African Journals Online
JOURNAL OF THE GHANA SCIENCE ASSOCIATION
VOLUME 2 No. 2 – 2000
The non-acidogenic potential of two Ghanaian meals
1Frederick Kwaku Addai and 2Isaac
Kwasi Nuamah
1Department of Anatomy, University of
Ghana Medical School, P.O. Box 4236, Accra, Ghana
2 Private Dental Practitioner, 15 St.
Chad Road, Withington, Manchester M20 4WH, England
ABSTRACT
This study tested whether a meal of Ga Kenkey and fried fish
with tomato/pepper sauce (kenkey and fish), or fried ripened
plantain with beans (Red-Red) is acidogenic. The pH of baseline
saliva given by volunteers prior to eating a meal, and at
specific intervals after the meal (effect saliva) was
measured using a Kent EIL 7020 pH meter. As control, volunteers
were given a “glucose challenge” in which they rinsed
their mouths with a 5% glucose solution for exactly 60 seconds.
Changes in pH of effect saliva were determined with
reference to their respective baseline saliva. The mean pH
of saliva changed significantly by negative 0.50 ten minutes
after the glucose challenge and negative 0.23 a further five
minutes later. Immediately after a meal of “Red-Red”
the mean pH of saliva significantly changed by positive 0.45. Ten
and 15 minutes after the meal the mean saliva pH changes were
positive 0.13 and positive 0.06, respectively. The mean pH of
saliva changed by positive 0.39 fifteen minutes after volunteers
ate kenkey and fish, and twenty-five minutes after the meal the
mean change in pH was positive 0.10. The reduction in pH of
saliva below baseline value after the glucose challenge
confirmed its acidogenic potential. Since there was no depression
of saliva pH below baseline values after volunteers had eaten
either of the two meals, it is concluded that
“Red-Red”, as well as kenkey and fish have
non-acidogenic potential. By extension, this suggests that either
meal has non-cariogenic or cariostatic effect.
Functional role of ascorbic acid in bread-making
E. Dadzie-Mensah and G.S. Ayernor
Department of Nutrition and Food Science, University of
Ghana, P. O. Box LG 134, Legon.
ABSTRACT
The banning of bromates and the substitution of ascorbic acid
as flour improver in 1997, generated a lot of controversy among
bakers and flour milling industries in Ghana. This research was
carried out to investigate the effects of ascorbic acid on
wheat-bread characteristics. Various levels of ascorbic acid and
bromate were used in the bread production to compare critical
functional properties of bread. The results showed that the
specific volume of the loaves increased from 2.80 cm3/g
(control) to 3.86 cm3/g at ascorbic acid concentration
of 250.0 mg/kg beyond which no significant increases were
observed. Loaf tenderness was found to increase with increasing
ascorbic acid concentration registering the least value of
hardness (2.2 N) at an ascorbic acid level of 500.0 mg/kg.
Capillarity, which is an inverse measure of vesicular size of the
loaves, decreased with increasing loaf volume registering the
least value (3.40 gWater/gLoaf) at the highest loaf volume of
481.70 cm3 at ascorbic acid level of 250.0 mg/kg.
Crust thickness of the loaves also followed an inverse relation
with loaf volume. The use of ascorbic acid as a flour improver
was found to correlate well with the controversial potassium
bromate within its accepted levels in terms of the various bread
characteristics at correlation coefficient values of 0.85, 0.95,
0.99 and 0.80 for the specific volume, capillarity, tenderness,
and crust thickness registered, respectively.
Some problems with the food packaging practices in Ghana
P-N. T.1 Johnson and H.A. Obiri2
1 Food Research Institute, CSIR,
Box M. 20, Accra
2 Institute of Industrial
Research, CSIR, Box LG 576, Legon, Accra
ABSTRACT
This paper examines the problems with the present methods and
practices used for the packaging of both fresh and processed
foods in the informal and formal sectors of the food industry in
Ghana. The use of unsuitable packaging materials, inadequate and
ineffective packaging, especially during transportation, cost of
packaging, absence of appropriate packaging machinery, poor
labelling, lack of standards and specifications and environmental
issues have all been discussed. The effect of the increasing use
of plastics as the main packaging material was examined. How
these problems impact on the country's drive towards food
security as well as promoting the export of food products have
also been examined. Some recommendations have been made.
