock solution 10 times
i.e. Take 10 ml of stock solution and dilute to 100 ml using distilled water
Standards
|
Mg SiO2/l
|
Volume (ml) taken from substock into 25***
ml flasks and then with reagents to 50ml
|
|
0.4
|
0.1
|
|
1
|
0.25
|
|
2
|
0.5
|
|
3
|
0.75
|
|
4
|
1
|
4.0.9
ANALYSIS OF SAMPLES FOR NITRATE AND NITRITE
NITRATE AND NITRITE
The
nitrate in water is reduced almost quantitatively to nitrite when a sample is
run through containing cadmium filings coated with metallic copper (Cu)
NO3
+2H+ +2e- = NO2 +H2
Cd
o =Cd 2++2e-
The
nitrate thus produced is quantified by diazotising and coupling with N- (1-
napthyl) ethylene to form a highly coloured azo dy
NH2SO2C6H4NH2.HCl
+HNO2 =NH2SO2C6H4N=NCl
+2H2O
NH2SO2C6H4N=NCl
+C10H7NHCH2CH2NH2.Cl=NH2SO2C6H4N=NC10H6NHCH2CH2NH2C.2HCl+HCl
Reagent
Concentrated
ammonium chloride solution
Dissolve
125g of ammonium chloride in 500ml of distilled water. Store in glass or
plastic bottle.
Diluted ammonium chloride solution
Dilute
50 mls of the concentrated solution to 2000ml with distilled water. Store in a
glass or plastic bottle
Preparation of the copper -cadmium
colum
Cadmium /copper filings
Stir
about 100g of cadmium filings (enough for 2 columns) with a 2% Copper sulphate
(w/v) ie (10g in 500ml) until the blue colour has left the solution and semi
colloidal copper sulphate particles begin to enter the supernatant. Roll the
very fine copper tunnings between the fingers and make a small plug and push
this to the bottom of the column (wool can also be used). Fill the column with
dilute ammonium chloride solution and pour in sufficient Cd-Cu mixture to produce a column 30 cm in
length. Add the filings a little at a time, tapping the column to make sure
that the filings are well settled. Wash the column thoroughly with the diluted ammonium
chloride. The flow rate must be such that 100ml of solution takes between 8 and
12 minutes. Finally, add a plug of cotton wool at the top of the chamber. When
not in use, columns must be left with the copper filings completely covered
with dilute ammonium chloride. To regenerate a column that has lost effficiency
repeat the above outlined procedure with copper sulphate and ammonium chloride.
Preparation of reagents
Sulphanilamide
5 g of
sulphanilamide are dissolved in 300 ml (Millipore Milli-Q), 50ml of
concentrated HCl are added and the solution is made to final volume of 500ml.
The solution is stable for many months
N-1-Napthyl ethylene diamine
dihydrochloride
0.5 g N-1-Napthyl ethylene diamine
dihydrochloride (C12H14N2.2HCl) is dissolved
in (Millipore Milli-Q) water and diluted to make 500ml. The solution should be stored in a dark bottle and renewed
monthly.
For the
analysis 50ml containing water sample is run through the column. The first 25
mls are wasted and the final 25 ml are saved for analysis.
To 25 mls
add 1ml Sulphanilamide and shake thoroughly. Allow the reagents to stand for 2-8 minutes. Then add a further
1ml of N-1-Napthyl ethylene diamine dihydrochloride and mix completely. After
10 minutes to 2 hours, measure the extinction of the solution against distilled
water at a wavelength of 543 nm.
Standards
Stock solution: (1g NO3-N/l)
Weigh accurately
7.218g of Potassium nitrate (KNO3) and dissolve this in distilled
deionised water and make upto 1000ml (1l).
Calculations:
101KNO3
=14N
7.218 KNO3
=(7.128*14)/101 =(1g NO3-N/l)
Substock (10mg NO3-N/l)
Make a
substock solution by diluting the stock solution 100 times (i.e.). Take 1 ml of
stock solution and dilute to 100 ml using distilled water
Working solution: (1000 µg NO3-N/l)
Make a
substock solution by diluting the stock solution 10 times (ie). Take 10 ml of
stock solution and dilute to 100 ml using distilled water
|
µg NO3-N/l
|
Volume
(ml) taken from substock into 50 ml flasks and finally reduced to 25 ml
|
|
5
|
0.25
|
|
10
|
0.5
|
|
15
|
0.75
|
|
20
|
1
|
|
30
|
1.5
|
4.9.10
ANALYSIS OF SAMPLES FOR AMMONIUM
AMMONIUM: Except under very alkaline
conditions (pH>9) most of the (NH3) in freshwater exist in the
ionic form (NH4+). Ammonium is an important source of
nitrogen for bacteria, algae and larger plants in lakes and streams and because
concentrations are very low, the content of the water samples can change
quickly and markedly. Thus, the samples should be analyzed as soon as possible
after collection.