Isozyme and storage protein polymorphisms in seventeen
accessions of groundnuts (Arachis hypogaea
L.)
E.Y. Danquah1, E.T. Blay1,
K.M. Bosompem2, J. Fosu-Nyarko1
and J. Dosoogla1
1Department of Crop Science, Univ. of
Ghana, Box LG44, Legon, Ghana;
2 Noguchi Memorial Institute of Medical
Research, Univ. of Ghana, Box LG25, Legon, Ghana.
ABSTRACT
Knowledge of the genetic relationships among the genetic
resources of crop plants is important for facilitating the
transfer of useful genes and maximising the use of germplasm. The
aim of this study was to characterise 17 accessions of
groundnuts. The methods employed were starch gel and sodium
dodecyl sulphate polyacrylamide gel electrophoresis for isozymes
and storage proteins, respectively. Starch gel electrophoresis of
crude protein extracted from the root-tip of two-week old plants
followed by staining in appropriate stain solutions for three
enzymes, acid phosphatase, esterase and peroxidase exposed
variations among the accessions. Peroxidase revealed the most
variation, while acid phosphatase showed the least variation.
When the results of the three isozymes were combined, 13
accessions could unambiguously be distinguished. The remaining
four accessions fell into two groups of two each. Similarity
indices were estimated to determine relatedness among the
accessions based on the isozyme data. There was very little
variation in storage protein patterns. Only three phenotypes were
observed. Combining both isozyme and storage protein data allowed
distinction of the accessions. These results suggest that an
integrated approach utilising both morphological and molecular
markers can allow a proper characterisation of the genetic
resources of the crop.
Intercrop performance of maize, sorghum and soybean in response to planting pattern
A.K. Quainoo,1 I.Y.D. Lawson1
and A. Yawson2
1Department of Agronomy, University for
Development Studies, Tamale, Ghana
2Department of Agricultural Mechanization,
University for Development Studies, Tamale, Ghana
ABSTRACT
Mixed cropping of cereals and legumes dominate the cropping
systems of most farmers in the northern Guinea Savanna
agroecological zone of Ghana. The objective of the study was to
determine the appropriate crop mixture ratios for higher
productivity of maize/soybean and sorghum/soybean cropping
systems. The experiment was conducted during the 1997 and 1998
cropping seasons at the Research Farm of the Faculty of
Agriculture, University for Development Studies, Tamale, Ghana.
Results showed that seed yields of the monocropping maize,
sorghum and soybean were higher than the intercropping yields of
maize/soybean and sorghum/soybean. The sorghum/soybean
intercropping gave a mean Land Equivalent Ratio (LER) of 0.88 and
0.93 in 1997 and 1998 respectively while the maize/soybean
intercropping gave mean LER of 0.82 and 0.81 in 1997 and 1998,
respectively. There was lesser interspecific competition between
the sorghum/soybean while greater interspecific competition
between maize/soybean intercropping was observed. The
sorghum/soybean intercropping gave a mean Relative Crowding
Coefficient (RCC) of 1.57 and 1.23 in 1997 and 1998 respectively
which was more productive than the maize/soybean intercropping
with mean RCC of 1.01 and 0.88 in 1997 and 1998, respectively.
Based on the LERs and RCCs analyses, three rows of sorghum or
maize alternating with three rows of soybean seem more
productive.
Effect of fouling organisms on cultured oysters, Crassostrea tulipa, in three Ghanaian lagoons
E.A. Obodai1 and K. Yankson2
1Department of Renewable Natural
Resources, University for Development Studies, Tamale, Ghana
2Department of Zoology, University of
Cape Coast, Cape Coast, Ghana.
ABSTRACT
The study was conducted to monitor spatfall regimes of oysters
(Crassostrea tulipa) in Nakwa and Jange lagoons, and also
to assess the seasonal abundance and effects of fouling organisms
on cultured oysters in Benya, Nakwa and Jange lagoons. Spatfall
was higher in Nakwa than in Jange lagoon. The spat preferred the
concave surfaces to convex sides of the coconut shell collectors.
Seasons of abundance of barnacles, the main fouling organism, and
oyster spat were out of phase; but the abundance of tubeworms and
Sargassum natans on one hand, and spat on the other,
showed an overlap. Biofouling had very little influence on
spatfall, growth and survival of the osyters cultured on cultches
in the three water bodies. However, oysters on fouled cultches
had better survival in Nakwa and Jange lagoons. It is concluded
that biofouling may not constitute a potential problem to oyster
farming in the three Ghanaian water bodies investigated.
Some biological characteristics of pupae of two species of
lepidopterous maize stemborer laboratory reared for inherited
sterility control programme in Ghana
C.E. Annoh1, M.A. Botchway2,
B.A. Mensah2 , D.A. Adabie-Gomez1,
G.K. Montford1
1Biotechnology and Nuclear Agriculture
Research Institute,
P.O. Box AE 50, Atomic Energy, Accra, Ghana.
2Department of Zoology, University of
Cape Coast, Cape Coast, Ghana.
ABSTRACT
Studies were conducted on pupal development of two
lepidopterous maize stemborers, Eldana saccharina Walker
and Sesamia calamistis Hampson. Biological characteristics
of differences in length, weight, adult emergence, and pupal
longevity were determined, having fed larvae of the two species,
one group on fresh maize stem cuttings (natural dieters) and the
other group on artificial formulated diet (artificial dieters),
respectively. Pupal length increased proportionally with increase
in mean weight for both dieters. Generally, natural dieters
showed heavier weights than artificial dieters for both species
of stemborers. There was decrease in change of pupal weight with
respect to increasing days of pupal development. Percentage of
adult emergence was high for both natural and artificial dieters
of E. saccharina (50%-100%) and S. calamistis
(70%-100%), respectively. In E. saccharina, relatively
smaller-sized pupae (9–12 mm) showed higher percentage of
male emergence (50%-67%), while larger pupal sizes (> 12-16
mm) emerged as females (53%-100%) for both natural and artificial
dieters. Similar trend of characteristics was also observed in S.
calamistis. Mean pupal longevity for both natural and
artificial dieters of E. saccharina ranged from 10 to 11
days and that of S. calamistis was between 10 and 13 days.
The biological characteristics observed in this study have shown
that laboratory-reared species were competitive and comparable
with species in the wild.
Biological effects of plant extracts against the rice
weevil Sitophilus oryzae in stored maize
D. Obeng-Ofori1 and R.K. Akuamoah2
1Department of Crop Science, University
of Ghana, Legon;
2Department of Chemistry, University of
Ghana, Legon
ABSTRACT
Toxicity and protectant potential of chloroform extract of the
leaves of the siam weed Chromolaena odorata (L.) and
mahogany tree Khaya senegalensis (Ders.) against the rice
weevil Sitophilus oryzae (L.) were assessed in the
laboratory using contact toxicity, progeny production, damage
assessment and repellency assays. The extract of C. odorata
was moderately toxic to S. oryzae but that of K. senegalensis
was highly toxic to the weevils, evoking 100% mortality in maize
treated with the highest dosage after 72 h of exposure. Grains
treated with extract of the two plant materials caused a highly
significant reduction in the number of progeny produced by S.
oryzae and the higher dosages completely inhibited progeny
production by the weevils. Leaf extracts of both plant species
were highly repellent to S. oryzae and repellency was
dose-dependent. The extract of C. odorata and K.
senegalensis lost their toxicity after only 24 h following
application against the weevils. Phytochemical screening of the
plant extract indicates that K. senegalensis contains
chiefly saponins, alkaloids, cardiac glycosides and some
anthraquinones. C. odorata, on the other hand, contains
mainly alkaloids and flavonoids. The potential practical use of
leaf extracts of the two plant species as grain protectants in
farm-stored grains in rural communities in Ghana is discussed.