Ammonium
reacts with phenol and hypochlorite under alkaline conditions to form
indophenol blue. The colour development is prorpotional to the concentration of
ammonium within a given range (0-1000µg
NH4-N /
Reagent
Reagent 1
17.5
g of phenol and 0.2 g of sodium nitroprusside are dissolved in Millipore
Milli-Q water to make a final volume of 500 ml. Store in a refrigarator until
us
Reagent 2
140
g of tri-sodiumcitrate- dihydrate p.a and 11 g of sodium hydroxide are
dissolved in 300 ml of Millipore Milli-Q water. When complete dissolution has
reached, 20 ml of sodium hypochlorite (Javel 10° BE) are added and made to a final volume of 500 ml. Store
in refrigerator until use. This solution
is stable for 2 weeks and should not be used after 14 days !.
To
a sample of water (50 ml), add 3 ml of reagent 1 and 2 respectively with
vigorous shaking, between additions of each reagent. The samples are
subsequently kept in the dark at ambient temperatures until analysis after 24
hours. Measure the absorbance at 630 nm using highly purified water as a blank.
Procedure
The most
common method for ammonium determination is the indophenol blue photometric
determination (Koroleff, 1969). The blue colour-forming reaction, called
Berthelot reaction, was discovered more than a century ago and adapted to
seawater analysis after a method was found to avoid precipitates of magnesium
and calcium hydroxides at high pH. Basically, the ammonium is converted to
monochloroamine by hypochlorite, and after addition of phenol in alkaline
conditions, the indophenol blue complex is formed. Usually nitroprusside is used as a catalyst (Patton and
Crouch, 1977; Lesage, 1984). Precipitation of hydroxides is hindered by metal
complexing sodium citrate.
The
Berthelot reaction does not proceed rapidly enough to achieve adequate colour
formation in a short time, but final complex remains stable for over 24 hours.
Therefore, samples are stored at ambient temperatures in the dark for one day
after addition of the reagents. The absorbance is measured at a wavelength of
630 nm on a spectrophotometer.
Standards
Stock solution (1g NH4-N/l)
Weigh
acurrately 3.821 g of unhydrous ammonium chloride (NH4Cl) and
dissolve this in distilled water and make upto 1l
Calculations
53.5 NH4Cl
= 14N
3.821g NH4Cl
= (3.821*14)/53.5) = 1g NH4Cl /l
Substock (10mg NH4-N)
Make a
substock by diluting the stock solution 10* i.e. Take 10 ml of the stock
solution and dilute to 1000 ml
Standards
By
application of the dilution law viz. (M1*V1 =M2*V2),
the following standards are prepared
|
µg NH4-N
/l
|
Volume of
substock taken into 50ml flasks
|
|
20
|
0.1
|
|
50
|
0.25
|
|
80
|
0.4
|
|
100
|
0.5
|
|
200
|
1
|
Chemicals for nutrient analysis
|
Nutrient
|
Amount
|
|
Silicates
Disodium
EDTA
Sodium
sulphite
HCl
Ammonium
molybdate
Sodium hexafluorosilicate
(standard)
|
500 g
(A.R)
500 g (A.R)
5l (A.R)
500 g
(A.R)
500 g
(A.R)
|
|
Alkalinity
HCl
Sodium carbonate
Bromocresal
green
Methyl red
|
2.5 L
(A.R)
500g (A.R)
25 g
25 g
|
|
Hardness
Magnesium
sulphate
Ammonium
chloride
Ammonium
hydroxide
EDTA
Eriochrome
black T
|
500 g
(A.R)
1 Kg
(A.R)
2.5 L
(A.R)
500 g (A.R)
25 g
|
|
Nutrient
|
Amount
|
|
Nitrate
Spongy
Cadmium granules
Ammonium
chloride
Sulphanilamide
Copper
sulphate
N-1-Napthyl
ethylene diaminedihydrochloride
Potassium nitrate (standard)
|
500g (A.R)
250 g
(A.R)
500 g
(A.R)
20 g (A.R)
|
|
Nutrient
|
Amount
|
|
Phosphorous
Sulphuric
acid
Ascorbic
acid
Potassium
antimony tartarate
Potassium
dihydrogen phosphate
Ammonium
molybdate
|
500 g
(A.R)
500g (A.R)
2.5 L
(A.R)
500 g (
A.R)
|
|
Nutrient
|
Amount
|
|
Ammonium
Phenol
Sodium hydroxide
Sodium
nitroprusside
Sodium
hypochlolite (Java BE)
Trisodium
citrate dihydrate
Ammonium chloride (standard)
|
1Kg (A.R)
1Kg (A.R)
100g (A.R)
1 Kg (A.R)
|
CHAPTER
FIVE
5.0.0
CONCLUSION
KMFRI
kisumu station is mainly involved with the analysis of samples from inland
waters of Kenya, it also engages in research activities that focus mainly on