The development of simple field based procedures for
extraction of volatiles from Adenia cissampeloides for
subduing
African honey bee (Apis melifera adansonii)
Kwadwo Yeboah-Gyan1 and Kwabena
Oppong-Boachie2
1Department of Biological Sciences,
University of Science and Technology, Kumasi, Ghana
2Centre for Scientific Research into
Plant Medicine, Mampong-Akwapim
ABSTRACT
Field and laboratory experiments were conducted to develop
procedures for extracting volatiles from the vine of Adenia
cissampeloides which could effect the highest yield at the
lowest extraction costs and also could be produced at the cottage
industry level. The participatory rural appraisal technique was
used to ensure high degree of local beekeepers' participation in
the development of extraction procedures. The results indicated
that extracts obtained by shaking thoroughly, pieces of crushed
vine in a tightly closed flask in solvent alcohol for about six
hours was as effective as extracts obtained by boiling the
crushed vine in alcohol. Such cold extraction procedure should be
most practical method for local beekeepers and could be useful
for the small-scale work of beekeepers. To increase the shelf
life of the extract, two formulations, namely, emulsifiable and
fumigant were made. The relative efficacy of these formulations
was estimated by comparing the bioactivity of the formulations
against the bee in the laboratory. The efficacy of the
emulsifiable extract was similar to the unformulated extract. The
fumigant did not, however, have any visible subduing effect
against the bee.
Efficiency of 'Ghana 813 16S forward' primer in the detection of West African coconut phytoplasma
R.N. Quaicoe1, A. Tymon2
and P. Jones2
1 Oil Palm Research
Institute, P.O. Box 74, Kade, Ghana.
2 IACR Rothamsted Experimental Station,
Harpenden, Herts, AL5 2JQ, UK.
ABSTRACT
Cape St. Paul Wilt Disease (CSPWD) of coconut in Ghana is
believed to be caused by phytoplasma(s) (MLOs). These pathogens
are non-culturable, obligate prokaryotes, and therefore cannot be
studied by conventional microbiological methods. DNA
amplification by PCR using primers based on the nucleotide
sequence of the 16S rRNA gene, is routinely used in detecting
phytoplasmas. Many of the primers available are universal for
mollicutes. Primer Awka SR, however, is specific for the
CSPWD-phytoplasma. In combination with Deng & Hiruki
P1(universal for mollicutes), Awka SR has been used for specific
detection of the CSPWD-phytoplasma. The primer `GH813' was later
developed at the Rothamsted Experimental Station, UK. Since the
sequence of this `forward' primer was based on the
CSPWD-phytoplasma, it was anticipated that in combination with
the `reverse' primer Awka SR also based on the same phytoplasma,
a primer set with a higher specificity for CSPWD-phytoplasma
would be obtained. This study was to verify the efficiency of the
GH813 primer. Fourteen mollicute DNAs, from 6 different sources,
were screened by PCR using different primer combinations. PCR
products were separated on 1 % agarose gel and visualised on the
UV transilluminator after ethidium bromide staining. `GH813'
showed high specificity in detecting West African coconut
phytoplasma. GH813/Awka SR primer set also yielded more amplified
product from the phytoplasma, compared with the Deng & Hiruki
P1/Awka SR combination. The GH813/Awka SR primer set is hence a
better choice for a more efficient routine detection of the
pathogen and should give a new impetus to the search for the
CSPWD-phytoplasma vector(s) which has remained elusive till now.
Some characteristics of the Sri Lanka Green Dwarf (SGD):
a variety resistant to the Cape Saint Paul Wilt Disease of
coconut
J. Owusu Nipah
Oil Palm Research Institute (CSIR), Coconut Programme, C/o
M.O.F.A., P.O. Box 245, Sekondi
ABSTRACT
The Cape Saint Paul Wilt Disease (CSPWD), a lethal
yellowing-type disease, has decimated thousands of hectares of
coconut plantations in Ghana. Eighteen years of field screening
showed varying levels of tolerance/resistance to the disease. Out
of 27 different types screened only the Sri Lanka Green Dwarf
(SGD) has so far shown complete resistance. This has been
considered a very major step in finding a solution to the
disease. Following this, studies were conducted on selected palms
of SGD to have basic knowledge about some agronomic parameters
and to assess the possibility of using the acquired knowledge to
plan for future SGD improvement programmes. Characters studied
included rate of germination, flower, stem, crown and leaf
morphologies. The local West African Tall (WAT) variety was used
as a check. The monoecious inflorescence was observed to be
completely autogamous, as contrasted with the WAT, which
exhibited partial to complete allogamy. Though the inflorescence
of SGD had fewer number of female flowers (mean = 24.5) as
compared to that of WAT (means = 32.15) a higher proportion of
the flowers (34.4%) were set as nuts, resulting in higher number
of matured nuts/palm in SGD. Other important observations made on
SGD included fragile leaf and bunch attachments, and more
susceptibility to insect attack. The implications of these
observations make SGD unsuitable for release as a straight
variety. Rather, it is being exploited in hybrid seed production
with other tolerant types.
Use of Round Up (glyphosate) in weed control under oil
palm: some cost implications
K. Baidoo-Addo, B.N. Nuertey and T.E.O. Asamoah
Oil Palm Research Institute (CSIR), P.O. Box 74, Kade.
ABSTRACT
The cost effectiveness of Roundup in weed control under oil
palm was assessed using four treatments in four replications in a
randomised complete block design. Whole plots and strips of the
planting lines were cleared using manual and chemical means.
Costs of all operations were noted. Weed re-growth rates were
assessed at 4, 8 and 12 weeks after treatment application. There
was a significant difference at P = 0.05 between weed re-growth
rates in herbicide-treated and manually weeded plots. Within
treatments weed re-growth rates were practically the same.
However, economic analysis carried out indicates that roundup
applied in planting rows is more cost-effective than either
roundup in whole plots or manual weeding in planting rows and
whole plots.
Assessment and comparison of current rodent control techniques towards the protection of young oil palms
(Elaies guineensis) in
the field
S.O. Appiah1 and D.K. Attuquayefio2
1 Crop Protection Division, Oil Palm
Research Institute, CSIR, P.O. Box 74, Kade, Ghana
2 Department of Zoology, University of
Ghana, P.O. Box 67, Legon-Accra, Ghana
ABSTRACT
A field study was conducted in the Eastern region of Ghana to
assess and compare five methods for the protection of young oil
palms (Elaies guineensis) against rodent pests. The
rodents attack the bulb of the young oil palm trees leading to
eventual death and a reduction in plant stands. The methods
(treatments) were broadly grouped into two, with one group
comprising two treatments (use of double and single wire nets)
recommended by the Oil Palm Research Institute (OPRI), and the
other group comprising three traditional methods used by the
local farmers (use of basket collars, Jatropha curcus
seedlings and regular maintenance schedules). The experiment
involved the use of a randomized block design with four
replications, each treatment plot consisting of 15 seedlings of
oil palm in three rows of five at a spacing of 8.7 metres in a
triangular array. Over a twelve-month period, monthly records
were taken of the number of dead palm plants and the number of
rodent pest attacks as indicated by signs of physical damage to
the palm. The results indicated that use of wire nets
(OPRI-recommended) was more effective in protecting the young
palms against rodent attacks than the “traditional”
methods variously employed by local farmers. Economic analysis of
the two OPRI-recommended methods, however, indicated that single
wire netting (consisting of a single wire collar wound tightly
around the basal area of the palm, and placed slightly deeper
into the ground to prevent rodents from burrowing through) was
more cost-effective than double wire netting, and therefore holds
promise for the protection of young oil palms against rodent
pests.
Flocculation and dispersion behaviour of two kaolinitic
soil clays as affected by organic matter and iron oxides
B.A. Osei, J.D. Owusu-Sekyere and J.K. Akati
School of Agriculture, University of Cape Coast, Cape
Coast, Ghana.