the inland waters of Kenya. We got to learn on the various methods of sampling
water and sediment samples for the various components from the nutrient to the
heavy metals to the clarity and all. In the analysis department to got to learn
the need for accuracy and professionalism when one is carrying out a research
duty so as to get the correct value of the experiment in question, and in thus
doing we got to learn that no matter how time consuming or how tiresome a
process is, the ethics demanded of us demands us to carry out our work
diligently and professionally
KMFRI
also has a natural products division who are concerned with ensuring that they
come up with new technologies that can be useful to the local community and
that can be used to improve the handling of fish during the post harvest
period. It is also mandated to come up with ways to improve the value we get
from fish by coming up with new ways of utilizing the components of fish.
Through the aquarium department the institute has carried research on the
feeding patterns of fish, come up with new and better feeds, contributed
towards sensitization of the locals on the need for conservation so as to
improve the fish catch, they have also portrayed to the visiting teams the ways
one can be able to build his own aquarium and contribute towards the
sensitization on the need for conservation and the fast pace of biodiversity
loss of aquatic organisms especially fish in our inland lakes
KMFRI
has partnerships with several donor agencies that fund its research activities e.g.
the European Union, The Royal Belgium government, The Netherlands, F.A.O and
even the UNDP so as to come up with new scientific knowledge in the field of
aquatic sciences that will improve the
livelihood of the people depending on these lakes, improve the environmental
conditions of the lakes, come up with new methods for dealing with emerging
threats to aquatic ecosystems e.g. the water hyacinth that has engulfed the
Lake Victoria basin
CHAPTER
SIX
6.0.0
RECOMMENDATIONS
Ø Field attachment course should continue
existing as it helps familiarize young scientists and other students in
different fields on working techniques and environment.
Ø The Government should
abolish bench fee levied on students on attachment and instead adopt a system
of appreciating their studies by paying them some token to boost their studies
and morale
Ø
The
institution should put up a low-cost hotel or mess to cater for the interests
of the students on attachment. This will save on their time and energy which
they spend going to look for food ‘bandani’ over the lunch break.
Ø Students on attachment
should be given temporary identification cards to facilitate their identity
especially during transport by the institution’s vehicles
Ø The institution should
arrange for regular seminars to provide an avenue for interaction between the
students and other established scientists
Ø The institution should
only admit students on attachment based on the availability of facilities at
the centre so as to ensure maximum gain on the attachment period
CHAPTER
SEVEN
7.0.0
REFERENCES
Wetzel, R. A. (1991):
Limnological analysis. Edited by Robert G. Wetzel, Gene E. Likens (2nd
Edition)
Bendschneider,
K. and Robinson, R. J. (1952): A new spectrophotometric method for
thedetermination of nitrite in sea water. Journal of Marine Research. 11:87-96.
D’Elia, C.F.
(1983): Nitrogen determination in sea water. In: Nitrogen in marine
environments. Carpenter E.J. and Capone D.G. (eds) Academic press, New York,
pp.731-762.
Manual of methods in chemical
analysis of water methods used in Kenya marine and fisheries research institute
Chris
Augusta: Cichlids of African lakes Worldboro, ME,USA
Hallo sir, due to the wide reach of this blog and the fact that its visited a lot by students, you could comment with your number so that they can reach you more easily
ReplyDelete