ABSTRACT
The effects of removal of organic matter, crystalline Fe
oxides and amorphous Fe oxides on the flocculation and dispersion
behaviour of two kaolinitic soil clays were measured. The
critical coagulation concentrations (CCCs) of dilute suspension
(0.01-0.26 moles m -3) of the kaolinitic soil clays in
NaCl solution were determined for (i) untreated clays, (ii) clays
treated with H2O2 for the removal of
organic matter, (iii) clays treated with
dithionite-citrate-bicarbonate (DCB) for the removal of
crystalline Fe oxides, (iv) clays treated with ammonium oxalate
for the removal of amorphous Fe oxides and (v) clays treated
successively with H2O2/DCB/oxalate for the
removal of organic matter, crystalline Fe oxides and amorphous Fe
oxides. The treatment for the removal of organic matter decreased
the CCC values, implying a decrease in clay dispersivity. This
indicated that dissolved organic matter enhanced clay dispersion.
The removal of crystalline Fe oxides increased the CCC values,
indicating an increase in the clay dispersivity. This showed that
crystalline Fe oxides were important in stabilizing the structure
of the soils studied. The amorphous Fe oxides, however, did not
play a stabilizing role. The clays whose crystalline Fe oxides,
amorphous Fe oxides and organic matter were successively removed
were the most flocculated and therefore had the lowest CCC
values.
Electrical resistivity of quartzite obtained from the
gold-belt of the Tarkwaian rock formation in South-Western Ghana
Aboagye Menyeh
Department of Physics, Kwame Nkrumah University of Science
and Technology, Kumasi, Ghana
ABSTRACT
The variation of the electrical resistivity between room
temperature (300 K) and elevated temperature (500 K) has been
investigated for quartzite obtained from the Gold Belt of the
Tarkwaian rock formation in the south-western part of Ghana. The
resistivity was measured for the passage of current through the
samples in two orthogonal directions, parallel and perpendicular
to the rock foliation. The average value of the room temperature
resistivity for electrical conduction in the two directions were
respectively, 9.02 x 105 W m and 1.95 x 108
W m. These values indicate that the ease with which current flows
in the direction of foliation is about 200 times greater than in
the perpendicular direction which confirms the general
anisotropic behaviour of rocks. The average anisotropic
coefficient was found to be 14.7. It was observed that generally,
the resistivity increased with increase in temperature, attaining
a maximum value at about 430 K, above which the resistivity
decayed exponentially. This trend in conductivity is suggestive
that two types of conduction take place in the quartzite within
the temperature range studied. Between 300 K and the maximum
temperature, it appears, that conduction is due to ions within
the electrolytes filling the pores of the rock samples. Above the
maximum temperature, the pores become dry and most probably
charge carriers are responsible for the conduction as it occurs
in a semiconductor. The average activation energies obtained for
conduction above the maximum temperatures, in the parallel and
perpendicular directions were respectively, 0.20 ± 0.03 eV and
0.83 ± 0.04 eV. These values compare favourably with the
activation energies of other rock samples and are also similar to
the values for some semiconductor materials.
The nuclear fuel cycle associated with the operation of nuclear power plants
S. Anim-Sampong, J.H. Ephraim, H.O. Boadu, I. Ennison,
B.J.B. Nyarko,
Y. Serfor-Armah, S.D. Asiamah
Ghana Atomic Energy Commission, P.O. Box LG 80, Legon,
Accra.
ABSTRACT
Electric power generation in Ghana is presently achieved
through hydro and fossil fuel energy sources. However, recent
energy crisis due to sporadic rainfall patterns has mandated the
search for alternate and more secure electricity generating
technologies. The nuclear power option has been mentioned as an
alternative for Ghana but the issue of waste management worries
both policy makers and the public. In this paper, the nuclear
fuel cycle associated with the operation of nuclear power plants
(NPPs) for electric power generation has been extensively
reviewed. Different methods or schemes for dealing with the
management of spent fuel arisings from the operation of these
power plants have also been analyzed. Particular attention has
been paid to providing answers to vital questions often asked by
the public regarding the front- (nuclear fuel supply) and back-
(spent fuel disposal) ends of the nuclear fuel cycle. Different
strategies of the fuel cycle have been mentioned. The wet and dry
storage methods of spent fuel management required for temporal
storage of spent fuel at-reactor (AR) and away-from-reactor (AFR)
sites have also been reviewed. Some recommendations have been
made for the adoption of a nuclear power program in Ghana by
concentrating on management and disposal of nuclear waste.
Reformulation of anisotropy corrections in the static dose
calculations in high dose rate brachytherapy
Emmanuel Kwaku Nani1 and Rex James
Keddy2
1 National Nuclear Research Institute,
Ghana Atomic Energy Commission, P.O. Box LG 80, Legon.
2 University of the Witwatersrand, 1 Jan
Smuts Avenue, Johannesburg 2001, South Africa.
ABSTRACT
Current polynomial methods used in the modelling of the dose
distributions in high dose rate (HDR) brachytherapy
have been reformulated to improve accuracy. An example is
provided in order to assess the errors in some of the
conventional methods. We observed relatively high discrepancies
between our accurate results and those from some of the standard
models, but acknowledge that our algorithm is not very easy to
use. We therefore advocate a departure from the polynomial
methods of modelling, which are merely empirical and do not
reflect the physical processes of the interaction of
radiation with tissue. We suggest the use of the
parameters like the absorption and attenuation coefficients for
the primary and scatter photon beams. With this, we shall have
easy - to - use algorithms; doses could be calculated accurately
both within and beyond the region of parametrization. Corrections
could also be made for finite patient sizes and shapes.
A review of the chemical status of the Weija lake
G.K. Ameka,1 K.A.A. De
Graft-Johnson2 and R.K. Akuamoah3
1Department of Botany, University of
Ghana, P.O. Box LG 55, Legon
2Water Research Institute, C.S.I.R., P.O.
Box 38, Achimota
3Department of Chemistry, University of
Ghana, P.O. LG 56, Legon
ABSTRACT
Weija lake, a man-made lake, was sampled in 1993 at different
sites along the lake. The water was slightly alkaline and the
temperatures reflected the generally high tropical temperatures
and fluctuated with the seasons. The dissolved oxygen
concentration was high and varied from site to site being lower
at sites with high organic matter. The mean transparency was 60
cm. The dominance pattern for nitrogen compounds for the lake was
NO3- ¾ N > NH3 ¾ N > NO2-
¾ N while the ionic pattern was
Na2+ > Mg2+ > Ca2+ >
K+: HCO3- > Cl-
> SO42-. The cation dominance pattern of
the lake was similar to sea water near the estuary, but the
present study and previous work indicate that the proportions of
ions (cations and anions) are changing to that of fresh water.
Residues of drugs, chemicals and hormones in meat, milk, eggs and fish in Ghana - a review
E.N.W. Oppong
P.O. Box 316, Legon
ABSTRACT
Everyday activities of humans inevitably generate a lot of
pollutants. These activities may be industrial, agricultural, and
even such mundane activities as the use of plastic bags. Our
concern in this paper is with agricultural activities,
specifically a number of livestock production techniques and the
dangers they may pose to humans through their consumption of
meat, milk, and fish. For drugs, pesticides, insecticides and
hormones are variously used in animal production and some of
these are passed directly or indirectly into food derived from
these animals and fish. Meat and milk may be directly polluted
through drugs and hormones administered parenterally, which have
not been completely biodegraded before the animal was slaughtered
or its milk offered for human consumption. Such drugs may lead to
the development of drug resistant strains of micro-organism in
humans and the hormones may lead to the development of cancers or
malignant effects on unborn children. Acaricides used on animals
to rid them of ticks and fleas may contaminate milk. In addition,
when improperly disposed of, these acaricides may run into ponds,
dams and streams and underground water systems, thus poisoning
people who drink them. Some fishermen use acaricides and
chemicals in fishing, making such water unsafe for drinking and
the poisoned fish dangerous for consumption. Accordingly, in view
of such threats to human health and development there is the need
for research into the drug, chemical and hormonal content of
meat, milk, eggs and fish both locally produced and imported for
consumption. The authorities responsible for the safety of the
food we eat need urgently to put in place appropriate measures to
ensure that we are not being poisoned. Best practice from a
number of countries could provide suitable models.
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